Foreword

SAC/TC93（NationalTechnicalCommitteeonLandandResources）isinchargeofthisenglish

translation.Incaseofanydoubtaboutthecontentsofenglishtranslation，theChinese

originalshallbeconsideredauthoritative.

ThisdocumentisdraftedinaccordancewiththerulesgivenintheGB/T1.1-2009Directives

forstandardization-Part1：Structureanddraftingofstandards.

ThisdocumentreplacestheDZ/T0054—1993TechnicalStandardforDirectionalDrillinginwhole.

OnthebasisofinheritingtheimportanttechnicalcontentsofDZ/T0054-1993,this

specificationsupplementedandmodifiedthename,chapterstructure,technicalcontentsand

annexcontentsofthestandard.Inadditiontoanumberofeditorialchanges，thefollowing

technicaldeviationshavebeenmadewithrespecttotheDZ/T0054—1993:

——Thenameofthestandardischangedto"TechnicalSpecificationforDirectionalDrilling";

——Structuralcontentssuchas"Preface","TableofContents"and"References"areadded;

——Chapterssuchas"NormativeReferences","SpecialDirectionalDrilling","Controlof

DirectionalBoreholeTrajectory","MeasurementofDirecitonalBoreholeandCalculationof

Trajectory"areadded,andthetextarrangementistechnicallymodified;

——Somesignificantmodificationsaremadeinchaptersof“DesignofDirecitonalDrilling

Engineering”,“SelectionofDirectionalDrillingEquipmentandApparatus”,“Construction

TechnologyofDirectionalDrilling”,and“PreventionandTreatmentofDirectionalDrilling

Accidents”;

——Someoutofdateandunsuitablecontentsoftechnologyaredeleted,andnewcontents

relatedtonewequipment,newapparatusandnewtechnologyareadded;

——Theparametertablesofmudpump,continuouswhipstockandhydraulicbottomholedrilling

toolrecommendedin"SelectionofDirectionalDrillingEquipmentandApparatus"aredeleted,

andsomerecordtablesforinclinationmeasurementduringkick-offdrilling,finalhole

acceptanceinspection，andcalculationoftrajectorycoordinatesofdirectionholeaxisare

supplemented;

——Twoannexesrelatedto"CalculationofDirectionalToolFaceAngle"and"Methodfor

III

CalculatingtheAxisTrajectoryofDirectionalBorehole"areadded.

ThisdocumentwasproposedbyMinistryofLandandResourcesofthePeople'sRepublicofChina.

ThisdocumentwaspreparedbySCA/TC93(NationalTechnicalCommittee93onLandandResources

ofStandardizationAdministrationofChina).

ThepreviouseditionofDZ/T0054isasfollows：

——DZ/T0054-1993.

IV

TechnicalSpecificationforDirectionalDrilling

1Scope

Thisdocumentspecifiesthetechnicalrequirementsfordesign,equipmentselection,

constructiontechnology,trajectorycontrolandmeasurement,Accidentspreventionand

treatment,constructionmanagementandothertechnicalrequirementsfordirectionaldrilling.

Thisdocumentisapplicabletodirectionaldrillingingeologicalcoredrillingengineering.

Thedesignandconstructionofdirectionaldrillinginengineeringexploration,engineering

construction,hydrologicalwelldrilling,andpetroleumandgaswelldrillingcanreferto

thisdocument.

2NormativeReferences

Thefollowingreferenceddocumentsareindispensablefortheapplicationofthisdocument.

Fordatedreferences,onlytheeditioncitedapplies.Forundatedreferences,thelatest

editionofthereferenceddocument(includinganyamendments)applies.

GB/T5005SpecificationsforDrillingFluidMaterials

GB9151TermsofDrillingEngineering

AQ2004SafetyRegulationsforGeologicalProspectingOperation

DZ/T0227GeologicalCoreDrillingRegulations

3TermsandDefinitions

Forthepurposesofthisdocument，thefollowingtermsanddefinitionsapply.Forthe

convenienceofusage,sometermsanddefinitionsrelatedtodirectionaldrillinginGB9151

arelistedhere,andsomeofthemaresupplementedandimproved.

3.1

directionaldrilling

Drillingmethodthatmakesuseofthenaturalbendinglawofboreholeorusesaritificial

deflectingtooltoproduceacertainbendintheboreholetoforcetheaxisoftheborehole

toextendaccordingtothedesignedtrajectory

1

3.2

preliminarydirectionalborehole

Directionalboreholethatisdrilledbyusingconventionaltechniquesandtechnologiesand

thenaturalinclinationtrendandlawofformation

3.3

controlleddirectionalborehole

Directionalboreholedrilledwithdeflectingtoolandtechnologicalmeasures,anditsaxis

extendsalongthedesignedtrajectory

3.4

mainborehole

Boreholethatisfirstlydesignedandconstructed

3.5

branchborehole

Boreholethatisseparatedfromthemainborehole

3.6

horizontalborehole

Boreholethattheaxisofitsfinalsectionisnearlyhorizontal

3.7

intersectedborehole

Twoormoreboreholesthatseparatedbyacertainofdistanceandrequiredtobeconnected

withinthetargetarea

3.8

driftangle

Anglebetweenverticallineandthetangentlineofagivenpointontheaxisofaborehole

[GB/T9151-1988，Definition14.1.4]

2

3.9

azimuthangle

Inhorizontalplane,startingclockwisefromtheduenorthdirection,theanglebetweendue

northandthetangentlineofapointonthehorizontalprojectionoftheboreholeaxis

[GB/T9151-1988，Definition14.1.1]

3.10

deflectionrate

Totalbendingangleofaboreholeperunitfootageproducedinkick-offdrilling

3.11

target

Designedterminalpointofaborehole

3.12

targetarea

Allowabledeviationareacenteredatarget

3.13

toolfaceangle

Anglebetweentheplaneofthebendingdirectionofadeflectingtoolandtheverticalplane

oftheboreholeaxisatthekick-offpoint

3.14

inversetorqueangle

Angleofashellthathousingdownholedrillingtoolrotatesanticlockwiseduetothenegative

torquegeneratedbypositivedisplacementmotor(PDM)

3.15

measuringwhiledrilling(MWD)

Techniquethatiscapableofreal-timemeasuringdownholeparametersduringdrilling.

3.16

3

electro-magneticmeasuringwhiledrilling(EMWD)

TechniqueofMWDthatutilizingelectromagneticwavefordatatransmission

3.17

verticaldrillingsystem(VDS)

Drillingsystemthatiscapableofmaintainingaverticalboreholebyreal-timemeasuringand

automaticallycorrectionofboreholedeflection.

3.18

mudpulsemeasuringwhiledrilling(MP-MWD)

TechniqueofMWDthattransmittingdataviathepressurechangeofdrillingfluid

3.19

target-hittingguidancesystem

Drillingsystemthatguidingthedrillbitintothetargetbymeasuringtherelativeposition

betweendrillbitandthetargetwiththehelpofmeasuringtechniquessuchasartificial

magneticfield

4.DesignofDirectionalDrillingEngineering

4.1BasicDesignRequirements

4.1.1Eachdirectionaldrillingengineeringshouldbedesignedbeforeconstructionandshould

notbeconstructedwithoutbeingapproved.

4.1.2Incasethattherearemultipledirectionalboreholestobedrilledinonearea,the

overallconstructiondesignandsingleholedesignshouldbeprovided.Fordirectional

boreholeswiththesamestructure,therepresentativesingleboreholedesignisenough.

4.2DesignBasis

4.2.1Geologicalconditions

4.2.1.1Geologicalstructure,occurrenceofrockstratumororebed,morphologyofmine,

formationpressure,geothermalgradientandcharacteristicsofdrilling.

4.2.1.2Stageofexploration,densityofexplorationgridanddepthoftargetstratum.

4

4.2.1.3Ifmagneticinstrumentsaretobeused,itisalsonecessarytounderstandthe

geomagneticfieldparametersintheconstructionarea,suchastheintensityofmagneticfield,

theangleofmagneticinclinationanddeclination,etc.

4.2.2MetrologicalData

Meteorologicaldataoftheexplorationareaincludesannualtemperature,humidity,barometric

pressureandprecipitation,etc.

4.2.3TopographicConditions

Thelimitationofgroundsurfacetothelocationofboreholes.

4.2.4HistoricalConstructionData

Inclinometerdataofcompletedboreholes(ifany)inthesamearea.

4.2.5RequirementsforTarget-hitting

Requirementsforthedimensionoftargetarea.

4.2.6ContractorAgreement

Acontractoragreementbetweentheclientandthedesignerthatconcerningthedesignof

explorationprojects.

4.3DesignContents

4.3.1DesignofAxisTrajectoryofDirectionalBorehole

4.3.1.1Selecttheappropriatedesignandcalculationmethodofdirectionalborehole

trajectory.Therecommendedmethodforthedesignandcalculationofdirectionalborehole

trajectoryisshowninAnnexA.

4.3.1.2Determinethetypeandprofileofdirectionalboreholes.

4.3.1.3Determinetheaccuracyoftarget-hitting.

4.3.1.4Determinethepenetrationangleatthetarget.

5

4.3.1.5Determinethepositionofkick-offpointorbranchpoint.

4.3.1.6Determinethecurvatureandlengthofcurvedboreholesection.

4.3.1.7Determinethespatialelementsofeachboreholesection.

Onthebasisofthedeterminedtargetarea,penetrationangleatthetarget,thepositionof

thedeflectingpointorbranchpoint,andthecurvatureofthecurvedboreholesection,the

followingparametersshouldalsobeinvestigated:

a)Thelengthofeachboreholesection;

b)Driftandazimuthanglesofstartingandendingpointofeachboreholesection;

c)Verticaldepthandhorizontaldisplacementofstartingandendingpointofeachborehole

section.

4.3.1.8Drawthedesigned3Dgraphor2Dprojectionchartofboreholetrajectory.

4.3.1.9Checkthecurvatureoftheborehole.

4.3.1.10Determinetheboreholestructure.

4.3.2DesignofDirectionalBoreholeDrillingTechnology

Thefollowingcontentsforthedesignofdirectionalboreholedrillingtechnologyshouldbe

included:

a)Selectionofequipment,tools,andinstruments;

b)Parametermatchingcalculationamongdrillrig,mudpumpsanddirectionaldrillingtools;

c)Designofbottomholeassembly;

d)Designofkeytechnicalparameters;

e)Directionaldrillingmethodandmeasurementtechniques;

f)Technicalmeasurementsfororientation,anglebuildingandangleholdingdrilling;

g)Toolsandtechniquesforcoresampling;

6

h)preparationofdrillingfluidandmeasurementsforboreholeprotectionandleakingplugging;

i)Preparatoryplanincasekick-offoperationfails.

4.3.3DesignofConstructionOrganizationforDirectionalBoreholeDrilling

Thefollowingcontentsshouldbeincludedinthedesignofconstructionorganizationof

directionalboreholedrilling:

a)Stafforganizationandpre-servicetraining;

b)Maintenance,usageandstorageofequipment,instrumentsandmaterials;

c)Constructionperiodplan;

d)Supplyofwaterandelectricity,andlogisticsupportmeasurements;

e)Contingencyplan;

f)Safetyandenvironmentalprotectionmeasures;

g)Estimatedeconomicbenefits.

4.4TechnicalRequirementsofDesign

4.4.1Fullyunderstandtherawdataofdirectionalboreholes.

4.4.2Ensurethepurposeandrequirementoftheengineering.

4.4.3Makefulluseofthenaturaldeflectionlawofformationstominimizetheworkloadof

artificialdeflection.

Ifconditionspermit,theprimarydirectionalboreholeshouldbeusedasfaraspossibleto

hitthetarget.

4.4.4Choosereasonablesequenceintrajectorydesign.

Thedesignsequenceofthetrajectoryofboreholeaxisshouldbereasonablyselectedaccording

tothefollowingrequirements.

7

a)Ifthepositionofhole-openingpointorbranchpointisdetermined,generallythetrajectory

shouldbedesignedfromthispositiontothetarget;otherwise,thetrajectoryshouldbe

designedfromthetargettothepositionofhole-openingpointorbranchpoint.

b)Formultiplebranchboreholes,themainboreholeshouldbedesignedfirstly,thenbranch

holes.

4.4.5Thepenetrationangleshouldnotbelessthan30°.Chooselargeranglewhenconditions

permit.

4.4.6Chooseanappropriateboreholecurvature,toobtaintheminimumboreholedepthonthe

basisofensuringthatcoarsediameterdrillingtoolsandcasingpipescanpassingthrough

smoothly,andthesafetyofthedrillstringisguaranteed.

4.4.7Thedriftangleoftheboreholeshouldbeselectedreasonably,andthemainborehole

ofdeeperdirectionalholesandmulti-branchholesshouldbedesignedasastraighthole.

4.4.8Determinetheappropriatepositionofkick-offpointandbranchpoint.

Attentionshouldbepaidtothefollowingpointswhendeterminingthepositionofkick-off

pointorbranchpoint:

a)Thepositionofkick-offpointorbranchpointshouldbeselectedinstablerocklayer,

avoidinghard,brittle,fracturedrocklayers,karstcavesandsandlayers.

b)Iftheverticaldepthofthetargetissmallandhorizontaldisplacementislarge,the

positionofkick-offpointorbranchpointshouldbeselectedattheshallowpartofthe

borehole;otherwise,itshouldbeselectedatthedeeppartoftheborehole.

c)Kick-offpoint,branchpointandthedeflectingsectionofboreholeshouldnotbeselected

intheorebed,theroofoftheorebed,theflooroftheorebedorthegeologicalmarker

layer,avoidingtheorebedandmineralizedzone.

4.4.9Theconvenienceandsafetyofdrillingoperationshouldbeconsideredinthedesignof

thetrajectoryofboreholeaxis.

4.4.10Determineanappropriateboreholestructure.

Whendeterminingtheboreholestructure,attentionshouldbepaidto:

a)Factorssuchaspropertiesofformation,measurementsforboreholewallstability,drilling

8

methodandendholediametershouldbeconsideredcomprehensively.Theboreholestructure

shouldbesimplifiedonthepremiseofsafetydrillingoperation.

b)Incaseofcomplexstrata,multipleboreholediametersandcasingpipesshouldbeadopted.

4.4.11Payattentiontosocialandeconomicbenefits.

5.SelectionofDirectionalDrillingEquipmentandApparatus

5.1SelectionofConventionalDrillingEquipment

5.1.1Equipmentforconventionaldrillingshouldbeselectedbasedonthestratumconditions

ofminingarea,designedboreholedepth,boreholestructure,drillingmethodandthetypeof

deflectingtool,etc.

5.1.2Hydraulicdrillrigwithlargespeedrangeanddrillingparameterinstrumentshouldbe

selected.

5.1.3Mudpumpthatiscompatiblewiththedeflectingtechnologyshouldbeselected.When

drillingwithPDM,themudpumpshouldalsomeettherequirementsofPDMrunning.

5.2SelectionofDeflectingTool

5.2.1EccentricWedge

5.2.1.1Theeccentricwedgeissuitablefortheintegralformationwithdrillabilityabove

grade4.

5.2.1.2Dependingonthedrillabilityofrocksandrequirementsofkick-offdrilling,the

vertexangleofeccentricwedgeshouldbeintherangeof2°to5°.Ifdrillinginsoft

formation,oronlyashortdistanceneedstobedrilledafterdeflectionbyeccentricwedge,

alargervertexanglecouldbechosen.Otherwise,asmallervertexangleshouldbeused.

5.2.1.3Fixedeccentricwedgeissuitableforbranchholekick-offdrilling,whileretrievable

eccentricwedgeissuitableforkick-offdrillingfromtheoriginalholebottom.

5.2.1.4Theopentypeeccentricwedgewithfullyopentopcouldbeusedforthesamediameter

directionaldrilling,whiletheclosetypeeccentricwedgewithsupportringontheupperpart

canonlybeusedforthesituationthatthediameterofeccentricwedgeisonegradesmaller

thanthatofdrillingholeinkick-offdrilling.

5.2.1.5Whenthedriftangleoftheboreholeisgreaterthan30°,eccentricwedgeisnot

9

suitableforazimuthcorrection.

5.2.2Continuouswhipstock

5.2.2.1Continuouswhipstockshouldbeusedinintegralformation.

5.2.2.2ContinuouswhipstockcouldbedrivenbydrillstringorPDM.

5.2.2.3Continuouswhipstockshouldbefixedfirmlyintheborehole,otherwiseitcouldn’t

beusedforkick-offdrilling.

5.2.2.4Continuouswhipstockissuitableforthesamediametercontinuouskick-offdrilling,

andtheintensityofdeflectionshouldberestrictedintherangeof0.3°/mto1.8°/m.

5.2.3PDM

5.2.3.1Whencontinuousdeflectingisrequiredandthedeflectingtoolisrequiredtohave

strongadaptabilitytotheformation,PDMshouldbeselected.PDMcanbeusednotonlyinmedium

hardtohardformations,butalsoinweakandbrokenrocklayers,orformationswith

drillabilityaslowasgrade3.

5.2.3.2Appropriateparametersshouldbeselectedinkick-offdrillingwithPDM.Itissuitable

thattheintensityofdeflectiontoberestrictedintherangeof0to1.2°/m.Inspecial

situations,thedeflectionintensitycanbeincreasedto1.2°/mto2°/m,butthisintensity

couldnotbeusedforlongdistanceorcontinuouskick-offdrilling.

5.2.3.3Appropriatestator-rotorratioofPDMshouldbeselectedaccordingtoflowrateand

pressureofmudpump,weightonbit(WOB)anddrillingtorque.

5.2.3.4TherotaryspeedandtorqueofPDMshouldbedeterminedaccordingtothedrillability

ofstratumandthetypeofdrillbit.

5.2.3.5Suitabledeflectionpartsshouldbeconfiguratedaccordingtotherequirementof

kick-offdrilling,suchasfixedbentsub,bentoutertube,doublebentoutertube,adjustable

bentsubandnear-biteccentricblock,etc.

5.2.3.6PDMshouldhaveprioritytobechosenasdeflectingtoolintheconstructionof

directionalborehole,suchashorizontalborehole,intersectedborehole,orhighprecision

verticalborehole.

5.2.3.7Afteroverhaul,thePDMisnotallowedtobefurtherusedifithasnotundergonefactory

10

test,issuedatestreportandobtainedaproductqualitycertificate.

5.3SelectionofMeasuringInstruments

5.3.1Measuringinstrumentshouldbeselectedaccordingtothetypeofdeflectingtool,the

requirementoforientationprecisionandtheexistenceofmagneticfielddisturbance.

5.3.2Innon-magneticminingarea,magneticinductivemeasurementinstrumentscanbeselected,

suchassingleshotclinometer,multishotclinometer,MWDclinometer,etc.Inmagneticmining

area,measuringinstrumentsthatarefreefrommagneticfielddisturbanceshouldbeselected,

suchasgyroclinometer,photoelectricclinometer,andstraingaugetypeclinometer,etc.

5.3.3Whenorientatingwitheccentricwedgeorcontinuouswhipstock,generallysingleshot

orientationinstrumentshouldbeutilized,andthedriftangleofboreholeshouldbenoless

than3°.

5.3.4Inkick-offdrillingwithPDM,singleshotclinometer,multishotclinometer,orMWD

clinometercanbeused.

5.3.5Whenhighprecisionverticalboreholesaredrilled,verticaldrillingsystemcanbeused.

5.3.6Whenintersectedboreholesaredrilled,MWDclinometerandtarget-hittingguidance

systemshouldbeused.

5.4SelectionofDeflectingBit

5.4.1Thedeflectingbitshouldbeselectedaccordingtotherockdrillabilityofthedeflecting

sectionandthetypeofdeflectingtool.

5.4.2Forstratumwithdrillabilityequaltoorlowerthangrade6,conebit,carbidebit,

PDCbitordiamondbitshouldbeused.Forformationswithdrillabilityequaltoorlarger

thangrade7,diamonddrillbitissuitable.

5.4.3Whenafullfacedeflectingbitisusedinhardrockstratum,thedrillbitshouldbe

setacentralwaternozzletodrillsmallcorestoavoidforminga"deadpoint"inthecenter

ofthebit;whenusingafullfacedeflectingbitinsoftandmediumhardrocks,anasymmetric

innerconeeccentricwaternozzleshouldbeset.

5.4.4Atthebottomofthediamondbit,thereshouldbeaconcaveangleofaround170°and

enoughpassageforwaterflow.

11

5.4.5Highgradediamondshouldbeselectedfortheoutercuttingbladeofdiamondbit.The

heightofthecuttingbladeshouldbeshort,andthebladesshouldbestrengthened;theinner

cuttingbladesofthedeflectingbitwithcentralwaternozzleshouldalsobestrengthened.

5.4.6Whenthecontinuouswhipstockisusedtomakeadeflectdrilling,thedrillbitwith

sharpcuttingbladesshouldbeused.

5.5SelectionofAuxiliaryToolsforDirectionalDrilling

5.5.1Non-magneticdrillpipe

Thelengthofnon-magneticdrillpipeshouldnotbelessthan5m.Therelativemagnet

conductivityofnon-magneticdrillpipemustbelessthan1.02,andhightensilestrengthand

goodcorrosionresistancearealsorequired.

5.5.2Cableswivel

Cableswivelisakindofswivelwhosecenterishollow,allowingacabletopassthrough.

Thecableswivelshouldbeselectedby:

a)Thediameterofthethroughholeshouldbebigenoughtoallowthemeasuringinstrument

topassthroughsmoothly;

b)Ensurethesealingperformancebetweenthearmoredcableandthethroughholeoftheswivel;

c)Itscapacityofenduringpressureshouldmatchwiththeworkingpressureofmudpump;

d)Itshoistingweightshouldmatchwiththehookload.

5.5.3Armoredcableandwinch

Armoredcableandwinchshouldbeselectedby：

a)Thenumberofcoresofarmoredcableshouldbeselectedaccordingtothesignaltransmission

modeofmeasuringinstrument;

b)Thediameterandlengthofarmoredcableshouldbedeterminedaccordingtothedepthof

directionalborehole.Also,thetotallengthofcableshouldbereserved;

c)Thewinchshouldbeselectedaccordingtothediameterandlengthofthearmoredcable;

d)Thewinchshouldbeequippedwithgearshift,reliablebrake,andinstrumentthatiscapable

ofmeasuringthelengthofcableprecisely.

12

5.5.4Highpressurehose

WhenPDMisusedforkick-offdrilling,thepressureresistanceofhigh-pressurehoseshould

benolessthan20MPa.

5.5.5pressurestabilizingtank

WhenPDMisusedforkick-offdrilling,apressurestabilizingtankmustbeinstalledinthe

outputpipelineofthemudpump,anditssafetypressureshouldnotbelowerthan20MPa.

5.5.6Selectionofmudpurificationfacilities

Solidcontroldevicesshouldbeequippedinmudcirculationsystem,andfilterdevicesshould

beinstalledinthesuctionpipelineandtheoutputpipeline.

5.5.7Anti-torquedevice

FordirectionaldrillingwithPDM,anti-torquedeviceshouldbeinstalled.

6ConstructionTechnologyofDirectionalDrilling

6.1PreparationPriortoDirectionalDrilling

6.1.1Beforekick-offdrilling,theboreholeshouldbecleaned,theresidualcoreshouldbe

removed,thecuttingchipsinthebottomoftheholeshouldbewashedaway,andtheholedepth

shouldbecalibrated.

6.1.2Ifitisdifficulttodrillanewboreholeinbranchkick-offdrilling,anartificial

bottomofboreholeshouldbeconstructed.

6.1.3Beforekick-offdrilling,allpartsofmeasuringinstrument,cableandwinchshouldbe

checkedtoensurethemrunningproperly.

6.1.4Beforekick-offdrilling,thedrillrigs,mudpumps,drillstrings,powersystemsand

high-pressurepipelinesystemsshouldbeinspectedandconfirmedtobeinnormaloperation.

Theinstrumentsequippedinthedrillrigshouldbesensitiveandreliable.

6.1.5Appropriatedrillingfluidshouldbepreparedtoensurethecirculationsystemworks

normally.

13

6.2ConstructionofArtificialBoreholeBottom

6.2.1Theconstructionofartificialboreholebottomistofillthewellsectionbelowthe

branchpointwithfillingmaterialsorappliance,soastoprovideasolidfoundationforthe

deflectingoperation.

6.2.2Theartificialholebottombridgingmaterialscanbewoodplugs,metalplugsandcement

plugs,andcementplugsarerecommended.

6.2.3Iftheupperandlowerboreholewallsofthebranchpointareregularandthereisno

diameterenlargementphenomenon,woodenplugormetalplugcanbeusedasabridgeinthehole,

andtheupperpartabovetheplugisfilledwithcementtoformartificialholebottom.

6.2.4Ifthebranchpointisclosetothebottomoftheborehole,oriftheholewallisirregular

orexcessivelylarge,woodenormetalplugscannotbeusedto"bridge",theninertmaterial

suchassand,gravelorcementcouldbegroutedfromboreholebottomtothepredetermined

position.

6.2.5HighgradePortlandcement,superhardeningcementandoilwellcementcanbeusedas

cementplugmaterialsforartificialholebottom,andthelattertwoshouldbeusedwhen

conditionspermit.

6.2.6Intheprocessofartificialcementholebottomestablishing,theboreholeshouldbe

cleanedbeforegrouting,andthecementshouldbepouredto15m—20mabovethebranchpoint.

Thecementcoreshouldbedrilledoutaftercuringfor48—72hours,andwhethertostartthe

branchdrillingcanbedeterminedaccordingtothesolidificationconditionofthecement.

6.3CheckofDeflectingTool

6.3.1CheckofEccentricWedge

6.3.1.1Thesupportingclampshouldbeabletostretchoutanddrawbackfreely.

6.3.1.2Thesurfaceofwedgeshouldbesmooth.

6.3.1.3Theconnectionofeachcomponentafterassemblyshouldbefirmandreliable.

6.3.2Checkofcontinuouswhipstock

6.3.2.1Beforeuse,thecontinuouswhipstockshouldbeassembledandtestedinaccordancewith

therequirementsoftheinstructionmanual.

14

6.3.2.2Afterassembly,allpartsofthecontinuouswhipstockshouldberotateflexibly,and

thesupportingclampcouldbestretchedoutordrewbackfreely.

6.3.2.3Afterusingfor1-2times,itshouldbedisassembledforcleaningandinspection,and

thewornpartsshouldbereplaced.

6.3.3CheckofPDM

6.3.3.1Thedrillingtoolmustbeassembled,disassembledandtest