DRILLING DRICTIVE FOR GRADE ONE GEOTHERMAL RESOURCE ...
Transcript of DRILLING DRICTIVE FOR GRADE ONE GEOTHERMAL RESOURCE ...
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Ethiopian Energy Authority
DRILLING DRICTIVE FOR GRADE ONE GEOTHERMAL
RESOURCE DEVELOPMENT
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1. This directive is General Standards Applicable to Drilling Operations including drilling
plan, drilling program, and well design and drilling, conducting drilling operation and well
abandonment for geothermal resource development.
PART ONE
1. GENERAL
1.1. Short title
2. This directive may be cited as the “Geothermal Resource Development Grade I drilling
directive No.______/2019.”
1.2 Definitions
3. For purposes of this Directive:
It is the purpose of this Directive to set forth the Proclamation No. 981/2016 and Regulation No.
453/2019 governing the geothermal resource development program of the Ethiopian Energy
Authority (EEA).
Anchor CSG / the production casing means the cemented casing on which the permanent
wellhead is mounted.
Byproducts are minerals (exclusive of oil, hydrocarbon gas, and helium), found in solution or in
association with geothermal fluids, that no person would extract and produce by themselves
because they are worth less than 75 percent of the value of the geothermal steam or because
extraction and production would be too difficult.
Direct Use means as defined in the proclamation for Grade II geothermal resource, utilization of
geothermal resources for commercial, residential, agricultural, public facilities, or other energy
needs other than the commercial production or generation of electricity. Direct use may occur
under either a Grade I geothermal license or a Grade II license.
Exploration operations mean any activity relating to the search for evidence of geothermal
resources, where you are physically present on the land and your activities may cause damage to
those lands. Exploration operations include, but are not limited to, geological, geophysical &
geochemical operations, drilling temperature gradient wells, drilling holes used for explosive
charges for seismic exploration, core drilling or any other drilling method, provided the well is
not used for geothermal resource production. It also includes related construction of roads and
trails, and cross-country transit by vehicles over public land. Exploration operations do not
include the direct testing of geothermal resources or the production or utilization of geothermal
resources.
Geothermal resources operational order means a formal, written, numbered order issued by
The Licensing Authority that implement or enforces the regulations or this directive.
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Licensee means a natural or juridical person holding certain rights and responsibilities granted
under a geothermal license issued by Licensing Authority.
Operating rights (working interest) means any interest held in a license with the right to
explore for, develop and produce.
Operating rights owner means a person who holds operating rights in a license. A lessee is an
operating rights owner if the licensee did not transfer all of its operating rights. An operator may
or may not own operating rights.
Operator means any person who has taken responsibility in writing for the operations conducted
on licensed lands.
Produced or utilized in commercial quantities means the completion of a well that:
(1) Produces geothermal fluids in commercial quantities; or
(2) Is capable of producing geothermal fluids in commercial quantities so long as
Licensing Authority determines that diligent efforts are being made toward the utilization of the
geothermal resource.
Stipulation means additional conditions Licensing Authority attaches to a license or permit.
Subsequent well operations are those operations done to a well after it has been drilled.
Examples of subsequent well operations include: cleaning the well out, surveying it, performing
well tests, chemical stimulation, running a liner or another casing string, repairing existing
casing, or converting the well from a production well to an injection well or vice versa.
Surface management agency means any government agency, other than the Licensing
Authority, that is responsible for managing the surface overlying government-owned minerals.
Temperature gradient well means a well authorized under a geothermal exploration permit
drilled in order to obtain information on the change in temperature over the depth of the well.
Unit agreement means an agreement to explore for, produce and utilize separately-owned
interests in geothermal resources as a single consolidated unit. A unit agreement defines how
costs and benefits will be allocated among the holders of interest in the unit area.
1.3 Purpose
It is the purpose of this Directive to set forth the rules and regulations governing the geothermal
program of the Ethiopian Energy Authority (EEA).
1.4 Scope and Exemptions
This directive shall apply throughout the Federal Democratic Republic of Ethiopia, with the
following exceptions.
1.4.1 Pre-existing Wells Exemption
The Licensing Authority, after inspecting a pre-existing geothermal well and finding it to be in
good working condition, may “grandfather”, i.e. exempt, that well from the provisions of this
directive.
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1.4.2 Small Non-commercial Direct Use Exemption
The Licensing Authority may exempt any shallow (less than 200 meters total depth) geothermal
well from this directive if the resource is used in a residential or in a non-commercial manner.
The Licensing Authority may, in its discretion, approve Tempreture Gradient Wells (TGWs)
greater than 150 meters in depth. Drilling prognosis for drilling any TGWs will include criteria
to recognize and prevent direct contact with the geothermal resource. Exploration operations do
not include resource assessment or confirmation activities such as direct testing of the
geothermal resource. The Licensing Authority may approve the drilling of TGWs at any location
the Licensing Authority deems advisable, so long as no part of the well is drilled within 5 (200)
meters of the outer boundary of the parcel of land on which the well is situated or within 5 (200)
meters of a public road prior to the commencement of drilling.
PART TWO
2. ACTIONS THAT NEED THE LICENSING AUTHORITY NOTICE
Prior to engaging the following activities, license holder needs to inform/notice the Licensing
Authority. Activities that need the notice include, but not limited to the following.
2.1 Intension to drill
Before a Licensee or Operator can commence drilling a well, a Notice must be filed on a
prescribed form attached in Appendex-1 and submitted to the Licensing Authority, accompanied
by the appropriate fee and bond. The Operator shall not commence drilling until the Licensing
Authority approves and give drilling permit to the Notice. The Notice shall include drilling Plan,
drilling program, well design plan and, all information required on prescribed form, geothermal
regulation and the following:
A drilling program describes all the operational aspects of your proposal to drill, complete, and
logging & tests a well and must include the following;
a) General scope of work including a detailed description of the equipment, materials, and
procedures to be used;
b) The proposed/anticipated depth of the well(s);
c) The proposed bottom hole location and distances from the nearest license boundary;
For deviated wells also provide the kick-off point; the direction of deviation, the angle
of build-up and maximum angle and plan and cross section maps indicating the surface
and bottom hole locations.
d) Site preparation description and access road alignment;
e) Mobilization scope and duration;
f) Measurements for each well segment including casing and cementing programs;
g) Drilling fluid program for each well segment including the circulation media (mud, air,
foam, etc.);
h) Electric logging program and a description of the logs to be run;
i) Casing program;
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j) Cementing program;
k) Well control methods with a description and diagram of the blowout prevention
equipment you will use during each phase of drilling;
l) The expected depth and thickness of fresh water zones;
m) Anticipated lost circulation zones;
n) Anticipated reservoir temperature and pressure;
o) Anticipated temperature distribution vs depth in the area;
p) Anticipated formation pressure distribution;
q) A plat certified by a licensed surveyor showing the surveyed surface location and
distances from the nearest section or tract lines;
r) Procedures and durations of well logging & testing before rig release and after;
s) All environmental documentation for the proposed well(s), the name and address of the
agency or a copy of the final environmental documents. If operations on an exploratory
well(s) or observation well(s) for which the Licensing Authority is required to prepare
environmental documents have not commenced within two years from the date the
drilling permit to Drill was approved, the Licensing Authority shall cancel the notice
unless, prior to the expiration date, the Operator requests an extension on a
Rework/Supplementary Notice. If operations on a development well(s), exploratory
well(s), or observation well(s) for which the Licensing Authority is not required to
prepare environmental documents have not commenced one year from the date the
notice is approved, the Licensing Authority shall cancel the notice unless, prior to the
expiration date, the Operator requests a time extension on a Rework/Supplementary
Notice. The Licensing Authority may extend these time limits at its discretion.
t) Any other information the Licensing Authority may require.
2.2 Notice for drilling Temperature Gradient Well (TGW)
A Licensee or Operator may submit for the Licensing Authority for approval a written program
to drill a shallow well or wells for temperature-gradient monitoring purposes. In order to qualify
under this section, a program shall not contain more than 25 wells and the maximum total depth
of each of these wells shall not exceed 200 meters. The scope of exploration operations does not
include the direct testing of geothermal resources (e.g., flow tests or injection tests) or the
production or utilization of geothermal resources. The definition of exploration operations
excludes any well that makes contact with or penetrates the geothermal resource. Each program
submitted for approval shall include:
Well designation.
Well locations and elevations.
Geologic interpretation of the area under investigation, including any known or inferred
temperature data.
Such other data as may be required by the Licensing Authority.
The drilling application for a TGW must contain enough geologic, geophysical and other data to
demonstrate the expected depth to the top of the geothermal resource. The data must detail the
geologic information and provide an interpretation of that data that supports the operator’s
estimation of the depth to the top of the geothermal resource. The Licensing Authority may
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require temperature monitoring and reporting, possibly combined with pressure monitoring, so
that the Licensing Authority can determine when the drilling activity nears direct contact with
the geothermal resource and will require that drilling operations cease when contact with the
geothermal resource occurs or is deemed imminent. The Licensing Authority may impose
monitoring requirements that reflect local drilling practices and expected characteristics of the
geothermal resources that may be present in the area described in the operator’s Drilling Permit.
Other restrictions may include increasing the technical capabilities of the proposed drilling
equipment to control pressures and the disclosure of temperature, pressure, and other data that
may indicate that the geothermal resource is near. To accomplish these tasks:-
The Licensing Authority may oblige the immediate transmission of logging results to the
Licensing Authority for evaluation but not reasonable with respect to the actual
performance of drilling operations. To conduct the intended monitoring, the Licensing
Authority person may be present full time at the site.
2.3 Workover/ Supplementary notice
If there is any change in the original Drilling Permit, or if the Operator plans to deepen, re-drill,
expand, plug and abandon, or perform any operation that will permanently alter the well casing,
a Workover/Supplementary Notice must be filed with the Licensing Authority. A fee and/or
bond may be required if, for example, the proposal concerns entering a plugged and abandoned
or suspended well. If the drilling operations the Licensing Authority approved on a
Rework/Supplementary Notice have not commenced one year from the date the notice is
approved, the Licensing Authority shall cancel the notice unless, prior to the expiration date, and
the Operator requests a time extension on a Rework/Supplementary Notice. The Licensing
Authority may extend this time limit at its discretion.
If a modification of the original program might be necessary during drilling operations is
on-going because of unexpected conditions or operating needs the original well program
to be performed on well, since the operator cannot wait with the highly expensive drilling
rig on site for the Licensing Authority processing of its notice, the changes should be
communicated but the workover can continue while the licensing authority evaluate the
notice. The licensing Authority may stop if it is not satisfied on the notice at any point
and require the operator for more justification.
If those planned modification well already drilled and completed by bringing a new rig at
the site, in such a case a notice of workover is necessary and should be approved by the
Licensing Authority before any field operation is started.
2.4 Notice to convert to Injection
An Operator or a Licensee planning to convert an existing well to an injection or disposal well
during the field operation phase, even if there will be no change in mechanical condition, must
file a Workover/Supplementary Notice with the Licensing Authority must approve the notice
before injection is commenced.
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2.5 Approval of notices
Written approval of the Licensing Authority is required prior to commencing drilling, deepening,
re-drilling, or plugging and abandonment operations. The written approval shall list any and all
requirements of the Licensing Authority. In an emergency, the Licensing Authority or a designee
may give verbal approval to the Operator to start any operations covered by this directive,
provided the Licensee sends the Licensing Authority a written notice of the emergency
operations conducted within 5 days after receiving the verbal approval. The Licensing Authority
may issue conditional approvals based on Operator performing works they may deem necessary
to be completed prior to issuing the final permit. The Licensing Authority supervisor may grant
approval for the Operator to build necessary infrastructure such as access roads and well sites
while waiting on final approval.
PART THREE
3 GRADE ONE GEOTHERMAL WELL DESIGN
3.1 Design review
Well design should be prepared by engineers competent in geothermal well design, and familiar
with the Ethiopian Geothermal proclamation, regulation, this directive and African Union Code
of Geothermal Drilling Practices (AUC of GDP), and shall be peer reviewed by an appropriately
qualified and experienced person.
3.2 Subsurface condition
Prior to the well design, an assessment shall be made of the subsurface conditions anticipated
throughout the well path. To do this, use information from nearby wells and from relevant
scientific and engineering appraisals. The assessment should include expected temperatures,
fluid types, fluid compositions, and pressures as well as the relevant geological information
listed below:
a) Lithology of geological formations including the location of any specific stratigraphic
marker beds;
b) Intensity and nature of rock alteration;
c) Compressive strength, or at least the degree of rock consolidation;
d) Faulting, fracturing, and gross permeability;
e) Potential for unstable formations, such as unconsolidated breccias or volcano-
sedimentary sequences, or lithologies that might contain water-sensitive swelling clays;
and
f) Fracture pressures obtained from FLOTs on nearby wells or from similar formations.
In exploratory wells, sometimes temperature and pressure profiles versus depth cannot be
inferred using data from nearby wells or from surface investigations. In this case, information to
be used for well design shall be determined as follows:
a) Unless there is a suspicion of artesian conditions, subsurface fluid pressures shall be the
hydrostatic values for a column of cold water below the general groundwater level of the
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area. If the groundwater hydrology, local topography, or natural thermal features suggest
artesian conditions, design fluid pressures shall be increased to the extent implied by such
indications; and
b) Subsurface temperature values shall be assumed to follow saturation conditions for a
column of boiling water below the same level defied by (a).
3.3 Casing requirement
All wells shall be cased in such a manner as to protect or minimize damage to the environment,
ground waters and surface waters (if any), geothermal resources, life, health and property. Well
casing designs should consider:
a) the intended purpose;
b) the design lifetime;
c) ongoing operation and maintenance; and,
d) The nature of the resource (fluid, vapor, or combination), and whether the well is a
flowing well or a pumped well.
The permanent well-head completion equipment shall be attached to the production casing or to
the intermediate casing if production casing does not reach to the surface.
Division specifications for casing strings shall be determined on a well-to-well basis. All casing
strings reaching the surface shall provide adequate anchorage for blowout-prevention equipment
(BOP), hole pressure control, and protection for all-natural resources. The following casing
requirements are general but should be used as guidelines in submitting proposals to drill.
A. Conductor Pipe
Conductor pipe shall be cemented with sufficient cement to fill the annular space from the shoe
to the surface. An annular blowout preventer, or its equivalent, approved by the Licensing
Authority, shall be installed on conductor pipe for exploratory wells and development wells
when deemed necessary by the Licensing Authority. THE LICENSING AUTHORITY may
waive this requirement for low-temperature geothermal wells.
B. Surface Casing
Surface casing shall provide for control of formation fluids, for protection of shallow usable
groundwater, and for adequate anchorage for blowout prevention equipment. All surface casing
shall be cemented with sufficient cement to fill the annular space from the shoe to the surface.
The surface casing shall not be used as production casing unless otherwise authorized by the the
Licensing Authority supervisor to meet special well conditions. The following requirements may
be modified or waived by the Licensing Authority for low-temperature geothermal wells.
1. Length of Surface Casing
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a) In areas where subsurface geological conditions are variable or unknown, surface casing
in general shall be set at a depth equal to or exceeding 10 percent of the proposed total
depth of wells drilled in such areas. The surface casing depth selection procedure must
be designed to avoid underground blowouts so that chosen a depth that can competently
withstand the pressures of reasonable kick conditions.
b) In areas of known high formation pressure (high temperatures at shallow depth, or
because of pressure exceeding the hydrostatic gradient), surface casing shall be set at a
depth determined by the Licensing Authority after a careful study of geological
conditions.
c) Within the confines of designated geothermal fields, the depth at which surface casing
shall be approved by the Licensing Authority on the basis of known field conditions
utilizing a procedure that has been proved in field applications described below or
equivalent.
2. Cementing Point for Surface Casing
Surface casing shall be cemented through a sufficient series of low permeability, competent
lithologic units (such as claystone or siltstone) to ensure a solid anchor for blowout prevention
equipment and to protect usable groundwater and surface water from contamination. A second
string of surface casing may be required if the first string has not been cemented through a
sufficient series of low permeability, competent lithologic units, and either a rapidly increasing
thermal gradient or rapidly increasing formation pressures are encountered.
C. Intermediate Casing
Intermediate casing shall be required for protection against anomalous pressure zones, uncased
fresh water aquifers, cave-ins, and washouts, abnormal temperature zones, rapidly increasing
thermal gradients, uncontrollable lost circulation zones or other drilling hazards. Intermediate
casing strings shall be, cemented solid to the surface. If a liner is used and an intermediate string,
the lap shall be tested by a fluid entry of pressure test to determine whether a seal between the
liner top and the next larger casing string has been achieved. The liner overlap shall be a
minimum of 50 meters. The test shall be recorded on the driller’s log and may be witnessed by
the Licensing Authority Supervisor. In the event of lap or casing failure during the test, the lap or
casing must be repaired or re-cemented and successfully re-tested as required by the Supervisor.
D. Production Casing
Production casing may be set above or through the producing or injection zone and cemented
above the objective zones. Sufficient cement shall be used to exclude overlying formation fluids
from the zone, to segregate zones, and to prevent movement of fluids behind the casing into
zones that contain usable groundwater.
Production casing shall either be cemented with sufficient cement to fill the annular space from
the shoe to the surface or lapped into intermediate casing, if run. This cement shall be a high-
temperature-resistant admix, unless waived by the Supervisor. Production casing lapped into an
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intermediate string shall overlap at least 50 meters; the lap shall be cemented solidly; and shall
be pressure-tested to ensure its integrity. Cold water is recommended as the testing fluid.
Pressure declines of 10% or less in 30 minutes shall be considered satisfactory.
3.4 Review and Modification of well design during drilling
During well construction, the well design shall be reviewed for safety and modified if required if
any of the following conditions are encountered during drilling:
a) Downhole fluid conditions such as temperature, pressure or gas that may create pressures
greater than the Maximum Design Pressure as calculated for the initial well design.
b) Downhole formation conditions such as faults or weak formations that may indicate the
Effective Containment Pressure is less than the values used for the initial well design; and
c) Casing setting depths are materially changed from the depths used for the well design (for
instance, if a casing hangs up and must be cemented shallower than the design depth).
PART FOUR
4 GEOTHREMAL WELL SITE SELECTION AND PREPARATION
4.1 Field Designation
EEA may designate geothermal fields for administrative purposes that contain at least one well
capable of producing geothermal resources graphically constructing each well circle of 200-
metre-radius around the well field. Each such well shall be at the center of a circle and no
producing interval of any well shall be located within 30 meters of the outer boundaries of the
field except where approved by EEA.
The Licensing Authority may notify a well field site to public if it is needed. The public shall
have free and unrestricted access to geothermal license area, excepting however, where
restrictions are necessary to protect public health and safety or where such public access would
unduly interfere with the Licensee's operations or the security thereof. The Licensee shall
provide warning signs, fencing, flagment, barricades, or other safety measures deemed necessary
by the Supervisor to protect the public, wildlife, and livestock from hazardous geothermal or
related activities.
4.2 Amending field rule
When sufficient geologic and engineering information is available, the Licensing Authority may
adopt or amend existing field rules for any geothermal resource field or area. Before adopting or
amending field rules, the Licensing Authority shall notify affected persons, including but not
limited to operators, inhabitant, and any utilities or other commercial users, and allow at least 30
days for them to comment on the proposed rules. The Supervisor shall notify affected persons in
writing of the adoption of the rules.
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4.3 Well site access
Roding, bridges, and culverts shall be provided and maintained to enable continuous access to
the site for the drilling rig and associated equipment at all times during the drilling of the well.
Following well completion, and until the well is abandoned, site access shall be maintained to a
standard that:
a) Allows safe access for normal well logging and maintenance activities by light vehicles;
and
b) Can be readily reinstated to a condition allowing for the access of a rig or other
equipment to work over the well
Consideration in well site design and construction, the site shall be designed and constructed to:
a) Support all loads imposed by the drilling equipment and associated plant (such as
cranes);
b) Control run-off and contain drilling fluids during drilling operations;
c) Review the geotechnical assessment during site preparation and carry out additional
remedial work as required;
d) Consider consolidation grouting, where subsurface conditions warrant have finished
grades in the site area covered by the drilling rig within tolerances specified in the rig
equipment OEM documentation. Outside this area, the surface of the site should be
finished to grades that provide controlled drainage
4.4 Unstable terrain
If the construction of drilling sites, roads, sumps, steam transmission lines, and other
construction attendant to geothermal operations could cause or could be affected by slumping,
landslides, or unstable earth conditions, the Licensing Authority shall require that the Licensee
submit a written analysis of the proposed work prior to the commencement of any construction
and prior to approving a permit to drill. At the request of the Licensing Authority, the report shall
be prepared by a civil engineer, with the appropriate competency certificate in Ethiopia and
experienced in soils engineering; if slumping or land-sliding could be involved, the requested
report shall also be prepared by an engineering geologist, the appropriate competency certificate
in Ethiopia and experienced in slope stability and related problems. No permit to drill shall be
approved unless the report indicates that the work is planned in such a manner as to avoid or
mitigate the problem throughout the life of the project. Upon completion of any construction
authorized by the Supervisor pursuant to this section, the Operator shall certify in writing to the
Supervisor that the work was carried out according to the approved plans subject only to changes
approved by the Supervisor.
4.5 Compliance
Well sites and associated works shall be built and operated to comply with requirements of the
applicable environmental consents and permits of the country as well as all applicable
occupational health and safety statures.
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4.6 Consideration for waste sump
Consider the following when designing and using waste sumps:
a) Waste sumps are constructed to contain cuttings and liquid drilling and cementing
wastes and all other contaminated fluids generated by the drilling operations;
b) The sump is usually designed to allow isolation of part of the volume for primary
settlement of solids, with any necessary secondary settlement and treatment occurring in
the remaining volume. Alternatively, two separate sumps can be used;
c) Operating procedures should ensure that the maximum fluid level in the sump will
remain below the cellar floor level;
d) The sump design and construction should ensure that there will be no erosion or collapse
of the sump walls during operations;
e) Where two waste sumps are constructed close together, the design shall prevent leakage,
erosion or collapse of the material separating the two sumps when the upstream sump is
full and the downstream sump is empty;
f) The design of the upstream sump should allow for a holding capacity of at least five
times the total volume of the solid material expected to be drilled from the well;
g) The volume necessary to contain all drilled solids, waste mud and cement will be
determined by the following:
i. Hole volumes – when brought to the surface, drill cuttings will occupy
approximately twice the in-situ volume downhole;
ii. Formations to be drilled – erodible formations can result in over-gauge hole and
excess cuttings;
h) Waste sump volume requirements can be reduced where:
i. Cuttings are removed directly from the shale shaker
ii. Solids-removal equipment with the drilling rig results in drilling wastes with a
low water content and minimal mud waste;
i) Waste sumps should be periodically monitored in accordance with relevant environment
consents and permits.
4.7 Water supply
An adequate supply of water shall be available to the site during all drilling operations. The
quantity of water available shall be adequate to meet maximum projected requirements for
quenching, drilling (including drilling without returns of circulation) and cementing operations;
and equipment and infrastructure shall be placed and fully operational to provide the volume and
rate of flow needed in emergencies as well as under normal operating conditions. All applicable
statues as well as rules and regulations related to water rights of the country shall be adhered to.
4.8 Storage facility
Storage facilities for hazardous substances used in the drilling operation be designed and
operated to prevent adverse impact to human health and safety and the environment.
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Fuel storage tanks shall be designed and located to minimize potential hazards and shall comply
with relevant national and/or local/regional statues and regulation.
4.9 Security
Appropriate security shall be maintained to allow only authorized personnel access to the site
during drilling operations.
4.10 Fencing and signage
Appropriate fencing and signage shall be erected and maintained. Signage shall be located at the
site entrance advising of:
a) Hazards, constraints on entry, and requirements for personal protection equipment;
b) Waste sumps that constitute hazards; and
c) Areas where hazardous gases may be discharged or can accumulate.
All safety-related signage shall include recognized international safety and hazard symbols to
ensure maximum safety for workers, local residents and visitors. Symbols for Flammable, Crane
Overhead, Danger of Suffocation, Watch for Falling Objects, Watch Your Step, High Voltage
and Hard Hat Area are among those highly suggested, along with any other signs deemed
necessary.
PART FIVE
5 GEOTERMAL WELL DRILLING EQUIPMENT AND TOOLS
5.1 Suitability of equipment
Equipment associated with drilling works shall be assessed for suitability and wherever
applicable, should comply with national, international, and API standards.
5.2 Mast guy Anchor
Where the drilling rig requires the installation of mast guy line anchors in the ground around the
well site, the design and construction of these anchors shall comply with the original equipment
manufacturers (OEM’s) documentation.
5.3 Rig and Hoisting capacity
On completion of the well design all loads to be imposed from drilling operations, including the
running and cementing of casings, shall be assessed, and a margin of safety shall be added to
establish the minimum hoisting capacity required. The capacities of all components of the
equipment specified and selected for the drilling shall exceed the minimum capacities estimated
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to be required to meet the loadings. Assessment of the capacities of separate components of the
drilling rig equipment certifications should be presented to the Licensing Authority.
5.4 Generator, electrical systems and lighting
5.5 Gas detection
An appropriate gas detector system comprising at least four sensors with the capability of
detecting both H2S and CO2 shall be on site and functioning at all times while the rig is
operating. Gas detectors shall be maintained in accordance with the manufacturer’s OEM
documentation, and shall activate both audible and visual alarms.
A gas hazard abatement plan shall be prepared and all rig crew and support personnel shall be
familiar with its application.
Gas hazard escape equipment shall be provided at appropriate locations and available for use at
all times when the rig is operational. All rig and support personnel shall be trained and
competent in the use of Emergency Life Support Apparatus (ELSA) or equivalent escape
equipment. At least one Self-Contained Breathing Apparatus (SCBA) shall be onsite, and at least
two of the rig crew on every shift shall be trained and competent in its use. There should also be
at least two muster points and wind sock on the drilling rig.
5.6 Rig instrumentation
Minimum requirements for rig instrumentation shall be:
a) Total weight indicator;
b) Tank volume and gain-loss indicators;
c) Standpipe pressure gauge;
d) Wellhead pressure gauge; and
e) Indicators for temperatures of rig pump suction fluids and returning fluids (drilling fluid
going in and coming out of the well).
Other instrumentation shall include:
a) Pump speed indicators;
b) Rotary torque indicator;
c) Drilling fluid flow rate indicator (including air flow if appropriate) for downhole flow,
return flow, or both;
d) Kelly height and rate of penetration indicators;
e) Drilling fluid density;
f) Recorders which record any or all of these parameters;
g) Rotary speed indicator; and
h) Makeup torque indicator.
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Rig instrumentation shall be inspected, maintained and recalibrated as necessary at the start of
each well, and at intervals specified in the OEM standards during drilling operations.
5.7 Blow out preventer and gas accumulator
Blowout-Prevention Equipment (BOP) installations shall include high temperature-rated packing
units and ram rubbers, if available, and shall have a minimum working-pressure rating equal to
or greater than the lesser of:
a) A pressure equal to the product of the depth of the BOP anchor string in meters times 0.2
bar per meter;
b) A pressure equal to the rated burst pressure of the BOP anchor string;
c) A pressure equal to 138 bars (13.8 megapascals).
Specific inspections and tests of the BOP shall be made by the Licensing Authority or assigned
advisor. The requirements for such tests will be included in the Licensing Authority's answer to
the notice of intention to drill maintained and function tested in accordance with API STD 53
5.8 Blowout Prevention Equipment and Procedures
All necessary cautions shall be taken to keep all wells under control at all times, utilize trained
and competent personnel, and utilize properly maintained equipment and materials. Blowout
preventers and related well control equipment shall be installed, tested immediately thereafter
and maintained ready for use until drilling operations are completed. Certain components, such
as packing elements and ram rubbers, shall be of high temperature resistant material as
necessary. All kill lines, blow down lines, manifolds and fittings shall be steel and shall have a
temperature rated minimum working pressure rating equivalent to the maximum anticipated
wellhead surface pressure. Dual control stations shall be installed with a high-pressure backup
system. One control panel shall be located at the driller’s station and one control panel shall be
located on the ground at least 15 meters away from the wellhead. Air or other gaseous fluid
drilling systems shall have blowout prevention assemblies. Such assemblies may include, but are
not limited to, a rotating head, a double ram blowout preventer or the equivalent, a banjo-box or
an approved substitute and a blind ram blowout preventer or gate view, respectively. Exceptions
to the requirements of this section will be considered by the the Licensing Authority Supervisor
only for certain geologic and well conditions such as stable surface areas with known low
subsurface formation pressures and temperatures.
a) Conductor Casing. Before drilling below this string, at least one remotely controlled
hydraulically- operated expansion type preventer or an acceptable alternative, approved
by the Licensing Authority Supervisor, including a drilling spool with side outlets or
equivalent shall be installed. A kill line and blow down line with appropriate fittings
shall be connected to the drilling spool. This requirement may be eliminated by
approval of the Licensing Authority Supervisor.
b) Surface, Intermediate, and Production Casing. Before drilling below any of these
strings, the blowout prevention equipment shall include a minimum of:
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i. One expansion-type preventer and accumulator (Annular Preventer) or a rotating
head;
ii. A {Non-Return Valve (NRV)} on the drilling string - to prevent inflow of annular
fluids or formation into the bottom of the drill string. NRVs should also be used in
the upper sections of the drill string to minimize the volume of aerated fluid to be
vented from the drill string when making a connection;
iii. A manual and remotely controlled hydraulically-operated double ram blowout
preventer or equivalent having a temperature rated minimum working pressure
rating which exceeds the maximum anticipated surface pressure at the
anticipated reservoir fluid temperatures;
iv. A drilling spool with side outlets or equivalent;
v. A fill-up line;
vi. A kill line equipped with at least one valve; and,
vii. A blowdown line equipped with at least two valves and securely anchored at all
bends and at the end.
c) Testing and Maintenance. Ram-type blowout preventers and auxiliary equipment shall
be tested to a minimum of 138 bars or to the working pressure of the casing or
assembly, whichever is lesser. Expansion-type blowout preventers shall be tested to 70
percent of the above testing requirements.
i. The blowout prevention equipment shall be pressure tested:
(a) When installed;
(b) Prior to drilling out plugs and/or casing shoes;
(c) Not less than once each week, alternating the control stations; and,
(d) Following repairs that require disconnecting a pressure seal in the assembly.
ii. During drilling operations, blowout prevention equipment shall be actuated to test
proper functioning as follows:
(a) Once each trip for blind and pipe rams, but not less than once each day for
pipe rams; and,
(b) At least once each week on the drill pipe for expansion-type preventers
(Annular BOP).
All flange bolts shall be inspected at least weekly and re-tightened as necessary during drilling
operations. The auxiliary control systems shall be inspected daily to check the mechanical
condition and effectiveness and to ensure personnel acquaintance with the method of operation.
Blowout prevention and auxiliary control equipment shall be cleaned, inspected, and repaired, if
necessary, prior to installation to assure proper functioning. Blowout prevention controls shall be
plainly labeled, and all crew members shall be instructed on the function and operation of such
equipment. A blowout prevention test shall be conducted weekly for each drilling crew. All
blowout prevention tests and crew drills shall be recorded on the driller’s log.
d) Related Well Control Equipment. A full opening drill string safety valve in the open
position shall be maintained on the rig floor at all times while drilling operations are
being conducted. A Kelly cock shall be installed between the Kelly and the swivel.
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PART SIX
6 GEOTHERMAL WELL DRILLING AND TESTING
Prior to drilling a well and during the drilling, in addition to requirements mentioned under the
Geothermal Resource Development Proclamation No. 981/2016 and the Geothermal Regulation
No. 453/2019 Part 6 and the Licensee must follow the following operational requirements for
drilling.
6.1 Competence and supervision of personnel
Personnel in immediate control of any drilling or workover operations shall be trained and
competent in blowout prevention and control of geothermal wells and should be certified, and
one such person shall be directly in control of the rig while it is operational.
6.2 Unstable area
Drilling any wells, including water wells, is prohibited in areas containing fumaroles, geysers,
hot springs, mud pots, etc. (unstable areas), unless the Licensing Authority determines in
consultation with appropriate water law and agency, after a thorough geological investigation,
that drilling in an unstable area is feasible. In this case, a special permit may be issued. The
following may be required for a well drilled in an unstable area:
a) The Licensing Authority engineer or witness shall be present at the well at all times
during the initial phases of drilling until the surface casing has been cemented and the
BOP has been pressure-tested satisfactorily. The Licensing Authority engineer may
observe all drilling operations at the well and if, in his or her opinion, conditions
warrant, may order a second or third string of surface casing to be run.
b) The Licensee, while drilling the surface casing hole or for any well and well section,
shall continuously monitor and record the following:
i. Drilling fluid temperature (in and out),
ii. Drilling fluid pit level,
iii. Drilling fluid pump volume,
iv. Drilling fluid weight, and,
v. Drilling rate.
6.3 Subsidence and seismic activity
With responsible organ for the detection and abatement of subsidence like GSE and other
government organ, the Licensing Authority will follow the geothermal areas:-
a) Surveys and Bench Marks
i. Subsidence bench marks, at well sites, tied to existing first- and/or second-order
networks, are required for all wells that will be tested or produced. These bench
marks shall be the responsibility of and at the expense of the Operator. Surveys
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shall precede extensive production testing of the well {which could be located in a
new prospect or in a field already under exploitation}
{For the purpose of monitoring ground movements due to production/reinjection activities,
satellite surveys, such as inSarcan be used comparing radar images captured by satellites over
time. Deformation can be measured with millimetre accuracy and 25 years back in time. As,
InSAR Monitoring generates up to 100,000 measurement points per km², this approach is
obviously much more powerful than a traditional one. It is the state-of-the-art approach for
ground movement monitoring (subsidence & rebound) related to O&G operations.}
ii. All survey work shall be identified with the GPS coordinates by Provincial
Surveyor.
iii. All work shall be done under the direct supervision of a Registered Civil Engineer
or Licensed Land Surveyor.
iv. An adequate series of bench marks shall be set as required by the Licensing
Authority and shall be tied to existing survey nets.
v. All field work, computations, etc., shall conform to GCS_Adindan or other
Ethiopian equivalent standards.
vi. All surveys shall be second-order or better.
vii. All single-point tie-ins shall be double-run. Survey loops between two points on
existing surveys may be single-run.
viii. Equipment shall be equal to or better than that accepted by the GCS_Adindan or
other Ethiopian equivalent standards for second-order surveys.
ix. Types of acceptable bench marks are:
(a) Brass rod driven to refusal or 10 meters and fitted with an acceptable brass
plate; and,
(b) Permanent structure (head walls, bridges, etc.) with installed plate.
x. Bench marks at well sites shall be situated so as to minimize the possibility of
being destroyed during any subsequent work-over activity at the wells. Each
bench mark shall be well marked so as to be plainly visible to work-over crews.
xi. Between the wellsite and the network, bench marks shall be set at one-kilometer
intervals or as specified by the Licensing Authority.
xii. Surveys shall be run annually by and at the expense of the Operator while well(s)
are being produced unless otherwise specified by the Licensing Authority.
xiii. The adjusted data from all surveys shall be submitted to the Licensing Authority
within 60 days after leveling is completed.
xiv. Resurveys of the first- and second-order networks shall be coordinated by the
Licensing Authority.
b) Reservoir Engineering.
i. Initial bottom-hole pressures and temperatures (allowing a minimum of one-
month static time) shall be submitted to the Licensing Authority within thirty (30)
days of completion of work.
ii. All preliminary test data shall be submitted to the Licensing Authority within 30
days of completion of the tests.
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iii. Monthly surface recordings of production, injection, temperature, and pressure
shall be reported to the Licensing Authority on the appropriate forms.
iv. Periodic development and review meetings between Operators and the Licensing
Authority shall be required (at least one per year).
6.4 Drilling fluid
The properties, use, and testing of drilling fluids and the conduct of related drilling procedures
shall be such as are necessary to prevent the blowout of any well, or the uncontrolled flow of
fluid from any well. Sufficient drilling fluid materials to ensure well control shall be maintained
in the field area and readily accessible for immediate use at all times.
a) Drilling Fluid Return Temperatures
The temperature of the return drilling fluid shall be monitored continuously during the drilling of
any boreholes section. Either a continuous temperature monitoring device shall be installed and
maintained in working condition, or the temperature shall be read manually. In either case, return
drilling fluid temperatures shall be entered into the log book after each joint of pipe has been
drilled down every 10 meters.
b) Drilling Fluid Control
Before pulling drill pipe, the drilling fluid shall be properly conditioned or displaced. The hole
shall be kept reasonably full at all times; however; in no event shall the annular mud level be
deeper than 30 meters from the rotary table when coming out of the hole with drill pipe. Mud
cooling techniques shall be utilized when necessary to maintain mud characteristics for proper
well control and hole conditioning.
c) Drilling Fluid Testing
Mud testing and treatment consistent with good operating practice shall be performed daily or
more frequently as conditions warrant. Mud testing equipment shall be maintained on the drilling
rig at all times. The following drilling fluid system monitoring or recording devices shall be
installed and operated continuously during drilling operations, with mud, occurring below the
shoe of the conductor casing:
i. High-low level mud pit indicator including a visual and audio-warning device, if
applicable.
ii. De-gassers, de-silters, and de-sanders.
iii. A mechanical, electrical, or manual surface drilling fluid temperature monitoring
device. The temperature of the drilling fluid going into and coming out of the hole
shall be monitored, read, and recorded on the driller’s or mud log for a minimum
of every 10 meters of hole drilled below the conductor casing.
iv. A hydrogen sulfide indicator and alarm shall be installed in areas suspected or
known to contain hydrogen sulfide gas which may reach levels considered to be
dangerous to the health and safety of personnel in the area.
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No exceptions to these requirements will be allowed without the specific prior permission of the
Supervisor.
d) Monitoring
For surveillance purposes, from the time drilling operations are initiated and until the well is
completed or abandoned, personnel(s) of the drilling crew shall monitor on the rig floor at all
times unless or until the well is secured with blowout preventers or cement plugs.
6.5 Geothermal Wastes and Refuse
Wastes and refuse attendant to geothermal operations, including but not limited to water, oil,
chemicals, mud, and cement, shall be disposed of in such a manner as not to cause damage to
life, health, property, freshwater aquifers or surface waters, or natural resources, or be a menace
to public safety. Disposal sites for geothermal wastes shall also conform to the Laws of Federal
Democratic Republic of Ethiopia. Dumping harmful chemicals where subsequent meteoric
waters might wash significant quantities into freshwaters shall be prohibited. Drilling mud shall
not be permanently disposed of into open pits. Cement slurry or dry cement shall not be disposed
of on the surface. Unused equipment and scrap attendant to geothermal operations shall be
removed from a production or injection operations site and/or stored in such a manner as to not
cause damage to life, health, or property, or become a public nuisance or a menace to public
safety. Trash and other solid waste materials attendant to for geothermal operations shall be
removed and disposed consistent with applicable laws and regulations. Use of hazardous
chemicals shall be minimized. If such chemicals are used, their transport, handling and disposal
shall be in conformity with the laws of Ethiopia and international environmental standards.
6.6 Directional drilling
On completion of the well, the casing condition shall be monitored for any damage, where:
a) The kick-off point and interval of hole where the hole angle is built up are inside casing;
kick off can be in open hole too and
b) The section of hole below the casing subjects the casing to potential wear from
subsequent drilling.
Any indicated casing damage shall be assessed. If it is likely to diminish the safety or integrity of
the well then it shall be repaired.
6.7 Installation, Testing and Inspection of permanent wellhead and BOP
All permanent wellhead components shall be pressure tested prior to installation on the well.
Where possible, pre-assembled components should also be pressure tested as an assembled unit
prior to installation.
6.8 Security of wellhead valve
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Upon completion of works, the wellhead equipment shall be secured against operation by
unauthorized personnel.
6.9 Specified operating range
Following well completion and before the well is put in service, the range of conditions under
which the well can be safely operated shall be specified and documented. This specified
operating range shall be reviewed throughout the lifetime of the well to ensure it reflects any
changes in reservoir or well condition.
6.10 Well logging
The operator has to do at least one wells per exploration prospect, except observation wells and
low-temperature thermal wells, shall be logged with an induction electrical log, or equivalent,
from total depth to the bottom of the conductor pipe, except in the case where air is used as the
drilling medium.
6.11 Post well stimulation (Acidificatio, thermal fracturation, hydraulic fracturation)
a) Within 60 days after the cessation of a well stimulation treatment, the Operator shall
submit a report to the Licensing Authority describing:
i. The pressures (downhole or wellhead pressures) recorded during monitoring
during the well stimulation treatment;
ii. The pressures recorded during the first 30 days of production pressure
monitoring;
iii. The date and time that each stage of the well stimulation treatment was
performed;
iv. How the actual well stimulation treatment differs from what was anticipated in the
well stimulation treatment design;
v. How the actual location of the well stimulation treatment differs from what was
indicated in the permit application; and,
vi. A description of hazardous wastes generated during the well stimulation activities
and their disposition, including copies of all hazardous waste manifests used to
transport the hazardous wastes offsite to an authorized facility.
6.12 Hydraulic fracturing operation
While conducting stimulation work on wells, especially for hydraulic fracturing, the following
procedures should be followed by the licensee
a) A Licensee must not conduct a hydraulic fracturing operation at depth less than 600 m
below ground level.
b) During fracturing, injection or disposal {injection is defined in the proclamation but if
need, disposal can be defined in this directive} operations on a well, a well
authorization holder must immediately report to the commission any seismic event
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within a 3km radius of the drilling pad that is recorded by the well permit holder or
reported to the well permit holder by any source available if;
i. The seismic event has a magnitude of 2.5 or greater, or
ii. A ground motion is felt on the surface by any individual within the 3 km radius of
the drilling pad.
c) If a well is identified by the well permit holder or the commission as being responsible
for a seismic event under subsection (a), must suspend fracturing, injection and disposal
operation on the well immediately.
d) Fracturing and disposal operation suspended under subsection (B) may continue once
the well permit holder has implemented operational changes satisfactory to the
Licensing Authority to reduce or eliminate the initiation of additional induced seismic
events.
PART SEVEN
7 GEOTHERMAL WELL OPERATION AND MAINTENANCE
7.1 Well Completion
A well is considered to be completed upon the earlier occurring of the following dates: 30 days
after drilling operations have ceased and the well is capable of producing a geothermal resource,
or 30 days after the well has commenced to produce a geothermal resource, unless drilling
operations are resumed before the end of the 30-day period For the purpose of filing drilling
records, the 60-day time limit for filing such records shall begin when the Licensing Authority
determines that a well is completed, idle, or plugged and abandoned.
7.2 Well integrity monitoring plans
A Well Integrity Monitoring Plan can cover multiple wells or even reservoirs. Where this is the
case:
a) The scope of the Well Integrity Monitoring Plan shall be stated, along with any
individual wells or groups of wells that are specifically excluded from that plan; and
copies forwarded to the Licensing Authority (EEA) which is responsible for the granting
of geothermal drilling licenses and/or maintaining geological data.
b) Processes shall be put in place to record any variation to the Well Integrity Monitoring
Plan for individual wells or groups of wells.
The Well Integrity Monitoring Plan shall be designed to indicate the presence of any of the
following defects or impairments:
a) External, near surface, corrosion or leakage of the anchor casing;
b) Any corrosion leakage of the wellhead components;
c) Broken or perforated casing;
d) Failed casing connections (for example, by pullout, compressive telescoping, or fracture);
e) Leaks into or out of the casing;
f) Buckled or distorted casing;
g) Collapsed casing;
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h) Corroded casing;
i) Annular flow outside the casings; and
j) Chemical deposition or scale.
The Well Integrity Monitoring Plan shall provide for observation of the following types of
change, all of which can be observed at the surface:
a) Changes in discharged fluid chemistry, enthalpy, pressures or flow rates of production
wells;
b) Changes in surface manifestations of geothermal flow, and particularly the development
of new hot areas on or near the well site;
c) Any indication of fluids entering into a cemented casing annulus at surface and any
deterioration of that cement near surface (such as may arise from rain water draining into
a cellar);
d) Alternatively, any variation in flow from casing annuli; and
e) Loss of pressure measured at a side valve when the well is otherwise known to be under
pressure.
7.3 Wellhead inspection and maintenance
In addition to the Well Integrity Monitoring Plan, or alternatively, as part of it, each wellhead
shall have a documented annual inspection, and at least the following information shall be
recorded by the well owner and copies forwarded to the Licensing Authority (EEA) which is
responsible for the granting of geothermal drilling licenses and/or maintaining geological data.
a) Wellhead pressure;
b) Well Status (for example, shut-in, bleed, production, injection);
c) Operating condition of wellhead valves;
d) Leakage from valve gate or valve stem seals;
e) Condition of protective paint systems;
f) Condition of the anchor casing;
g) Condition of the site and cellar drainage; and
h) Changes in the vertical position of the wellhead measured relative to other casings and to
the cellar and the position of the CHF measured relative to the cellar datum.
7.4 Well tests and remedial works
a) Requirements. The Licensing Authority Supervisor shall require such tests or remedial
work as in his or her judgment are necessary to prevent damage to life, health, property,
and natural resources, to protect geothermal reservoirs from damage or to prevent the
infiltration of detrimental substances into underground or surface water suitable for
agricultural, industrial, municipal, or domestic purposes, to the best interest of the
neighboring property owners and the public.
b) Type of Tests.
i. Casing Tests
(a) Spinner surveys;
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(b) Wall thickness;
(c) Pressure; and,
(d) Radioactive tracer surveys.
ii. Cementing Tests
(a) Cementing of casing;
(b) Pumping of plugs;
(c) Hardness of plugs; and,
(d) Depth of plugs.
iii. Equipment Tests
(a) Gauges;
(b) Thermometers;
(c) Surface facilities, lines, and vessels; an
(d) Blowout-prevention equipment.
BOP inspections and/or tests are normally performed on all drilling wells.
Any remedial works identified by the inspection program shall be completed as soon as
practicable. Where there is a potential for further deterioration that threatens personnel safety,
immediate steps shall be taken to eliminate that risk or to reduce the risk of harm to a level as
low as is reasonably practicable.
7.5 Suspended wells
When a well is suspended, the following apply:
a) A cement plug or plugs shall be placed to provide not less than 100 m of continuous
sound cement inside the production casing;
b) The cement plug should be placed on a bridge plug or packer located at or near the
production casing shoe and not less than 10 m above the top of any liner;
c) The cement plug should also be placed in a manner that minimizes dilution of the cement
slurry by fluids in the well;
d) The cement materials should be selected to withstand ambient fluids and temperatures,
and to develop a limited compressive strength to avoid casing damage when the cement is
subsequently drilled out;
e) The casing above the sound cement should be filed to the surface with a weak bentonite
and cement type of filer; and
f) The cement plug shall be pressure tested to a sufficient test pressure and duration to
confirm the cement plug is sound and provides sufficient integrity for the duration of the
well suspension.
PART EIGHT
8 INJECTION WELLS
Injection wells are those used for the disposal of waste fluids, the augmentation of reservoir
fluids, pressure maintenance of reservoirs or for any other purpose authorized by the Licensing
Authority Supervisor provided that, disposal of hazardous material shall be consistent with
25
requirements for storage handling and use of those chemicals under Ethiopian Law and
International environmental standards. New wells may be drilled and/or old wells may be
converted for water injection or disposal service. An Operator planning to convert an existing
well to an injection or disposal well, even if there will be no change in mechanical condition,
must file a Workover /Supplementary Notice with the Licensing Authority and the Licensing
Authority must approve the notice before injection is commenced. Injection wells shall conform
to the licensing Authority spacing regulation and African code of Practice.
There are two types of fluids that can be injected in the subsurface using a geothermal well
which are Reservoir fluids (such as separated brine, condensate, or NCG) and fluids of other
origin. The Reservoir fluids are allowed to be re-injected, provided that they will not impair
groundwater resources, etc.
On the other hand, injection of water from other sources should be allowed, providing it will not
impair groundwater or surface water resources, etc., and is compatible with the availability of
water resources in the area. This will allow increasing the water recharge where a low amount
of brine is produced, like in two-phase vapor dominated reservoirs. For instance, waste water
from municipal treatment plants should be allowed to be injected. But, some fluids like injected
harmful wastes such as solutions contaminated by organic compounds or radioactive species
cannot be injected in the subsurface in accordance with other applicable laws of the country.
8.1 Projects
For short term injection operations performed during an exploration drilling project the
application and approval processor will be quickly facilitated than prolonged injection
operations performed during the exploitation of the geothermal field.
Following is an outline which sets forth the requirements for initiating an injection project. Data
and exhibits need only extend or cover the injection zone and zones which will possibly be
affected by an injection project:
a) Letter setting forth the entire plan of operations, which should include:
i. Reservoir conditions;
ii. Method of injection: through casing, tubing, or tubing with a packer;
iii. Source of injection fluid; and,
iv. Estimates of daily amount of water to be injected.
b) Map showing contours on a geologic marker at or near the intended zone of injection.
c) One or more cross sections showing the wells involved.
d) Analyses of fluid to be injected and of fluid from intended zone of injection.
e) Copies of letter or notification sent to neighboring operators.
8.2 Project Approval
A written approval of a project will be sent to the Operator and such approval will contain those
provisions specified by the Licensing Authority as necessary for safe operations as fast as
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possible. Injection shall not commence until approval has been obtained from the Licensing
Authority.
8.3 Notice to Drill New Well or Convert Existing Well
Prior to the Operator doing work on a well, the appropriate notices must be approved by the
Licensing Authority. Proposals to drill new wells for injection purposes shall be filed with the
Licensing Authority by the Licensee on the form entitled Notice of Intention to Drill New Well
(designation to be determined). Proposals to convert existing wells shall be filed on the form
titled Workover/Supplementary Notice (designation to be determined).
Bonds and fees are required for all proposed wells in accordance to the geothermal regulation.
The bonds and fees for an injection well are the same as those required for a development well.
Injection wells shall conform to the Licensing Authority's spacing directives to be issued.
8.4 Subsequent Work
A Workover/Supplementary Notice is required for any subsequent work that alters the well
casing(s) or changes the use of the well as provided in Section 8.6(6).
8.5 Surveillance
a) Surveillance of waste water disposal or injection projects is necessary on a continuing
basis to establish to the satisfaction of the Supervisor that all water is confined to the
intended zone of injection.
b) When an Operator proposes to drill an injection well, convert a producing or idle well to
an injection well, or workover an injection well and return it to injection service, the
Operator shall be required to demonstrate complete casing integrity to the Licensing
Authority by means of a specific test.
c) To establish the integrity of the casing and the annular cement above the shoe of the
casing, within 30 days after injection is started into a well, the Operator shall make
sufficient surveys to demonstrate that all the injected fluid is confined to the intended
zone of injection. Thereafter, such surveys shall be made at least every two years or more
often if ordered by the Supervisor or his or her representative. All such surveys shall be
witnessed by a Division engineer.
d) After the well has been placed on injection, a Division inspector shall visit the well site
periodically. At these times, surface conditions shall be noted and, if any unsatisfactory
conditions exist, the Operator shall be notified of required remedial work. If this required
work is not performed within 90 days, the approval issued by the Licensing Authority
shall be rescinded. The Supervisor may order that the repair work be done immediately if
it is determined that damage is occurring at a rapid rate.
e) Injection pressures shall be recorded and compared with the pressures reported on the
monthly injection reports. Any discrepancies shall be rectified immediately by the
Operator. A graph of pressures and rates versus time shall be maintained by the Operator.
Reasons for anomalies shall be promptly ascertained. If these reasons are such that it
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appears damage is being done, approval by the Licensing Authority may be rescinded,
and injection shall cease.
f) When an injection well has been idle for two years, the Licensing Authority may inform
the Operator, by letter, that approval for use of the well for injection purposes is
rescinded. If the Operator intends to reclaim the well for injection purposes, a
Rework/Supplementary Notice shall be filed proposing to demonstrate by specified tests
that the injected fluid will be confined to the intended zone of injection.
PART NINE
9 GEOTHERMAL WELL PLUGING AND ABANDONMENT.
9.1 Objective
The objectives of abandonment plugging are to block interzonal migration of fluids so as to:
a) Protect life, health, environment, and property
b) Prevent contamination of the fresh waters or other natural resources
c) Prevent contamination of ground waters (potable and irrigation waters)
d) Prevent damage to geothermal reservoirs
e) Prevent loss of reservoir energy
f) Protect integrity of reservoirs
9.2 Purpose and requirements for abandonment
The following are general requirements which are subject to review and modification for
individual wells or field conditions. The Licensing Authority may require the witnessing of any
or all of the field operations listed below:
a) General requirements
i. Any well that the Licensee does not intend to use or that is no longer active shall
be properly decommissioned by the Licensee.
ii. Notice to plug and abandon Geothermal Resources Well is required for all wells.
iii. History of Geothermal Resources Well shall be filed within 60 days after
completion of the plugging and abandonment.
iv. The Licensing Authority's Report of Well Plugging and Abandonment will not be
issued until all records have been filed and the site inspected for final clean-up by
a Division engineer.
v. Subsequent to the plugging and abandonment of the hole, all casings shall be cut
off at least 2 meters below the surface of the ground. All concrete cellars and
other structures shall be removed, and the surface location restored, as near as
practicable, to original conditions when all the wells of the cluster are abandoned.
vi. Good quality, heavy drilling fluid approved by the Licensing Authority
Supervisor shall be used to replace any water or geothermal fluids in the hole and
to fill all portions of the hole not plugged with cement.
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vii. All cement plugs, with the possible exception of the surface plug, shall be
pumped into the hole through drill pipe or tubing.
viii. All open annuli shall be filled solid with cement to the surface.
b) Exploratory Well Requirements and ( Production Casing)
i. Base of fresh waters: a minimum of 30 meters cement straddling the interface or
transition zone whether behind casing or uncased. {Rewrite}
ii. Shoe plug (all casing, including conductor pipe) straddle with 30 meters of
cement.
iii. Where the well has been drilled with air, a bridge plug shall be placed at the shoe
of the surface casing and the bridge plug shall be capped with at least 60 meters of
cement.
iv. Surface plug: 15 meters minimum. May be either neat cement or concrete mix.
c) Cased Wells
Cased exploratory, uncompleted development, former producing and injection wells:
i. Geothermal zones (uncased or perforated). Cement plugs shall extend from the
bottom of the zone or perforations to 30 meters over the top of the zone or
perforations.
ii. Liners. Cement plugs shall be placed from 15 meters below to 15 meters above
liner tops.
iii. Casing may be salvaged within protection, if first approved by the Licensing
Authority. A minimum overlap of 15 meters is required.
iv. Casing stubs and laps. Cement plugs shall be placed, if possible, from 15 meters
below to 15 meters above top of casing. If unable to enter stub or lap, 30 meters
of cement shall be placed on the top of the stub or lap.
v. Fish, collapsed pipe, etc. Cement plugs shall be squeezed, with the use of a
retainer or Braden head, with sufficient cement to fill across the production zone
or perforations and to 30 meters above the zone or perforations.
vi. Base of fresh waters: a minimum of 30 meters of cement straddling the interface
or transition zone, whether behind casing or uncased.
vii. Shoes plug (all casing, including conductor pipe): straddle with 30 meters of
cement.
viii. Where the well has been drilled with air, a bridge plug shall be placed at the shoe
of the surface casing and the bridge plug shall be capped with at least 60 meters of
cement.
ix. Surface plug: 15 meters minimum. May be either neat cement or concrete mix.