天然氣欠平衡鉆井關(guān)鍵技術(shù)研究及現(xiàn)場應(yīng)用

王長寧張漢林

WangchangningZhanghanlin中國石油川慶鉆探工程工程技術(shù)研究院CCDCEngineeringTechnologyInstitute二00九年十月October,2021天然氣欠平衡鉆井關(guān)鍵技術(shù)研究

及現(xiàn)場應(yīng)用ResearchandFieldApplicationonKeyTechniquesofNaturalGasUnderbalancedDrilling概述General天然氣鉆井Naturalgasdrilling空氣鉆井Airdrilling氮?dú)忏@井Nitrogendrilling專用設(shè)備少Fewerspecialequipments低的鉆井綜合本錢LowercomprehensivedrillingcostAdvantages優(yōu)勢現(xiàn)場試驗Fieldtest:蘇里格氣田特點試驗?zāi)康牡蛪旱蜐B低產(chǎn)保護(hù)儲層提高機(jī)械鉆速試驗井位S242井S39-14-1井S39-14-4井S35-18井ThecharacteristicsofSuligegasfieldTestObjectiveTestWellsLowpressureLowpermeabilityLowproductionProtectionreservoirImprovingROP表14口天然氣鉆井情況S39-14-1S39-14-1S39-14-4S39-14-4試驗結(jié)果

TestResults

機(jī)械鉆速大幅度提高

TheROPhasbeenimprovedgreatly

最大限度的保護(hù)儲層Themaximumprotectionofreservoir

不會發(fā)生井下燃爆事故ToavioddownholeexplosionS35-18井的平均機(jī)械鉆速18m/h,是鄰井泥漿鉆井的9倍

TheROPofS35-18is18m/h,whichis9timesofmuddrillinginthisregion

欠平衡鉆井UBD

關(guān)鍵技術(shù)Keytechnologies地層出水與地層穩(wěn)定性預(yù)測Formationwaterproductionandformationstabilityforecast

井眼凈化與最正確注氣參數(shù)Holecleaningandthebestgasinjectionparameters鉆頭失效機(jī)理及選型Bitfailuremechanismandselection井下復(fù)雜情況處理Downholecomplicationtreatment

平安鉆井Safedrilling地層出水量評價方法

Formationwaterproduction圖1地層出水預(yù)測分析Formationwaterproductionforecastanalysis

延安組延長組石盒子

地層出水Formationwaterproduction井壁坍塌

Holecollapse

卡鉆!Sticking!地層出水危害Harmfulness井眼凈化惡劣Holecleaningworse

井壁失穩(wěn)原因及井壁穩(wěn)定性評價方法Boreholestability

氣體鉆井井壁失穩(wěn)Instabilityofgasdrilling

在鉆井過程膠結(jié)強(qiáng)度低的地層出現(xiàn)掉塊甚至坍塌Thefall-blockofrockorcollapseintheformationwhichhaslowbondingstrengthduringthedrilling；在轉(zhuǎn)換泥漿過程中的井壁坍塌Theboreholecollapseduringtheprocessoftransferringmud.氣體鉆井井壁失穩(wěn)原因Reasonofgasdrillingboreholeinstability

化學(xué)－應(yīng)力耦合作用Chemistry—stresscouplingeffect

滲流－應(yīng)力的耦合作用Infiltration—stresscouplingeffect微裂紋—損傷區(qū)Micro-crack-injuryarea

泥頁巖水化Argillutitehydration

導(dǎo)致嚴(yán)重的井壁失穩(wěn)坍塌!Causetheseriousboreholeinstabilityandcollapse!

圖2巖石應(yīng)變軟化特性

Thestrainsofteningofrock

圖3非均勻地應(yīng)力與損傷區(qū)的關(guān)系Therelationshipofnon-uniformin-situstressandinjuryarea

(a)σH:σh=1:1(臨界狀態(tài))(Criticalconditions)

(b)σH:σh=1.5:1(c)σH:σh=2:1(臨界狀態(tài))(Criticalconditions)

井壁失穩(wěn)原因及井壁穩(wěn)定性評價方法

BoreholestabilityFourkindsofrockinuniaxialcompressiontest延長組石盒子組山西組石千峰組井壁穩(wěn)定性分析與實鉆情況吻合!Itisidenticalwiththerealdrillingsituations!圖4井壁穩(wěn)定性分析Figure4Boreholestabilityanalysis井壁失穩(wěn)原因及井壁穩(wěn)定性評價方法

Boreholestability井眼凈化與注氣參數(shù)設(shè)計

Holecleaningandgasinjectionparametersdesign

攜巖能力Thecapabilityofcarryingcutting氣體攜帶巖屑的能力比泥漿差Gasislessthanmud氣體鉆井的井眼凈化問題比泥漿鉆井應(yīng)該更加關(guān)注!Theproblemofholecleaningofgasdrillingismoreimportantthanthemuddrilling

圖5巖屑團(tuán)泥餅環(huán)的形成過程Rockcuttingsgroup

mudcake

圖6攜巖關(guān)節(jié)點Thejointpointofcarryingcuttings

泥餅環(huán)的形成Theformationofmudcake當(dāng)?shù)貙映鏊畷r，在井壁上或鉆具上都有形成泥餅環(huán)的趨勢Itwillhavetrendofmudcakeontheboreholewallordrillingtoolswhenformationwaterproductionhappened處理措施

Treatmentmeasures

優(yōu)化注氣參數(shù)

Optimizationofgasinjectionparameters

轉(zhuǎn)化鉆井方式

Tochangethedrillingmode

增加注氣量Increasetheinjectionofgas霧化鉆井Mistdrilling泡沫鉆井Foamdrilling泥漿鉆井Muddrilling井眼凈化與注氣參數(shù)設(shè)計

Holecleaningandgasinjectionparametersdesign

地層不出水Noformationwaterproduction地層水或氣體本身非常潮濕Formationwaterproductionorgasisverymoist注氣參數(shù)設(shè)計Gasinjectionparametersdesign最小環(huán)空返速是15m/hThemin.annularvelocityis15m/hS242井和S35-18井最小注氣量是28m3/min對于6

6?

井眼,最小注氣量約21m3/minFor6

6?

borehole,theminimumgasinjectionisabout21m3/min增加注氣量Increasetheinjectionofgas

對于6

6?

井眼,在注氣量大于120m3/min條件下，純氣體有效攜帶地層水最多10m3/h的出水量

For6

6?

borehole,puregasatmostcarriesover10m3/hwateryieldwhentheinjectiongasismorethan120m3/min井眼凈化與注氣參數(shù)設(shè)計

Holecleaningandgasinjectionparametersdesign

鉆頭冷卻與失效機(jī)理分析

Bitcoolingandfailure

鉆頭在井底工作產(chǎn)生的熱量Theheatarisingfromthebitworking地層巖石溫度Therocktemperature

鉆頭溫度升高Thebittemperaturerise泥漿鉆井Muddrilling

氣體鉆井Gasdrilling

高比熱容和熱傳導(dǎo)率

Highheatabsorptioncapacityandheatconduction低比熱容和熱傳導(dǎo)率

Lowheatabsorptioncapacityandheatconduction有效地將鉆頭熱量帶走Effectivelytaketheheatway鉆頭整體溫度升高Thewholebittemperaturerise氣體鉆井鉆頭的冷卻問題需要!Thebitcoolingproblemingasdrilling!圖7陜242井鉆頭解剖分析

由圖7知，密封系統(tǒng)油脂略發(fā)黑和變味，井底溫度偏高，但對密封件及鉆頭牙齒、牙輪根本無影響，由此可見氣體的冷卻效果不可低估。Thegreaseofsealingsystemturnsslightlyblackandalittlesmell,butthisdonotaffectthesealandthebittoothandgearwheel,fromwhichwecanseethatthecoolingeffectofgasshouldnotbeunderestimated地層出水Formationwaterproduction鉆頭泥包Balledbit

鉆頭局部溫度升高M(jìn)akingpartialtemperatureofdrillingbitistoohigh最終“燒壞〞鉆頭Eventually“burn〞thedrillingbit不能有效冷卻鉆頭大大降低了井底氣體流量Greatlyreducingthegasflowinbottomhole

圖8S39-14-1井損壞的鉆頭由圖8可知，

S39-14-1井天然氣鉆井鉆進(jìn)1310-1388m井段地層少量出水，被水化的泥巖包裹鉆頭降低了氣體冷卻鉆頭效率，其后由于地層出水量逐漸增大，最終在井深1685m，鉆頭失效被迫起鉆。Hasasmallamountofformationwaterproductionin1310-1388m,packedwithaqueousmudstone,reducestheefficiencyofgascooling.Ultimately,alongwiththeincreaseofformationwaterproduction,thebitisforcedtobepulledoutin1685mduetobitfailure井眼凈化不良

Poorholecleaning

鉆頭冷卻與失效機(jī)理分析

Bitcoolingandfailure

井斜機(jī)理分析及防斜措施研究

Holedeviationandanti-deviationmeasures

天然氣鉆井井斜機(jī)理分析Mechanismanalysisofholedeviationinnaturalgasdrilling

圖9天然氣鉆井井斜角變化Deviationanglechangeinnaturalgasdrilling影響井斜的因素Influence

factors:鉆壓

WOB井眼擴(kuò)大Holeenlargement

由圖9可知，井斜最大處也是井眼擴(kuò)大的峰值處。Themaximumdeviationhappensinthepeakofholeenlargement.井眼擴(kuò)大的原因Reasonsofholeenlargement

:

地層出水和地層力學(xué)不穩(wěn)定

Formationwaterproductionandunstableformationmechanics

參考圖1:

最大井斜段有三個小水層Seefigure1:thereare3watersub-layer參考圖4:在井深3050

3200m井段有力學(xué)不穩(wěn)定趨勢

Seefigure4:thereisatrendofmechanicsinstability圖10光鉆鋌鉆具降斜力分析影響井斜的因素Influence

factors

:井底巖石受力狀態(tài)改變Downholerockstress-strainedconditionchange

鉆頭破巖時，每次都是巖石拉應(yīng)力最大的一面先被破碎，最終導(dǎo)致井斜。Inrockbreaking,everytime,themaximumtensilestresssideisalwaysthefirsttobebroken,thiswillleadtodeviation.鉆井介質(zhì)及鉆柱力學(xué)的影響Drillingmediaanddrillingstringmechanics

由圖10可知，動力學(xué)條件下，泥漿中光鉆鋌組合的降斜力遠(yuǎn)遠(yuǎn)大于空氣中的降斜力，這與靜力學(xué)結(jié)果具有相反的特征。

Seefigure10:Indynamicconditions,deviationangledropofslickassemblyinmudisgreaterthaningas,whichisoppositeinstaticconditions.井斜機(jī)理分析及防斜措施研究

Holedeviationandanti-deviationmeasures

Figure10Angledropanalysisofslickassembly防斜技術(shù)措施研究Anti-deviationmeasures本卷須知Notes:有卡鉆的風(fēng)險Hastheriskofsticking圖11帶預(yù)彎曲結(jié)構(gòu)的雙穩(wěn)定器鉆具組合的結(jié)構(gòu)示意圖針對天然氣井井斜問題，從改變鉆具結(jié)構(gòu)上入手，采用預(yù)彎曲防斜鉆具控制井斜。Forcontrollingholedeviationinnaturalgasdrilling,pre-bendinganti-deviationtoolsareused.

井斜機(jī)理分析及防斜措施研究

Holedeviationandanti-deviationmeasures

Figure11Structuraldrawingofbi-stabilizerdrillingtoolsassemblywithpre-bendingstructure平安措施及井下復(fù)雜情況處理

Safetyprecautionanddownholeproblemhandling平安措施Safetyprecautions風(fēng)險識別與評估Riskidentificationandassessment培訓(xùn)Training建立天然氣鉆井巡回檢查制度

Establishingnaturalgasdrillingtoursofinspection

建立崗位責(zé)任制Establishingsystemofjobresponsibility

設(shè)備和工具的平安管理Thesafetymanagementofequipmentandtools加強(qiáng)平安設(shè)計Strengthenthesafetydesign制定井下復(fù)雜問題處理措施Establishingmeasuresofdownholeproblem井下復(fù)雜問題處理Downholeproblemhandling不能有效攜帶地層水Noteffectively轉(zhuǎn)為霧化鉆井或泡沫鉆井Tomistdrillingorfoamdrilling轉(zhuǎn)為泥漿鉆井Muddrilling說明地層出水量大Alargevolumeofwateryield排屑管出口有巖屑團(tuán)Cuttingclustersatcuttingoutlet轉(zhuǎn)盤扭矩增大Tabletorqueincrease上提鉆具遇阻Encounteringresistanceinpickupdrillingtools注入高粘度泡沫洗井Injecthighviscosityfoamliquidtocleanborehole泥漿鉆井Muddrilling鉆頭泥包、井壁上形成泥餅環(huán)或巖屑堆積Ballup,mudcakeringorcuttingscluster卡鉆風(fēng)險!Sticking!繼續(xù)正常鉆進(jìn)!Normaldrilling有效攜帶地層水

Effective

立管壓力迅速上升SharpincreaseofSPP不能有效攜帶地層水Noteffectively蹩跳

Bitbouncing平安措施及井下復(fù)雜情況處理

Safetyprecautionanddownholeproblemhandling有效攜帶地層水

Effective

認(rèn)識Someviews

實施天然氣鉆井之前，要收集相關(guān)的測井資料進(jìn)行地層出水與井壁穩(wěn)定性綜合評價分析，并以此結(jié)果做天然氣鉆井可行性分析；Beforenaturalgasdrilling,collectingtherelativelogdatatoevaluateandanalyzetheformationwaterproductionandboreholestability,andtakefeasibilityanalysis天然氣鉆井〔也適用于其它氣體〕完成后，轉(zhuǎn)換為泥漿鉆井發(fā)生嚴(yán)重的井壁坍塌。其主要原因是天然氣鉆井過程中，在井壁周圍產(chǎn)生有放射狀微裂縫的損傷區(qū)，在應(yīng)力－滲流的耦合作用與應(yīng)力－化學(xué)耦合作用下導(dǎo)致嚴(yán)重的井壁坍塌。Aftercompletionofnaturalgasdrilling(italsosuitforothergasdrilling),seriousboreholecollapsehappenedwhenconvertingintomuddrilling,mainlybecauseduringtheprocessofnaturalgasdrilling,thereisinjuredareawithradiantmicro-crackaroundboreholewall,whichisthecommonresultsundertheactionofcouplingeffectsbetweenstress—infiltratingandstress—chemicaleffects認(rèn)識Someviews

天然氣及其它氣體鉆井破巖機(jī)理與泥漿鉆井有所不同，以純滾動破巖為主，應(yīng)選擇無移軸