SPE-7518-MS Side Cutting Characteristics of Rock Bits and Stabilizers While Drilling

8/10/2019 SPE-7518-MS Side Cutting Characteristics of Rock Bits and Stabilizers While Drilling

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SPESPE7518

w~~ ~c AIME

SI DECUTI NGCHARACTERI STI CSFROCKBI TS

ANDSTABLlZERS i HI LERI LLI NGby Kei thK. M l l hi emand TOW M warr@nsMembersSPE-AI ME,Amoco Product i onCompany

DCogw f J M9T8. Amw canI nsti tute fMnl rw etal lurgical . andPotrol wmnwrm s. nc .

Thi s gape r waa gresenteda t theS3rd Annual Fal l Techn ica lConfs r snceand Exh lb l t ionof t l roSocmty ofPe t roleum Engmeeraof AIME,hel d nHous ton . ) txas . Oc t . t . 3 . 19T8 .Thems te r t al i a suDjec tby NW au thor. Permission to COPYlarestrl ctad oanaost ract 1notmor ethan3 3 WOrdS.W~X6ZI XI N.Centr al x9Y.. DallaS. Texas TWX.

The trajectoryof a drill bit is controlledby thecomplexinteractionof the bit, bottom-holeaaaembly,penetrationrate,and formationproperties. This holdetrue for all wells,whetherthey are “directional”wellsor “straightholes”.

Extensiveresearchind%cateethat the trajectoryof a bit can be understoodand predictedif the follow-ing informationis @town: (1) the side forceeandvectordirectionsat the bit and stabilizer, (2) thepenetrationrate, (3) the rotaryspeed, (4) the sidecuttingcharacteristicsf the bit and stabilizers,and(51 the amountof hole enlargementdue to hydraulicand/orchemicalaction. All of theseparameterscan bemeasuredor calculatedwhile drillinga well exceptitems (4) and (5).

This paper describesa full-scale,automateddrillingapparatuethat meaeuree the side cuttingcharacteristicsf a bit or stabilizerin the labora-tory. The drillingmachineis equippedwith sewo-controllersto msincainconstantpenetrationrate andside forceduringa test. The rotaryspeed and bithydraulicsare also maintainedat a constantlevel.All data fs recordedin digitalform on magnetictapeto facilitatecomputerprocessing.

The test resultscited in this paper were obtainedwith a 9-7/8 inch (25.08cm) seriee1-1-1,bit and withfull-scale9-7/8 inch (25.08cm) etabilizera. Theteetswere conductedin BedfordLimestoneand CarthageMurble. The resultsof the tests supportthe theorychat both che bit and stabilizerscut sidewaysunderconditionstypicallyexperiencedin the field. Therate of displacementis a functionof penetrationrate,eide force,rotaryspeed,and rock type.

This paper outlineethe trajectorymechanismmodeland detailstt,eevolutionof thismodel as well as theresultingside force testingprogram. A descriptionofthe drillingapparatus,testingprocedure,and teetresultsere presented.

Referencesand illustrationsat end of paper.

INTRODUCTION

Drillingcostsare a significantportionof anypetroleumfuel developmentscheme. The economiceuc-cessof many of the new oi’ recoveryprocessesiecloselylinkedto drillinr:osts. Some of the projecrequireepecialhigh-ang.edirectionallydrilledwellswhileothersrequirewells drilledto very closelyspacedsmall targets. The successof many of theseprojectsdependeon the technologyand economicsofnrillingthesewells.

Offshoredrillingcosts are spiraling. Alreadysome fields that couldhave been economicallydevelopedone or two years ago are now marginal. Higheroil agas pricesoffset some increasein costsbut there areimmensesavingsto be achievedby si gni fi cantl ying drillingcoste.

Ths goal of every companyengagedin drillingisto optimizethe drillingprogramso thateach well iadrilledas cheaplyae possible. In many areae this isachieved. In others,i t is not. The succsssof anyoptimizationprogramreliesheaviiyon the men that aredirectlyresponsiblefor the actualdrilling. This iaespeciallytrue for wells that have a controlledtra-jectory.

The major considerationwhile drillinga direc-tionalwell has traditionallybeen to hit a particulartarget. Managementhas acceptedthe longerdrillingtimesand highercostsas a necessarysacrificeinorder to hit the target.

The personin chargeof the directionaloperationcontrolsthe drtllingof the inclinedportLonof thewell. The mcjcr tool he uses to optimizethe well ishis experienceand ab%lityto relatecausesand effectsas the well is beingdrilled. In view of the complexmechanismsthat are involvedin trajectorycontrol,hedoes an admirablejob.

Post-analysiaof directionalwells drilledinNorthAmerica,the North Sea, Iran,Trinidad,andEollandindicatethat many unnecessarychangesare madewhile drillinga typicaldirectionalwell. AU theseextra operation of changingthe bottom-hole,assembly,rotaryspeed,snd/orweight-on-bithave the effectofincreasingthe overalldrlllint?ime. This increasee



2 SIDE CUTTINGCHARACTERISTICSF ROCK BITS ?m

the costof the well. At high penetrationrates, the stabilizercutslessand thus transfersmore side force to the bit.

The lar8enumberof unnecessarychangesin the The followingcan cause increaeesin the eide cuttingdrillingparametersreeultsfrom the nature of the of the stabilizer: (1) decreasein penetrationratetrial-and-errorrocessthat is used to drill a direc- and formationhardnees,(2) increase in side forceantionalwell. Bottom-holeassembliesare chosenbased rotaryspeed (notverifiedyet). Hole enlargementon theirperformancein otherwells. They may not causedby mechanicalor chemicalerosionby the drill-performas expectedbecauseof formationchanges,hole ing fluidcan also reducethe amountof side cutting.ctnvatureeffects,or a numberof changesin conditions The boreholediameterincreasesdue to theseeffectsthat are noc noted. Buildingand droppingassemblies until an equilibriumis reached. The side cuttingofusuallygive the expectedtendencybuc the magnitudeof the bit behavesin a similarmann?r to that discussedbuild or dropmay not be as expected. HOld%n8assem- previouelyfor a stabilizer. Bit and stabilizerdesi~blies have an averagesuccessrate of only,50% affectsthe amountof side cutting. Presently,little

is’knownhow th~ deeignaffectsthe side cuttingComputerprogramshave been developedto determine ability.

the vectordirectionsand magnitudesof the eide forceeof variousbottom-holeassemblies.1’2’3The initial The totalmechanismfor a givenbottom-holeas-resultsfrom theseprogramswere disappointingbecause sembly,runningconditions,and formationtype isthe predictedvectordirectionsoften did not match the postulatedas follows:obeervedtrajectories.Thie led to the discoveryofthe impo~tanceof hole curvaturein predictin8bottoru- 1. The stabilizerand bit have an effectiveeidehole aeeemblyperformance.4The inclusionof the forcein the staticcondition.effectso< hole curvatureimprovedche predictivecapabilityof the program,especiallyin hard rock 2. Rotationcommences.drillingwhere lower penetrationrateswere experi-enced. 3. The bit drilleforwardand sidewaysdue to

the weight-on-bitand side force.The side forceethat are calculatedby the com-

puter modelsare often greaterthan can be maintained 4. The stabilizercuts sidewayeand reduceechein a borehole. This impliesthat the bit and stahi- effectiveside forceon the bit and stabilizer.lizershave to cut sidewaysuntil an equilibriumsideforce is obtained. Laboratoryexperimentsproved chat 5. An equilibriumis reachedin which the re-this processoccure. The incorporation of this phe- sultantbit trajectorycan be translatedinto inclina-nomenoninto the interpretationof the output from the tion and direction.bottom-holeaseemblyprogramled to anotherimprovementin the capabilityt’oaccuratelypredictthe vector Whether an f.ncreaeen the rate of build is causedirectionsof a bottom-holeaseenbly. by an increaeein the penetrationrate dependeon the

relativechangesin the side cuttingof the stabilizerAt the presenttime,thereis no methodavailable and bit. The relativechangeof the side cuttingof

to predictrateeof build,drop,or turn for a particu- the stabilizerand bit dependson che penetrationrate,lar set of conditions. This is the reasonthatdLrec- bottom-holeaesemblytype, rotaryspeed,hole diameter,tionalwells are still drilledby the trtal-and-errormethod. The developmentof a way to relatethe calcu-

and the Iithologyoppositeche bit and stabilizer(s).For example,if the bit %s drillingin a hard formation

leted sideforceson a bottom-holeaeeemblyto dis- and the stabilizeri~ oppositea much softerformation,

placementswould allowaccuraterateeof build, drop, most of the side cut;ingwill be doneby the etabi-and turnto be calculated. This paper discuesesthe Uzer. This conditioncould reeultin leesdisplace-resultsOC laboratorydrillingteste that relateside ment at the bit than if the bit and stabilizerwereforces to displacement for a verietyof drilling both in a formationof equalhardness.conditions.

Since~he eide forcesat the stabilizersand bitMECNANISXTHAT CONTROLSTRE TRAJECTORYOF A BIT can be calculatedfor any situation,a trajectorycan

be predictedif the side cuttingcharacteristicsf theFigure 1 showsa typicalbottom-holeassembly stabilizerand bit are known.

positionedat the bottomof a hole. The bit ad sta-bilizersexert a side forceon che formet%onat each DESCRIPTIONOF’TESTEQUIPMENT-point of contact. The magnitudeof these forc(mcan becalculatedby the bottom-holeassemblyprograuspre- In an actualdrillingsituation,the drillbit andviouslydiscuseed. Figure2 presentssome t~lcal side stabilizersapplya side force to the format:ton.Asforcesfor severaldifferentbottcm-holeassemblies. lateralcuttingtakesplace, the bottom-holeassemblyThe side forceat the bit rangesfrom -1000 pounds moves so that the side forcesare relaxed. In an

(-4450N) to 9000 pounds (40000N) for this example. experimentaleituation,it is much eaaier to allowtheThe rangeof magnitudeof the side force on the first rock to apply the side.fo,rceo the bit and let theetabtlizerie approximatelythe same. rock move as side cutt%ngtakesplace. Figure3 chows

a echematicof how CMS is accomplished. The rockWhen the assemblyis rotated,the stabilisers allowedto move on rollerswhile the bit is constrained

begin to cut sidewaysinto the formationat a rate by a @tiffdrillcollarso that it can move only in adependenton thehardnessof the formationand the verticalpath.magnitudeof the side force. This lateral movementre?cxeethe internalstressesin the bottom-holeas- It would”bemuch easierto set up an apparatustosemblyand reducesthe side force. It is theorized conductthe side cuttingexperimentsfor smell scal~thst the distancecut by the stabilizeris a function holes ratherthan for full-scaleholee. Becauseof theof penetrationrate, eide force,rotary @peed,Mth- historyof problemsthat resultsfrom tryingto scaleology typeand hardness,and stabilizerdesign. ‘ microbitdata to full-scalebits, it wee decidedthat

the in%tialwork would be with 9-7/8 tnchbits (25.08



,-95 cla IL K. Mil%hiemand T. M. Warren

:m). A machine to test small-scalebits end siabili-:ershas also been constructedko use if a scaling>rocedurecan be developedfrma the full-scalemachine.L’hisould allow the CSS:G to be run fasterand moreeconomically.

The full-scaleside force testingapparatuswasconstructedby modifytngan existingdrillingmechlne:hathad previouslybaen designedto test the weight%ndrotaryspeed rasponseof b~ta. This machineis:apableof testing6 inch (15.24cm) to 12-1/4 (31.12

:m)inch bits at .exialloadsup to 70,000pounds(311,300N) and rotaryspeedsfrom50 to 300 RPM. Thetestsare conductedin rock specimensthat are 40inchesx 57 inchasx 60 inches(102cm x 145 cm x152cm) high. This rock size allowesix, 4 foot (1.22u) deepholes to be drilledwith a 9-7/8 inch (25.08au)bit.

The weight-on-bitis generatedby a sarvo con-trolledhydraulicsystemso that weight-on-bitcan beReidconstantfor a test. A digitalramp generatorcan31s0 be utilizedin conjunctionwith the servocon-trollerto drive the bit at a constantpenetrationrate>f 1 to 300 feet per hour (.3 to 91 matersper hour).I’herotarycableis drivenby a Sunatrand27 serieshydraulicpump and motor that is capableof developing

7500 foot-pounds(10160J) of torqueat the bit. AHalliburtonHT-400-Dtriplexpump and a Mission&aplexpump are availableto pump the drillingflu%d.

The rig is equippedwith en electronicdata col-lation systemthat can rscordup to 30 channelsofdata on magnetictape. Straingage-typetransducersare used to measureloads,torque,end pressures.Potentiometersare used to maasure the dspth dr%iledand rock displacement.

Three main modificationswere made to the machineso it could be used for side force t esting: “

1. The rock was put on a rollersystemso thatit wag free to move In one directionin a horizontalplane. The only restrainton the rockmovementin thisiirectionis frictionend the contactforce betweenthe~it and rock.

2. A hydrauliccylinderwas installedso that aforcecould be appliedto the rock in the samedirec-tioain which it was free to move. This hydraulicramis servo controlledso that a constantforce is appliedto tha rock. The ram can be positionedin-linewithany hole that is being drilledso thatno momentisappliedto the rock. ,

3. An 8-L14 inch (20.9cm) drill collarand tworestrainingbushingsin the drillstringwas incor-poratedto keep the drillstringfrom bendingwhen aforcewas appliedco the rock. Figure4 showsa sch-ematicof the rig after it wae modified. Figure5 is aphotographof the rig setup for testinga stabilizer.

The major problem that has been encounteredwtththe rig is estimatingche magnitudeof frictionthat %spresentfor a particulartest. Tha frictionin therollersystem is a functionof weight-on-bitend rigvibration. The staticfriccionwith no wei ht-ou-bitcan be measuredand is in the range of 300-400pounds(1334-1780N). Dur&ngan actual drllkingtest, thevibrationsinducedon the rock tend to reducesomepercentageof the staticfrictionwhile the weight-on-bit load tends to tacreasethe frictionfrom the staticlevel. The rig is currentlybeing modifiedto eLfmi-nate this problemby suspendingthe rock on cables.

ESTPROCEDURES

Differentproceduresare used to test bits end~tabilizers.The bits are testedby firstdrillingaIixinch deep pilot hole with the rig being operatedinhe constantpanetratlonrate mode. While this depth.sbeing drilled,the rotaryspeed is adjustedto somemeeelectedvalue that will be used duringche test.he side force is appliedto the rockwhen the bit ist a depthof six inchesend drilling. This is re-@red to keep the bit from cuttingtoo much sideways

m one place. The test hole is drilledto a depthof ourfeet with all the parametersheld constant. The[rillingmachiaeautomaticallystops at four feet.:able1 presentsdata that was obtainedfrom a typicalIole. Figure6 is a photographshowingthe displace-mentthatwas obtainedfor a typicaltest in the Bed- ordLimestone.

The stabilizertestsare conductedwith a spe-:iallymodifiedstabilizer. The stabilizerbody is cut>Ifimmediatelybelow the lower end of the bladesend a>inis machinedimmediatelyabove the top of the>lades. The stabilizercan then be screwedonto the%114 inchcollarjust like a bit. The stabilizer]ladee.re not modifiedin any way. The stabilizer:estsare conductedin pre-drilledholes in the same

?izerock specimensthat are used for bit tests.Iolasmust be vertical. Deviation fron top to bottom>f less Chan .05 inches (.13cm) have been measured.Rtisassuresus that any rock displacementrscordediuringche stabilizertest Ls not causedby che pre-irilledhole being non-vertical.

The meximumdisplacementthat can be obtainedislimitedto about 9.8 inchesby the clearancebetweenthe 9-7/8 inch (25.08cm) hole and che drill collar.l%a maximumside force that is used is generallylimitedto a value that ,tillgive a displacementof nomorethan .75 inches (1.9cm) over the four feetdrilled. The minimumside forceused in the teets isdeterminedby the value that is requiredto overcomeshe frictionin the rollersystem.

tESULTSOF THE INITIALTESTS

Figure7 shows the reeultsof two side force testsfora 9-7/8 inch (25.08cm) series1-1-1bit in Car-:hageMarble. The depth scale has been adjustedso the>riginis at the point that side forcewas appliedto:herock. Noticathat the rateof side cuttingde-:reasedfrom this point until en equilibriumwaereachedand then the rate of displacementremained:onstant. This shape was consistentlyobservedfor the~%splacementcurve for both bits end stabilizers.

Figure7 aleo shows that therewas a considerablektfferencein the rate of side cattingfor a smell:hangein aide force. This phenomenonwas obsexvedinboth the Carthageand Bedfordrock and possiblyindf-catesthat a thresholdexisteabovewhich d%eplacenentgreatlyincreases.

Figure8 shows the dieplacemantcurve for a series1-1-1bit in BedfordLimestone. It indicateethatthereis a slightdifferencein the displacementratefor differentpenetrationrates. Figure9 shows thedisplacementcurve for a spiralblade stabilizerBedfordLimestone. The rate of displacementfor thisstabilizerat 1500 pounds (6670N) side forcewassimilarto the displacementrate of the bit at only 800pounds (3560N) side force.



4 SIDE ~~TING CRARAOTERISTICSF ROCK BITS &?.—

Table 2 shows the resultsof 11 tests for che Field Ceste of the lab deriveddata is needed. Aseries1-1-?,bit in both Carthegeand Bedfordrocks. Failing“1250”ri~ used on a companyleaseto drillThe side forceshownin thie cable is the totalside 300-500foot (91-152m) experimentalwellswill be usedforceappliedCO the rock. This table shows that initiallyfor this purpose. The drillingmodelwillgenerallyan increasein side forcereeultedin an thenbe testedin the field in areaewhere gooddata isincreaseddisplacementrate end en increasein pene- availablefrom the post-analysisof previouslydrilledtracionrace resultedin a decreaseddisplacamencrate. wells.No conclusioncan be drawn from the data about theeffectof rotaryepeed. CONCLUSIONS

It shouldbe noted that the da~a preeentedin Experlmantaldata has shownthat bits and stabi-Table 2 is affectedby friccion. We currentlyhave no lizerswill cut laterallyunder conditionsGhataremethodof correctingfor this. Generally,it can be similarto those experiencedin a wellbore. Thisdataconcludedthat the frictioneffeccafor the stabilizer has shown that it shouldbe possible.tobuild a modeldata shouldbe less shan chat for bits becauseof the to predicta well Crajeccorybased on experimentaldatamuch loweraxialforceappliedto che rock duringthe and a finitaelementbottom-holeaseemblyprogram.stabilizertests. For both the stabilizertastsandthe bit tests,the resultscouldbe repeatedfor a The side cuttingrata of a bottom-holeassemblyg~.ven t o f conditionswhich indicatesthat che fric- componentie shown to be a functionof penetrationCion was consistentfrom test to test,even thoughitsmagnitudewas unknown. “Itis also noteworthythat the rate,contactforce,componentdesign,and rock type.recordedratesof displacementrepresentminimumvalues There probablyare other factorsthat affectthe dis-for the appliedside force. The eliminationof frfb- placementrate that may be identifiedby additionaltion effectscouldonly increasethe amountof dis- cesting.placement.

ACKNOWLEDGMENTAPPLICATIONOF THE TEST RESltiTS

The authorswish to thank the shop personnelat

The side force-displacementata can be used in Amoco for theirlarge contributionin the designandconjunctionwith the finiteelementbottom-holeas- constructionof the test equipment. Specialthanksaresemblyprogramto developa model that will predictthe givento John Lsndrethend Jim Reed who make everythingbit trajectory. This would be the firsts tep in work. The authorsalso thankAmocomanagementforbuildinga real-timedrillingsimulator. Such a pro- theirtotalsupportof this drillingrasearchand theirgram couldbe uc~lizedwith a minicomputerat the rig permissionco presentthis paper.locationto greatlyaid in makingmany of the decisionerelatedco directionalwells. REFERENCES

The drillingsimulatorwould also have great 1. Fischer,J. F.: “Analysisof Drill Stringsbenefitin well planningand post-analyeisof wells. in CurvedBorehole,” SPE PreprintNo. 5071 presentedIt couldbe used as a trainingaid for both experiencedOctober6-8, 1974,”in Houston,Texas.and non-experienceddrillingpeople to gec decision-mekingpraccicewithoutbeing on a rig. 2. Walker, H. B.: “DownholeAeeemblyDeeign

IncreasesROP, Cuts Cost,”World Oil, Juna, 1977,pp.ADDITIONALWORK 59-65.

The work on testingthe side cuttingabilityof 3* Millheim,K. K., Jordan,S., and Ritter,bottom-holecomponentshas just begun. Additionalwork C. J.: “Bottom-HoleAssemblyAnalysisUsing the FiniteDustbe done to quantifythe parametersthat affect the ElementMethod,”Jour. Petro,Tech. (February,1.978),side cuttingrate of thesecomponents. Work is planned pp. 265-274.to test che effectsof rock type, componentdesign,holesize,hydraulics,differentialpressure,and mud 4. Millheim,K. K.: “The Effectof Hole Curva-properties.Many of these testsmey be donewith the cureon the Trajectoryof a Wellbore,”SPE PreprtntNo.smell-scaletestapparatusdiscussedearlier. 6779presentedOctober9-12, 1977, in Denver,Colorado.



TABII 1

EKAMPLEOF lYPICAL SIDE CUTTINGTESTOUTPUTFORA ROCKBIT

DEPTH(FT)

1.28

1.48

1.661.83

2.01

2.19

2.36

2.55

2.72

?.90

3.08

3.26

3.44

3.61

3.79

SIDE ROCK RPMFORCE DISPLACEMENT(Ibs) (INCHES)

x S- G

761.0 0.97 93.8

799*o . 1.03 10205792.0 1.o? 98.6

806,0 1.13 97.2

789.0 1.20 98.5

808.0 L 27 la). 9

786.0 1.36 95.8

802.0 1.38 98.9

815.0 L44 96.4

783.0 1.48 94.2

801.01.51 97.8

793.0 1. 96.7

805.0 L 61 97.9

alo.o 1.64 101.9

TABLE 2

WOB(lDOOlbsi

24.1

21.5

22.323.2

20.8

22*7

22.2

22.0

22.4

22.5

18.9

20.32’0.3

19.6

20.1

PENETRATIoN

F H:

z

117.4

94.5103.2

91.8

107.8

105.1

95.1

I(I3.2

90.1

110.3

106.492.3

10308

90.7

RI SPIACt M ENT RESULTS FOR ROCK BIT S1 DE CLJ171NG TESTS

ROCK RPM PENETRATION SIDE DISPLACEMENTRATE FORCE RATE

FTIHR LB. IN IFT— . — .

BEDFORil 100 60 500 .055

BEDFORD lM 60 .375

BEDFORD 100 ~~ 480 ‘ ‘ .085

BEDFORD la No 520 075

BEDFORD m 100 800 230

BEDFORD No 150 800 180

CARTHAGE 100 4 I 600 090

CARlliAGE Ml@ 40 800 090

CARIHAGE 100 60 800 .085

CARTHAGE 100 60 low 220

CARTHAGE 100 40 1000 245



?4iKIDE ‘ I -

~~RCE , / INIT16L GIWGE HOLE

BIT ( ‘F1 / F4< F;-- ~e

Fig. 1- I l schsni wn f tra jectory departu re.

Lmrmlurcc

STQTICf 3SEMBLY

UEIA. BORE RFiDIUSINCRERSED BYSTABILIZER

SIDE FORCE WHILE9RILLING CRUSES

a~,I

i9X I RL

WEIGHT.U

12.2S’ HOLE 10 PPG MU2.25” X 8.0” COLLRRS

10 000

[

so. ~ 90° ~oo’

Sooo -

L-----

50” 60& 3Qoa8000

I 30 “

10”

m 2000

[~A

30 “

1000 ~’I 10”

WEIGHT ON BIT (1000 LBS

Fig. 2- Side force w weight+wbit for various building aase

—

‘ 1I

SIDE IFORCE I

I

III

CONTACTI

POINT Il.OWFRWTION I

ROLLERS -’ -- .DISPLACEMENT

Fig. 3- Kcu the eide force is applied to the bit.



9,* @?~WORAWC

L 0-70.000 lb WOB

R

tam”

0-250 RPM3.400 HP RWARY DRIVE4. “ 12 ” sm

S

5. O-S.OOO ik S O FORCEc

I

. 0.7 1* w *W I?88- =* *W .**’ :

d Nibbs. w Waml-x.aww.’.-

. “a& Z&- Uau. nu s a : 7. .. . . Z* “2s 99 31s ,’JW - 14ea .1s4 .

. J.*

mmAUuc Wwmrrt-.-a “

.“*AZ8 Y* 319 Ilmz * M s “ rww.. .

Y . __. . : ’~ ;::--L-— --FIG, 4- RESEARCH DRILLING RIGSCHSMATIC,

FIG, 5 - DRI LLI NG RI G WTH BLOCK POSI TI ONED FOR STA61LXZER TESTS,



o. a

~ l awIL

sgUi

0 2.C

3.C

9-7/S” SERIES 1-1-1 BITSEDFORD LIMESTONE1 YJ RPMS00 IA, SIDE FORCE

o

~ l-a

Uius

r“1-aMJQ

2.a

3.9

Fig, 6- Bit side force test hole dri 1led with 9-7/8” series 1-1-1 bit.

“ ’/.

FT/HR

4 -

1 I I I I I .2 .3 .4 .5 .8. .7

HORIZONTAL DISPLACEMENT, INCHES

Fig. 8- Bit side force test data - vsrisble penetration rate

9=7/8 SERIES 1-1-1 BIT

CARTHAGE MARBLE100 RPM

I 1.

I 1 I I

1 .2 .3 .4 .5 .6

HORIZONTAL 131SPLACEMENT, INCHES

Fig. ? - Bit side force test date - variable side force.

.h 9-7/5” SPIRAL BLADE STABBEDFORD LIMESTONE100 RPM100 ~/HR1600 LB.

3.O_i~S7. .

\

HORIZONTAL DISPLACEtVIENT, INCHEFig. 9- Stabil ;zer side force tsst data.

Documents

SPE-7518-MS Side Cutting Characteristics of Rock Bits and Stabilizers While Drilling