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1、气水两相煤层气井井底流压预测方法第31卷第6期2010年11月石油ACTAPETR0LEISINICAVol_31NO.6NOV.2O1O文章编号:0253—2697(2010)06—0998—06气水两相煤层气井井底流压预测方法刘新福綦耀光刘春花李延祥赵培华.(1.中国石油大学机电工程学院山东东营257061;2中国石油煤层气有限责任公司北京100011)摘要:基于井筒流体稳定流动能量方程,建立了煤层气柱段压差和两相液柱压差的数学模型,给出了气水两相煤层气井底流压的预测方法,并分析了各排采参数间的相互关系及其对产能的影响.研究结果表明,该算法较为准确地预测了煤层气井进入稳定排
2、采后的井底流压;井底流压是井口套压,气柱和液柱压力综合作用的结果,能充分反映产气量的渗流压力特征;该模型充分考虑了井筒中压力增量随井深增量的变化关系,在两相液柱段每等份长度不超过25m时,井底流压预测结果的相对误差可控制在5%以内;调整井底压力,可有效增大生产压差,控制排液量,利于煤层气体的解吸,从而提高产气量;产水量较大,动液面较高时,宜加大排液量,降低井底压力,而动液面较低时,宜放开套压.关键词:煤层气井;井底流压;煤层气柱压力;两相液柱压力;产能中图分类号:TE349文献标识码:APredictionofflowingbottomholepressuresfortwo—p
3、hasecoalbedmethanewellsLIUXinfuQIYaoguang'LIUChunhuaLIYanxiangZHAOPeihua(1.CollegeofMechanicalandElectronicEngineering,ChinaUniversityofPetroleum,Dongying257061,China;2.PetroChinaCoalbedMethaneCompanyLimited,Beijing1()0OI1,China)Abstract:Flowingbottomholepressure(FBHP)inthecoalbedmethane(CBM
4、)wellsisthekeyparameterofdeterminingthedeliver—abilityofcoalfields.Periodiccalculationandsupervisionofbottomholepressures(BHP)canpredictfuturereservoirbehaviorandhelptOadjusttheworkingsystem.Themathematicalmodelsofgascolumnpressureandtwo—phaseliquidcolumnpressurewerede—velopedbasedontheCBMwe
5、llliquidflowequation.ThepredictionofFBHPwasgivenoutfortwo—phaseCBMwells.Andtherelationshipamongoperationalparametersandtheireffectsondeliverabilitywereanalyzedonthebasisofresults.TheresultsshowthattheproposedalgorithmprovidesaccuratepredictionforFBHPinCBMwells.BHPresultsfromthecombinedaction
6、ofwellheadpres—sure,gascolumnpressureandtwophasefluidcolumnpressure.AndBHPcanfullyreflectpercolationcharacteristicsofCBMproduc—tion.BHPisafunctionofdepthofeachcolumnsegment,andthesmallerrorsoflessthan5%areachievedwhileeachsegmentiswithin25m.AdjustingBHPduringtheproductioncaneffectivelyincrea
7、seproducingpressuredropandcontrolwaterflowrate,whichisbeneficialtOgasdesorptionandenhanceCBMproduction.BHPcanbedecreasedduetoincreasingwaterdisplacementwhiledynam—icfluidlevelishighanddecreasingwellheadpressurewhileitisrelativelylow.Keywords:coalbe
