i R. A. PATTERSON & ASSOCIATES
.M.El'-IOR.ANDTJM Date: November 9, 1992
TO: Manabu Tagamori-DOWALD
SUBJECT: BOP Manual draft - Suggested reviewers REVISED
A REVISED listing of suggested reviewers for the draft BOP Manual, is as follows:
Bill Rickard
Paul Stroud
Louis E. Capuano, Jr.
Allan Frazier
Jerry Hamblin
Pete Wygle
Bill Teplow
Bill Craddick
Gary Hoggatt
Dunn, James C.
Gene Anderson
Robert Wagner
1
PGV Consultant
PGV Consultant
ThermaSource, Inc. P. 0. Box 1236 Santa Rosa, CA 95402
Tecton Geoligic P.O. Box 1349 Healdsburg CA 95448
UNOCAL Geothermal Division P. 0. Box 6854 Santa Rosa, CA 95406
California DOG 1000 South Hill Rd. Ventura CA 93003-4458
1518 Excelsior Oakland CA 94602
Barnwell Industries 2828 Paa St. Ste 2085 Honolulu HI 96818
TRUE Geothermal Drilling P. 0. Box 2360 Casper WY 82602
Sandia National Laboratories P. 0. Box 5800, Division 6252 Albuquerque NM 87185
Nabors Loffland Drilling Co. P. 0. Box 418 Bakersfield CA 93302
PARKER Drilling Co. 8 East Third St. Tulsa OK 74103
Richard Thomas
Bowen E. Roberts
Geothermal Officer California DOG 801 K Street - MS 22 Sacramento CA 95814-3530
ARCO Oil & Gas 4550 California Ave. Bakersfield CA 93309
We have not included any Hawaii State or County officials, as many of these will likely see the draft anyway. A possible draft cover letter is attached.
If there are any questions about the above list, or if we can provide more information on possible reviewers, please call.
2
DEPARTMENT 0~ LAND AND NATt..JR.A..!_. RESOURCES
DRAFT TRANSMITTAL LETTER
(DATE)
Mr. __________________ __
Dear
As a result of recommendations made in the "Independent Technical
Investigation of the Puna Geothermal Venture Unplanned Steam Release",
of June 12-13, 1991, the Department of Land and Natural Resources,
State of Hawaii, contracted for a preparation of the Hawaii Geothermal
Blowout Prevention Manual.
This document is intended to provide clear guidance that both
regulatory agencies and geothermal development organizations can use
for plans and procedures regarding blowout prevention in their Hawaii
drilling activities. The enclosed draft of the Manual is designed to
improve operational and safety procedures for ALL geothermal drilling
activities in the State.
A draft copy of this Manual is enclosed for your information,
review, and comment; we would appreciate your review and comments on
the draft so that the final Manual will reflect the experiences and
thoughts of the industry and other regulatory agencies.
In order to maintain our production schedule, we would appreciate
your forwarding comments to us by ____ (date) ____ . Your comments, and
others that we may receive, will be considered in the preparation of
the final document.
Your help to the State of Hawaii in this review is appreciated;
we hope to manage the Hawaii geothermal resources so that the best
possible development practices are followed at all times.
Sincerely,
DRAFT
HAWAII GEOTHERMAL BLOWOUT PREVENTION MANUAL
DRAFT
I. INTRODUCTION
. The prevention of an uncontrolled well flow, commonly known as a "blowout", is .£' )IL.f..:~( •iM P.off.::(>'\d!~ fr\ 1mportant consideratioii for geothermal oper:-ators, drilling crews, state and county,.,
:I"'vl ... s~-r w•h1 h.:(~ ~o~e""- ~ cc..<.ts.e o'r ct regulators, and the general public. ~eotner1mal well blowouts qpe' noe'-a!!seeiateeJ-~
3 a-t d ~ rt)ef no I -exi Sf; significant number of fatalities, Ror is t.here a practical. danger of fire, as in petroleum
drilling. However, blowout incidents may have af'~~X~t on surface and subsurface
environments, cause resource waste, and develop unfavorable public perceptions of
geothermal activity. These concerns ~t:>rovide powerful incentives to operators and
regulators to minimize the risks of a blowout.
This Manual has been developed to promote safety and good resource
management by discussing and describing blowout prevention as it can best be
practiced in Hawaii.
intended to supplement State and County regulations, especially those pertaining
directly to drilling permits and operations~ ...blowout prevention pradice~, espeeie:l1y -when modifications are Pequir ed due to
clrattges il"' erillil"' 9 een e=itiott~
This first edition of the Blowout Prevention .. Manual is a likely candidate for
revision as more drilling experience and information is gathered in the exploration and
development of Hawaii's geothermal resources.
1 Department of Land and Natural Resources (DLNR) Title 13, Subtitle 7. Water and Land Development; Chapter 183.
BOPINTROOUCTION/RAP/October 13, 1992 1-1
DRAFT
I I . SCOPE
The material in this Manual has been extracted from ~ key information
sources in order to present a complete and accurate review of the practices of
geothermal well control in Hawaii. In developing this Manual, a careful review of ---r"'-e K E ~ "'Z
:!ec-k\tefWial drilling to date in the Kilauea East Rift Zone (KERZ) was conducted.~ is where
nearly all Hawaii geothermal drilling has taken place, and is where most experts believe
the geothermal resource~ "Yill be developed. . /1,4~a,l J.dc~/ irtf••i1b1fy cf 1hAi· e.-dt q~ .:\ <.ur 1qUL1 fr-r.~( ~-"le~{ ar'l!!lf -fh"'"'"'"""'" &:tf'tee eaeh prospesti¥-e -geotl-rerFRa.l.-ar ea ~ HI-I~• ~e world has pro'V'en
to have its own characteristics in terms of drilling conditions, resource chemistry,
geology, e ., e ral · 1 · y 1 · 'q '. While fent<ll ri .. il4 .. ·d.,.e1 dP eJCtiJ. ~e .... qe~~# welt f:t
c..t~;1.ttll.t-i~ -tiris" may be true in detail, \:he1 e a.rli same similaritili&, and va.111ablQ le~~o1 13 te be
-learAed, From geutl1e1mal dsvelop111ellt activities Llla'e-arelocated in or nearby, active
volcanic areas. Thus, it has been helpful to briefly review well control techniques and
experiences from other similar volcanic areas around the world.Some of the information
gathered may have an influence on ~tttq,wa#---sit.uatiefrr----·jiF flr...~,;;.,t A,; 1/;,~i· ... Jl-· " ;/. In order to review the experiences in Hawaii and in other geothermal areas
where active volcanism is prevalent, a great number of specific publications and
selected references wer~ consulted. These are listed in Appendix C, References. In i~~~~ addition, much of the ~and many recommendations contained in this Manual
came from the accumulated experience of others who were consulted on various
elements of the items presented. A partial list of those consulted is also contained in
Appendix C.
This Manual defines a blowout prevention strategy for geothermal drilling in the
State of Hawaii. The essential components of this strategy are:
~f> Improved risk analysis and well planning. · L. 1 a ~ft>GI'if'~
II 2) Sound selection of blowout prevention stacks and~ equipment.
3) Rigorous use of drilling monitoring procedures.
4) Expertise in kick control and blowout prevention equipment utllization.
5) Excellence in supervision and training of drilling personnel.
BOPSCOPE/RAP/August 24, 1992 I I- 1
DRAFT
III. GEOTHERMAL DRILLING RISKS IN HAWAII
THE VOLCANIC DOMAIN
The State of Hawaii consists of a chain of volcanic islands. Each island is a
composite of several volcanic eruptive centers builtr"'rfy a succession of basaltic lava
flows, first as submarine deposits and subsequently as volcanic lands (or subaerial. "'llv.zN i>4SC4I~<-l~ Pf~s &-. o.. s-c (.Ao&Ao\.c. cP £..t.-, .-..1-....1 l.:t'(e..--sc-~dff~
deposits.) · · t::r~ ~ ....... .£ c.,.,.,*-' l(,·""-'Z ~ -roG(!....'' t"' ~b-e~ t.o),f1'\ l'<2'>~e.r u~..,h. o "'-•sk"- ~~~He ..sl.l:bs'l::ui~aeet reek §eoH!etry of hard, sry.talljnQ fleu roelts, interbeeiaed1 with lesser y"IH/1.<,. ck.P/•f• -t1M-~'€ ..a~;~eunts o~ hif§Jhll'. variable roelt GQbd.a\~ flow sequences ~
.. .,..e e "1 ~+- 1~k<A 1 ._ ~,,.,..,...,..,...~fl:a¥C!.-J;~m-Tl!~fC'ID·~~ in extensive outcrops and 'lA..lithology logs from ~
~water well drilling. \.D.-Btrnc,essful exploitation of the large an~aiuable
..,_grol.lnd l•later rQiOOl.lrce that S'l:l_!?OrtS sotb ?iripulture and utba11 <~eueJep~QRta ~ I J(f'f rr~ete rece,f > (/ re -
v'V\.e c~ks F~vf-a~"""¥ ~ec~~ Yef~-e4 2-rc..~rttef..n~ ~ • ....J.
1 T~e H!ere re~n-t:tr reC2,9'¢zea g~thcrff\al r~e:1.1J;s~ is leeateci in Hll:lefi smeilet
fJli"" roe t..A.h~!. F"n-t.41f lfi(;4-A<;; (..l)J?,c'-1 t~~re ,Jyf>f I e>Ct~d' · · · with active or recent volcanism. The
VI•~~~ p~;,., b,-41.... a,r-e~ ~ qeotfur-~ 11<e I•P.fHPif' ~~racliVe at eaY o~rlie the volcanic rift zones which are, or recently were, deep
conduits for magma transport away from the volcanic .eruptive center. Hawaiian acJute
geothermal drilling to date has been confined to therKilauea East Rift Zone (KERZ).
--wh±drts an active ma~nna tl:ansperlin§J and lava er upling slt uctl:lie. In the KERZ, ~ {tqoo•ra~ kiQ!..v) -httSf?n+ . . ...... .
magma ~ ·woces~es prov1t1.e very high subsu~ace temperatures,-r~t::~. -~ .• ~b--f'~~L .t} laf<~ k1""x... o~ MR~'" ~(fl..-e,kc.,,.,_e~ ··
~· Bet.h meteor:i:s water (g:roYRd. t•~V and sea water mtr1:1d:e into the KEt<:.
geothermal resource zones, :prov.idlli19(ari:~al:HiriAant:::tiUi(fs\:( pliiC · /J r...ov-;;.w ~ ~;;;;;..:. :P fk../.,';.1~ Z"vf~ d,,.~~s crf w ~·
Geothermal drilling in Hawaiian rift zones involves distinctive risks.
drilling experience, combined with extensive studies by the Hawaii Volcano Observatory
(HVO) of KERZ rift zone function, structure and_ dyna,mic processes.~~ - ---~-- . IS V?&t.) p~c;td·£.e~ to
reasonable initial identification of hazards and risks;c This an:a.~:ys~ CR.n be used to -e>'< r---~ -.£.-<: ~ kVJ.-:l I.e~ e
refine geothermal drilling programs and procedures to minirmz~ upsets and blowouts .
..ftu. Yl.fk<, ~f
KERZ DRILLING TO DATE
The most valuable subsurface information for this Blowout Prevention Manual
comes from 11 deep geothermal wells and three exploratory slimholes drilled in the
KERZ between 1975 and 1991. Rotary drilling rigs' appropriate to the drilling
objectives' were used on the vte~"thermal wells. Common drilling fluids used in this
BOPRISKS/WLD/October 13, 1992 III-1
~ rotary drilling are mud, water, aerated fluids and air. ~'Well depths range between
.f't-. ~4s (?'-eet bela-V q.-..d ~",..~) 1,670"' to 12,5001\. T.t'l'e l>perators tot the well drilling included four private resource
companies and one public sector research unit.
demonsb
subsequent
electrical generation
As of 1992, nine wells had penetrated prospective high
temperature rocks and s~ven of these were flow tested or manifested high temperature
fluids. Two of t:f1':f:S:'~ells incurred casing contained blowouts in 1991 upon
encounterin hi h ressured geothermal fluids at S~tas~~e'jff* \';lila~ ~ ~ r~:,tft<4."Cg J.s~over7 ~/i,#wP-1/, c,_1 re-k.i ;.....,,.,"J- tft1(,, f"~ ~la--...f.e. ct.
'$+tv/ ~-;1Y'•Ii-- e.l~IY·c-""' c,.QIIn'-.t,;;-. f'M .. /- beku...... 1'1~1-..1 1 c;qo . _) - L:..,. qeo-#t.er'JM<t-( r'eSoufct evcot{l.44tt~1
Three deep scientific observation holes (SOH) were drilledTaS continuously cored fl. b,a~ ~:o~w.- A6()~ t'\'\1• ~
exploratory slimholes to 5,500'-6,80tY".-dep-ths m the H~O 1991 mtervaJ.. These SOH s
helped to prove that favorable high temperatures pr~vail ov~r a te:u _mile interval {'.J.i,r~~ c-1,./y~ Pt-1' ,,fv./~
along the KERZ. These holes did not encountert-Signifi.cant blowout risks; however,
special blowout prevention equipment ia !h l!ilaele and must be considered for future
use of the slimhole technology in Hawai.:i.ttu:.,:.l""'a
SUBSURFACE CONDITIONS IN PROSPECTIVE AREAS
High temperatures, commonly in the 600-700°F range, are characteristic of~ \It> leo""' ~CA {1)1
production zones in · oc ~ctive ntt zones. The prospective
geothermal reservoir occurs in the roof rock above the deeper magma conduits. The
well completion targets are loci of permeable, highly conductive fault and fracture
zones' which are gene;:-ally e_nclosed by extensive secondary mineralization. Magma
transport downrift ·ana it:$ planar injeCtion upward into the roof rock :<a.It~ the primary
heat sources for the geothermal resource.
The primary hazard of geothermal drilling in the volcanically active KERZ
is the currently unpredictable distribution of fault planes and major fractures. ~ . r ~·/., • -fk .... s ae:?.~j
v.JaJk 0 -t ~t regional geologic structures f}fer sealed by secondary mineralization_,~ -aet as ~l~L+ ~~cl-e cAA.h ~ c~; t-~geothermal fluidS',.ee;ndu#:s: aUl an fractures, particularly as they extend upward
into cooler ground water regions~·::~~ < :: :·· :~·-·:··: " ·: ~:~::· .,. .. ~,·::··: ·: ". ·: ·::~ ca
present pressures in the range of 500 to 750 si above normal hydrostatic pressure.,
Unexpected entry into '.~·::·: : · (u;ft Ill\ ~ (?f'efJ4I~et f_, /{- j'f~ t7t-d .;i-a.e.fu~
BOPRISKS/WLD/October 13, 1992 f I I I -2
---fl'Uilr can cause substantial upsets to all well control procedures.
A si~n:ificant hazat d :is Pl: e~en'eed in the Rear surface volcanic rocks (subaerial
-deposits) of t.he rift BOI):fi• Primary features such as lava tubes, irregular layers of
ash and rubble, and g~ fractacing conse~ueet to laua.-fl:.,w aem19 contribute. ,;)J.t.it."'- <-a"'- -oe;~ ... 1r-~:>te- ......,.; 11-\ Lo .s Q [ Jr:u . ...., fL. R. ir"A,&...ft..n-...
to very high vertical permeability1 Yo nuids anc1 to low rock strengths. Thes.e;(Eeatures ,?,.,,..,,._., diminish down ward, but appear to present ~a~;ards iB the deptl:t ran9e of l!1500' te . ~ k f.-- •V'I _.f.- #......., I~ ~ Zooo f!.;. &3s.
···:···_"'i'_··:··::··::······:····_t·· f f ~ e'!3K~ •) ~ .'i~~d. ?(,,;>- +:. •. d !-,.~ {' 1 h 5d?.(f4~~~ffl?r"'- /l4#\K An mportan eatu;!:'e o cross rift tenSJ.OnaJ. stress _partie arly operates m the c-... .. ~ ir'l cr~s- fltt e....._~,.m~ $~~~· 111~, s-.....-.~ 7 I iJ,...,, e7,F -f1.u< ~p . n:oc:..¥;,.ccn.p ld ....;.,ftt S';~S~1c..:.h.., shallow. volcamcs ~nd. rqof ~ock dll~ to .th~ sea ward sll~g or t.he southeast flanlt of., ··I '(l!l~l~ "'' IIVl."lh d.•.l<:< .... •'\1:':'.~·•~'> ~ ~"'"u• 1/1Ke \•\tf''-<l<..n'\l d(-cJ 0.>\ At>UA:Jc<,.f· -, .. U9.b_:,..j. l. •.• t the _KER~. 'F~ -~~ie.ttf.til stre~~ ~ ~ ·:abttfidarit' heat s\iipPl}t'lii(>~Qltea t~e, """'-
. . . . ..... ?P ........ ~~l~ ~??YJ; .. ... --...,.. P pecti e ractunng for the -llitr\1sl&i\s; eott lea" d·~~f' dO . ··=:..;;.;.;~ :cr_ei:lt'~• res . v f .
geothermal reservoir. d~.t-:6~ hrlhijf' contribtite~~-~hese-~~ low roc~ strengths in the shai16wjl'leM"-~ttr£aee volcanics, ~~s\tf-9'i=~• ~~ma~efimil ~ ~ (oUtte. e"+eiaif'~ a sound ea~~-anchor for eompl-etioft-of.-the wellheai! wit:h-~
blowout prevention $'qtiipmehti
~;~h7rftiaa::fi'ki.~~t;:~i;i-'de'~~~~;-: ... · · ~~r . ~~n.ter-a~Lirrtitless (~ ·· :..;.,~-- · · ···· ····· ······· M.. :;;_~ C'kA-l~-~~- g~k ~ GetJ~ Y"eieri-v~i.;~ u
~~ij~~,li~~;~~F;i~"'~M-~~~~;~ f~arrifol·~m.rv'6iri l.,jjb{y""tlfrisiigp:·{~···~4~~ei.t·tli'•~q&'i!ke..."" fty'dros~tfc!.;~;~e~·fre~at:~ti~'to''P~~e.fu fr:ctti~e-rift zones,· but these can be
escalated to higher fluid pressures in the temperature conditions prevailing. The
~hMl:ow-f:i:i$.h jlri~Ls~Url.~L9l:"()\irid:~~~~~J:)Odyj~ regions; shown to prevail as deep as 2,500'
in the Puna geothermal field, may prove to be a generiu condition, but not one that can
be expected at every proposed well location.
SUMMARY
The KERZ geothermal drilling experiences prove two significant hazards that
must be addressed in a blowout prevention strategy for every proposed well:
1. Significant fault and fracture planes ~f can be sealed conduits fo'r • ell~~ b.
overpressured geothermal fluid$. These features ITU.ghtrprove ·'to e
BOPRISKS/WLD/October 16, 1992 III-3
~predictable or detectable by drilling precursors. Blowout
prevention planning, equipments and procedures must be taken as a
critical requirement, ready for immediate and proficient use.
2. Weak and broken near surface volcanic rocks.
--a. reliable casing anchor: must be abtain&d before the fundament:sl-of
--orowout prevention ey complete shut off is safely workah~
~ veco'7Vlt-.h.;._ e; .{ ht.cf c..~-~ ~s ~ pr"Q..Curs<H' -f-o <D ~ t.·,,..W,
~ ve.(L~(c.e' ca-s··~ -c.."'-rl., w~•~l\. ~~ ~a~W J- c_,qk,
c~~ l-<2k c:[hv.-4- t:> ..f, b C~ ouJ- ~~ .
BOPRISKS/WLD/October 16, 1992 III-4
IV_ GEOTHERMAL WELL PLANNING
DRAFT
INTRODUCTION
The proven higher costs and uncertainties in Hawaiian geothermal drilling
operations are sound reasons to make an extraordinary investment in well planning.
Detailed planning is a must for each c;nd every type of well because of the paucity of (€l<Af-lilelJ
subsurface information and thersmall base of drilling experience to date. Blowout
prevention is an integral element of geothermal well planning.
WELL PLANNING OBJECTIVES
Safety The concept of safety must be carefully applied for all workers and
activit."s on the wellsite, and for the public. A blowout
prevention strategy is a crucial part of any successful practice of safety in geothermal
drilling; it is a necessity in Hawaii.
Well Function Geothermal wells, if beneficial development is to be attained, must
convey and control very large quantities of fluid and energy, hopefully for the
greater part of the 30-year life that is expected in electric power systems. The HGP-A
discovery_ well demonstrated a reasonable performance in the production mode-£"~ I'\ g) -4- \ 'tf1o. ~; Jaut no othm; wall has atte:ifted either the proda~ or injeet:iOk.
Reasonable Cost Hawaiian geothermal wells are in the very costly category;
perhaps $2,500,000 per well is a representative minimal cost (1992$) if no significant
problems impact a good drilling plan. Competent planning might cost only 1 or 2% ~ ~ ~.f -1tv2. (!1'\/9\" 41. ~ CD?-}. ~ {: ~ ...v6 l(.
High quality well planning will assure a greater degree of safety and improved
well functions. Proper well planning will allow the Operator to be more confident in
responding to the upset conditions that can't be avoided and actual dtillirig
performance can be better assessed for continued improvements in future Hawaiian
geothermal wells.
DRILLING TARGETS AND WELL TYPES
BOPPLANXING/WLD/October 13, 1992 IV-1
Geothermal drilling targets in the volcanic realm of Hawaii can be organized into
three simple classifications:
and fractvres ~oids). Targets that can win drilling funds, but which present
a high risk exposure, are classified as exploratory by the Operator and
participants.
Reservorr targets - to develop the resource, are generally qualified by high
ffe.,-c;..-"Ce.() ~ temperatures, indicated fault planes and fracture. systems or by nearby well
production data. The probability of penetrating both high temperatures and
fluid producing permeability intervals is high. Hawaiian geothermal reservoirs
are of the hydrothermal type (~Aii'- predominate type now in :\4\i)~~~i;iiiCI.$
utilization.)
Supplemental targets - to conduct research on the resource, are comprised of
scientific and/or observational objectives which can contribute to a better
understanding of a geothermal resource and its enclosing subsurface
environment.
At the present level of knowledge in Hawaiian rift zones, no class of geothermal
drilling target can be confidently identified with lower blowout risks. Off-rift
geothermal drilling targets may offer the perception of lower drilling risks, however,
no such drilling has been undertaken as of 1992.
Geothermal wells can be categorized as to function and several additional
features. The common types of wells include the following:
Exploration well. Any well drilled to evaluate a prospective geothermal resource
target, usually at some significant distance from an established or proven
geothermal reservoir. Hard and proximal subsurface data are not likely to be
available for a blowout prevention plan; diligent drilling monitoring procedures
(see Section VII) and casing plan flexibility are essential to blowout risk
reduction in exploration wells.
Production well. Any well designed to exploit the energy and fluids of a
BOPPLANl!ING/IlLD/October 13, 1992 IV- 2
geothermal reservoir for beneficial use or demonstration purpose. Blowout
prevention plans for production wells can be better specified to more
confidently known subsurface conditions.
Injection well. Any well designed to return the geothermal effluent to the
reservoir or other deep disposal zones. Injection wells will have blowout
prevention requirements similar to nearby production wells.
~Deep versus shallow wells. These are terms of convenience in their general
I usage; however, regulations may impose a legal definition on them. A historical
point of interest in the KERZ should be noted; several early geothermal
exploration holes, drilled safely with cable tools, encountered near boiling waters
I I i
at very shallow depths next to recent lava flow fissures and vents. Depth seems
to have no correlation with blowout risk in Hawaii's geothermal drilling to date.
However, it should be evident that relatively shallow blowouts in the porous
surface lava rocks and large fissures, broadly prevailing in Ha waii,could be
particularly difficult to kill.
Vertical versus deviated wells. It appears that Hawaiian geothermal wellfields
will be extensively developed with deviated wellbores. Blowout prevention
requirements are not altered in any type of geothermal well by the vertical or
deviated course of its wellbore.
· (p h lf ir~Cike.s 11" v-r.- B~ ;"v~e~ ~limhole. F type of geothermal fell U; identified by its small diameter
1 borehole,~~ compared to the ~ b4r/t diameter range commonly I / used world wide in the geothermal industry. The slimhole technology, presently
. I I , surging in evaluation and use in the petroleum industry, has a distinct blowout LJ 1 risk and prevention requirement. The technology has been safely introduced
I in the KERZ when HNEI accomplished three continuous boreholes between 5500
! and 6000 foot total depths in its Scientific Observation Hole Program (1989-91).
l_giscussion of the blowout prevention in slimholes is presented in Section XII.
THE DRILLING PLAN
Every geothermal well proposed for funding and permitting will require a
drilling plan. Regardless of the geothermal well type, the drilling plan is the specific
technical document that should reflect the best thinking on how the well can be safely
BOPPL&~!NG/RLD/October 13, 1992 IV-3
constructed and it!=' .c:unction obtained at reasonable c-- -:;t. Safety is considered on a
broad front in a ca:?efully prepared drilling plan. ComrTionly the deliberate actions to
optimize safety in geothermal drilling will be specified or reflected in four distinct
sections of the drilling plan, as follows:
l. Casing and cement. The intended function of the proposed well will be
a factor in casing design and cementing procedures selected. However,
the best available subsurface data sets on geology, hydrology 1 pressure
and temperature profiles, formation failure thresholds (fracture gradient),
together with the wellsite elevation, comprise the basis for increased
safety in drilling and quality of construction. The subsurface conditions
and wellsite elevation are unique to each intended wellbore; the proposed
casing and cement plan must reflect a reasonable response to these
conditions. KERZ drilling experience reveals several special concerns for
blowout prevention.
~0- ;nd-. a. A preference to cement the surface casing (commonly ~
diameter) below the lctwe~~-aq-tri:£er--contsin±n~-pot.ab±e-water ~p~~
can be acknowledged. Where the ground water table is within
600-800 feet below the surface, an approximate 1,000-foot length of
surface casing would meet this objective. Where the ground water
table is much deeper 1 it could be cliffi.cult to obtain a good cement
sheath on surface casing set at, say 1 1 700 feet/ because of the
presence of lost circulation zones and incompetent rock in which
to cement the ~~ii.i~sn~o.~n:P:~~4e,pee.)~li99~~$i~P.:~t.:~t~~:A~t~et~~
()~t~:::::a:Jq\l@ty:::c~~m~ti~:~s~;.~~;p;~qti~:~J-~ll.e>:rt:et::l~fist;h.i::of:~u:r:face
(i$.fi.Hj:; --into--eomp~ent- -t"'C'k,--e~en- -if--ehe--p1."'0CedttJ:&e-~
ee~~-~he-bo~-~into~rotl~a~~
b. Independent of the quality of cement sheath obtained on surface
casing 1 the possibilities of fractures/ other permeable paths to the
surface and low formation fracture gradients exist in the near
surface volcanic rocks penetrated by the surface casing. This
points to a serious risk in using a complete shut off (CSO) blowout
prevention system on the surface casing while drilling to the
intermediate casing depth. A CSO could force unexpected hot and
possibly pressured formation fluids to an external blowout (outside
BOPPLANKING/WLD/October 13, 1992 IV-4
the surface casing and cellar). External venting of this type can
posa•more•·eomplex··and·p:r~riliu$·kur·op:erations; arid aJ.® M-mg
an--±n'l"!'nediat-e--threateri the drilling rig's ground support.
Accordingly, a diverting capacity and large diameter flow line from
the wellhead to a distant disposal point is to be considered. This
approach would contain such~~ncontrolled flow inside the surface
casing and afford a safer kill procedure confined to the wellbore.
1? ~/e-·.:,"'"' c. Intermediate casing (commonly 1~ diameter) may be set at
depths between 1,000-2,500 feet below the surface casing shoe if no
unexpected geothermal fluids or anomalies are encountered. The
intermediate casing shoe depth should optimally be below the major
ground water body. !fshbUld also be k>eloijj extensive fracturing that
may reach up to the ground water table, frequent occurrence of lost
circulation zone~~ and less competent volcanic tock:elastie-zones:
Because the intermediate casing becomes the anchor ¢aslli9 for the
complete BOP equipment stack required to drill to total depth, it is Y"t- i"'dl.
critical that the cement sheath in the open hole (17 Y diameter)
annulus be of the highest possible quality. The findings in the 17
Jt.-.nth -? Y drilled hole should be carefully studied. Any adverse downhole
conditions can be mitigated by cementing the bottom portion of the
intermediate casing as a liner in the open hole interval (lapped
several hundred feet into the bottom of surface casing). The upper
portion can be run and cemented as a tie back string inside the
surface casing. Each of the two cement jobs required should be of
enhanced quality, should offset the external natural hazards and
should optimize the anchor for the complete BOP equipment stack
with its multiple CSO capacity over a full range of drilling fluids.
2. Drilling fluids. The subsurface conditions encountered within the KERZ
are prompting the use of many drilling fluids ranging from moderate to
low density muds, water, aerated muds and water, to foam, and air.
Additionally, the ability to switch drilling fluids promptly is being
recognized as a cost effective advantage in greater well control. This
pradti(tifi ea-pe.eit:y demands the use of BOP equipment compatible a
BOPPLAKNIHG/WLD/October 16, 1992 ~J (.di[,~,~-5
broad range of drilling fluid options in a single wellbore. The diversity
and flexibility of drilling fluid utilization in Hawaii is encouraging, not
only because all fl\ii<}~ t:hey-can be controlled by available BOP equipment,
but because this approach should lead directly to advanced safety
margins, reduced drilling times and lower costs. Drilling fluids and
geothermal well control are further discussed in Section VII.
rillin. . . his )~f~~~ . all . d . h h 3. D g Momtonng. T ~L lS usu y mtegrate m t oroug
drilling plans at many points. It is, however, quite important and
deserves more recognition as an effective method to reduce blowout risks.
A detailed consideration of drilling monitoring procedures is presented in
Section VII.
4. Blowout Prevention. Drilling plans may contain minimal specific
discussion of blowout prevention; a graphic sketch of the proposed BOP
equipment stack may be the lone obvious recognition of the subject.
However, a competent drilling plan will reflect, in its detailed provisions,
an Operator's blowout prevention strategy. The implementation of risk
reduction will be evident in the casing, cementing and drilling fluid aniA 1-1"4•" i.,~
provisions, in the drilling monitoring j...procedures and finally in the BOP
stack and its supplemental equipment. The drilling plan should reveal the
Operator's awareness that a blowout can happen, and reflect the drilling
supervisor's responsible determination that it has been given the least
possible chance to occur in the proposed well. Blowout prevention is every
Operator's final responsibility; it is achieved first in the thinking and
actions of all drillsite personnel through training, J.5Y. :tl'j_~ practice of
sound procedures, and by the use of reliable, proper equipment.
30?PLfulNING/~LD/Octaber 13, 1992 IV-6
DRAFT
V_ BLOWOUT PREVENTION STACKS AND EQUIPMENT
INTRODUCTION
Hawaii's geothermal drilling industry, still in a formative stage, has gained
sufficient experience and information to provide reasonable guidance to the
identification of more reliable and safer blowout prevention stacks and equipment. The
blowout prevention stack on the wellhead, when all other well control procedures have
failed, must function reliably \J:Qb.ta~:~ a complete closure or effective control of
unexpected fluid flows from the wellbore. Blowout prevention stacks and related
equipment are not simple systems; they rely on integrated mechanical, hydraulic and
electrical processes to operate. Both redundancy and sophistication exist; however, the !.le>..o.,..+rfel) .a"'h.,...
risks of human error in criticaP'utilization have not been eliminated. Blowout
prevention systems require careful selection, maintenance, and repetitive training
of drilling crews to attain the reliability and safety which are essential in the final
defense against an actual blowout.
BOP DEFINITIONS AND FUNCTIONS
1. Definitions
• The term blowout prevention equipment (BOP) here means the entire array
of equipment installed at the well to control kicks and prevent blowouts. It includes
the BOP stack, its activating system, kill and choke lines and manifolds, kelly cocks,
safety valves and all auxiliary equipment and monitoring devices. (see Glossary in
Appendix D for these terms).
• The BOP stack, as used here, is that combination of preventers, spools,
valves, and other equipment attached to the wellhead while drilling.
• A diverter stack is a BOP stack that includes an annular preventer, with a
vent line beneath. A valve is installed in the vent line so that the valve is open
whenever the annular preventer is closed, thus avoiding a complete shut off (CSO),
and diverting the flow of fluids away from the rig and personnel.
A full BOP stack is an array of preventers, spools, valves, and other equipment
attached to the wellhead such that complete shut off (CSO) is possible under all
BOPSTACKS&EQUIP/HEW/WLD/October 13, 1992 V-1
conditions.
2. Functions
The main function of the BOP equipment is to safely control the flow of fluids
at the surface, either by diversion or by complete shut off. The equipment must be
adequate to handle a range of fluid types, pressures, and temperatures, and to
accommodate different drilling situations such as active drilling and trippin~11 or out
of the hole. The requirements of the BOP stack are to:
a. Close the top of the wellbore to prevent the release of fluids, or, to safely
divert the fluids away from the rig and personnel.
b. Allow safe, controlled release of shut in, pressured fluids through the choke
lines and manifold.
c. Allow pumping of fluids (usually mud or water) into the wellbore through kill
lines.
d. Allow vertical movement of the drill pipe without release of fluids.
Selection of BOP stacks and equipment should be made jointly by an experienced
geothermal drilling engineer and drilling supervisor. It is preferable to employ a
supervisor that is experienced in Hawaii geothermal drilling experiences and
conditions.
THE BOP ANCHOR
Complete shut off capability with a BOP stack requires the existence of a BOP
anchor. Three key factors are required for a sound BOP anchor:
1. A mechanically sound, continuous steel casing of reasonable length, which
probably will be 1000 feet or more, attached to·the BOP stack.
2. A continuous and solid cement sheath in the annulus between the casing and
the rock wall of the wellbore.
3. An impermeable rock interval around the wellbore and cement sheath. The
entire section of rock need not be impermeable,but priority is given to placing
and cementing the casing shoe in a thick interval of competent a;ng iifti:p~romeab'le ;--low-per-mea-bm'ey rock.
BOPSTACKS&EQUIP/HEW/WLO/October 13, 1992 V-2
IMPACTS OF SUBSURFACE RISKS
Hawaii geothermal drilling has inherent risks due to the unpredictability of
subsurface conditions. Recognizing the risks and being prepared for all possible
conditions is the best form of blowout prevention. Subsurface conditions that may pose
the risk of a well blowout are listed below:
1. The almost certain inability to obtain a sound BOP anchor with surface casing
in the weak, often broken,11and vertically permeable near surface volcanic rocks. As
• (.t a w ttl l<1C.k occ.a('' discussed in Section III,Vthese shallow rocks will not allow a CSO at the wellhead
without posing a significant risk of creating :ain\~$.x~rf1a~ly':v6,ritie~ '}/elF¢asin9 hlp¥fout; (For discussion of externally vented blowouts, see Section IX.)
2. The unexpected entry while drilling into a major fault and fracture conduit.,
which is charged with overpressured geothermal fluids. Termination and control of
such events requires the certainty of a wellhead CSO with a full capacity BOP stack. i
The risk factors cited above reveal the importance of knowing when a BOP
anchor and consequent CSO capacity nee~to;--be-*','e. available to PH~:Ye:~t~~
a blowout. If they are not available, diversion of uncontrolled flows is judged to be
the more prudent response. On these fundamental considerations, two basic BOP stacks
are recommended for Hawaii geothermal wells which are drilled with rotary rigs for
exploration, production or injection purposes.
BOP STACK RECOMMENDATIONS
1. Diverter Stack (Figure 1-Appendix B)
A diverter consisting of an annular preventer and a vent line should be 40 ~"c:. .. e.$'
installed on the surface casing. In Hawaii, this casing is typically J.E". in diameter
and is cemented in the ~ depth range. /' ~oo- t 1\00 .PI!Iet
1 In the KERZ, sudden geothermal fluid flows, which subsequently registered 500 to 700 psi shut-in wellhead pressures, were encountered at depths shallower than expected; in one case as shallow as 1,400 feet.
BOPSTACKS&EQUIP/HEW/WLD/October 13, 1992 V-3
Incompetent near surface
volcanic rock and the high risk of cementing failure will not provide an
adequate BOP anchor. CSO is not intended with this equipment; diversion of
fluids is deliberate to avoid creating externally vented blowouts, and for
personnel and rig safety.
2. Full BOP Stack (Figure 2)
A full BOP stack should be installed on the intermediate casing. In Hawaii, this v'"3 ~~ ioc.heo; zeoo -1,5"= r.;.,.t
casing is typically ~ in diameter, and is cemented in theY~
depth range. This deeper casing, cement sheath, and host rock serves as a BOP
anchor. The selection and arrangement of this stack allows for the use of a full
range of drilling fluids (mud, water, aerated fluid, foam, air) and should be a
geothermal industry premium stack that is capable of confident, immediate CSO
over the range of temperatures and pressures anticipated. If a sufficient BOP
anchor is not obtained, this stack also has diverter capacity because of the flow
"T"/vent line, or banjo box/blooie line, included in the stack.
ADDITIONAL RECOMMENDATIONS
1. Diverter stack. The diverter stack should have the following
characteristics:
a. A mm1mum pressure rating of 2,000 psi for all components.
b . . 1' d. te f ,.,.,..; rz ,~ ... ~e~ . Mm1mum vent me 1ame r o , ~
c. A full opening valve on the vent line that opens automatically
when the annular preventer is closed; OR a 150 psi rupture
disk and a normally open valve.
d. The vent line directed through a muffler.
e. H2s abatement capability connected to the vent line.
2. Full BOP Stack. The Full BOP Stack should have the following
characteristics:
a. A minimum pressure rating of 3,000 psi for all components.
BOPSTACKS&EQUIP/HEW/WLD/October 13, 1992
A pressure rating of 5,000 psi is recommended when indicated
by the risk analysis of the well. For temperatt.ir"e impaCtS on
V-4
b.
c.
d.
~:::~u=:~~::~~~fct~illi~~~~~nd ;f~~ ad~~:::~ine. The pressure ratings for the kill and choke lines the same
as the stack.
A 11 preventers should have high temperature rated ram
rubbers and packing units.
BOP EQUIPMENT RECOMMENDATIONS
-z.- ~f\Ch 1. Kill Line. r kill line from pumps to spool. Two full opening valves and
one check valve at the spool. Fittings for an auxiliary pump connection;
pressure rating for the kill line the same as the stack. The kill line is not
to be used as a fill up line.
4- 1~Ck
2. Choke Line and Choke Manifold. f" choke line and manifold; pressure
rating the same as the stack. Two full opening gate valves next to the
spool; one of these valves remotely operated.
3. Actuating system. The actuating system should have an accumulator
that can perform all of the following after its power is shut off:
a. Close and open one ram preventer.
b. Close the annular preventer on the smallest drill pipe used.
c. Open a hydraulic Y:alv~eiffie on the choke line, if used.
5o f-ee+ The actuating system is to be located at least ~ from the well, with two
control stations - one at the drillers station on the rig and one at the
actuating system location.
4. Other equipment. During drilling the following miscellaneous BOP
equipment is to be provided:
a. Upper and lower kelly cocks and a standpipe valve.
b. A full opening safety valve, to fit any pipe in the hole. Kept
on the rig floor.
c. An internal preventer, kept on the rig floor, with fittings to
adapt it to the safety valve.
d. Accurate pressure gauges on the stand pipe, choke manifold,
e. A 11 flow lines and valves rated for high temperature service.
BOPSTACKS&EQUlP/HEW/WLD/October 13, 1992 \/-5
DR..AFT
VI. EQUIPMENT TESTING AND INSPECTION
In general, a visual inspection and an initial pressure test should be made on
all BOP equipment when it is installed, before drilling out any casing plugs. The BOP
stack (preventers and spools, choke and kill lines, all valves and kelly cocks) should
be tested in the direction of blowout flow. In addition to the initial pressure and
operational test at time of installation, periodic operating tests should be made.
Pressure tests should subject the BOP stack to a minimum of 125% of the
maximum predicted surface pressure. If the casing is tested at the same time then the
test should not be more than 80% of minimum internal yield of the casing at the shoe.
If a test plug is used, the full working pressure of the BOP stack can be tested; a
casing test would be made separately. Testing of the actuating system should include
tests to determine that:
1) The accumulator is fully charged to its rated working pressure;
2) The level of fluid is at the prescribed level for that particular unit;
3) Every valve is in good operating condition;
4) The unit itself is located properly with respect to the well;
5) The capacity of the accumulator is adequate to perform all necessary
functions including any kick control functions such as hydraulic valves
that are using the same unit for energy;
6) The accumulator pumps function properly;
7) The power supply to the accumulator pump motor will not be interrupted
during normal operations;
8) There is an adequate independent backup system that is ready to operate
properly; and Gof-t.ot.+ 9) The control manifold is at least ~ from the well and a remote panel is
located at the driller's station.
10) All control valves are operating easily and properly, have unobstructed
access and easily identifiable controls.
The sequence of events to test the BOP stack and all other valves depends on
the stack configuration, but it is important that all equipment is tested, including the
annular preventer, pipe rams, CSO rams, upper and lower kelly cocks, safety valves,
BOPTEST!NG\HEW\WLD\October 13, 1992 VI-1
internal preventers, standpipe valve, kill line, choke manifold and choke control valve,
pressure gauges, and any other items that are installed as part of the BOP equipment.
In addition to the initial testing of BOP equipment when it is first installed,
there should be frequent BOP testing and drills. The closing system should be
checked on each trip in or out of the hole and BOP drills should be held at least once
a week for each crew. It is most important that every member of the crew be familiar
with all aspects of the operation of the BOP equipment, along with all of the
accessories and monitoring devices that aid in detection of a kick. The main purpose
of drills is to train the crew to detect a kick and close the well in quickly. BOP drills
should cover all situations, while drilling, tripping, and with the drill string out of the
hole.
BOPTESTIHG\REW\WLD\October 13, 1992 VI-2
VII. DRILLING MONITORING PROCEDURES
INTRODUCTION
Operators commonly provide for some level of monitoring in the drilling of most
geothermal wells. All types of monitoring procedures will incur additional costs, which
may limit the selection of specific procedures. However, most Operators determine the
specific procedures in the context of what is known and not known about the
subsurface environment to be penetra~ed by the wellbore. This discussion of
monitoring will use the broad sense of the term, including mud logging.
Monitoring procedures may be defined as an array of continuous sensing actions
which attempt to accurately indicate subsurface conditions as the drill bit is advancing
through the:@~ formation.
MONITORING RATIONALE
Geothermal wells, drilled within the prospective, active volcanic rill zones of
Hawaii, merit carefully planned and integrated monitoring procedures. This view is
supported by two primary concerns. First, the subsurface geology, hydrology,
temperatures and pressures in the rock roof above the deep magma conduits, which
create the rift zon~are only partially known. Only 14 deep geothermal bores (11 wells
and three scientific observation holes) have provided hard, factual subsurface data
as of mid-1992. Secondly, two geothermal wells have demonstrated that fault or
fracture conduits, charged with high pressure, high temperature fluids can ef{t~nd ~~~-\- C(W'I \V\~
upward to relatively shallow depths from a deeper subsurface domain ')n: >600VF
temperatures. These near vertical and planar conduits present both blowout risks and
significant geothermal energy production potential. This recent finding, proven by
drilling, has major implications. Geothermal drilling requires the evaluation and more
effective utilization of monitoring procedures as a supplemental strategy for blowout
prevention.
VITAL SECTORS
Monitoring focuses on three vital sectors during the drilling of a geothermal
BOPMONITORING/WLD/October 13, 1992 VII-1
well:
1. Drilling penetration rate and drill bit performance measurements. The
penetration rate, commonly measured anq recorded in feet per hour, ~<crp~f'l"'g, "'-.l>•<e~o\e
indicates the mechanical progress of~ in the host rock. Weight
on bit, rotational speed and torque are additional measurements that are
made to better understand the variations of the drilling penetration rate.
2. Drilling fluid circulation in the wellbore which clears the new made hole
of drilled rock debris, cools and lubricates the rotating ~bi.~~~ ,drilling assembly)i:f)Ji:id.!~:<:I~W~ri9T~~~¥iS· Importantly, the density and
hydrostatic pressure gradient of the drilling fluid are commonly used to
control the formation fluids and pressures encountered.
3. Physical conditions and resource potential of the newly penetrated rock
formation. The array of information gathered in this sector is commonly
presented in a continuous "mud log" graphic record over the entire
interval drilled.
The information products from the sectors discussed above have important
potential applications. Possible immediate improvements might be indicated in drilling
procedures, drilling fluid properties or casing plan in the well itself. Enhancements
in well design, drilling program and/or cost ~tmcan be determined for future
wells. ~...--....+..frlli\. .. the information products of mon~to~ing procedures, with careful -... "'r'""'V•""-'-If'f JI'I•K~ "-:'. i"'.vor~411l#-" ccmtnbuf-i611\
integration and evaluation, can r~ to an Operator's strategy of blowout
prevention.
OPTIMIZING BLOWOUT PREVENTION
Any effective reduction in blowout risks is primarily contingent upon accurate
interpretation of monitoring data and ultimately depends on the decisions made, based
on this data. This must be achieved by the Operator. Having made the risk analysis,
written the drilling plan and obtained the funding for the well, the Operator's
geologist and drilling engineer presumably would be the most qualified persons to
establish the method by which the selected monitoring procedures would be used to
BOPMOMITORI~G/WLD/Octaber 13, r992 VII-2
contribute to a blowout prevention plan. In prospective Hawaiian rift zones, the
prudent Operator, making careful use of monitoring information, can better identify
the potential for hot and overpressured fault and fracture conduits, and can better
prepare for penetration of such conduits and reduce impacts of kicks and lost
circulation. Alternatively, a decision on whether or not to set casing can be made,
particularly if a long open hole section is exposed above the interval of concern.
Critical data that may reveal the degree and/or immediacy of a blowout risk are
probably first observed by key personnel of the drilling and mud logging contractors.
Exercising personal control of drill bit performance in making hole, drillers are the
first to sense change at the bottom of the wellbore. Additionally, drillers must have
an accurate, real time knowledge of the drilling fluid upflow in the annulus between
drill pipe and the wall of the open hole. Gain or loss departures from 100% of the
drilling fluid pumped down the drill pipe and through the bit orifices are critical
indicators that, alone or with other corroborating information, signal a disruption of
a normal drilling mode.
The mud logger and a supporting multiple sensor system continuously survey
the changing rock features, formation fluids and temperature variations reflected in
the returning drilling fluid. This work is both time critical and time short because it
focuses evaluation on the narrow window of freshly exposed hole behind the
continuously advancing drill bit. Accordingly, good quality, competitive mud logging
has become a highly automated, computer assisted service with an impressive
reliability. The mud logger is the first to evaluate the formation gas and liquid
entries, via the returning drilling fluid, that may signal the penetration of high
temperature, high pressure conditions.
Operators of Hawaiian geothermal drilling projects need to assure that a high
level of cooperation in comprehending the norm and the upset hole conditions are
mutually practiced by their contracted drillers and mud loggers. The Operator's
drilling engineer and geologist should establish and maintain active communications
with these key specialists throughout the drilling process. It is essential that drillers
and mud loggers have reliable, instantly available electrical communication between
their work stations if monitoring procedures are to more effectively contribute to the
reduction of blowout risks. These simple procedures are intended to eliminate a
BOPMONITORING/iiLD/October 13, 1992 VI I- 3
common problem: too often a key piece of new information is received, but is not
properly read, understood or communicated. Operators must lead their drillers and
loggers to consistent cooperation in monitoring procedures as an important protection
against the loss of well control. O'l'lersi.~ht-:i:n-~1-hadequateroespbnS$$ to new
well monitoring information must be e1i'fTti1otstedmiriimiZ.ed in Hawaiian geothermal
drilling.
DRILLING FLUIDS AND GEOTHERMAL WELL CONTROL
All authoritative publications on blowout prevention (which to date exclusively
address oil and gas drilling) stress the role of drilling fluids in minimizing, if not
precluding, entries of normal or high pressured formation fluids into the wellbore
during the active drilling process. This is achieved by circulating a weighted mud or
salt water drilling fluid which creates an excess or overbalance of internal hydrostatic
pressure on every square inch of the open wellbore. The normal hydrostatic pressure
gradient for the formation fluids in Hawaii rift zones should approximate 433 psi per
1,000 feet of vertical depth for fresh water and 442 psi per 1,000 feet for salt water.
This range of pressure gradients may prevail over much of the KERZ in the deep
geothermal zones because several geothermal wells were drilled through 2,500 foot
intervals of hot (760°F) prospective rock interval by circulating fresh water as a
wholly satisfactory drilling fluid. Well control was maintained confidently in these
operations and subsequently these fresh water drilled intervals yielded proven
geothermal fluids during flow tests following well completion. It should be noted that
the greater cooling capacity of water, as compared with mud drilling fluids, played a
positive role in these achievements.
Cooling by the circulation of drilling fluid is an inherent physical process in
geothermal well drilling. Where accelerated or optimized, the cooling process itself can
be recognized as a well control function. The efficient cooling of circulating drilling
fluids particularly will require an adequate surface cooling facility in the loop. Mud
cooling towers which allow the hot returning mud to fall in a baffle system against a
cool air draft are a standard equipment option for geothermal drilling. It is important
that mud cooling towers be adequate for the heat load anticipated and that they be
carefully maintained and monitored during use to assure that cooling is being
effectively accomplished. Additionally, geothermal well control in Hawaiian rift zones
BOPMONifORI!G/WLD/October 13, 1992 VII -4
requires ready access to an ample supply of cool water for wellbore circulation as a
well control option.
I< 6fZZ J(,[l,~g Both the specific ~experience and the practice of world wide geothermal
drilling demonstrate the disinclination tO:' dtillor~ with heavily weighted muds
or saline solutions as a preferred means of well control. This relates to the
expectation of finding fractures in the prospective hot zones which have much higher
permeability and production potential than a bulk rock interval of some uniform
primary (commonly lower) permeability. Fractures present the immediate risk of lost
circulation and a possible well kick , particularly when overpressured fracture fluids
are released. The perceived benefits of significantly weighted drilling fluids
(significant overbalance) usually is lost immediately in geothermal wells which
successfully penetrate fractures. The loss of drilling fluid from the wellbore anmti~
into formation fractures is accelerated in direct proportion to the overbalance ue to
tf:itcii:tSSively~ weighted~ ri\Uq~;-n~4lead. If, as indicated to date, blowout risks
in Hawaiian r:ift zones are predominantly fracture controlled and fracture specific, it
does not appear that excess weighting of drilling fluids will be a common means of
blowout risk reduction.
MONITORING INDICES FOR BLOWOUT PREVENTION
Monitoring procedures, taken as an aid to blowout risk reduction in Hawaiian
geothermal drilling, can be focused on a group of fi.ve categories, as discussed below.
The sequence of the categories is believed to be in order of importance when they are
examined with the assumption that the sudden encounter of high pressured geothermal
fluids in fractures constitutes the primary blowout hazard in these volcanic r:ift zones.
A. DRILLING WITH MUD OR WATER CIRCULATION
1. Bottom hole temperature variation. The blowout hazards in Hawaiian
rift zones have a strong correlation with high subsurface
temperatures. A working impression that 600°F and higher
temperatures were present below 4,000-foot depths under the
Kapoho-State geothermal leaseholds, and at greater depths upr:ift
in KERZ, may have prevailed before the KS-7 and 8 blowout events.
BOPMON!TOR!NG/WLD/October 13, 1992 VII-5
These wells respectively vented 500°F fluids from below 1,400 feet
and 620°F from below 3,476 feet in uncontrolled flows at the
wellheads. Bottom hole temperatures (BHT) cannot be measured in
the active drilling process because of the cooling induced by the
drilling fluid circulating around the rotating bit.
Alternatively, the exit temperature of the drilling fluid vented at
the wellhead annulus is continuously recorded. The sharper
excursions of increasing temperature with depth are the features
of interest in the automated plot of exit temperature. The mud
logger can immediately read such temperature increases in the
context of the complete temperature profile (surface to current
depth) and detect possible correlations with events on other ·fo-1
indices. A supplemental temperature,iiepth record is frequently
obtained by measuring with maximum reading thermometers inside
the drill pipe at a stop immediately above the drill bit for some
consistent time interval (say 20 minutes) at some regular frequency 1-~"1-
the Operator finds appropriate. This independent survey does not
obtain equilibrated BHTs; however, it provides a more discriminate
reference for the exit temperature plot. With respect to blowout risk
reduction, neither the existing BHT value or any specific high
temperature value has primary importance. Rather, it is sharply
rising temperatures, coincident with other dynamic events observed
in an integrated monitoring procedure, that ate'tOea!'l be taken as
a caution or evidence that a blowout threshold is being approached.
2. Drilling penetration rate. Variations in drilling rate commonly
reflect rock conditions encountered by the drill bit, provided such
factors such as weight on bit, rotational speed and torque are
uniform or their coincident variations are understood. Increases
in drilling rate (a drilling break) can indicate a porous and
permeable interval containing formation fluids; fractured rock can
cause sudden erratic perturbations in all these mechanical drilling
indices. Major fractures in the KERZ can allow the drilling assembly
to free fall into open voids. The consequences of such a fracture
BOPMON:~ORING/~D/October :3, :992 VII-6
~·dl encounter are frequently immediate. Competent drillers llquickly
determine the status of their drilling fluid return flow ~~1~praising the situation and appropriate response, if required. Increases in
drilling rates coincident with the penetration of high pressure
zones are described in some blowout prevention treatises on the
conclusion that bits drill faster in underbalanced mud weights
approaching high pressured zones. It needs to be determined if
KERZ drilling experience, past or future, suggests any basis for
reading drilling rate variations as an indicator of penetration of
high pressures. One prudent option in drilling fractured, high
temperature intervals, especially with initial formation fluid entries
identified in the return drilling fluid, is to deliberately reduce
penetration rate or briefly hold in a full circulation mode to confirm
drilling fluid system status and to observe more of the impact of
the formation fluids encountered.
3. Drilling fluid circulation. Accurate knowledge of the drilling fluid
condition, particularly its weight in pounds per gallon, and its
Je_g-ree o.f functioning in the wellbore, are critical to drilling with effective
well control. Any departure (gain or loss) from a 100\ return of
the pumped circulating volume, delivered through the drill pipe to
the drill bit, needs to be promptly evaluated as to magnitude and
meaning. Continuous measurement and recording of the drilling
fluid gain, loss, or 100\ return is made in specific tanks (mud pits)
included in the fluid circulation loop. Either gain or loss of drilling
fluid must be taken as a warning o£" increasing blowout risk. A gain
is a reliable indicator of formation fluid entry into the wellbore
(kick). If well flow is indicated or suspected following a gain,
drilling should be halted, the kelly pulled above the rotary table,
the mud pump shut down and the exit flow line visually examined
for possible flow. If the well is flowing in these circumstances, the
anri'Ul#;ciri:H--pi~-ram preventer should be closed to identify
pressure buildups on both annulus and drill pipe. These pressures,
when stable, would identify the increases in mud weight and
wellbore hydrostatic pressure necessary to terminate the formation
BCPMONITCR:NG/IG/Cct~ber :3, :992 VII-7
4.
fluid inflow. An evaluation of the option of circulating cool water
in the wellbore should be made if the kick is associated with a
temperature increase.
Partial or complete loss of drilling fluid returns is the more common
problem consequent to fracture penetration. Complete loss of
circulation, followed by a falling fluid level in the wellbore annulus
is a most likely trigger for a blowout event. Drilling must be
halted, the drilling string pulled up (only to the first drill pipe
tool joint) and the preventer closed until the situation is evaluated
and a response determined.
Formation fluid entry. All geotherm.al fl.W;d beari;ng. zones, both high vb~ j det~ri f~d v'Y ~"'ill btt
and normallx pressured, will first~~ penetration ~ ~~{~ ) <Ab\e'(Wtt-
~ ·~ charge of gases into the drilling fluid ~ in the
annulus. Mud logging systems will automatically measure and
record carbon dioxide, hydrogen sulfide, methane and ethanol in
parts per million on a log scale whenever the drilling fluid is being
circulated. Although this information has a time lag compared to
the immediacy of a drilling break, it is the most positive specific
indicator that geothermal fluids have been encountered. Gas:..::cut drillili9' flUid' returris~T~~~ ct:tt:~ coupled with temperature
increases, are a clear warning that a high pressure zone of
considerable flow potential may be at hand. With additional
penetration, geothermal formation liquid fractions may cause
detectable salinity increases in the return drilling fluid. Salinity a~ . -
determinations are notrautomated monitoring procedure, but are
optionally performed by the mud logger in evaluating fluid entry
events.
5. Secondary mineralization. Geothermal fluid bearing faults, fractures
and zones are predominantly enclosed in a sheath or seal of
secondary minerals. Secondary minerals are continuously identified
and recorded in geothermal mud logging with the intent of
discerning, in correlation with the wellbore temperature profile, the
most prospective intervals for fluid production. Logic would
BOPMONITORING/W~~/October l3, l992 VII-8
SUMMARY
suggest that the larger hot fluid conduits, which present both
significant production potential and blowout risk, would likely have
a thicker sheath of secondary minerals. The extent to which this
prevails in the Hawaiian rift zones and to which it may be a
particular precursor to high pressured geothermal fluids in
fractures is not well known. Natural variations in the secondary
mineralization process, consequent to a new fracture opening for
geothermal fluid conduction, may be extreme; any secondary mineral -~o.fl\etllllil
sheath could presage a V"fluid filled fracture or a fracture that is
completely sealed by mineralization., particularly in the active
faulting and fracturing of the KERZ. Whatever may be the present
view of this apparent index, it appears to merit careful evaluation
within the concept of integrated monitoring as a logical part of
blowout prevention strategy.
An optimal use of monitored drilling information in a blowout prevention strategy
requires the informed participation and responses of competent drillers and mud
loggers. A logical assignment of primary responsibility for the categories discussed
above would be:
Driller
drilling penetration rate
drilling fluid circulation
Logger
temperature variations
secondary:: mme~auzatlli* fbi"mat.ion: 'flUid': ~htrw
Computer based graphic data presentations are increasingly used at the driller's
stations to quickly provide both present status and cumulative record on the drilling
and fluid circulation processes. Both caution and alarm thresholds can be set on the
incoming real time information streams to alert drillers and supervisors to upset
conditions. Such systems offer an advantage to the blowout prevention objectives
necessary to Hawaiian geothermal drilling, provided that competence in their use is
created by diligent training.
3CPMON:~cR:NG/m/Cc:ober :3, :992 VII-9
The mud logging services contracted to most of the geothermal drilling
operations in the KERZ have been state of the art quality at the time of every
execution. Very substantial improvements in reliable automation have been made since
the rnid-1980s. In summary, Operators have adequate monitoring procedures at hand
to reduce blowout risks. The driller's main focus is on immediate deviations from the
controlled drilling process, and the mud logger's main focus is on subsurface physical
consequences of borehole advancement. Blowouts are commonly preceded by multiple
warning signs of increasing risks. The Operator's drilling engineers and geologists,
with the close cooperation of drillers and mud loggers, can more accurately recognize
such risks and more quickly act to control or reduce them with the drilling monitoring
procedures discussed here.
A final comment should be made on drilling fluid monitoring requirements while
tripping the drilling string. Frequently in geothermal well drilling with mud and
water, the hydrostatic pressure of the fluid has only a moderate overbalance on the
formation fluids. This is further reduced with the cessation of circulation immediately
before pulling the drill string, as for a new bit. In hot, prospective rock zones, the
large diameter drilling assembly moving uphole can swab, or pull formation fluids into
the borehole, by further reducing the hydrostatic pressure below the bit. The
greatest danger of swabbing occurs when pulling the first few stands of drill pipe
(drilling assembly just pulling off bottom). At this point, a careful confirmation of the
drilling fluid fillup volume, r~quired to hold the fluid level at the wellhead, is
essential. If the well ~~Y'~olume is less than the volume of drill pipe pulled,
swabbing should be inferred, the bit returned to the bottom and the hole recirculated
to clear the formation fluids from the well. In summary, swabbing is a mechanism that
can and has caused blowouts. A slower pulling of the initial stands and the fillup
check are the defensive procedures to use.
B. DRILLING WITH AIR, AERATED LIQUIDS OR FOAM
These drilling fluids are utilized in the underbalanced drilling option which is
often employed in geothermal drilling, particularly in known vapor dominated
reservoirs. Air or aerated liqUids Tdrilling I signified by substantial additional
equipment and service requirements, (air compressors, rotating head, banjo box, blooie
line, drilling muffler and H2s abatement backup) has been employed on a geothermal
BOPHOKITORING/~n/October ~3, l9S2 VII-10
exploration well in the KERZ. Expectedly, air and aerated fluids drilling will be used
and further evaluated in the Hawaii environment. Air drilling eases the driller's
concern with circulated fluid controls on formation fluids; the formation fluids, with
relatively unrestrained entry to the annulus, are transported to the surface and
through the drilling muffler for chemical and noise abatement before release to the
atmosphere. The mud logger's interpretation of rock and mineral cuttings is degraded
somewhat by the much reduced rddk particle size p~~«-th~pt'dd"(lced:: py air
drilling-1naO.~. Otherwise the drilling monitoring procedure discussed above will apply
for the same objective of blowout risk reduction.
BOPMON!TORiNG/W~D/October :3, 1992 VII-11
DRAFT VIII. KICK CONTROL
INTRODUCTION
In drilling terms, a 'kick' is often the first indication at the wellhead that there
are problems with control of formation pressure. A kick is defined as the entry of
formation fluids (water, steam, or gasses) into the well, which occurs because the
hydrostatic pressure exerted by the drilling fluids column has fallen below the
pressure of the formation fluids. If prompt action is not taken to control the kick and
to correct the pressure under balance, a blowout may follow. Some of the main causes
of these pressure imbalances are:
1. Insufficient drilling mud weight.
2. Failure to properly fill the hole with fluids during trips.
3. Swabbing when pulling pipe. If the drill string is pulled from the hole too
rapidly, the pressure may be reduced, allowing formation fluids into the
bore.
4. Lost circulation.
KICK IDENTIFICATION
There are a number of warning signs that indicate that a kick is occurring or
that it may soon occur. Some of these signs, which may not be present in all situations,
are:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
An increase in the returning drilling fluids flow rate, while pumping at
a constant rate.
An increase in mud pit volume.
A continuing flow of fluids from the welf when the pumps are shut down.
Hole fill up on trips is less than the calculated amount.
A pump pressure change and a pump stroke increase while drilling.
An increase in drill string weight.
A drilling break. (A sudden increase in penetration rate)
Gas cut mud or reduced mud weight at the flow line.
Lost circulation.
A rapid increase in flow line temperature.
Each of the above warning signs individually does not positively identify a kick.
BOPKICKS/WLD/HEW/Auqust 2C, 1992 VIII-1
However, they do warn of a potential for a kick. Every driller and derrick man should
be expert in recognizing these indicators and all crew members should be trained to
take action. In geothermal drilling, in addition to being alert to the above warning
signs, it is of prime importance to: 1) monitor drilling fluid temperatures in and out
while drilling; 2) maintain a frequent and close analysis of the formation cuttings for
a change in mineralization; and 3) exert caution when drilling through formations
where lost circulation zones are expected. Difficulties or abnormal conditions with any
of these indications or procedures can also indicate of a potential kick.
SHUT IN PROCEDURES
The severity of a kick depends on the volume and pressure of the formation
fluid that is allowed to enter the hole. For this reason, it is desirable to shut the well
in as quickly as possible. When one or more warning signs of a kick are observed,
procedures should be started to shut in the well. If there is doubt as to whether a
kick is occurring, shut in the well and check the pressures and other indicators.
Specific shut in procedures when one or more kick warning signs are observed
1. WHILE DRILLING
a. Pick up kelly until a tool joint is above the table.
b. Shut down the mud pumps.
c. Close the annular preventer.
d. Notify the company supervisor.
e. Record the drill pipe and annular pressure build up.
2. WHILE TRIPPING
a. Pick up kelly until a tool joint is above the table.
b. Install the full opening safety valve.
c. Close the safety valve; close the annular preventer.
d. Notify the company supervisor.
e. Make up the kelly; open the safety' valve.
f. Record the drill pipe and annular pressure build up.
3. WHILE OUT OF THE HOLE
a. Close the well in immediately.
b. Record the pressure build up.
c:; J ~otiflf: theJ co mP: aii:Y:: ~u P~rviSCi~;
BO?KICKS/WL~/EEW/August 2C, lS92 VIII-2
4. WHILE USING A DIVERTER
a. Pick up kelly until a tool joint is above the table.
b. Shut down the mud pumps.
c. Open the diverter line valves.
d. Close the annular pre venter.
e. Start pumping at a fast rate.
d. Notify the company supervisor.
KICK KILL PROCEDURES
Several proven kick killing methods have been developed over the years, based
on the concept of constant bottom hole pressure. Two of the most common methods are
know as the "drillers" method and the "wait and weight" method. Rig personnel should
be familiar with, and trained in, these procedures.
Selection of the method to be used in a particular kick situation should be made
by an experienced, qualified drilling supervisor. The actual method used will depend
on knowledgeable considerations of surface pressure, type of influx, the time required
to execute the procedure, complexity of the procedure, down hole stresses that may
be present or introduced, and available equipment.
All of the above are suggested procedures, to be modified by a knowledgeable
drilling supervisor to suit the particular conditions existing at the time of the kick.
30?K:i~KS/W:::/F.Et:/Augu.s: 2C I : m VIII-3
_. .t·. _,,I
DRAFT
IX- BLOWOUT CLASSIFICATION
INTRODUCTION
Any uncontrolled flow of steam, brine or other well fluids constitutes a blow out.
A discharge of these fluids at the surface is usually taken as the basic identifier of a
blowout. However, surface discharge, if it occurs, is only the symptom or consequence
of the fundamental upset condition that results in a blowout.
In the context of Hawaii geothermal activities, a broader, yet more precise,
definition of a blowout can be stated as a "loss of control of the natural pressures and
fluids encountered in the drilling of a geothermal well."
There are several types of geothermal well blowouts, varying in their severity and
in the techniques needed to control them. The impacts on surface and subsurface
environments, resource waste, and public perceptions of these incidents demand that
Operators and regulators minimize the risks of blowouts. The types of blowouts that may
be experienced in Hawaii include the following:
A. SURFACE BLOWOUTS
1. Casing Contained. An uncontrolled flow of steam or other fluids through ..lk4
the casing and wellhead will result inrescape of fluids to the atmosphere. This
may result in unabated gas emissions and noise disruptive to the surrounding
community and the surface environment surrounding the well. This type of
blowout may cause minor to major damage to the wellhead, BOP equipment
stack, or drilling rig. Response to the blowout will depend on the specific
situation. Efforts will focus on wellhead repairs, control of fluid discharge,
and access to the area for specific procedures. The availability of drilling
fluid supplies (including water), and the condition of the drilling string and
casing will be key elements in an effective operation to regain well control.
2. Externally Vented.
• Moderate case - low-to-moderate fluid venting outside the casing
or the cellar; the drilling rig, wellhead and BOP are generally
BOPTYPES/WLD/July 14, 1992/REV October 13, 1992 IX-1
undamaged and operable. May or may not be disturbing to surrounding
community. Responses may include grouting at the leak to terminate
surface flow.
• Worst Case - venting volume and/or velocity leads to rig collapse
and/or cratering around or near the wellhead. Response will probably
require a relief well if the hole doesn't bridge or collapse on its own,
thus terminating the flow.
B. UNDERGROUND BLOWOUTS
Although this class of blowout lacks any surface display, the event could escalate
into a surface blowout if not recognized and resolved at an early time .
.1_ High pressure fluid upflows, in the open hole, from a deep zone to a
shallower permeable zone (lower temperature reservoir or groundwater). Such
events may range from serious degradation or destruction of the open hole,
to minor resource loss and conservation problems. Response is generally to
subdue the flow with water, weighted muds, or cement plugs as required.
Additional casing/liner probably will be required, or the well may be plugged
with cement for redrill or suspension.
~ High pressure fluid upflows, in the open hole, from a deep zone to an
escape by hydraulic fracturing at the deepest casing shoe, where the
formation (pressure) gradient is exceeded by higher fluid pressure from the
deep zone. Response as above in 1.
BOPTYPES/WLD/July 14, 1992/REV October 13, 1992 IX-2
DRAFT
X- SUPERVISION AND TRAINING
INTRODUCTION
The major cause of most blowouts is human error; either none of the crew or the
Operator's advisors recognizes an existing well control problem, or steps to control the
situation are not performed soon enough. Most blowouts are fully preventable by
properly trained drilling personnel. Thus, proper training of the crew is as important
to successful well control as is the proper selection and use of blowout prevention
equipment, as discussed in the preceding sections. The Hawaii conditions for
geothermal drilling require that every Operator recognize its prime responsibilities
to provide supervision and training that is several levels above the industry average.
Hawaii's geothermal drilling industry is still in a formative stage. Because there
is no pool of operators and drilling personnel thoroughly familiar with all potential
problems in Hawaii's geothermal resource areas, there is a need for operators and
drilling contractors to pay extraordinary attention to all elements of training for their
crews. There must be a proper balance between practical, on-the-job-training,
operational drills, and formal study for a wide range of individual experience levels.
In a few cases, drilling and monitoring crews will have worked together closely m
other geothermal areas, some of which may exhibit well control challenges similar to
Hawaii's. In other instances, crews will be made up of a mixture of individuals that
have not worked as a team before, and may have a larger percentage of new workers,
especially at lower skill levels in the drilling and production jobs.
An additional consideration in the Hawaii case is the known occurrences of
relatively high levels of H2s gas in the geothermal resource. Proper well planning and
equipment selection can mitigate many of the hazards of H2s drilling in the well control
sense, but it is necessary that all drilling crews have a clear understanding of the
dangers and rules that accompany drilling in known H2s zones.
SUPERVISORY EXPERIENCE
Although complete training for specific crews that will drill in Hawaii's
geothermal zones is of primary importance, the art of well control is not learned from
classroom training alone. Therefore, experienced supervisory personnel are vital to the
BOPTRAINING/RAP/October 13, 1992 X-1
process of training the drilling crews, as well as in lending their experiences to the
ongoing supervision of the drilling. Drilling plans submitted should discuss the levels
of experience of the drilling crews, supervisors, consultants and managers, with
comment on the methods to be taken to ensure that such experienced persons will be
directly involved while drilling activities are underway in Hawaii.
DRILLING TEAM TRAINING AND DRILLS
The training of drilling teams, including supervisory, management and operating
personnel, in well control and blowout protection can be discussed in three basic
levels. Level one:training through formal courses that are infrequently offered by
industry and regulatory organizations, often at a regional or national level; level two:
the training that an Operator conducts on a more or less formal, or classroom, basis
with its drilling supervisors, drilling crews, and others who directly support its Hawaii
drilling operations; level three: Operators must have a program of drills that ensure
all personnel actually have 'hands-on' experience with the installed blowout prevention
equipment.
A number of organizations conduct training and certification in well control,
mainly directed toward the petroleum drilling industry. However, recent classes in the
specifics of geothermal well control have been held by a cooperative effort of the
Geothermal Resources Council and the National Geothermal Association, with funding
in part by the Federal Department of Energy. This course has been approved by the
Federal Minerals Management Service for training and certification in well control
subjects, and is recommended for supervisory and other drilling personnel, as an
indication of the level of specific well control training and experiences of these
personnel assigned to Hawaii drilling tasks. There are no plans to hold these formal
courses often, and most certainly not in concert w-1th specific drilling schedules of
individual projects. Therefore, each Operator and drilling contractor will need to
supplement the experiences of their supervisory personnel with direct team training
pointed toward developing an integrated effort for Hawaiian projects.
Operators should outline the formal (classroom) training proposed for drilling
personnel, with specific references to 'kick' recognition and blowout prevention,
including monitoring systems, equipment, and drilling procedures. A number of study
guides and references are available for these purposes; publications to be used should
be listed in drilling plans so that they can be reviewed by regulatory review
personnel. A list of specific references is not included in this Manual because these
30PTRAlNlNG(m(October 13, 1992 X-2
publications may become obsolete by newer editions. Appendix C, References, contains
documents and sources used in preparing this Manual, and should be consulted for
suitability to each drilling plan.
In addition to classroom training and periodic updates as drill crews may shift
or the drilling may enter new phases, blowout prevention drills should be conducted
on a regular (but unannounced) basis to provide further training, and to keep crews
focussed on the possibilities of well kicks, and blowouts. Crews should be familiar with
the equipment in use, and be able to properly and safely shut in the well before a
control problem becomes dangerous to personnel or the well itself. These drills should
be directed at well control and proper blowout prevention procedures in three basic
situations - when drilling ahead, when 'tripping out' of the well, and when the drill
pipe is out of the wellbore.
Other blowout prevention and general safety training - both informal and on
the-job situations, should be outlined in the drilling plan. Subjects covered should
include new employee orientation, visitor briefings and general safety training. Formal
training sessions, regular review training and blowout prevention drills held should
be noted in the daily reports of the drilling operation.
BOPTRAINING/RAP/October 13, 1992 X-3
DRAFT
X I. POST COMPLETION BLOWOUT PREVENTION
It is important to realize that blowout risks are not restricted to the initial
drilling and completion of a geothermal well. At a much lower incidence rate, blowouts
can occur at producing wells and at shut-in idle wells. Wellhead equipment should be
recognized as vulnerable to natural surface conditions and vandalism. The capacity,
integrity, and security of geothermal wellhead equipment are all the responsibility of
a production engineering expertise which is not within the scope of this Blowout
Prevention Manual.
Two areas of subsurface risks to casing string integrity in existing Hawaiian
geothermal wells should be noted. The corrosion potential of wellbore fluids, in both
the production and shut-in (static) modes should be identified. Baseline chemistry and
casing evaluation procedures should be established shortly after well completion. The
objectives here are to assure and prolong casing integrity, and to preclude any
blowout consequent to a casing failure due to corrosion. Wells that have been tested
or have produced high temperature fluids, and then are shut-in for periods of time,
particularly require regular and accurate monitoring of casing conditions. Temperature
decreases imposed by the active Hawaiian ground water regime can accelerate H2s corrosion in shallow casing strings in idle wells. Finally, the tt~w-n-risk of casing
failure in rift zone eruptions and earthquakes e't'~{sha11o~i"faUlt movernerits;'gf¢uhd. di:Sfuptio!i or'tptati9h.~lf$fllir~~l), should be recognized.~-the--by-wo~d-of·eoneel 1"1-t:o
W"e1lbo1 e!!.
Blowout prevention requirements durins remedial work, redrills, recompletions
and abandonments, in all geothermal wells, must be e-valuated and provided for by the
same process of consideration required in every new geothermal well drilling permit
proposal.
80P'CS!CCMPLE7:0N/ILD/August 13, 1992 Xl-1
DRAFT
X I I - BLOWOUT PREVENTION IN SLIMHOLES
INTRODUCTION
Deep drilling with slimhole (approximately 4-6 inch bit diameters) technology and
equipment has achieved major advances in the mining industry in the last several
decades. However, the mining drilling environment does not present pressure control
problems comparable to those encountered in petroleum and geothermal drilling. For
this reason, well control practices in slimholes were poorly understood until recently.
This hindered an expanding use of th~ technology. However, the technical and
economic advantages of slimholes have recently registered with several petroleum
companies; Amoco Production Company has particularly investigated the requirements
' of well control and blowout prevention in slimhole drilling. 1
KEY ATTRIBUTES
Much smaller volumes of drilling fluids are circulated in slimholes. Kicks of any
volume are of more consequence, and immediate detection of fluid entry, or lost
circulation, is critical. Quantitative electromagnetic flow meters are used to measure
drilling fluid entry and exit volumes at the wellhead. These flow meters are reliable
and accurate, measuring gains of one barrel or less as compared to pit gains of 15
barrels or more as frequent kick events in the standard drilling mode. Unfortunately,
the much greater size of this type of meter required for standard diameter wellbores
make them cost prohibitive. Another feature of importance is the high annular
pressure loss (AP L) incurred by drilling fluid circulation in slim holes. The higher
rotary speeds (RPM) used in slimholes also adds, wit!T the APL, a substantial increase
(overbalance) above the hydrostatic pressure of the drilling fluid on the borehole
while actively drilling or coring. This physical phenomena relates to the very smal~
annuli between drill tubulars and the rock wall. The high APL can be used
advantageously to effect a dynamic kill and control of formation fluid entry below
2,500-foot depths in slimhole by accelerating the pumping rate to maximum levels in
Well Control Methods and Practices in Small-Diameter Wellbores; D. J. Bode, et al Amoco Production Co., October 1989. (Available from the Society of Petroleum Engineers, P. 0. Box 833836, Richardson, Texas 75083-3836; Telephone 214-669-3377.)
BOPSOH/WLD/Ju1y 13, 1992 X I I -1
circulating out the intruding fluids. In summary, blow out prevention in slim holes
requires special training, precision flowmeters, real time data presentation and
dynamic kill proficiency. It is likely that additional slimhole drilling will be considered
in Hawaii geothermal exploration and development; Operators should carefully evaluate
the Amoco paper referenced when developing plans for these boreholes.
BCPSOH/WLD/Ju1y 13, 1992 X I I -2
• I
HAWAII GEOTHERMAL BLOWOUT PREVENTION MANUAL
APPENDIX A
MANUAL- REVIEW AND REVISIONS
DRAFT
APPENDIX A-
MANUAL REVIEW AND REVISION
Geothermal drilling experience in Hawaii, as of mid 1992, has been quite limited.
Only 14 deep geothermal boreholes had been drilled, and these were located on only
one prospective feature, the KERZ. Reasonable increases in geothermal drilling in the
KERZ, and perhaps other areas, can be anticipated. New operational and regulatory
experiences should accumulate in the next few years.
This Blowout Prevention Manual can best be accepted as a first edition. Ideally,
it should serve as a working reference for operators and regulators in a cooperative
approach to the achievement of blowout risk reduction.
It is recommended that this Manual be reviewed and revised within 5 years of
its date of issue by DLNR. Such a time interval seems ample for the collection of new
operating information and for a reasonable application of the blowout prevention
procedures recommended in the Manual. Frequent and informed discussion of blowout
prevention procedures between operators and regulators could prove to be one of the
most important consequences of the use of this Manual.
DLNR authorities might consider a workshop process as an appropriate element
of the review process. Both Hawaiian geothermal operators, and those working
elsewhere in similar volcanic domains, could join DLNR in a thorough evaluation of
blowout prevention in geothermal drilling. Such an invitational workshop might best
be conducted 6 to 8 months before the first revision of this Manual.
BOPREVISIONS-APPEND A/ILD/August 12 1992 1
HAWAII GEOTHERMAL BLOWOUT PREVENTION MANUAL
APPENDIX 8
ILLUSTRATIONS
'
HAWAII GEOTHERMAL DIVERTER STACK
Fi9ure I.
A 2M ANNULAR PREVENTER
FLOW TEE or BANJO BOX
API ARRANGEMENT SA
2000 PSI
5
HAWAII GEOTHERMAL FULL BOP STACK
FiQure 2.
ROTATING HEAD
I G l When usinQ air
-installed on top of ANNULAR PREVENTER
RAM PREVENTER
RAM PREVENTER
KILL 2"
API ARRANGEMENT RSRS RRA
MIN. 3000 PSI
A ANNULAR PREVENTER
VENT/BLOOIE 12''
BLIND RAM ..
Remotely operated .. V.ALVE
CHOKE 4"
PIPE RAM
DRAFT
FI<3LJRE 3
In Hawaii, where wellhead temperatures in excess of 600°F may occur, Operators
must consider the pressure derating of steel due to elevated temperatures when
selecting wellhead equipment. The table below, from the American Petr-oleum Institute
(API) Specification 6A, provides the recommended working temperatures for steel at
high temperatures; this table goes only to 650°F.
In addition to the steel in wellhead equipment, the temperatures found in
Hawaii far exceed the temperature ratings of elastomers found in most BOP equipment.
Operators often use all steel rams in ram type preventers for a more effective seal.
The API recognizes temperature ratings of elastomers up to 250°F, but some
manufacturers can now produce elastomers that are rated to 420°F.
BOPFIGURE 3 HEW/October 14, 1992 APPENDIX B, FIG 3 -1
RECOMMENDED WORKING PRESSURES AT ELEVATED TEMPERATURES
E.1 Pressure-Temperature Derating. The maxi~um working oressure ratings given in this section are apoiicable to steei parts of the wellhead she11 or pressure containing structure, such as bodies, bonnets, covers, end flanges, metallic ring gaskets, welding ends, bolts, and nuts for metal temperatures between 20F and 650F (-29 and 343°C). These ratings do not aoply to any non-metal~ic resilient seaiing materials or plastic sealing materials, as covered in Par. 1.4.4.
Maximum Working
Pressure, psi (Bar)
TABLE E.1 PRESSURE-TEMPERATURE RATINGS OF STEEL PARTS
(See Par. 1.2.4) (1 BAR : 100 kPa)
(See Fa-ewa-d fa- Explanati:m ri Units)
Temperature, F CO-c)
0
(-29 to 121) 300 (149) 350 ( 177) 400 (204)
2000 ( 138. 0) 1955 ( 134 . 8) 1905 (131.4) 1860 (128.2) 3000 (2D7. D) 2930 (202.0) 2880 ( 197. 2) 2785 (192.0)
5ooo* (345. D) 4980 (336. 5) 4765 (323.5) 4645 (320.3)
~net apply to 500l psi 6BX conn«tD!s
Maximum Working
Pressure, psi (Bar)
TABLE E.1-Continued PRESSURE-TEMPERATURE RATINGS OF STEEL PARTS
(See Par. 1.2.4) (1 BAR: 100 kPa)
Temperature, F ~-C)
500 (260) 550 (288) 600 (316) 650 (343)
1735 (119.6) 1635 ( 113. 7) 1540 (106.2) 1430 (93.6) 2605 (179.6) 2455 (169.3) 2310 ( 159. 3) 2145 (147.9)
4340 (299.2) 4090 (232. 0) 3850 (285.5) 3575 (246. 5)
450 (232)
1810 (124.8) 2715 (187.2)
4525 (312 .D)
BOPFIGURE 3 HEW/October 14, 1992 APPEND I X B, FIG 3 -2
HAWAII GEOTHERMAL BLOWOUT PREVENTION MANUAL
APPENDIX C
REFERENCES
AUTHOR: TITLE: API RECOMMENDED PRACTICES FOR SAFE DRILLING OF WELLS CONTAIN
PUBLISHER: API PUB_DATE: 1974
EDITION: PAGES:
ISBN: NOTES: API Amer. Petroleum Inst. RP 49
AUTHOR: TITLE: API RECOMMENDED PRACTICES FOR SAFE DRILLING OF WELLS CONTAIN
PUBLISHER: API PUB_DATE: 1974
EDITION: PAGES:
ISBN: NOTES: API Amer. Petroleum Inst. RP" 49
AUTHOR: TITLE:
PUBLISHER: AN APPLICANT GUIDE TO STATE PERMITS AND APPROVALS FOR LAND DPED/CZM
PUB_DATE: EDITION:
PAGES: 22 ISBN:
1986
NOTES: AND WATER USE AND DEVELOPMENT
AUTHOR: TITLE: BLOWOUT PREVENTION EQUIPMENT SYSTEMS FOR DRILLING WELLS
PUBLISHER: API PUB_DATE: 1984
EDITION: 2nd PAGES:
ISBN: NOTES: API-Amer. Petroleum Inst. RP 53
AUTHOR: TITLE: REGULATIONS AND RULES OF PRACTICE & PROCEDURE-GEOTHERMAL
PUBLISHER: Nevada PUB_DATE: 0
EDITION: PAGES:
ISBN: NOTES:
AUTHOR: TITLE: CAILIFORBNIA ADMINISTRATIVE CODE-Title 14, NATURAL RESOURCES
PUBLISHER: CA State PUB_DATE: 0
EDITION: PAGES:
ISBN: NOTES: chap.4, Sub-Chap. 4- State Wide Geothermal Re
AUTHOR: TITLE:
PUBLISHER: PUB_DATE:
EDITION:
RULES FOR GEOTHERMAL AND CABLE SYSTEM DEVELOPMENT PLANNING DLNR-DOWAL
1989
PAGES: 22 ISBN:
NOTES:
AUTHOR: TITLE:
PUBLISHER: PUB_DATE:
EDITION: PAGES:
ISBN: NOTES:
AUTHOR: TITLE:
PUBLISHER: PUB_DATE:
EDITION: PAGES:
ISBN: NOTES:
CHAPTER 185
PLANNING FOR DRILLING IN H2S ZONES PET EX
1978
44 0-88698-129-8
Golns.w.c. BLOWOUT PREVENTION Gulf Publ
0
214
PRACTICAL DRILLING TECHNOLOGY - VOL 1
AUTHOR: HALLMARK+ TITLE: OIL AND GAS BLOWOUT PREVENTION IN CALIFORNIA
PUBLISHER: CA DOG PUB_DATE: 1978
EDITION: Second PAGES: 65
ISBN: NOTES: Manual #M07
AUTHOR: Hills, A.+ TITLE: OVERVIEW OF STATUS, DEVELOPMENT APPROACH AND FINANCIAL FEASI
PUBLISHER: DBED PUB_DATE: 1988
EDITION: PAGES: 52
ISBN: NOTES:
AUTHOR: R.Thomas+ TITLE: INDEPENDEN"' ~~TECHNICAL INVESTIGATION 01:-·~GV UNPLANNED STEAM R
PUBLISHER: PUB_DATE: 1991
EDITION: PAGES: 22+
ISBN: NOTES:
AUTHOR: Rowley, J. TITLE: GEOTHERMAL STANDARDS .. A DECADE OF LEADERSHIP CONTINUES
PUBLISHER: GRC PUB_DATE: 1991
EDITION: Decemb PAGES: 4
ISBN: NOTES: Article, GRC Bulletin
AUTHOR: Sumida, G. TITLE: ALTERNATIVE APPROACHES TO THE LEGAL, INSTITUTIONAL AND FIN-
PUBLISHER: DPED PUB_DATE: 1986
EDITION: PAGES: 17
ISBN: NOTES: ANCIAL ASPECTS OF DEVELOPING AN INTER-ISLAND
HAWAII GEOTHERMAL BLOWOUT PREVENTION MANUAL
APPENDIX D
GLOSSARY
Al?FEN'D I X D
GLOSS.AR.Y
A
accumulator n: 1. a vessel or tank that receives and temporarily stores a liquid used in a continuous process in a gas plant. 2. on a drilling rig, the storage device for nitrogen-pressurized hydraulic fluid, which is used in closing the blowout preventers.
annular blowout preventer n: a large valve, usually installed above the ram preventers, that forms a seal in the annular space between the pipe or 'k$llfj and wellbore or, if no pipe is present, on the wellbore itself. Compared to a ram blowout preventer.
API abbr: American Petroleum Institute
B
BHP abbr: bottom hole pressure.
BHT abbr: bottom hole temperature. ~ v;;d<
blowout n; A blowout is an uncontrolled flow of formation fluids or gas rom a well bore into the atmosphere or into lower pressure subsurface zones. A occurs when formation pressure exceeds the pressure applied by the column of drilling fluid) -:::L"P q \!(; cl<.. ~ '5 "" o.t- c. ~ -lv o t \e oP , j -1- ~ H \""e Hd ~ · • "' a. t=- ( et.D ooc .... .+ .
BOP equipment n: The entire array of equipment installed at the well to detect and control kicks and prevent blowouts. It includes the BOP stack, its actuating system, kill and choke lines, kelly cocks, safety valves and all other auxiliary equipment and monitoring devices.
bottom hole temperature n: The temperature of the fluids at the bottom of the hole. While drilling, these temperatures may be measured by minimum reading temperature devices, which only record temperatures above a .designed minimum, and may not provide an accurate bottom hole temperature. Bottom hole temperature readings should be recorded after a period of fluids circulation at a particular depth, in order to stabilize the reading.
blowout preventer n: the equipment installed at the wellhead to prevent atn:ontrolthe escape ofU .. J jpressure -~~'Jl~-~Heither in the annular space between the casing and drill pipe or in an open hole (i.e., hole with no drill pipe) during drilling and completion operations. The blowout preventer is located beneath the rig at the
1 Rotary Dri 11 ing BLOWOUT PREVENTION Unit I I I, Lesson 3; Petroleum Extension Service, The University of Texas at Austin, Austin Texas, in cooperation with the International Association of Drilling Contractors, Houston Texas. 1980; 97 pages.
BOPGLOSSARY/RAP/Auqust 14, 1992 1
surface See annular blowout preventer and ram blowout preventer.
BOP abbr: blowout preventer
BOP stack n: The array of preventers, spools, valves and all other equipment attached to the well head while drilling.
borehole n: the wellbore; the hole made by drilling or boring.
~k c
cap rock n~ 1. ridatl'ii:el:Y''impermeable rock overlying a geothermal reservoir that tends to preven~migration of formation fluids out of the reservoir.
casing n: steel pipe placed in a geothermal well as drilling pY09E'eBSeet advances. to prevent the wall of the hole from cavi.r}.g during drilli.ng,'[J.O.~:pro~':potable wat$t toni$~ and to provide a means of extracting steam or hot water if the well is productive.
cellar n: a pit in the ground to provide additional height between the rig floor and the wellhead, ·)m'a to accommodate the installation of blowout preventers, rathole, mousehole, and so forth. It also collects drainage water and other fluids for subsequent disposal.
cementing n: the application of a liquid slurry of cement and water to various points inside or outside the casing.
conductor pipe n: 1. a short string of large-diameter casing used to keep the top of the wellbore open and to provide a means of conveying the up-flowing drilling fluid from the wellbore to the mud pit. 2. a boot.
CSO abbr: complete shut off (of a geothermal well)
D
diverter n: a system used to control well blowouts~x-tll•lrL,..:1i~naril.litigL:at relatively shallow depths by directing the flow away from the rig. The diverter is part of the BOP Stack that includes an annular preventer with a vent line beneath. A valve on the vent line is installed so that it is opened whenever the 4ii••'~••-a:ririUlar preventer is closed.
drill collar n: a heavy, thick-walled tube, usually steel, used between the drill pipe and the bit in the drill stem to provide a pendulous effect to the drill stem.
drilling fluid n: a circulating fluid, one function of which is to force cuttings out of the wellbore and to the surface. While a mixture of clay, water, and other chemical additives is the most common drilling fluid, wells can also be drilled using air, gas, or water as the drilling fluid. Also called circulating fluid. See mud.
drillin s ool n: . 1 •• 1" a s acer m~tu?ljjiiilU)I~:.th*-' wellhead 9 P llitJII!!I_ i!!L 4&-, .. t .. M,;... P A4!4.. ..... ........ . equipment. It provides room between various wellhead devices (as the blowout preventers) so that devices in the drill stem (as a tool joint) can be suspended in it.
drill pipe n: the heavy seamless tubing used to rotate the bit and circulate the drilling
BOPGLOSSARY/RAP/Auqust 14, 1992 2
fluid. Joints of pipe are coupled together by means of tool joints.
drill string n: the column, or string, of drill pipe with attached tool joints that transmits fluid and rotational power from the kelly to the drill collars and bit. Often, the term is loosely applied to include both drill pipe and drill collars. Compare drill stem.
E
electric well log n: a record of certain electrical characteristics of formations traversed by the her~ dt1lt'bit, made to identify the formations, determine the nature and amount of fluids they contain, and estimate their depth. Also called an electric log or electric survey.
F
flange n: a projecting rim or edge (as on pipe fittings and opening in pumps and vessels), usually drilled with holes to allow bolting to other flanged fittings.
formation pressure n: the force exerted by fluids in a formation, recorded in the hole at the level of the formation with the well shut in. Also called reservoir pressure or shut-in bottom-hole pressure. See reservoir pressure.
J
joint n: a single length of drill pipe or of drill collar, casing, or tubing, that has threaded connections at both ends. Several joints, screwed together, constitute a stand of pipe.
K
kelly n: the heavy steel member, four-or six-sided, suspended from the swivel through the rotary table and connected to the topmost joint of drill pipe to turn the drill stem as the rotary table turns. It has a bored passageway that permits fluid to be circulated into the drill stem and up the annulus, or vice versa.
kelly cock n: a valve installed between the swivel and the kelly. When a high-pressure backflow begins inside the drill stem, the valve is closed to keep pressure off the swivel and rotary hose. See kelly.
kick n: an entry of water, gas, or other formation-fluid into the wellbore. It occurs because the 1~ressure exerted by the column of drilling fluid is not great enough to overcome the pressure exerted by the fluids in the formation drilled. If prompt actiDn is not taken to control the kick or kill the well, a blowout will occur.
kill linen: a high pressure line that connects the mud pump and the well and through which heavy drilling fluid can be pumped into the well to control a threatened blowout.
L
L.C. abbr: lost circulation
log n: a systematic recording of data, as from the driller's log, mud log, electrical well log, or radioactivity log. Many different logs are run in wells to obtain various characteristics of downhole formations. v: to record data.
BOPGLOSSARY/RAP/August 14, 1992 3
lost circulation n: the loss of quantities of whole mud to a formation, usually in cavernous, fissured, or c:earseb-:lillilUY permeable beds, evidenced by the complete or partial failure of the mud to return to the surface as it is being circulated in the hole. Lost circulation can lead to a Xllilf/ W~li~ if 'riot eohttb1l.Jid~ ea~lei~'bj"if'blo wout. 'LOSt dtthi!aftiljdt.A.Cdy~:riatie«t$-aftd;-i:ft-geft'M"M,--red\:!ce the efficiency of the drilling operation. It is also called lost returns.
M
manifold n: an accessory system of piping to a main p1pmg system (or another conductor) that serves to divide a flow into several parts, to combine several flows into one, or to reroute a flow to any one of several possible destinations.
mud n: the liquid circulated through the wellbore during rotary drilling and workover operations. In addition to its function of bringing cuttings to the surface, drilling mud cools and lubricates the bit and drill stem, protects against blowouts by holding back subsurface pressures;~-~~revent loss of fluids to the formation. Although it was originally a suspension of earth solids (especially clays) in water, the mud used in modern drilling operations is a more complex, three-phase mixture of liquids, reactive solids, and inert solids. The liquid phase may be fresh water, and may contain one or more conditioners. See drilling fluid.
mud logging n: the recording of information derived from examination and analysis of formation cuttings S.U.jadid]ii~th4!l•tM'IIsa, ..... ,....,mud:~~-d .circulated out of the hole. A portion of the muci is diverted through a gas-detecting device. Cuttings brought up by the mud are examined to detect potential geothermal production intervals. Mud logging is often carried out in a portable laboratory set up _,e.~the well. .
mud pits n pl: a series of open tanks, usually made of steel plates, through which the drilling mud is cycled to allow sand and sediments to settle out. Additives are mixed with the mud in the pits, and the fluid is temporarily stored there before being pumped back into the well. Modern rotary drilling rigs are generally provided with three or more pits, usually fabricated steel tanks fitted with built-in piping, valves, and mud agitators. Mud pits are also called shaker pits, settling pits, and suction pits, depending on their main purpose. Also called mud tanks.
mud weight n: a measure of the density of a drilling fluid expressed as pounds p~r gallon (ppg), pounds per cubic foot (lb/ft3), or kilograms per cubic meter (kg/mJ). Mud weight is directly related to the amount of pressure the column of drilling mud exerts at the bottom of the hole.
p
permeability n: 1. a measure of the ease with which fluids can flow through a porous rock. 2. the fluid conductivity of a porous medium. 3. the ability of a fluid to flow within the interconnected network of a porous medium.
pipe ram n: a sealing component for a blowout preventer that closes the annular space between the pipe and the blowout preventer or wellhead. See and blowout preventer.
pit-level indicator n: one of a series of devices that continuously monitors the level of the drilling mud in the mud pits. The indicator usually consists of float devices in the mud pits that sense the mud level and transmit data to a recording and alarm
BOPGLOSSARY/RAP/Auqust 14, 1992 4
device (called pit-volume recorder) mounted near the driller's position on the rig float". If the mud level drops too low or rises too high, the alarm sounds to warn the driller that action may be necessary to control lost circulation or to prevent a blowout.
pounds per gallon n: a measure of the density of a fluid (as drilling mud).
ppg abbr: pounds per gallon.
pressure n: the force that a fluid (liquid or gas) exerts when it is in some way confined within a vessel, pipe, hole in the ground, and so forth, such as that exerted against the inner wall of a tank or that exerted on the bottom of the wellbore by drilling mud. Pressure is often expressed in terms of force per unit of area, as pounds per square inch (psi).
R
ram n: the closing and sealing component on a blowout preventer. One of three types - blind, pipe, or shear - may be installed in several preventers mounted in a stack on top of the wellbore. Blind rams, when closed, form a seal on a hole that has no drill pipe in it; pipe rams, when closed, seal around the pipe; shear rams cut through drill pipe and then form a seal.
ram blowout preventer n: a blowout preventer that uses rams to seal off pressure on a d~i'P'fhch:HaYop~;lhole ... .._. .. .,.,......_._._, __ ..,_., It is also called a ram pre venter. See blowout preventer and ram.
reservoir pressure n: the pressure in a reservoir under normal conditions.
s
stack n: a vertical pile of blowout-prevention equipment. Also called preventer stack. See blowout preventer. v: to allow a geothermal well to flow to the atmosphere, usually without mufflers or abatement.
surface pipe n: the first string of casing (after the conductor pipe) that is set in a well, varying in length from a few hundred to several thousand feet. Compare conductor pipe.
T
trip n: the operation of hoisting the drill stem from_and returning it to the wellbore. v: shortened form of make a trip.
w
wellbore n: a borehole; the hole drilled by the bit. A wellbore may have casing in it or may be open (Le., uncased), or a portion of it may be cased and a portion of it may be open. Also called borehole or hole.
wellhead n: the equipment installed at the surface of the wellbore. A wellhead includes such equipment as the casinghead and tubing head. adj: pertaining to the wellhead (as wellhead pressure).
BOPGLOSSARY/RAP/August 14, 1992 5
DRAFT
APPENDIX D
GLOSSARY
A
accumulator n: 1. on a drilling rig, the storage device for nitrogen-pressurized hydraulic fluid, which is used in closing the blowout preventers.
annular blowout preventer n: a large valve, usually installed above the ram preventers, that forms a seal in the annular space between the pipe ~ifn:~~Y:i::and wellbore or, if no pipe is present, on the wellbore itself.
API ahhr: American Petroleum Institute
B
BHP ahhr: bottom hole pressure.
BHT ahhr: bottom hole temperature.
blowout n; A blowout is an uncontrolled flow of formation fluids or gas from a well bore into the atmosphere or into lower pressure subsurface zones. A blowout occurs when formation pressure exceeds the pressure applied by the column of drilling fluid.l
BOP equipment n: The entire array of equipment installed at the well to detect and control kicks and prevent blowouts. It includes the BOP stack, its actuating system, kill and choke lines, kelly cocks, safety valves and all other auxiliary equipment and monitoring devices.
bottom hole temperature n: The temperature of the fluids at the bottom of the hole. While drilling, these temperatures may be measured by minimum reading temperature devices, which only record temperatures above a designed minimum, and may not provide an accurate bottom hole temperature. Bottom hole temperature readings should be recorded after a period of fluids circulation at a particular depth, in order to stabilize the reading.
blowout preventer n: the equipment installed at the wellhead to prevent ~n¢P~i*-Pf:the escape of ~:li.!11pressure ~mfi~P.~\~N~~f:neither in the annular space between the casing and drill pipe or in an open hole (i.e., hole with no drill pipe) during drilling and completion operations. The blowout preventer is located beneath the rig at the surface See annular blowout preventer and ram blowout preventer.
1 Rotary Dri 11 ing BLOWOUT PREVENTION Unit I I I, Lesson 3; Petroleum Extension Service, The University of Texas at Austin, Austin Texas, in cooperation with the International Association of Drilling Contractors, Houston Texas. 1980; 97 pages.
BOPGLOSSARY/RAP/August 14, 1992 Appendix D-1
BOP abbr: blowout preventer
BOP stack n: The array of preventers/ spools1 valves and all other equipment attached to the well head while drilling.
borehole n: the wellbore; the hole made by drilling or boring.
c
casing n. steel pipe1 cemented in the wellbore to protect it against external fluids and rock conditions1 and to facilitate the reliable and safe production of geothermal fluids from the well.
cap rock n: 1. !t,~~~V~tlimpermeable rock overlying a geothermal reservoir that tends to prevent migration of formation fluids out of the reservoir.
cellar n: a pit in the ground to provide additional height between the rig floor and the wellheadnn~*-~ to accommodate the installation of blowout preventers/ rathole/ mousehole1 and so forth. It also collects drainage water and other fluids for subsequent disposal.
cementing n: the application of a liquid slurry of cement and water to various points inside or outside the casing.
~~p~:~m;:~:~:~g::~~~@!!q~lt~!i~4i!!qqij~m~~t!a~~::~~P9~~~!~$.1!~4iitP~~*~~ ~ :~~r::~~ljljti.ii,«f.~
conductor-pipe n: 1. a short string of large-diameter casing used to keep the top of the wellbore open and to provide a means of conveying the up-flowing drilling fluid from the wellbore to the mud pit. 2. a boot.
CSO abbr: complete shut off.~a-g~hertnai-welij
D
diverter n: a system used to control well blowouts efteet::~:nte!oed-;#ll!,i~mlf::4.~g;gat relatively shallow depths by directing the flow away from the rig. The diverter is part of the BOP stack that includes an annular preventer with a vent line beneath. A valve on the vent line is installed so that it is opened whenever the di:verler~ij.,~ preventer is closed.
drill collar n: a heavy 1 thick-walled tube1 usually steel1 used between the drill pipe and the bit in the drill stem to provide a pendulous effect to the drill stem.
BOPGLOSSARY/RAP/AUCJUSt 14, 1992 Appendix D-2
drilling fluid n: a circulating fluid, one function of which is to force cuttings out of the wellbore and to the surface. While a mixture of clay, water, and other chemical additives is the most common drilling fluid, wells can also be drilled using air, gas, or water as the drilling fluid. Also called circulating fluid. See mud.
drilling spool n: aft--accessory-~ti--as-a spacer in--i!~4T~#F~D#D!.~H:wellhead equipment. It provides room between various wellhead devices (as the blowout preventers) so that devices in the drill stem (as a tool joint) can be suspended in it.
drill pipe n: the heavy seamless tubing used to rotate the bit and circulate the drilling fluid. Joints of pipe are coupled together by means of tool joints.
drill string n: the column, or string, of drill pipe with attached tool joints that transmits fluid and rotational power from the kelly to the drill collars and bit. Often, the term is loosely applied to include both drill pipe and drill collars. Compare drill stem.
F
:Bange n: a projecting rim or edge (as on pipe fittings and opening in pumps and vessels}, usually drilled with holes to allow bolting to other flanged fittings.
formation pressure n: the force exerted by fluids in a formation, recorded in the hole at the level of the formation with the well shut in. Also called reservoir pressure or shut-in bottom-hole pressure. See reservoir pressure.
J
jai.nt n: a single length of drill pipe or of drill collar, casing, or tubing, that has threaded connections at both ends. Several joints, screwed together, constitute a stand of pipe.
K
kelly n: the heavy steel member, four-or six-sided, suspended from the swivel through the rotary table and connected to the topmost joint of drill pipe to turn the drill stem as the rotary table turns. It has a bored passageway that permits fluid to be circulated into the drill stem and up the annulus, or vice versa.
kelly cock n: a valve installed between the swivel and the kelly. When a high-pressure backflow begins inside the drill stem, the valve is closed to keep pressure off the swivel and rotary hose. See kelly.
kick n: an entry of water, gas, or other formation fluid into the wellbore. It occurs because the 'ijj~~C,l~~ipressure exerted by the column of drilling fluid is not great enough to overcome the pressure exerted by the fluids in the formation drilled. If prompt action is not taken to control the kick or kill the well, a blowout will occur.
kill linen: a high pressure line that connects the mud pump and the well and through which heavy drilling fluid can be pumped into the well to control a threatened blowout.
L
L.C. abbr: lost circulation
BOPGLOSSARY/RAP/l119ust 14, 1992 Appendix D-3
log n: a systematic recording of data, as from the driller's log, mud log, electrical well log, or radioactivity log. Many different logs are run in wells to obtain various characteristics of downhole formations. v: to record data.
lost circulat:iDn n: the loss of quantities of ~if:~4~J~:t\ii.i~~m*'l-whele-ml1d to a formation, usually in cavernous, fissured, or eoarsel:y-'~9,ffifit\Permeable beds, evidenced by the complete or partial failure of the fliddiito return to the surface as it is being circulated · th h 1 L st · ul ... ~- ····~········d··· to ,..;z:;.;.,..;:::::···,...:a.w"''''"'"'"'"'ia.'''' .. , .. ~.,.;.;;.n.;;.;a='" ....... ",,...,.:;Ji"1',.. m e o e. o Cl.I'C ai..UJn can ea a ~'"Jiol:;:::1h~aq.::a::b~.n.<::CO~~Ji11ft'. :;::c.ati:::.a..~::w.
~!iblowou~~;;~:~~~:ts:~~~~~·~·~ift~ener1li~~·re~·th~eiener·:.o£ ehe-drilling--operatiorr.--R-i:s--also-ea:H.ed-lost:-retttrns:
M
manifold n: an accessory system of piping to a main p1pmg system (or another conductor) that serves to divide a flow into several parts, to combine several flows into one, or to reroute a flow to any one of several pnssi.hle destinations.
mud n: the liquid circulated through the wellbore during rotary drilling and workover operations. In addition to its function of bringing cuttings to the surface, drilling mud cools and lubricates the bit and drill stem, protects against blowouts by holding back subsurface pressureS.;':inClF-to-prevent loss of fluids to the formation. Although it was originally a suspensiDn.of'.earth solids (especially clays) in water, the mud used in modern drilling operations is a more complex, three-phase mixture of liquids, reactive solids, and inert solids. The liquid phase may be fresh water, and may contain one or more conditioners. See drilling fluid.
mud logging n: the recording of information derived from examination and analysis of formation cuttings ~iiij~~:~~~j)made--by-the--mt-a~~~lP~H¥A1iP!9.~f-Ji~),ll~~ circulated out of the hole. A portion of the mud is diverted through a gas-detecting device. Cuttings brought up by the mud are examined to detect potential geothermal production intervals. Mud logging is often carried out in a portable laboratory set up ~~ti~:jat-the well.
mud pits n pl: a series of open tanks, usually made of steel plates, through which the drilling mud is cycled to allow sand and sediments to settle out. Additives are mixed with the mud in the pits, and the fluid is temporarily stored there before being pumped back into the well. Modern rotary drilling rigs are generally provided with three or more pits, usually fabricated steel tanks fitted with built-in piping, valves, and mud agitators. Mud pits are also called shaker pits, settling pits, and suction pits, depending on their main purpose. Also called mud tanks.
mud weight n: a measure of the density of a drilling fluid expressed as pounds per gallon (ppg), pounds per cubic foot (lb/ft3), or kilograms per cubic meter (kg/m3). Mud weight is directly related to the amount of pressure the column of drilling mud exerts at the bottom of the hole.
p
permeability n: 1. a measure of the ease with which fluids can flow through a porous rock. 2. the fluid conductivity of a porous medium. 3. the ability of a fluid to flow within the interconnected per-e-network of a porous medium.
pipe ram n: a sealing component for a blowout preventer that closes the annular space between the pipe and the blowout preventer or wellhead. See and blowout preventer.
BOPGLOSSARY/RAP/August 14, 1992 Appendix D-4
pit-level indicator n: one of a series of devices that continuously monitors the level of the drilling mud in the mud pits. The indicator usually consists of float devices in the mud pits that sense the mud level and transmit data to a recording and alarm device (called pit-volume recorder) mounted near the driller's position on the rig floor. If the mud level drops too low or rises too high, the alarm sounds to warn the driller that action may be necessary to control lost circulation or to prevent a blowout.
pounds per gallon n: a measure of the density of a fluid (as drilling mud).
ppg abbr: pounds per gallon.
pressure n: the force that a fluid (liquid or gas) exerts when it is in some way confined within a vessel, pipe, hole in the ground, and so forth, such as that exerted against the inner wall of a tank or that exerted on the bottom of the wellbore by drilling mud. Pressure is often expressed in terms of force per unit of area, as pounds per square inch (psi).
R
ram n: the closing and sealing component on a blowout preventer. One of three types - blind, pipe, or shear - may be installed in several preventers mounted in a stack on top of the wellbore. Blind rams, when closed, form a seal on a hole that has no drill pipe in it; pipe rams, when closed, seal around the pipe; shear rams cut through drill pipe and then form a seal.
ram blowout preventer n: a blowout preventer that uses rams to seal off pressure on a 4.~i.P:'~~l¢, .. ~j:j~i.)i*"~j:».:::~n~;;hole--that:-is-"With-or-wi.t:hout-pipe. It is also called a ram preventer. See blowout preventer and ram.
reservoir pressure n: the pressure in a reservoir under normal conditions.
s
sl:aek-n~a-ve~"'lrile-c£-Nowout--prevention-equi-pment.--~eal:led-~-staek-: See-blowout-preventer-:-~-to--Mlow-e;~hennal weil-to-Bow-to~1!1t~:here1~:r witho11~-lfttlftlers--or-~
surface ~~-pipe n: the first string of ~:jj!i.P#Uea!Sin9-(after the conductor-pipe) that is set in a well, varying in length from a few hundred to several thousand feet. eom:pM"e'-eoftdlietor-pipe:
T
trip n: the operation of hoisting the drill stem from and returning it to the wellbore. v: shortened form of make a trip.
w
wellbore n: a borehole; the hole drilled by the bit. A wellbore may have casing in it or may be open (i.e., uncased), or a portion of it may be cased and a portion of it may be open. Also called borehole or hole.
BOPGLOSSARY/RAP/Auqust 14, 1992 Appendix D-5
wellhead n: the equipment installed at the surface of the wellbore. A wellhead includes such equipment as the casinghead and tubing head. adj: pertaining to the wellhead (as wellhead pressure).
BOPGLOSSARY/RAP/A119ust 14, 1992 Appendix D-6
R- A- PATTERSON & ASSOCIATES
~at~ September 25 1 1992
TO: Jonathan Flores/ Bill D'Olierr Herb Wheeler
SUBJECT: DRAFT BOP MANUAL
The enclosed material is a "redline/strikeout" revision to the draft BOP Manual. It has been marked with a ~t:r±keotlt to show DOWALD recommended deletions and with a redTirie indication to show additions. Minor typos, where noted, have been corrected without marking. Sections without DOWALD notations are not included.
Please review the documents for changes and agreement with the DOWALD comments. If any of the comments or markings are not clear 1 please call me. All of these marked changes can be made with one command on the word processor/ after any further changes are made following your review.
As discussed with .Jon Flores on 9/23, DOWALD's intention is to send copies to the at least some of the list of reviewers that we provided. After this round of review/comment, we would then produce the final version.
enclosure
LNRMEM 16/RAP
September 23,1992
TO: M. Tagomori and G. Akita
FROM: Jonathan Florez
SUBJECT: Progress of Hawaii Blowout Prevention Manual and Geothermal Drilling Guide
On September 23, 1992, I met with Ralph Patterson of Patterson & Associates to review and discuss DOWALD's edit requests for the first draft of the Hawaii Blowout Prevention Manual. Mr.Patterson agreed that the edit requests were valid, and he will now produce a copy showing the DLNR deletions and additions, which will be sent to Bill D'Olier and Herbert Wheeler (the principal authors of the manual), and DOWALD early next week for further review. Mr. Patterson will have clean corrected draft copies available for the suggested list of geothermal consultant/contractors in middle to late October, 1992.
Included in the attached packet are:
1) R. A. Patterson's August - September invoice
2) R. A. Patterson's Activity Report
3) DLNR mark-up copy of the Hawaii Blowout Prevention Manual
4) R. A. Patterson's Draft copy of the Table of Contents for the Hawaii Geothermal Drilling Guide
R. A. PATTERSON & ASSOCIATES
MEr:--10RAND'UM Date: September 22, 1992
TO: Manabu Tagamori-DOWALD
SUBJECT: Activity report - Contract RCUH #4361021
SUMMARY - 16 AUGUST - 15 SEPTEMBER
During the period of this report, activities consisted of:
-Shifting attention to completion of the review draft of the Drilling Guide. A copy if the revised Table of Contents for this document is enclosed.
- Forwarding of a suggested listing of reviewers for the BOP Manual draft.
- We have scheduled a visit to Hawaii by Messrs. D'Olier and Wheeler for a review meeting and discussion on OCTOBER 20, 1992. (Reservations were made to take advantage of the low air fares available in June)
PROBLEMS ENCOUNTERED
No specific problems have been encountered, either in the availability of resource information, or in the scheduling of the work.
enclosures
DLKR PROGRESS 07/RAP September 22, 1992
1
HAWAII GEOTHERMAL DRILLING GUIDE
DRAFT
TABLE OF CONTENTS (Revised: 4 September 1992/WLD)
I. INTRODUCTION WLD/RAP
A. Objectives of the Guide • Describe key concerns and issues of drilling as critical first
task to develop Hawaii's geothermal assets. • State the purpose: to assist developers, regulators and public
as a supplement to State geothermal drilling regulations. • Compare geothermal potential to Hawaii's ground water
resource; water well drilling has provided an incalculable pub lie benefit.
• Promote safe and least obtrusive drilling practices to contribute to optimal use of Hawaii's geothermal resources.
B. Geothermal historical summary
II. SCOPE
• Hawaii's knowledge of volcanic activity, culminating in King's realization of its energy potential through his inquiries to Thomas Edison regarding volcano's use for electricity.
• Hawaii Thermal Power Company's first holes in the KERZ -early 1960's.
• HGP-A project of UH/State/County; 1976 discovery well; >7 years of production of electricity (82-90); purchase of drill rig and early exploration by local firm - GEDCO.
• Recent drilling on Hawaii State leases ('80-'92); 30 MW plant built and tested for power delivery to HELCO - 1992.
RAP
A. Key Information Sources • KERZ drilling to date - > 14 wells/SOH; multiple operators. • Geothermal industry literature; selected industry experiences. • Drilling contractors, qualified in the geothermal sector.
B. Brief on contents and organization of the Guide • Guide's relationship to Chap 183 - DLNR Regulations for
Geothermal Drilling; indicate expected revision to these Regs.
Ill. PERMITTING HAWAII GEOTHERMAL WELLS RAP
A. Introduction B. Approval Process c. State and County Permits
DRILLING GUIDE CONTENTS/September 23, 1992 1
IV. GENERAL REQUIREMENTS FOR DRILLING OPERATORS ALL
A. Strong Operator needed; in experience, commitment and financing. B. Highest quality professionals needed to manage, supervise and execute drilling plans and operations. C. Careful selection of drilling contractor: quality of supervision, crews, equipment and geothermal drilling experience; costs a secondary element. D. Capacity to identify and manage difficult logistics/support services from distant sources.
V. GEOTHERMAL DRILLING ENVIRONMENT WLD
A. Active volcanism: basis of the geothermal resource. • Rift's magma transport function and subsurface heat. • Rift zone summary of geology (lava flow sequence and dikes),
hydrology, structure, seismicity, etc. • Vertical/directional drilling not difficult, but costly.
B. Subsurface conditions and hazards • High temperature ranges; consequent high fluid pressures. • Large torsional faults/fractures; entry and blowout risks. • Weak, near surface volcanics; shallow cementing problems;
possible lava tubes/consequences, ground disruptions. • H2s gas in the geothermal zones: safety requirements for the
crews, mitigation for the public. C. Drillsite Selection Criteria
• Elevated drillsites to offset surface lava flow risks. • Multiple wellhead pads - better defended from lava flows,
total land use considerations. • Occasional proximity to residential areas will raise visibility
and awareness of emissions and noise mitigation requirements. D. Summary
• Probable wellfield scene; clustered wellheads to reduce roads and powerline/piping grid.
• Optimal use of every well, of directional drilling and recompletion options to minimize total well count.
VI. GEOTHERMAL WELL PLANNING HEW/WLD
A. Introduction and Well Planning Objectives
B. Drilling targets and well types
C. Casing design and cementing; surface, intermediate, production casing
D. Drilling fluid options/uses; broad range and switching capacity
E. Drilling monitoring and blowout prevention
F. Well completion requirements; production, injection service, liners, hang-down strings, wellhead equipment grades
G. Safety issues, precautions, crew training
DRILLING GUIDE CONTENTS/September 23, 1992 2
VII. THE DRILLING PROGRAM HEW/RAP
A. Criteria/content for the written document - as attachment to drilling permit application given to DLNR. (study/compare PGV KS-9 & True KA3-1 documents) ·
B. Explain drilling program as 1. Product of a creditable well planning process. 2. The mutually accepted understanding, between Operator and DLNR, of the well construction process. 3. The baseline reference from which all required changes, in actual drilling conditions encountered, will be derived.
VI I I. WELL FLOW TESTING WLD
A. Rational for testing following well completion - safety issues
B. Water injection with wellbore temperature surveys for permeability identity.
C. Thermal recovery and wellbore heat up by bleed flow
D. Vertical venting, full flow to clean fluids for safer, continuous long flow test interval
E. Long flow mode; identify production capacity and parameters; sample all fluid components; mitigate all H2s emissions
F. Step rate flow for well deliverability plot and plant design input
G. Well shut in and pressures build up
IX. SLIMHOLE DRILLING OPTION WLD
A. Summary of SOH program in KERZ; attributes in Hawaii
B. Cite the potential of this technology for exploration, development step out wells, monitoring, and scientific objectives
C. Caution re: blowout risks; cite available special BOP equipment, procedures and skills required.
x. DRILLING DOCUMENTATION AND REPORTING ALL
A. Daily tour reports and special entries thereon
B. Well drilling history and well completion reports
C. Other documents, if appropriate
D. Operator - Regulator interface during drilling operations (Guide needs to point to necessity of good Operator-Regulator communications on drilling upsets and changes that will occur. Precise verbal communications, brief meetings on specific issues/problems, are invaluable tools when hole conditions force departures from the Drilling Plan.)
DRILLING GUIDE CONTENTS/September 23, 1992 3
R- A- PATTERSON & ASSOCIATES
Date: August 24, 1992
TO: Manabu Tagamori-DOWALD
SUBJECT: Activity report - Contract RCUH #4361021
SUMMARY - 16 JULY - 15 AUGUST
During the period, activities consisted of:
-Completion of the draft of the review draft of the BOP Manual, two copies of which are enclosed.
- We will present a suggested listing of reviewers for this draft under separate cover.
- We wi 11 be seeking cooperation to have the BOP Manual review completed by the first of October, and have scheduled a visit to Hawaii by Messrs. D'Olier and Wheeler for a review meeting and discussion on OCTOBER 20, 1992. (Reservations were made to take advantage of the low air fares available in June)
PROBLEMS ENCOUNTERED
No specific problems have been encountered, either in the availability of resource information, or in the scheduling of the work.
enclosures
DLHR PROGRESS 06/RAP August 24, 1992
1
HAWAI ~-~EOTHERMAL BLOWOUT PREVENTl6N MANUAL DRAFT
TABLE OF CONTENTS
(Revised: May 29, 1992/RAP)
__ I, INTRODUCTION AND SUMMARY
A. OBJECTIVES (a Statement of Purposes- with same sample concepts)
1 . B 1 owout Prevention as it can be best practiced in Hawaii, for safe drilling/ completion of all wells required in exploration & development.
2. One document to guide both operators and State regulators to determine, approve and use Blowout Prevention requirements appropriate to each dr i 11 i ng propos a 1 . Manu a 1 is intended to supplement regulations and to promote the use of an informed flexibility in Blowout Prevention practice, especially when modifications are required by drilling condition changes.
B. SCOPE (of Manual's contents)
1. Key information sources 2. KERZ Drilling to date 3. GT dri 11 ing in other
volcanic domains 4. Specific publications and
selected references C. Geothermal well types
1. Exploration 2. Production 3. Injection 4. SOH's 5. Vertical/deviated bores 6. Etc.
D. Organization of Manual Successful blowout prevention is a matrix of
1. Risk analyses 2. Procedures 3. Equipment
E. Hawaii situation Limited drilling experiences (14 KERZ wells to date) NOTE: Manual should became a basic working tool to all parties at interest. Expected1y, a large, we11 infonned group wi 11 contribute to a revision within five years.
F. Permitting Hawaii Geotherma 1 We 11 s 1. DLNR Admin. Rules, Chap 183 2. Other State permits 3. County permits
G. Resource Management and Safety
H. KERZ Drilling Experience
__ I 1 __ • GEOLOGY AND DRILLING RISK ANALYSIS A. SLITlllary
1. KERZ drilling to date 2. Prospective GT areas
a. High Temp (500-900F) b. Rift structure c. Rift functions d. Rock geometry e. Hydrology
Note: Ccmbination of high terrps. and large fracture conduits present risk of sudden meet i ng of overpressured high temperature fluids in the rift zones. We 11 s KS-7 and -8 proved the existence of this hazard and demonstrated penetration risk. Note: these are major f 1 u i d production zones, too.
B. Precursor signals 1 . Mud and bot tan temp.
increase 2. Mineral alterations 3. Entrained gasses/fluids 4. Impacts on mud or fluids 5. Changes in drilling and
casing programs Note: Operators and regulators must have an awareness/detailed knowJed9e of subsurface hazards in vo Jeanie rift zone; operator's proposa 1, and DLNR approva 1 of drilling/casing and blowout prevention plans always face two tests- pre-drilling and while drillin9.
_I _I 1_. WELL PLANN I NG AND DES I GN
A. Classification Of Reser-voir-s 1. High Temp. 2. Low Temp. 3. High Pressure 4. Low Press. 5. Hot Dry 6. Vapor Daninated 7. Water Dominated
B. Classification Of Wells
1. Exploratory ~lls 2. Production Wells 3. Injection Wells 4. Shallow Wells 5. Deep Wells 6. Slim Hole Wells
C. The Drilling Plan 1. Site Selection 2. Cellar -
a. Depth b. Construction
3. Personnel Training and Experience
D. Emergency Planning
C. Experience and Training 1. Drilling Supervision
a. Operator b. Drilling Contractor c. State and County
Agencies 2. Crew Training and
Instruction a T r a i n i n g
materials/subjects
~
~
b. Scheduling c. Testing and retraining
EQUIPMENT SELECTION
A. Selection of Rig/Drilling 1. PLfllJ Sizes 2. Circulation System 3. F 1 u i d Coo 1 i ng 4. Fluid Storage 5. Cooling Water Supply
B. Valves
c. Piping
D. lnstrunentation and Alarms
BOP EQUIPMENT
A. RAM Preventers 1. Single Gate 2. Double Gate 3. Annular 4. Rotating Head
B. Actuating System C. Control Stations
1. Back-up System D. Slab Gates E. Banjo Box F. BOP Stack Configurations
1. Kill and Choke Lines
Equip.
2
Internal Preventers 3. Safety Valves 4. Kelly Locks 5. Choke Manifold 6. Blooie Line 7. Muffler
G. Diverters H. Fluid Monitoring and Alarms I. Drill Pipe Floats
VI. EQUIPMENT TESTING AND INSPECTION
A. Testing and I nspect ion by State Authority
B. Periodic Testing of Closing System C. Periodic Crew Training and BOP
Drills
~ CASING PROGRAM
A. Conductor B. Surface Casing C. Protection Casing D. Cementing
VI I I. DRILLING PROCEDURES
A. Drilling fluid monitoring-first line of defense
B. Drilling penetration rate-fracture indicator
Alarms
c. D. E. F.
1. Bit weight 2. Torque
Drilling with Mud or Water Drilling with Air Drilling with Mud/Air, Foam, Misc.
Drilling Fluid Monitoring and
G. Formation and Lithology Monitoring H. Crew BOP Drills I. Changes in Dri 11 ing and casing
procedures due to changes in hole conditions
~ KICK CONTROL PROCEDURES
A. Training of Crews B. Kicks
1. While Drilling 2. While Tripping out of hole
C. Procedures involving H2S D. Notification of Authorities
LOGGING AND REPORTS
A. Mud Logging - On Site Geologist B. Reporting
1. Drilling Contractor
2. Operator 3. Regulatory authorities
~ POST DRILLING BLOW OUT PREVENTION A. Wellhead Equipment Specifications B. Inspection and Testing C. Flow Lines and Surface Equipment D. Corrosion and Erosion Centro 1 -
Inspection and Monitoring.
APPENDICES
- Procedures for Manual Updates
- Illustrations
- References
- Glossary of BOP terms
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R- A- PATTER~N & ASSOCIAT~ 1274 Kika Street Kailua, Hawaii 96734-4521 (808) 262-5651 (808) 262-5350 (FAX)
March 18, 1992
Mr. Manabu Tagomori Department of Land & Natural Resources Division of Water and Land Development P. 0. Box 373 Honolulu, HI 96809
Dear Mr. Tagomori;
As a result of our productive meeting yesterday, we have revised the proposed tasks and changed the attached Scope of Work For a DLNR Technical Services Contract, which was enclosed in our March 16, 1992 letter. The purpose of the contract which covers these tasks will be to provide
1) a Hawaii Blowout Prevention Manual, to include both operating procedures and equipment specifications, and 2) a Hawaii Geothermal Drilling Guide, including standards as they can be defined at this time.
We estimate that Tasks 1-3 of the work can be completed within five months (22 weeks) after the signing of the RCUH contract. We have estimated that 8 weeks will be required, after distribution by DLNR, for review of the drafts and the receipt of comments; revising the draft documents and final production (Tasks 4 and 5) is expected to take 3-4 weeks after comments are received.
Presentations to the DLNR staff and TAC can be completed in 4-6 days, including preparations of visuals, etc., and presentation, and will depend on schedules of these groups. Thus, the entire project is estimated to be finished in eight and one-half months (35 weeks).
Sincerely,
'\i?~ enclosure
SCOPE OF WORK FOR
A DLNR TECHNICAL SERVICES CONTRACT
REVISED
March 18, 1992
R. A. Patterson & Associates {RPA) proposes the following tasks to carry out the objectives requested by Department of Land & Natural Resources (DLNR) letter, dated February 27, 1992. Tasks will includi the conduct of research and analysis and then development, review, and production of two manuals for use in Hawaii geothermal drilling activities:
1) a Ha'W'aii B10'W'c:n . .1t Pr~"V~ti~ ~""U.a.1, and
2) a Ha'W'aii Geoth~Ln1161.1 Dr:i.11:i.:n.g Gu..::ide:
Task 1. Gather and review existing data, blowout prevention specifications and procedures, and drilling rules, standards, and procedures for Hawaii and other governmental and regulatory jurisdictions, with emphasis on geothermal areas with identified geophysical characteristics similar to Hawaii.
Gather existing data on geothermal drilling results problems to date in the Kilauea East Rift Zone (KERZ}, particular attention to the blowouts that occurred at the Geothermal Venture wells, KS-7 and KS-8.
Provide regular, informal progress reports to DLNR.
and with Puna
DELIVERABLES - Reference 1 isting of sources and data gathered. ESTIMATED HOURS - 180
Task 2. Draft proposed Hawaii Blowout Prevention Manual for geothermal drilling activities, using the attached draft Table of Contents as a guide.
Provide suggested list of reviewers for DLNR approval.
Present draft Manual to DLNR for review and discussion.
DELIVERABLES Two complete copies of draft Hawaii Blowout Prevention Manual. ESTIMATED HOURS - 96
1
Task 3. Draft proposed Hawaii Geothermal Drilling Guide, using and revising as necessary, the attached draft Table of Contents, and incorporating specific standards as they can be defined at this time.
Provide suggested list of reviewers for DLNR approval.
Present to DLHR for review and discussion.
DELlVERABLES Two complete copies of draft Hawaii Geothermal Drilling Guide. ESTIMATED HOURS - 96
Task 4 .. Revise Hawaii Blowout Prevention Manual and Geothermal Drilling Guide, based on comments of DLHR and other reviewers.
DELIVERABLES .- Revised documents (three Manual - one unbound for reproduction, copies). ESTIMATED HOURS -
Task 5.
copies of each and two bound
104
Present final Hawaii Blow-Out Prevention Manual and Drilling Guide to DLHR.
Develop materials (visual aids, handouts, etc.} and make presentations to DLNR staff and to the 'l'AC (2 presentations)
DELIVERABLES - Presentation materials. ESTIMATED HOURS -
Attachment - Draft Tables of Contents for Manuals
DLHRSOW.DOC-3/18/92/RAP
2
72
DRAFT HAWAII GEOTHERMAL DRILLING GUIDE
TABLE OF CONTENTS
- Introduction/Summary o Permit Process o Safety and Resource Management o KERZ Drilllng Experience/Wells Drilled
- Geothermal Well Types o Exploration, Production, Injection,. Monitoring,
Water Supply, ScienUUc Observation - Hawall Conditions
o Risks o Problem Areas
-General Requirements- Hawaii Drilling o Planning - Field/Wells o Safety o Operator Competence/Experience o Drilling Procedures o Monitoring and Reporting
- Well Testing o Safety o Equipment o Procedures o Reports
- Industry Oversight Organizations o Geothermal Drilling Organization - GDO o American Society of Testing & Materials - ASTM o Others
nn 1\ t.'T
DRAFT HAWAII BLOWOUT PREVENTION MANUAL
TABLE OF CONTENTS
- Introductio~ and Summary o Permit Process o Safety and Resource Management o KERZ Drilling Experience
- Planning and Design -Experience and Training - Equipment Selection
· o Cooling Water Supply o Valves o Piping o Instrumen taU on and Alarms
- Drilling Procedures o Supervision o Monitoring o Temperatures o Pressures
- Casing Program - Logging and Reports
APPENDICES • Manual Updates - Procedures • Graphics
SCOPE OF WORK FOR
A DLNR TECHNICAL SERVICES CONTRACT
SUMMARY - ESTIMATED TASK HOURS
TASK RAP HEW WLD 1 72 36 72
2 48 32 16
3 52 28 16
4 52 28 24
5 .!Q_ l.L 8 TOTAL 264 148 136
COSTS
TOTAL PROFESSIONAL HOURS (ESTIMATE)
TOTAL PROFESSIONAL FEES (EST-INCLUDES OVERHEAD)
HAWAII GET (4%) ..
SUBTOTAL, REVISED
TOTAL 180
96
96
104
TL 548
548
$54,800
$2,192
$56,992
It is our estimate that some travel will be required during the data gathering and presentation phases, and perhaps for hearings, etc. Travel costs wi 11 be treated as a reimbursable expense. An estimate of the travel required is presented below:
TRAVEL (ESTIMATE) Three RT SAC-HNL- $1,500, 14 days lodging @ $75/day, 12 days rental car@ $35/day, and 14 x$40/day meals and mise expenses. 3 RT HNL-AUCK - $1350, 12 days 1 edging at $7 5/day, 4 days rental car @ $30/day, 12 days meals and mise @ $40/day. 2 RT HNL-HILO - $200, 3 days rental car @ $30/day, 6 night's lodging @ $ 80/day, and 6 x$30/day meals and misc ... $7,330
TOTAL, REVISED $64,322
DLKRSOK.DOC-3/18/92/RAP
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