Review Article A Review of the Evaluation, Control, and ... · optimizing, wellbore design,...

Review ArticleA Review of the Evaluation, Control, and ApplicationTechnologies for Drill String Vibrations and Shocksin Oil and Gas Well

Guangjian Dong1,2 and Ping Chen1,2

1State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University,Chengdu, Sichuan 610500, China2College of Oil and Gas Engineering, Southwest Petroleum University, Chengdu 610500, China

Correspondence should be addressed to Guangjian Dong; [email protected] and Ping Chen; [email protected]

Received 15 May 2016; Revised 16 August 2016; Accepted 29 August 2016

Academic Editor: Tai Thai

Copyright © 2016 G. Dong and P. Chen.This is an open access article distributed under theCreativeCommonsAttribution License,which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Drill string vibrations and shocks (V&S) can limit the optimization of drilling performance, which is a key problem for trajectoryoptimizing, wellbore design, increasing drill tools life, rate of penetration, and intelligent drilling. The directional wells andother special trajectory drilling technologies are often used in deep water, deep well, hard rock, and brittle shale formations.In drilling these complex wells, the cost caused by V&S increases. According to past theories, indoor experiments, and fieldstudies, the relations among ten kinds of V&S, which contain basic forms, response frequency, and amplitude, are summarized anddiscussed. Two evaluation methods are compared systematically, such as theoretical and measurement methods. Typical vibrationmeasurement tools are investigated and discussed. The control technologies for drill string V&S are divided into passive control,active control, and semiactive control. Key methods for and critical equipment of three control types are compared. Based onthe past development, a controlling program of drill string V&S is devised. Application technologies of the drill string V&S arediscussed, such as improving the rate of penetration, controlling borehole trajectory, finding source of seismic while drilling, andreducing the friction of drill string. Related discussions and recommendations for evaluating, controlling, and applying the drillstring V&S are made.

1. Introduction

With increasing demand for oil and gas, conventional oil andgas production is declining. The trend of the global oil andgas exploration is from conventional to unconventional oiland gas resources [1], from deep well to ultra-deep well, fromthe deep water to ultra-deep water [2–4]. In order to achieveindustrial production capacity of unconventional oil and gas,directional well, horizontal well, and rotary steering system(RSS) must be used in the drilling process [5]. Vibrations areunavoidable since drilling is the destructive process of cuttingrock either by chipping or by crushing. Different drill stringvibrations and shocks (V&S) occur in complex drilling envi-ronments [6–16], especially the poor drillability formationwith extreme drill bit V&S, deepwell and ultra-deepwell withthe long drill string, the deep water to ultra-deep water with

vortex-induced vibration (VIV) of slender marine structures,coal and shale formation with borehole instability, irregularborehole diameter, and well trajectory increasing the levelof drill string V&S. Drill string V&S cause serious failuresof drilling tools and while-drilling-monitoring equipmentsuch as drill pipe, drill collar [17, 18], logging while drilling(LWD), measuring while drilling (MWD) [19], pressure andtemperature while drilling (PTWD), engineering parameterswhile drilling (EPWD), pressure while drilling (PWD) [20–22], and drill bits [23]. Typical drilling tools failure due to thedifferent drill stringV&S are presented in Figure 1. Accordingto statistics [18–23], nonproductive time (NPT) caused by thedrill string V&S account for 25% of total NPT every year,which seriously restrict the development of automatic drillingand the rate of penetration (ROP) as shown in Figure 2.On the other hand, the application of drill string V&S can

Hindawi Publishing CorporationShock and VibrationVolume 2016, Article ID 7418635, 34 pageshttp://dx.doi.org/10.1155/2016/7418635

2 Shock and Vibration

Cutters wear

(a) Reamer failure

Cracking

(b) Drill collars failure

Wear

Cracking

(c) Drill pipe failure

Wear

(d) Downhole measurementtool failure

Cone drop

Cutters wear

Cone drop

(e) Tricone bit failure

Cutters wear

(f) PDC bit failure

Figure 1: Typical drilling tools failure due to the different drill string V&S.

Input energy

ROP

Region I inadequate depth of cut (DOC)

Region II efficient bit

Region III founder(1) Stick slip(2) Bit bounce(3) Whirl

Potential performance

Performance is enhanced by redesigning to extend the founder point

Figure 2: The relationship of drilling parameters, ROP, and inputenergy.

bring immeasurable economic benefits for the oil industry.Consequently, the research and investigation of drill stringV&S are an important and interesting problem.

Over the past 70 years [6], an increasing number ofresearchers have put effort in the investigation of the drillstring V&S to understand its root causes, modelling, evalu-ation, control, and applications. Several review articles aboutthe theories and experiences of drill string V&S have beenpublished. The causes of severe drill string vibrations andguidelines of passive control were explained by Dareing[24]. The paper only focused on the bottomhole assembly(BHA) natural frequency to control drill string vibration.An overview on vortex-induced vibration (VIV) of slendermarine structures was provided by Pan et al. [25]. Theresearch and progress of concerning deep water riser VIVwere overviewed and discussed, including evaluation of VIV

analysis tools, experiments, appropriate fatigue calculationcriteria, and coupling effects induced by axial and inline VIV.The computational fluid dynamics (CFD) need to be givenmore attention in the future work [25]. The comparativereview of drill string torsional vibrations was focused byPatil and Teodoriu [26]. In this paper, the modelling andcontrolling torsional vibrations and experimentation usinglaboratory setups were reviewed. Based on the complexity ofdrilling phenomenon, using of the laboratory experimentsto study the drill string torsional vibrations has been thebest method. Another survey of approaches for stick-slipvibration suppression has been presented by Zhu et al. [27].The passive vibration control and active vibration controlwere reviewed. A broad survey of drill string vibrationmodeling literature was presented by Ghasemloonia et al.[28]. In this survey, the models for torsional, axial, andlateral vibrations (uncoupled and coupled), boundary con-dition assumptions, and application to vibration mitiga-tion were reviewed. Another broad study of seismic whiledrilling (SWD) technology has been presented by Polettoand Miranda [29, 30]. The general theory, data acquisition,date preprocessing, data processing, and applications of SWDwere overviewed which can provide essential guideline forthe researchers. However, there are very few overview articleabout the comprehensive evaluation, control, and applicationtechnologies for the drill string V&S.

From the above analysis, a broad overview of evaluationtechnologies, control methods, and applications of almostall drill string V&S types in the field of oil and gas wellscan help the engineers and researchers to develop moreadvanced technologies which can be applied to control andtake advantage of the drill string V&S. The structure of thepaper is as follows. The first part mainly compares the formsand evaluation technologies of drill string V&S; the second

Shock and Vibration 3

Stabilizer

Drill collar

Drill bitMeasurement tools

Drill fluid

BHA

Drill pipe

Drill fluid

Rotary table

Traveling block

Crown block

Derrick

Wellbore

Axial vibration/shock

Lateral vibration/shock

Torsional vibration Axial

vibration/shockLateral vibration/shock

Torsional vibration

(a) Drill string vibrations and shocksmode in the horizontal well

(b) Drill string vibrations and shocksmode in the vertical well

Figure 3: Typical drilling system and basic drill string V&S forms.

Bit bounce Stick slip Whirl

FastSlow Backward whirl

Forward whirl

Figure 4: Severe drill string V&S forms.

part pays attention to the passive control, active control, andsemiactive control of string V&S.The third part summarizedthe applications of drill string V&S. The key problem ofapplications of drill string V&S is discussed.

2. Vibrations Forms and Evaluation Methods

The investigation of drill string V&S can be traced back tothe 1960s [69, 70]; the researchers focused on the dynamicbehaviors of drill string bottom hole assembly (BHA). In the1990s [71, 72], experts began to study the V&S characteristicsof whole drill string system.These results pay attention to theimpact of bit-formation interaction on the drill string V&S[39]. Based on systematic research results, related discussionsand recommendations of key problems are proposed anddiscussed such as basic concepts, the classification andcomparison of drill string V&S forms, and the developmentand important indicators of vibration measuring instrument.

2.1. Vibrations and Shocks Forms. As a whole drilling system,slenderness ratio of the drill string is large, and the stiffnessis very small, which is prone to deformation as shownin Figure 3. Drill string V&S is divided into three basicforms such as axial (longitudinal) mode, torsional (rota-tional) mode, transverse (lateral) mode [24–28]. When thedrill string moves along its axis of rotation, this is calledaxial vibration/shock. Torsional vibrations are caused dueto an irregular rotation of the drill string when rotatedfrom the surface at constant speed. When the drill stringmoves laterally to its axis of rotation it is called lateral V&S.Due to many factors, very complex drill string V&S areproduced during actual drilling. According to past theories,indoor experiments, and field studies, the relationship of tenkinds of V&S is listed, which contains basic forms, modes,frequencies, amplitudes response, and tool damage as shownin Table 1.

Based on the research in Table 1, some important resultsand concepts were summarized and illustrated. Maximumfrequency and amplitude of drill string V&S are 350Hzand 200 g, respectively. Stick-slip [17, 27], whirl [10, 18, 33,34], VIV [25], lateral shock [39, 40], bit-chatter, and bitbounce [31, 32, 73] are the key research objects as shown inFigure 4.The stick-slip causing the drill string to periodicallybe torqued up and then spin free is a phenomenon ofnonuniform drill string rotation. The whirl is the eccentricrotation of the BHA & bits and is associated with the BHArolling around the wellbore. Drill string lateral shock not onlycauses harm to drill string itself but also can cause whirland serious damage to the wellbore quality [74]. VIV can beproduced by the riser-water interaction during deep water


Table1:Classifi

catio

nandcomparis

onof

drill

strin

gV&S.

Form

sMod

eofvibratio

nFrequency(H

z)Amplitu

de(g)

Tooldamage

Axial/lo

ngitu

dinal

Transverse/la

teral

Torsional/rotational

Stick-slip[27,31,32]

//

√0.1∼5

0∼10PD

Ccutte

rdam

aged,drillstringtwist

offor

washo

utBit-b

ounce[31,32]

√/

/1∼10

0∼100

Bitd

amaged

andBH

Awasho

utBitw

hirl[33]

/√

√10∼50

0∼200

Cutte

rand

/orstabilizers,increasedtorque

BHAwhirl[34–

38]

/√

√5∼2

00∼10

0Cu

ttera

nd/orstabilizers,increasedtorque

Lateralsho

ck[10,39–4

2]/

√/

1∼50∼14

BHAwasho

utTo

rsionalreson

ance

[26,43–4

8]/

/√

20∼35

0/

Cutte

rand

/orstabilizers,increasedtorque

Parametric

resonance[11–

15,49–

52]

√√

/0.1∼10

/Cu

ttera

nd/orstabilizers,increasedtorque

Bitchatte

r[53]

/√

√20∼25

0/

Bitd

amaged

andBH

Awasho

utVIV

[25,54–56]

/√

/0.1∼20

/Riserd

amage

Mod

alcoup

ling[36,57–6

0]√

√√

0.1∼35

0/

Drillstringtwist

off/w

asho

ut


drilling process [25] and is a kind of special lateral vibration,which has a great damage to the deep water drilling riser. Bit-chatter is the high-frequency resonance of BHA and bits. Bitbounce is the axis impact motion of drill string. The typicalenvironment of drill string V&S forms is also different andvery complex. The drilling environment where longitudinalvibrations develop frequently is hard rock, vertical well,cone bits (one-cone bits, two-cone bits, and tricone bits),and hybrid bits [19, 24]. The drilling environment wheretorsional vibrations develop easily is hard formations or salt,directional or deep wells, polycrystalline diamond compact(PDC) bits with high WOB, drag bits, and hybrid bits[17]. The drilling environment where transverse vibrationsdevelop typically is softer or interbedded formations withdifferent lithology, vertical, or horizontal wells [17, 19, 40].The borehole instability occurs easily in the interbeddedformations and causes the borehole size enlarging.The lateraldrill string V&S can be induced from either bit whirl or drillstring flexes during bit bounce.

From above review, there is a very complex couplingrelationship of the drill string V&S. The relationship has notbeen clarified so far. Many years of research for drill stringV&S guide us to find new method to study the key problem.Simplistic research methods and models are difficult to solvethe complex dynamic engineering problems of drill string.At present, rapidly developing computer technology haspenetrated into all social sectors which can solve complexcoupling issues. In order to clarify the rules of dynamicdrill string, the researchers should fully utilize moderncomputing methods and try to establish a model close tothe real drilling environment. According to field measureddata correct theory model, the macro- and micromethodsshould be combined; complex V&S problems of drill stringmay have a clear understanding.Macromethodsmainly focuson the structures dynamics and multibody dynamics. Themicromethods should pay more attention to the responsemechanism of V&S signals of bits breaking rock at themicro-and mesoscales, because the V&S signals contain complexmotion characteristics of drill string and bits.

2.2. Evaluation Technology. Before controlling the drill stringV&S, the relationship between vibration forms, vibrationlevel, and downhole tools failure must be clarified, so theevaluation technologies to solve the problem of drill stringdynamic failure need to be studied. Downhole drilling toolsfailure occurs in two typical modes [49]. On the one hand,when the vibration frequency is close to the natural frequencyof drill string, the drill string resonance occurs, and the peakresponse value approximates or exceeds the limit strength ofdrilling tools breakage failure. On the other hand, the drillingtools show fatigue damage in an environment with long-termor repeated vibrations or impacts. Fatigue is the main reasonfor drill string failure [75]; more than 75% of the fracturefailure belongs to fatigue fracture [76]. According to statisticdata [75, 76], gas drilling accounts for 50% and fluid drillingaccounts for 16% in all the drilling tools failure.

Evaluation technologies were established by long-termtheoretical research and application of measurement tech-nologies. There are two kinds of evaluation methods for drill

string V&S. One kind is to establish the failure model andpredict the life of the drill string based on fracture mechanicsand damage mechanics. The failure of drill string joints andload calculation methods under various working conditionswas studied by Bailey and Smith [77]. It is remarked thatmaterial fatigue strength decreases with the increase ofstatic stress, but the model did consider the dynamic stress.Permanent scratches on the drill pipe surface were analyzedby Hossain et al. [78]. It is noted that permanent scratcheslead to stress concentration and fatigue damage of the drillpipe. A comparative design approach to reduce the drill stringfatigue was established by Hill et al. [79].This design methodis to quantitatively express the relative fatigue performancebased on the crack extension model. A fatigue life model wasproposed by Wu [80]. This model considers the calculatingbending stress and fatigue of the dangerous drill string parts.The bending stress is directly related to the lateral drill stringV&C. The force and deformation of drill string using finiteelement method (FEM) were investigated by Millheim andApostal [71]. 2D and 3D model of drill string V&C weredeveloped. According to different rotating speed, the drillstring rotational energy levels can be divided into low energystable, moderate energy unstable, high energy unstable, andhigh energy stable. This study is a typical achievement ofdrill string V&C. A dynamic failure model of drill string wasproposed by Chi et al. [43]. This model considers the effectof torsional vibration and axial vibration at the same time. Acumulative failure method of drill string V&C was suggestedby Baryshnikov et al. [75]. This method based on full-scaledrill string fatigue test results considers the fatigue damageand crack propagation. However, this method is difficult tocalculate the drill string fatigue behavior under the downholecoupling V&S conditions. A working life calculation methodof drill string V&C considering the temperature for MWDwas developed by Wassell [81]. The method is used toestablish vibration limitation and determine accumulativevibration damage. A drill string failure model using thefault tree analysis method was established by Zang et al.[82]. This model considers many factors such as corrosionload, material strength, manual operation, and tool quality,but it did not quantify the effect of vibration. The above istheoretical research about the evaluation of drill string V&C.In the process of practical application, these models andmethods provide important support for the failure preventionof drill string. However, because of the complexity of drillstring V&C, the predicted results had a large deviation fromactual results on account of the above evaluation methods ofdrill string.

Therefore, the practical measuring method is anothereffective evaluation method of drill string. In order to obtaindynamic failure model range and experience model, themeasured V&S data and the observed failure are combined.Hence, the vibration measurement tools are the key technol-ogy and determine the accuracy and stability of evaluationapproach. The development of dynamic parameter measure-ment technology can be divided into four stages as shownin Table 2. In the first stage [61], downhole measure andstorage is an obvious characteristic, and the main purpose isto record bit data under different drilling conditions, which


Table2:Th

edevelop

mento

fmeasurin

ginstr

umento

fdyn

amicdrillingparameters.

(a)

Time

Author

orinventors

Equipm

ent

Measure

parameters

Worktemperature∘ C

Workpressure

MPa

WOB

TOB

Bend

ingmom

ent

RPM

Acceleratio

n1968

Esso

Prod

uctio

nRe

search

Co.[61]

Dow

nholer

ecorder

7434.5

√√

//

√1985

InstitutF

rancaisD

uPetro

le[62]

WTS

7434.5

√√

√√

√1985

NLIndu

striesInc.[63]

Wire

Telemetry

Syste

m/

/√

√√

√√

1988

ExplorationLo

ggingInc.[64]

MWD

//

√√

/√

√1988

Eastm

anCh

ristansen

Co.[65]

MWD

//

//

//

√1994

AmocoCo.&Hallib

urton[7]

Drill-stringdynamicssystem

(DDS)/D

rillD

OC

175

172.4

√√

√/

√1995

BakerH

ughes[8]

Nearb

itmechanics

tool

150

/√

√/

/√

1998

BakerH

ughes[9]

Dow

nholed

iagn

osisof

drillingdynamicsd

ata

150

137.9

√√

√/

√1999

BakerH

ughesINTE

Q&EIFCo.[13]

Cop

ilotsystem

175

206.8

√√

√/

√2003

Sand

iaNationalL

aboratories[11]

Diagn

ostic

whiledrilling

//

√√

√√

√2004

Hallib

urton[10,66]

SecurityDBS

175

172.4

√√

//

√2004

Geoservices

Co.&IFP[10]

ALS

-EVESyste

m/

//

√/

√√

2005

APS

Techno

logy

Inc.[12]

Vibrationmem

orysub(V

MS)

−40∼150

137.9

√√

//

√2005

Chen

Ping

[51,52]

Measurin

gdrillingengineeringparameters

125

60√

√√

//

2008

Weatherford

[67]

True-vibratio

nmon

itor(TV

M)

180

206.8

√/

/√

/2008

Schlum

berger

[14,15]

MWD/LWD/RSS/A

PWD

175

/√

√/

/√

2013

BakerH

ughes[66]

Nearb

ittemperature

measurement

175

206.8

//

//

√2013

ErnestNew

tonSumrall[50]

Mod

ular

dataacqu

isitio

nford

rillin

gop

erations

4010.3

//

//

√2013

NationalO

ilwellV

arco

[68]

BlackB

ox−40∼150

172.4

√√

√√

√

(b)

Time

Measure

parameters

Insta

llatio

nlocatio

nCh

aracteris

tics

Temperature

Hoo

kload

Pumping

pressure

inclinatio

nAnn

ulus

pressure

Pressure

drill

string(in

ner)

Bitp

ressured

rop

1968

//

//

√√

/BH

ADow

nholem

easurementand

store

data

1985

√√

√/

√√

√BH

ASamplingrate650H

z,real-timetransmission

1985

√√

//

√/

√BH

ASamplingrate650H

z,real-timetransmission

1988

//

//

//

/BH

ADeterminingthev

ibratio

nenvironm

ento

fMWD

1988

//

//

//

/BH

ADeterminingthev

ibratio

nenvironm

ento

fMWD

1994

//

//

√/

/BH

ARe

al-timed

atatransmission,

redu

cing

thed

rillstringresonance

1995

//

/√

//

/Surfa

ce/BHA

Syntheticallyestim

atingthed

rillstringvibration

1998

√/

//

√/

/BH

ASamplingrate1000

Hz,determ

iningdrill

stringvibration

1999

//

//

√√

/Surfa

ce/BHA

Real-timed

atatransmiss

ion(m

udpu

lse)

2003

√/

//

√√

/Surfa

ce/BHA

Real-timed

atatransmiss

ion(m

udpu

lse),samplingrate2080

Hz

2004

√/

//

√/

/BH

ASamplingrate2000

Hz,do

wnh

oles

tore

data

2004

//

//

//

/BH

ADeterminingthev

ibratio

nenvironm

ento

fdrillstring

2005

√/

//

√√

/BH

AWith

shockabsorber,real-tim

emon

itorin

g2005

√/

//

√√

/BH

ASyntheticallyestim

atingthew

orkenvironm

ento

fdrillstring

2008

//

/√

//

/BH

ADeterminingthev

ibratio

nenvironm

ento

fdrillstring

2008

√√

√√

//

Surfa

ce/BHA

Determiningthev

ibratio

nenvironm

ento

fdrillstring

2013

√/

//

//

/Bit

Determiningthev

ibratio

nenvironm

ento

fbit

2013

//

//

//

/Bit

Determiningthev

ibratio

nenvironm

ento

fbit

2013

√/

//

√√

/BH

A/Bit

Determiningthev

ibratio

nenvironm

ento

fdrillstring


Accelerometers

Gamma ray detectors

y

y

x

x z

z

(a) DDS sensor consists of triaxial accelerometers(Halliburton)

Cap

Module

Shank

PDC bit

(b) In-bit dynamic sensor (Baker Hughes) (c) Annular pressurewhile drillingmeasurements (Schlumberger)

(d) BlackBox Eclipse down-hole measurement tool (NOV)

(e) BlackBox HD downholedynamics recorder (NOV)

(f) Surface vibration measurement tool (CPU)

Vibration parameters measuring sensors collection

(g) BlackBox enhanced measurement system tool(NOV)

Vibration parameters measuring sensors collection

(h) Engineering parameters while drilling tool(SWPU)

(i) Vibration memory module(APS)

Figure 5: Typical and latest vibration measurement tools.

is provided for bit design. In the second stage [61–63, 65],data real-time transmission became a reality. It can be dividedinto wired transmission and wireless transmission. Wiredtransmission (cable transmission) rate is high, but it cannotbe applied to rotary drilling, and field operations are cumber-some.Wireless transmission (mud pulse transmission) rata islower than wired transmission, but the operation of wirelesstransmission is easy. In the third stage [8–10], monitoringdownhole drill string V&S is research priority, and reducingdrill string resonance is a main purpose. Sensor installationsite has drill collar and bit. In the latest stage [11–15, 50–52], the measuring instrument of dynamic drilling parameter(MIDDP) is combined with the rotary steerable system (RSS)and no drilling surprises (NDS) to solve practical problems.MIDDP has been successfully developed to improve theability to control the drilling process and reduce drilling risks.

There are several typical vibration measurement tools. Adetailed view section of these tools is depicted in Figure 5 and

they are the latest vibration measurement tools in the fieldof drilling engineering of oil industry. The extreme workingconditions are as follows. The maximum work pressure ofthese measurement tools is 206.8MPa and the maximumwork temperature is −40∘C∼180∘C.Measurement parameterscontain weight on bit (WOB), torque on bit (TOB), bendingstress, revolutions per minute (RPM), acceleration, annuluspressure, mud pressure, the drill bit pressure drop, andtemperature. The measuring system consists of four parts,downhole sensors (speed sensors and acceleration sensor),data acquisition, underground storage, interpretation, andthe ground data processing system. MIDDP can be installedon the wellhead [10, 61], drill collar [62], and bit [65], ormultiple sensors can be installed at the same time [12]. In-bit dynamic sensor (Figure 5(b)), BlackBox Eclipse downholemeasurement tool (Figure 5(d)), andBlackBoxHDdownholedynamics recorder (Figure 5(e)) are installed on the bitswhich can obtain the accurate vibration of bits. DDS sensor


HPHT

600

500

400

300

600

500

400

350

600

400

350

300

600

500

400

350

0Schlumberger

Baker HughesHalliburton

Total

Ultra HPHT

Extreme HPHT

10000 40000350002000015000 40000300002000010000 30000 400001500015000 400003000020000

Pressure (Psi)

Tem

pera

ture

(∘ F

)

Figure 6: HTHP classification system.

Table 3: Lateral vibration level classification.

Levels Axial accelerationRMS (g)Lateral acceleration

RMS (g) Limit time

Low 6 30 minutes, immediately reduce vibration

Table 4: Torsional vibration level classification.

Level Stick-slip (/r/min) State Limit timeLow 0∼40

Torsional vibrationNo

Medium 40∼60 NoMedium 60∼80 Suggest reducing vibrationHigh 80∼100 Stick-slip Completely, must reduce vibrationSevere >100 Stick-slip 30 minutes, immediately reduce vibration

(Figure 5(a)), annular pressure while drilling measurements(Figure 5(c)), BlackBox enhanced measurement system tool(Figure 5(g)), engineering parameters while drilling tool(Figure 5(h)), and vibrationmemorymodule (Figure 5(i)) areinstalled on the BHA. Data acquisitionmethod contains real-time transmission [7, 8, 13] and downhole storage method[62]. Maximum storage frequency is 650Hz [62] and maxi-mum sampling frequency is 2080Hz [11]. But the time delayproblem is serious in real-time transmission. Although thereal-time transmission can dynamically monitor the down-hole conditions, the downhole storage method is a better wayto analyze the high-frequency signals characteristics of drillstring V&C.

However, one of the key problems of measurement toolsis the adaptability to the ultra-deep wells and extremelycold area; the working temperature is the key factor. Theperformance of thesemeasurement tools, in comparisonwiththe HPHT classification system [87], can adapt to the ultra-high pressure environment, but only to high temperature

environment as shown in Figure 6, which limits themeasure-ment of drilling engineering parameters in ultra-high tem-perature and extremeHTHP formation. So the “drilling blindspot” of ultra- and extreme-HTHP formation has not beenrecognized without the true and real-time downhole drillingparameters. The research and development of MIDDP adaptto the HTHP environments which is one of the future keyproblems for the drill string vibration evaluation.

Another key problem of practical measuring method isthe date processing of dynamic signals and establishing ofevaluation criterion. Several new methods and suggestionsare investigated and discussed. According to the root meansquare (RMS) and the experience threshold of measuredacceleration value, evaluation criteria for drill string V&Swasdeveloped by Halliburton [7], Baker Hughes [8], APS [12],NOV, and Schlumberger [14, 15] as shown in Tables 3 and4. The applicable scope of practical measuring method toevaluate the drill string V&S levels is limited by the methodaccuracy, because of the fact that different oil fields have


different stratigraphic characteristics. The practical measur-ing method must be based on lots of measures and analysesfor the target oil field. A power spectrum density processor(PSDP) is located near the drill bit while drilling [88]. ThePSD of the vibrations generated by the bit while drillingwas computed by PSDP. The PSD date is telemetered to thesurface, which is used to enhance drill bit seismic techniques,as shown in Table 5.

Recently, there is no unified evaluation standard fordrill string to be used in oil industry. Lack of systematicresearch of evaluation methods for drill string V&S is thekey problem [7–15, 50–52, 61–66, 88]. However, there aremany kinds of evaluation methods about seismic level [83].In order to establish a unified evaluation method, we canlearn some knowledge from the area of seismic research. Theapproach used for quantification of vibration-related riskswas based on the indices used in geotechnical earthquakeengineering to describe the destructive potential of seismicmovements [83–86, 89–94]. Vibration intensity was used toobjectively determine the intensity of shaking by measuringthe acceleration of transient seismicwaves as the time integralof the square of the ground acceleration. An estimationof the average intensity of vibrations along the run wasprovided by power index [86]. Acceleration root squareis determined by obtaining the root square value of theplain integral of the squared acceleration [93]. Characteristicintensity was defined as a parameter related linearly to anindex of structural damage due to maximum deformationsand energy dissipation [84]. Real-time quantification of drillstring failure risk is shown in Table 6.𝑉rms is the root mean square, 𝑇𝑝 is the signal’s period,𝑉(𝑡) is the time dependent signal, 𝑔 is the acceleration dueto gravity, 𝑎 is the acceleration as a function of time, 𝐼𝐴is the Arias intensity, and 𝑇𝑑 refers to total time of the bitrun.

3. Control Technology

With increasing well depth and wide application of specialtrajectory technology [4, 6], the drill string V&S can causea great economic loss. A variety of control measures havebeen developed. According to the control theory and controlengineering knowledge, the control method of drill stringV&S can be divided into passive control, active control,and semiactive control. Comprehensive induction and clas-sification are discussed such as the typical structure ofkey equipment, principles and core control methods, andrepresentative results. Comparative analysis and discussion ofthe key methods, the corresponding key control equipmentand application ranges are carried out. Control programis formulated based on the previous research results; thefuture research direction of control of the drill string V&S isdiscussed.

3.1. Passive Control. Passive control of drill string V&S is thatthe control system did not need any external power but theenergy of existing system. Early control technologies belongto passive control.

3.1.1. Preventing Drill String Resonance. Preventing reso-nance is the first and the most common methods of drillstring passive control [24]. The main contents include estab-lishing amathematicalmodel, solving the inherent frequency,and conducting modal and harmonic analysis. This methodfocused on the optimizing drilling parameters and changingthe BHA structure in order to avoid the resonance frequencyof drill string.

Lots of researchers have focused on the solution of naturalfrequency and optimizing drilling parameters of drill string.The trial and error method to solve approximate naturalfrequency of drill string was studied by Finnie and Bailey[69].The frequencies of torsional and longitudinal vibrationswere observed, but the effect of damping was not consideredin themethod.The differential equation of torsional vibrationwas established by Aarrestad et al. [44]. The differentialequation assumed that rotary table was fixed, bit was free,and the torsional vibration frequency had nothing to do withRPM, WOB, and damping. The effect of BHA length on thedrill string vibration was focused byHuang andDareing [95].It is noted that the method in this paper can determine thenatural frequency of the lateral vibrations of long vertical pipesubjected to end thrust loads. However, this method cannotbe used to the horizontal well. Therefore, the transversalvibration of drill string contacting with the borehole wallin horizontal well was studied by Heisig and Neubert [41].The analytical solution for the threshold rotary speed hasbeen derived and is verified using the finite element model.It is remarked that a drill string in a horizontal borehole canvibrate in a snaking or in a whirling mode. A rigid modelof drill string was proposed by Menand et al. [96]. Wherethe helical buckling critical load of rotating drill string wasabout 50% of nonrotating drill string. The lateral vibrationequation and the buckling critical equation of drill stringwere derived by Wang [42]. The equation takes into accountthe effect of flow inside drill string, but the equation cannotbe verified in the field of drilling engineering. A naturalfrequency calculating model of drill string vibration wasdeveloped by Qu et al. [97], where the effects of fluid flowand temperature were considered. It is noted that the increaseof fluid flow rate in the wellbore can induce the instability ofthe lateral vibration of dill string. The BHA backward whirlusing the rotor dynamic theory was analyzed by Yucai andZhichuan [34]. The theory model was verified by the indoormodel test. Optimizing drilling parameters of dynamic is alsoa good way to prevent drill string resonance.The relationshipof WOB, RPM, and vibration for PDC bits was summarizedby Wu et al. [59] as shown in Figure 7. The optimum zone isdefined as a closed domain in the space of WOB and RPM.The drilling parameters in the optimum zone theoreticallyguarantee stability. The scope of the optimum zone dependson the bit and the rock to be drilled. Real-time optimizationof drilling parameters by combining themonitoring vibrationdata was carried out. The stability map of high-frequencytorsional vibration in the field was summarized [98, 99] asshown in Figure 8, which provided a basis for controllingthe drill string V&S. The low and high amplitude vibrationsdistinctly fall into zones, which indicate that high-frequencytorsional vibration occurs at higher WOB and low RPM.


Table5:Drillbitvibrationpo

wer

spectraldensity.

Measure

power

Spectrum

downh

ole

Use

precision

downh

olec

lock

Surfa

cemeasurementsof

drill

strin

gmotion

Measuremento

fbit

noise

atEa

rth’s

surfa

cep-wave

Totalw

aveform

Tagbeginn

ingof

power

spectrum

p-wave

p-wave

Torsionalw

ave

Up-going

waveform

Tagtim

eofenergeticevent

Torsionalw

ave

s-wave

Lateralw

ave

Dow

n-going

waveform

Limitedtim

edom

ainsample

Com

presse

vent

asaw

avele

tAc

celeratio

n/

Toolradialtangentia

laxis

/

(Futurec

ompress)telemeter

tosurfa

ce

Telem

eteringto

surfa

ceMud

pressure

/

Time/ph

ase

Fouriertransform

Wavele

tdecom

position

//

//

Alternatively

,dono

tuse

precision

clock

Alternatively

,dono

tuse

drillstrin

gmotionatsurfa

ce/


Table 6: Real-time quantification of drill string failure risk.

Name of equation Equation Units

Root mean square [83–85] 𝑉rms = √ 1𝑇𝑝 ∫𝑇𝑝

0𝑉(𝑡)2𝑑𝑡 g

Vibrations intensity [86] 𝐼𝐴 = 𝜋2𝑔 ∫𝑇𝑑

0𝑎(𝑡)2𝑑𝑡 g2h

Acceleration root square [83] 𝑎rs = √∫𝑇𝑑0𝑎(𝑡)2𝑑𝑡 h0.5g

RMS acceleration [83] 𝑎rms = √ 1𝑇𝑑 ∫𝑇𝑑

0𝑎(𝑡)2𝑑𝑡 g

Power index [86] 𝑃𝑎 = 1𝑇𝑑 ∫𝑇𝑑

0𝑎(𝑡)2𝑑𝑡 g2/h

Characteristic intensity [84] 𝐼𝐶 = 𝑎1.5rms𝑡0.5𝑑 g1.5h0.5Peak acceleration [83] 𝑎 = 𝑎peak g

RPM

WO

B

Low ROP Forward whirlBackward whirl

Optimum zone

Buckling due to excessive WOB

Figure 7: The relationship of WOB, RPM, and vibration for PDCbits.

The right “drilling dessert (optimum zone)” within a cer-tain range can be found by optimization drilling parameters;optimization drilling parameters only solved the vibrationsources frequency and nature frequency of drill string.However, the drilling efficiency could be reduced by excessiveadjustment of drilling parameters. Calculating the drill stringnatural frequency and vibration mode using the mathemati-cal model was a usual and simplifiedmethod, but it is difficultto get accurate inherent features; the drill string V&S couldnot be completely eliminated. Optimizing BHA to change thenatural frequency of the drill string is another well approachto suppress the drill string V&C.

Commonly used method of optimizing BHA is adjustingthe quantity and site of stabilizer or reamer. Shear stress alongthe BHA and the bit had greater volatility which was foundby Bailey et al. [35, 57, 100, 101]. It is remarked that therewere torque mutations in the stabilizer, and the stabilizerwas a main cause for the BHA backward whirl and stick-slip vibration.There are two new improvements on new BHAstructure as shown in Figure 9. The near-bit stabilizer ofdrilling tools was removed; roller reamer was moved to theheavy wall drill pipe (HWDP). According to the statistical

analysis of RasGas and ExxonMobil [57, 101], the transversevibration and stick-slip of the drill string can be controlled bynew BHA.The average ROP and total footage were increasedby 36% and 36%, respectively. New BHA was conductive tothe ultra-deep well and gas drilling. The method can be usedto the PDC bits and roller bits and hybrid bits.

3.1.2. Changing Energy Distribution of Drill String. Energydistribution was changed from the boundary condition ofdrill string system. Bit mainly changed the magnitude andforms of axial input force, and the stabilizer and reamerchanged the drill string lateral contact with the borehole wallincluding distance and contact force between the drill stringand the borehole wall.

First of all, the input energy of vibration source wasreduced by the use of antivibration bit. The antivibration bitwith special structure design can suppress or mitigate thevibration amplitude of drill bits as shown in Figures 10 and11. The bit-rock interaction caused axial vibration and stick-slip vibration, where this dynamic energy was transferred tothe drill string system, so the bit was the main source of drillstring V&S. The excitation source contained RPM, bit/rockinteraction, mud pump, and stabilizers [102]. The theorystudy of changing energy distribution focuses on the effect ofbit structure and bit type to the dill string V&S. The effect oftricone bit random vibration on the drill string longitudinalvibration was studied by Skaugen [103]. The model canbe used to predict sharply increased vibration amplitudeswhen rotary speed is a certain subharmonic of resonancefrequencies in the drill string. It is noted that there areaxial and rotational quasirandom components, both for axialand for rotational movement. A coupled vibration modelof drilling string was analyzed by Yigit and Christoforou[58]. The model considers the effect of axial, lateral, andtorsional vibration and quantitatively describe the effect ofPDC bit-rock interaction on the drill string vibration. Thephenomenon of bit whirl was studied by Sinor et al. [33].The antiwhirl bit was firstly developed with smooth edgesand reasonable cutter layout, but the bit just considers thebasic bit design. The well deviation was affected by the bitwhirl and stick-slip, and the concept of “flexible bit” wasproposed [104]. A flexible connector was installed on thecutting teeth of bit in order to reduce bit deviation. However,the flexible PDC bit was not applied to the field due to thefailure of flexible connector. Based on the response law ofbit eccentric motion, a new design method was proposedby Johnson [105], by which eccentric PDC bit increasedthe centripetal force and reduced side cutting force andtransverse vibration. Detailed configuration of the two-corePDC bit is presented in Figure 10(a). A new thermostablePDCbit to reduce bit vibrationwas developed byExxonMobiland Schlumberger [106, 107]. The structure of the PDC bitis depicted in Figure 10(b). There were some notable featuresabout the PDC bit: (1) 6 blades and 16mm cutter preferable;(2) tooth and auxiliary tooth structure in each blade; (3)tapered structure used. The structure reduced friction forceof bit and the friction force is the main reason of drill stringdynamic instability. The advantage of this design is makingfull use of the optimizing structure and the thermostable


Stick-slip Stable

Whirl/lateralvibration

High trequency torsional vibration

40

30

20

10

00 50 100 150 200

WO

B (k

lbf)

WO

B (k

lbf)

RPM (r/min) RPM (r/min) 0 50 100 150 200

0

10

20

30

40

Baseline

>15 g


(a) The self-adjusting PDC bit (b) The concept illustration of self-adjusting DOC control

Self-adjusting DOC control unit

Small contact force Small contact force

Enables gradual change in DOC

Small contact force Small contact force

Resists sudden change in DOC

RockA

RockB

RockC

Figure 11: The self-adjusting PDC bit and concept illustration.

Comparing to the standard cutter without DOC unit, thenew bit with the DOC unit limits the loading of high WOBto reduce the indentation depth of PDC cutters. The designconcept is easy to come true. However, the drilling industryfaces the task of drilling different rock type in one well witha single bit; the PDC bit with fixed DOC control (DOCC)elements limit vibration mitigation and the increase of ROP.Hence, an innovative PDC bit with self-adjusting DOCCelements was proposed by Schwefe et al. [110], which can self-adjust its DOCC ability to the constantly changing drillingenvironment and mitigate V&C while delivering improvedROP. The detailed structure of this new concept PDC bitis in Figure 11(a). To illustrate the concept, a hypotheticalformation with three rock types is considered as shown inFigure 11(b). Sections B and C are prone to stick-slip. ThePDC bit with fixed DOCC elements requires offset well datato drill the well which limit the ROP and ability of mitigatingstick-slip.The PDC bit with self-adjusting DOCC units offersan elegant solution to resist the DOCC fluctuation at the timescale of stick-slip in rock B and rock A. the gradual retractionof DOCC units enables faster drilling in the soft rock A.The advantage of the bit is anticipated to absorb shocks ininterbedded formations.

The second approach was the use of decoupled oradjustable reamer in reaming operations. Roller reamer coulddecouple stick-slip and the whirl of drill string [111]. Theconfiguration of the reamer is shown in Figure 12(a), becausethe friction force between roller and borehole wall wassmall. Roller reamer made wellbore more smooth, and repeatreaming reduced the bending moment and TOB of BHA.When a reamer was installed in the drill string about 40mfrom the bit, the borehole could have better quality. Theadvantage of roller reamer is not only suppressing the lateral

vibration and torsional vibration at the same time but alsoreducing the friction between the drill string and boreholewall. The fixed stabilizer installed on the reamer could notstabilize the upper drill string, which aggravated the drillstring V&S [112]. A new expandable reamer to mitigatedrill string V&S was developed by Schlumberger and BakerHughes [59] and its configuration is depicted in Figure 12(b).The reamer was expanded to support the borehole wall, andthen the drill string had small bending and amplitude ofV&C. The field test of expandable reamer was carried out inOklahoma; the test results show that when the well deviationis less than 30∘, the ROP increased by 35%. When the welldeviation is less than 20∘, the transverse vibration andwhirl ofthe drill stringwere reduced by 26%.The effect of suppressingvibration of expandable reamer used with dual core bit isbetter. There are some characteristics and advantages: (1)Each blade has two rows of cutting tooth, with the purposeof strengthening the ability of wear-resisting. (2) Gauge padcan reduce the dogleg angle of well trajectory and drill string.(3) Replaceable protection and stability block can avoid stressconcentration due to welding heat effect. However, comparedwith roller reamer, expandable reamer mainly control thelateral V&C.

Another effective method for controlling V&S was thestabilizer installed on the drill string. Based on the studyof Dareing [24, 72, 95], longitudinal and torsional vibrationresponse of drill string depended on viscoelastic damp-ing and support constant [36, 53]. The dynamic responsecan lead to chaotic movement of drill string. A new V-shaped stabilizer for stick-slip and whirl of coiled tubingoperation was developed by National Oilwell Varco (NOV)[113]. Detailed configuration of the stabilizer is presented inFigure 13(b). Two pieces of stabilizer blade were shaped like a


Whirlforce

Whirlforce

High frictionHigh torque

Low frictionLow torque

Cutter

Rollor

Upper pad

Lower pad

Screw

Screw

(a) Roller reamer

Upperstabilization pad

Lowerstabilization pad

Gauge pad

Cutter bladeNozzle

Sliding track

(b) Expandable reamer

Figure 12: Typical vibration reduction reamer and concept illustration.

nonaxisymmetric structure, and the core working principle isthe centrifugal force of drill string rotary.When the vibrationwas transmitted to the stabilizer, the vibration mode waseliminated. The V-shaped stabilizer can induce drill stringforward whirl (FSW) to improve ROP for the first time.The test results of V-shaped stabilizer in the Green Canyonsection of the Gulf of Mexico show that ROP increasedby more than 50%, and stick-slip decreased by more than75%.The downhole tool drop can be prevented by integrateddesign of the stabilizer. A new expandable stabilizer wasproposed by Al-Thuwaini [37, 38]. The detailed structureof the expandable stabilizer is shown in Figure 13(a). Theexpandable stabilizer is an improvement of the expandablereamer. The main difference is that the cutting tooth ofexpandable reamer was replaced by the stabilizer blade. Thesharp edge of stable blocks with double inclined plane radialdistribution improved ROP. A new near-bit stabilizer wasdeveloped byNOV [114]; the configuration of the bit is shownin Figure 13(c). This stabilizer with four spiral blades wasdivided into the totally enclosed type and the semienclosedtype. Fully enclosed structure could control vibration of drillstring and improved the signal-to-noise ratio (SNR or S/N)of bit. SNR is a measure used in science and engineeringwhich compares the level of a desired signal to the level ofbackground noise and is defined as the ratio of signal powerto the noise power. Semiclosed structure was conducive tothe cuttings carrying and hydraulic parameters optimization.Back pressure valve and vibration monitoring instrumentwere installed on the stabilizer. Compared with the V-shapestabilizer and expendable stabilizer, the advantage of the bitis that the simple structure makes full use of the ability ofmitigating vibration and cuttings transportation.

The forth method was passive control of deep water riser.Changing surface shape of the riser will change the flow fieldaround the structure, which could decelerate the formation,development, and peeling process of vortex [54]. Passivecontrol methods for controlling VIV were divided into three

types [55].The first type is the interference entrainment layerof vertex such as ribbon fairing. The second type is theinterference of separation line or separating shear layer suchas axial bar, blade, and half spherical structure.The third typeis the effect of entrainment layer wrapped such as pipe sleeve,screen structure. Currently the successful development andapplication are spiral stripe suppression structure as shown inFigure 14(a) and the fairing structure as shown in Figure 14(b)[56].

Means to change energy distribution were economic,effective, and simple, but the friction force of drill string willbe increased by this equipment. Protecting the importantequipment and the smooth work of the drill string is anothereffective method.

3.1.3. Shock Absorber Balances the Dynamic Energy Systemof Drill String. The shock absorber is one of the mosteffective passive control methods, divided into axial onesand rotational ones. The peak value of the drill string V&Sdepended on the damping caused by mud and drill pipes[115]. Two kinds of axial absorber are widely used in drillingengineering. One kind is disc spring shock absorber; thedetailed structure of shock absorber is shown in Figure 16(a).The optimal compression stroke is 10%–75% of themaximumcompression stroke.When theWOB is too high, the compres-sion spring will absorb one part of WOB. With the decreaseof WOB releasing energy to the bit, drill process will bealways smooth.The shock absorber close to the bit controlledsevere vibrations and extended the service life of bit. Theexpensive equipment was protected by the shock absorberinstalled below the MWD and LWD. The connector bodystrength of absorber can withstand ambient temperature of231∘C and a work time of 300 hours. The absorber is suitablefor directional drilling, hard formation, horizontal drilling,casing side tracking window, borehole reaming, and coiledtubing operations.The other axial absorber is hydraulic shock


Upperstabilization pad

Lowerstabilization pad

Gauge pad

Cutter blade

Nozzle

Sliding track

Backreamingcutters

Doublebevel/radius

Groundunder-gaugeon diameter

(a) Expandable stabilizer (b) V-shape stabilizer

(c) Antivibration near-bit stabilizer

Figure 13: Typical vibration reduction stability.

(a) Spiral band control device (b) Fairing control device

Figure 14: Typical deep water vortex-induced vibration controller.

absorber. The configuration of the absorber is in Figure 15.The control principle of drill string V&C is similar to thedisc spring shock absorber. The structure of the hydraulicshock absorber to balance the dynamic energy system of drillstring is hydraulic oil. Compared with the disc spring shockabsorber, the bearing capacity of hydraulic shock absorber islarge. A new rotational vibration absorber (antistall tool) fordeep hard formation and interaction formation of bit stick-slip was developed by Seines et al. [116] and its configurationis depicted in Figure 16(b). The core working principle is that

TOB was converted in the compression energy of torsionalspring to reduce the torsional vibration. An abrupt increasein torque (𝑀2) will cause a telescopic contraction (𝑆) to off-load the weight from the cutters (𝐹2).The concept illustrationof AST is in Figure 17. For anti-stick-slip tool (AST/antistalltool) installation position [117], it is close to the bit as faras possible; in order to meet the demand of RSS and sensormeasurement, AST was often installed above the MWD andthe reamer. According to the statistics [117], the test results inAzerbaijan show that total footage and ROP utilizing the AST


Oil cylinder PistonSeal assembly

Figure 15: Hydraulic shock absorber.

Bottomsub

Pistonhousing

Belleville spring Retaining ring SealsBalancepiston

Spline Spline mandrel

(a) Axial absorber

Bottom sub Spring Male helicalsplineFemale helical

splinePressure

sealsPreloaded

spring Top sub

(b) AST absorber

Figure 16: Typical V&S absorber.

S

M1 M2

F1 F2

Figure 17: The concept illustration of AST.

increased by 15% and 40%, respectively. Severe vibration timedecreased by 46%. Compared with the axial absorber, theadvantage of AST controls the torsional vibration and axialvibration to mitigate the stick-slip.

Although this passive control method to reduce the drillstring V&S is simple and economic, the control of shockabsorber is limited. Because of the complex V&S on the drillstring, engineers and researchers should propose a methodwith a wide range of control and flexible adjustment capacity.

3.2. Active Control. According to the dynamic characteristicsof the control system, the active control of the drill stringV&Sis by active application of force in an equal and oppositefashion to the forces imposed by external vibration. Theactive control of drill string can be divided into the wellheadcontrol, the bottomhole control, and the whole drill stringcontrol. Common methods include frequency methods androot locus methods. For active control of drill string, thedrill string model and external interference should be con-sidered, such as RPM, WOB, and damping. According to therelationship between the input and output of control system,the drill string system can be divided into open-loop andclosed-loop feedback control systems. Open loop control is toreduce or eliminate extraneous force (WOBorRPM).Closed-loop control is to change the stiffness and damping of thedrill string. Recently, vibration amplitude was reduced byautomatically adjusting the TOB and RPM is an importantmethod.

An active damping strategy of stick/slip vibrations wasdeveloped by Jansen et al. [45], which was realized eitherby emulating a passive absorber behavior or by using amore advanced (typically state-variable) drill string speedcontroller structures. The passive absorber behavior wasdescribed with rotational spring and damping coefficient.Indirect approaches are typically based on a WOB controlsystem coupled with the main RPM controller. An input–output type HN controller for practical applications wasproposed by Serrarens et al. [118], but it is not quite clearfrom the presented results if such a constant-parameterhigh-order controller can provide consistent performancefor a wide range of drill string lengths and configurations.


Drill string

BHA

Bit

Top drive

HPFLPF

Kp

+ +

+−

+−

+−

Sensors

Ωconst

Ω0

𝛼0

𝛼1 𝛽1

Ω1

B0 = Ωctrl

Figure 18: Controlling torsional vibrations of drill strings via decomposition of traveling waves.

A proportional-integral (PI) speed controller based on thespatial distribution model of drill string was designed byTucker and Wang [46]. However, the low order controllerwas difficult to completely control the torsional vibration.Thecoupled torsional and lateral vibration were eliminated bythe use of the state feedback controller [60]. A method forhandling a stuck tool situation was proposed by means of astate controller with a WOB feedforward action [119], but itdoes not consider the braking power and torque saturationeffect. A single input-output closed-loop control system (D-OSKIL)was established byCanudas-de-Wit et al. [120], whichwas verified by the indoor experimental model. A stick-slipcontrol model based on the error compensation method wasproposed by Puebla and Alvarez-Ramirez [121], where thecascading and distributed control framework were derived;the analog results can effectively control the uncertain factorsand instability of the system caused by friction. A stick-slipcontrol model based on the GA algorithm was developedby Karkoub et al. [47], which combined the lead lag andproportional-integral-derivative (PID) controller. Based onthe integrated controller, the drill string stick-slip was con-trolled by Majeed et al. [122]. The linearization of nonlinearsystem allows the pressure fluctuation to have errors, and theanalog results were ideal. A full-order state controller basedon the two-mass elastic process model was proposed by Al-Hiddabi et al. [123], but the “critical” aspect of robustnessof full-order nonlinear state estimation in the presenceof unknown stick-slip friction is not considered. A PID

controller based on the stable stick-slip model was designedby Abdulgalil and Siguerdidjane [124]. Controller sensitivitywas evaluated in connection with process parameters vari-ables. The full-order state feedback method and full-orderestimate method were unstable in the practical application. Awhole drill string control strategy based on adaptive Kalmanfilter estimating drill string nature frequency was proposedby Pavković et al. [125], and the backward whirl of drill stringcaused by the braking power of servomotor was studied. Atorque feedback PI motor speed controller for the drill stringwas developed by Deur et al. [126]. The controller has a highresponse speed for low inertial load tools. A state observerwas used to assess the drill string torque disturbance vari-ables.The controller and viewer were reconciled according tothe damping optimization criterion based on amplitude. Anadaptive PID control strategy was designed by Li et al. [48].The control strategy is suitable for the drill string stick-slip.Kreuzer and Steidl [73] presented a method for controllingstick-slip vibrations by exactly decomposing the drill stringdynamics into two waves traveling in the direction of the topdrive and in the direction of the drill bit. A detailed viewof this system is depicted in Figure 18. The decompositionis derived from the wave equation governing the stringvibrations and is achieved with only two sensors that can beplaced directly at the top drive and at a short distance belowthe top drive (e.g., 5m). Therefore, downhole measurementsalong the string and at the bit are not necessary, which is amajor advantage compared to other control concepts for drill


PLC controller

VFD

Motor

ST control panel

ST controller (IPC)

Actual speed

Line 1 Line 2

Line 3

Line 4

Line 5

Drill string

BHA

Bit

Top drive

Gearbox

Figure 19: Soft torque rotation system configuration.

M

M

Electric motor

Drive inertia

Pipe stiffness

BHA inertia

(1) Achieved by changing the drive controls

(2) Could be software or electronics

(3) Tuning is required: Cf and Kf

System

Added compliance

and damping

No STRS/STRS OFF STRS ON

Figure 20: The STRS working principle.

string dynamics. A linear quadratic controller for the stick-slip vibration was established by Sarker et al. [127], whichwas compared with spring damping vibration isolator. Basedon the ellipsoid method, the neutral delay comprehensiveclosed-loop control model for coupled axial and torsionalvibration was proposed by Saldivar and Mondié [128]. Themodel was verified by the results of numerical simulation. A

soft torque rotation system (STRS) for the torsional vibrationof drill string was developed by Javanmardi and Gaspard[129]; the active control system is the only available system forthe engineering conditions. The detailed configuration andworking principle of STRS is in Figures 19 and 20. The STRSwas installed in the top drive, and the torsional vibration wascontrolled by DC motor or AC motor. The STRS introduces


Magnet coils MR fluid Mandrel

Figure 21: Semiactive vibration dampers.

compliance and damping in the top drive to remove torsionalvibration energy instead of allowing it to build into stick-slip.

Controller of drill string V&S was developed based onthe classical control theory.The simulation results were good,but it was hard to get the accurate downhole vibrationdate. Calculation method of controller is complex; hardwaredevelopment is difficult.Wellhead closed-loop control systemhad the features of fast response and low cost but could notreflect the real transmission law of the bottom hole vibrationsignals. The delay time of system response is longer, andcalibration is difficult. Therefore, semiactive control methodis another excellent solution to eliminating the drill stringV&S.

3.3. Semiactive Control. The semiactive control technologyhas the advantages of passive and active control. In order toadapt to the optimal state of the structure, semiactive controlusing passive control devices only needs less energy to changethe parameters of the passive control system and workingstate. A semiactive vibration control damper (AVD) wasdeveloped by APS [130]. The axial and torsional vibrationscan be effectively reduced by AVD. The tool chamber isfilled with magnetic fluid [131, 132]; the configuration of thetool is shown in Figure 21. Drill string vibration signal givenwas returned to the solenoid control device, and V&S werecontrolled by increasing the viscosity damping of magneticfluid. Recently, this semiactive control found application inthe field, because of the limited ability of passive controland the time delay of conventional active control from thebottom hole to the surface. Many server drill V&C lost thebest opportunity to be controlled. An approach for miti-gating downhole V&C is to continuously monitor dynamicdownhole forces and BHA motion and to intermittentlytransmit the most recent vibration information to the drilleras shown in Figure 22(a).The driller then makes adjustmentsto surface control parameters whenever excessive shock orvibration levels are observed. Therefore, an intelligent self-adapting damper in the BHA without the driller’s decisionto frequently mitigate the drill V&C is necessary. The systemis shown in Figure 22(b). The AVD can use a part of self-adapting BHA V&C system.

3.4. Comprehensive Comparison Analysis and Discussion ofControl Technologies. Different controlmethods based on the

widely known theories are summarized. One kind of V&Shas different control equipment and control system. Differentforms of vibration or shocks can use the same equipment. Buteach device and system has its own limitations. Comparativeanalysis of the key methods, the corresponding key controlequipment, and the application range is carried out as shownin Table 7. The control program of drill string V&S is set out(as shown in Figure 23) based on existing research results,which can provide the guide of “harmless” drilling for fielddrill engineers. The program of drill string V&S containsseveral important segments, such as optimization of drillparameters, real-timemonitoring of vibration (Table 2), eval-uation of vibration levels (Tables 3 and 4), and distinguishingvibration types (Table 1) and control methods (Table 7) fordifferent vibration type and levels.

Control technologies for drill stringV&Shavemade someachievements and have achieved initial positive results. Thepassive control technology of drill string V&S is mature,especially for axial and transverse vibration. The torsionalvibration control technology was at the stage of experimenta-tion. The control methods for axial and transverse vibrationwere established. Theoretical model of passive control issimplified, but not systematic. Theory results vary widelywith practice results. Key equipment performance is notstable. The best parameter or new parameters by taking intoconsideration many comprehensive factors need to be found,which is to optimize the working performance of the keyequipment. In order to give full play to the role of differenttypes of the shock absorber, the control and optimizationmodel of shock absorber should be established.The design ofnumber and position fully considers the performance of theshock absorber (stiffness, natural frequency, and damping)and meets the standards for qualified transfer coefficient andreduction efficiency. The development of viscous materials isthe next research focus of shock absorber. Other equivalentdamping force can be used to deal with drill string V&S.

Active control theory and simulation technology of drillstring V&S are relatively mature. The semiactive control haspreliminary application. During the application process ofcontrol theory, the problem of drill string stability still has notbeen completely resolved. Namely, the complex motion andsignal transfer law along the drill string are not clear. Its keyresearch fields are in deep water, with ultra-deep and shallowunconventional oil and gas. The first stage of intelligentdrilling, automation drilling, and expert system is to builda stable control system. Once the structure and parametersof drill string system are determined, the stability problemsare identified based on the theory model, but actual drillingconditions are complex, and slender drill string, formation,and fluid formed a huge system. WOB, RPM, TOB, boreholequality, and other factors synthetically restrict each other.Every parameter has uncertain factors, which even causeopposite regularity of theory and practice results.

Downhole dynamic parameters measurement is accu-rate, but the development of measurement tools is difficultand expensive. Transmission signal attenuation and slowtransmission speed are another key problem. In order torealize the stable control system, transmission law betweenbottom hole and wellhead need to be solved. The real-time


Drill fluid

Lateral vibration/shock

Torsional vibration

MWD diagnosticstransmission

Rig floordisplay

Driller

Drill fluid

Axial vibration/shock

MWD diagnosticstransmission

Rig floordisplay

Driller

Automated damper(semiactive vibration dampers)

Downlinking

(a) Closing the loop with the driller (b) Closing the loop autonomously downhole

Driller IN the loop Driller ON the loop

Figure 22: Loop controlling system for the drill string V&S.

monitoring and analysis of underground and ground datecan show the real response mechanism. Classic controltheories are based on transfer function [133]. So we do notneed to solve complicated mathematical model to study theinput signal with zero initial conditions of dynamic process.Because of the huge drilling cost and high risk in field test,an accurate physical model on the ground can simulate thedownhole transmission rule. However, the physical modelon the ground of transmission law of slender drill stringdid not come true. It is necessary to establish the physicalmodel based on similarity criterion [134]. Aerospace andmilitary industry has developed rapidly, so themature controltechnologies in the aerospace and military industry areintroduced for the control of drill string V&S. Because theV&S increased control difficulty and uncertainty of drilling,it not only is related to the working life of the downhole toolsbut also involves the borehole quality and drilling cost. Itis a multiobjective dynamic optimization control problem,and the multiobjective dynamic and collaborative algorithmtrack control method of vehicles in the field of aerospace andmilitary industry can be introduced for the control of drillstring V&S.

In order to take advantages of control methods andreduce the drilling cost, the hybrid control system should beestablished based on various control methods [135]. Passivecontrol, active control, and semiactive control can be in adrill string system at the same time. Different control modescan be used according to the different levels of drill stringvibrations and impacts.

4. Application of the Drill StringVibrations and Shocks

The serious V&S of drill string should be controlled andeliminated as soon as possible; however, rational utilization

of the drill string vibrations will bring huge benefits to thedrilling engineering. Currently several applications of thedrill string V&S have achieved good results.

4.1. Improving ROP. ROP is one of the key technical dif-ficulties in shale gas reservoir, which increases the drillingtime and cost. Percussive-rotary drilling (PRD) plays anincreasingly important role in improving the ROP as shownin Figure 24. PRD is developed from rotary drilling andpercussive drilling, which take advantages of the bit V&S.There is torsional impact drilling and axial hammer drilling.One of the earliest reports of percussion drilling techniqueoccurred in 1940s [136]. Since then different terms havebeen used, such as downhole hammer, percussion hammer,Down-the-Hole hammer, percussive drill, and percussive-rotary drill [137, 138] as shown in Figure 25. The applicationand performance of air hammers were evaluated by Downset al. [139], but the application of air hammer was limiteddue to the manufacturing and design capabilities. The ROPwith a low WOB and RPM was improved by air hammers[140–147]. Recently, impact hammer [148, 149] has beenapplied in drilling engineering. High-frequency torsionalimpact drilling (HFTID) made a good use of the torsionalshock energy of drill string and bit [150, 151]. The problem ofROP of hard and fragile formation was effectively solved bythe HFTID. The use of HFTID can greatly improve the rockfragmentation efficiency, increase the tool life, and reducecost [152]. However, because of a lack of quantitative exper-iments and experimental facilities for the HFTID, the rockfragmentation mechanism of HFTID cannot be completelyrealized, and choosing of bit and drilling parameters forHFTID is difficult. Based on the conversion of vibrationenergy of drill string and hydraulics energy, a vibrationabsorption downhole pulse generator was designed by Guanet al. [153]; the simulation model of the tool was established.


Formation/well profile/

well trajectory

Drill string components/location/

vibration limited

Continue drilling

Ground date Underground

Change drilling parameters

Lateral Axial Torsional

Whirl Bit bounce Stick-slip

Decrease Same Increase

ROPWOBFlow

ROPWOB

ROPWOB

Lateral Axial/torsional

Motor RPM

Critical speed

Motor Drill string

Hole size

Finite element modelAnalytical solution

Static bending analysis

Deflection, side forces, bending moment , nominal stress

Vibration analysis

Achieve drilling object? (ROP,

target spot)

Drilling parameters

change?

Max value

Forces balanced at the

bit?

Predicted andmeasured critical

speed agree?

Vibration?

Yes

Yes

Vibration type(Table 1)

Remote database

No

Advise operator

PassiveActive

Semi-active(Table 7)

Vibration level(Tables 3 and 4)

Vibration level(Tables 3 and 4)

No

No

No

Revise model

Yes

Calculation warning value

YesNo

Real-time monitorvibration date

(Tables 2, 5, and 6)

>Vibration threshold?

Yes

YesNo

No

Figure 23: Controlling program for drill string V&S.


Table7:Com

prehensiv

ecom

parativ

eanalysis

ofdrill

strin

gV&Scontrolm

etho

ds.

Classifi

catio

nMetho

d/mechanism

Advantages

Disa

dvantages

Techno

logies

Adaptthe

form

Transverse/

lateral

Axial/

long

itudinal

Torsional/

rotatio

nal

Passive

control

Preventreson

ance

Thee

arliest,

them

ostcom

mon

lyused,m

ainlyconsideringthe

inherent

characteris

ticso

fdrillstring,fastcalculation,

canavoidthe

vibrationmod

e

Mod

elissim

plified,the

controlofd

rill

stringstr

ucture

optim

izationislim

ited

AdjustRP

M,drillin

gflu

idlubrication

√√

√

AdjustWOB

√/

√

Change

energy

distr

ibution

Them

ostcom

mon

,mainlyconsideringtheb

ound

arycond

ition

sof

thed

rillstringsyste

mecon

omicandeffectiv

e,sim

plea

ndfeasible,

maturetechn

ology

Thec

ontactbetweentoolsa

ndbo

reho

lewallw

illincrease

thefric

tionof

thed

rill

stringtorque,reduced

rillstringextension

abilityandthed

rillin

geffi

ciency

Rollerstabilizer/dou

blec

ore

bit/reamer/D

OCbit

Varia

bled

iameter/near-bit/V

stabilizer/fairing

/spiralstripes

√/

/

Hybrid

bit

/√

√

Absorber

Them

osteffectivea

ndsim

pled

evice,econ

omy

Con

trolabilityislim

ited,tooliseasy

todamage

Axial/A

STshockabsorber

Activ

econtrol

Who

ledrill

string

closedloop

Goo

dsim

ulationresult

Itishard

togetaccurateu

ndergrou

nddata,calculatio

niscomplex,and

hardware

developm

entisd

ifficult

𝜇/𝐻∞/PID

/PI/G

A√

/√

Wellheadclo

sedloop

Fastrespon

seandlowcost

Transm

issionruleof

vibrationsig

nalis

unkn

own

Transm

issionwaved

ecom

position

//

√

Who

ledrill

string

open

loop

Redu

cedrill

stringvibrationby

controlR

PMSyste

mrespon

setim

eislon

g,calib

ratio

nis

difficult

Softtorque

rotatio

nsyste

m

Semiactive

control

Semiactivev

aried

damper

Con

trolprecisio

n,high

energy

utilizatio

n,beingbette

rthanactiv

econtroland

passivec

ontro

l

Con

trolsystem

research

anddevelopm

ent

isdifficultandexpensive,belong

stothe

stron

glyno

nlinearc

ontro

lTh

emagnetic

fluid

damper

/√

√


Drill fluid

Vibration or shock tools

Drill fluid

Vibration or shock tools

Drill fluid

(a) Rotary drilling (b) Percussive/impact/vibration/high-frequency vibration drilling (c) Percussive (high-frequency

vibration) rotary/drilling

Figure 24: Rock fragmentation types in the dynamic drilling process.

Shell

Top sub

Hammer bit

Shock structure

Hammer bit(convex shape)

Hammer bit(concave type)

(a) Axial hammer

Shell Torsionalvibration structure

Connect the PDC bit

Shell

Torsionalvibration structure

Connect the PDC bit

(b) Torsional hammer

Figure 25: The structure and working principle of typical and latest hammer.

Compared with conventional drilling tools, the device canimprove the ROP, and effectively prolong the service life ofdrill bits. The ROP can be improved by the drilling tool withhigh-frequency harmonic vibration (HFHVT) [154]. Therock fragmentationmechanisms, experiments, andmodelingof HFHVT have been studied by Li et al. [155], but theHFHVT is not used in the drilling field. Although PRD andHFTID have been proposed for years, they do not have a widerange of applications in oil and gas reservoirs. The ROP ofPRD is unstable in the same formation or well. One reasonis that the indentation fragmentation mechanism of rockunder dynamic loads and coupled static-dynamic loads isunclear [156]. The indentation fragmentation mechanism ofanisotropy shale under dynamic and static loads was studiedby Dong et al. [157]. When the peak value of load is thesame, energy density under dynamic-static combination load

is higher than that under static load condition and rockfragmentation efficiency is also improved significantly. Aquantitative evaluation method based on microindentationtest technology was proposed by Chen et al. [158, 159]to research the mesomechanical properties of shale. Themesoscopic elastic modulus and indentation hardness areheterogeneous in distribution considering different influ-encing factor. Because of the complexity of rock hetero-geneity and dynamic mechanical characteristics, the futureefforts should focus on the comparative study of indentationfragmentation mechanism of shale at the multiscale andnumerical simulation of dynamic damage characteristics ofrock for full-sized drill bit.

4.2. Control Borehole Trajectory. Theanticollision of boreholetrajectory is one of the most important problems in drilling


Drill fluid

Wellhead

Wellhead monitoring system

Wellhead monitors

Casing

Driller’s log

Existing wells

Drilling well

Vibration wave BHA

Casing

Production casing

Productioncasing

Driller’salarm

Casing

Figure 26: Anticollision wellhead monitoring system.

engineering. The safety warning system for reducing thecollision probability of borehole trajectory was studied byStagg and Reiley [160]. The acceleration sensor installed onthe wellhead receives the downhole vibration date of rockfragmentation.The frequency range is 200Hz∼400Hz. Basedon the signal feature of drill string, the distance of the bit andcasing pipe of adjacent well was estimated. When the signalcharacteristic value goes beyond the system threshold, thesystem raised the collision alarm [161], which can be used inthe cluster wells as shown in Figure 26. The technology hasgreat significance for the control of well trajectory, such asdeep water well, ultra-deep water well, old oilfield drilling,and shale gas drilling.

4.3.The Source of SeismicWhile Drilling. Using drill bit vibra-tion as a power source for the subsurface imaging was firstproposed by Weatherby. It is remarked that the discreteimpulse signals produced by the impact drilling tool can bethe seismic source [162]. The technology gets fast develop-ment after the late 1980s [163]. The drill bit seismic whiledrilling (DB-SWD) take advantages of the drill bit vibrationenergy; the seismic signal was recorded by the offset arraygeophone and hydrophone on the surface ground or seelevel. The date as reference signals was measured by the pilotsensors fixed to the top of the drill string. The referencesignals are used to the cross correlation processing withsurface receiver records as shown in Figures 27 and 28. Dueto its observation system geometric form is reciprocal to theconventional vertical seismic profiling (VSP) [16, 29]. DB-SWD is also known as reverse VSP (RVSP) based on the reci-procity principle [16]. DB-SWD can obtain the overburdenvelocity and time-depth information used to the predictionof reflection and structures ahead of the drill bit. Using the

DB-SWD technology can overcome the drilling problems,such as sticking and loss of drill strings, and improve drillingsafety and efficiency [164]; the velocity information can beused to calibrate surface seismic imaging [165]. Comparedwith the conventional VSP and VSP while drilling (VSP-WD)as shown in Table 8, DB-SWD does not require additionaldownhole explosives or air gun seismic sources. There isno interruption to the drilling operation time, and no riskto wellbore and downhole tools [30, 166–168]. The MWDseismic surveying and logging operations can be realized.However, the complexity of signal processing and downholeworking conditions increase the design difficulty of downholeMWD seismic surveying and logging tools. The intensityand energy distribution of seismic source is one of the keyproblems of DB-SWD technology. A roller cone bit with hugeWOB and TOB break rock through shear and compressionfailure. In contrast to roller cone drill bits, the diamondbits and poly-diamond-composite (PDC) bits broken rockthrough shear and grinding action; the axial loads of PDCbits are more than 10 times lower than the vertical forces ofroller cone bit [169–173]. With the increase of well depth, thevibration energy attenuation of the roller cone bits increasesand the geophone on the ground receives the weak sourcesignal. Drill-rig noise enhanced the interruption to the SNR;the lower SNR of bit increase the difficulty of data processingand effective signal extraction. There are some effectivesolutions for the above problems. A swept impulse tool (SIT)can generate a broadband seismic signal at the DB-SWD.TheSIT was proposed to overcome the limitations of DB-SWDwith PDCbits in linedwells and in soft formations.The signaldate volume and a large receiver array can improve the SNR[164, 174–177]. Another approach is that the seismic signalprocessing is based on interferometry by deconvolution;


Drill pipe

Rotary tableTraveling block

Crown block

Derrick

Wellbore

BHA

Head waveemanation pointin drill string

Longitudinalwave in

drill string

SV amplitudeP amplitude

Head waveraypath

Directraypath

Reflectedraypath

Surfacereceiver array

Pilot sensor

Radiation ofdrill bit energyfrom drillingrig into earth

SH amplitude

Cross-correlation

Wellbore

Directraypath

Figure 27: Drill bit energy radiated by the drill rig and the drill string in the vertical well.

Cross corrlation

Directraypath

Head waveraypath

Reflectedraypath

Bit

SIT

Figure 28: Drill bit energy radiated by the drill rig and the drill string in the directional/horizontal well.


Table8:Con

trasto

fcon

ventionalV

SP,SIT

SWD,drill-b

itSW

DandVS

P-SW

D.

Items

Con

ventionalV

SPDrill-b

itSW

DSIT-SW

DVS

P-WD

Seism

icsource

form

Con

ventionalgroun

dor

seas

eism

icsource

Seism

icwaves

generatedby

aworking

drill

bit

Sweptimpu

lsesource

Con

ventionalgroun

dor

seas

eism

icsource

Seism

icsource

locatio

nTh

egroun

dsurfa

ceDow

nhole

Theg

roun

dsurfa

ceSign

alreceiver

locatio

nUnd

ergrou

ndcable

Groun

dor

seas

urveylin

eDow

nholetoo

lInterfe

rewith

thed

rillin

gop

eration?

Yes

No

No

Dataa

vailability

Afte

rdrillin

gWhiledrilling(nearrealtim

e)Afte

rdrillin

gRe

al-timed

atatype

Full-waved

ata

Full-waved

ata

Check-shot

time

Band

width

Larger

Narrower

(with

surfa

cepilots)

,com

parable(with

downh

olep

ilots)

Com

parable(with

downh

olep

ilots)

Sign

alto

noise

ratio

Higher

Lower

Higher

Datap

reprocessin

grequ

irements

No

Thec

rosscorrelationof

references

ignaland

record

signal(surfa

cereceiver

array)

Und

ergrou

ndpreprocessing,automatic

extractio

ncheckshot

time,andqu

ality

factor

Sign

altransm

issionrequ

irements

Con

ventionalcable

Ther

eference

signalistransmitted

throug

hthed

rillpipe

Mud

pulse

Rangeo

fapp

lication

Non

extend

edreachwells,

nonh

orizon

talw

ells

Non

-highinclinatio

nwe

lls,non

horiz

ontal

wells

Extend

edreachwells,

horiz

ontalw

ells

Deepw

ate

Review Article A Review of the Evaluation, Control, and ... · optimizing, wellbore design,...

Documents

Transcript of Review Article A Review of the Evaluation, Control, and ... · optimizing, wellbore design,...