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1、第35卷第9期岩土力学Vol.35No.92014年9月RockandSoilMechanicsSep.2014文章编号:1000-7598(2014)09-2535-08复杂岩性储层渗透率-应力敏感性及其对气井产能的影响1,231,34苟燕,孙军昌,杨正明,周学民(1.中国科学院渗流流体力学研究所,河北廊坊065007;2.中国石油勘探开发研究院,北京100083;3.中国石油勘探开发研究院廊坊分院,河北廊坊065007;4.大庆油田有限责任公司勘探开发研究院,黑龙江大庆163712)摘要:采用变流压定围压试验方
2、式,在高温、高压条件下模拟了气藏开发过程,研究了复杂火山岩气藏储层渗透率应力敏感性,对比了变流压定围压与常规的定流压变围压方式评价储层应力敏感性的异同。试验结果表明,火山岩储层渗透率随着孔隙压力的减小而减小,渗透率减小主要发生在孔隙压力从40MPa下降至25MPa的变化区间,渗透率损失率与其初始渗透率之间的相关性较差,这与常规沉积砂岩储层具有一定的差别。变流压定围压试验评价的应力敏感性强于定流压变围压评价结果,气藏储层有效应力变化范围内两种试验评价的应力敏感性结果差异更大。基于渗流力学理论,推导得到考虑应力敏感性的
3、气井产能方程。计算结果表明,考虑应力敏感性时气井无阻流量约为不考虑应力敏感性时的63.28%,应力敏感性对气井产能的影响随着生产压差的增大而增大。关键词:复杂岩性储层;火山岩气藏;渗透率-应力敏感性;有效应力;孔隙压力;孔隙结构中图分类号:TE112.2文献标识码:APermeability-stresssensitivityofcomplexlithologyreservoiranditseffectongaswellproductivity1,231,34GOUYan,SUNJun-chang,YANGZhen
4、g-ming,ZHOUXue-min(1.InstituteofPorousFlowandFluidMechanics,ChineseAcademyofSciences,Langfang,Hebei065007,China;2.ResearchInstituteofPetroleumExplorationandDevelopment,Beijing100083,China;3.LangfangBranch,ResearchInstituteofPetroleumExplorationandDevelopment,L
5、angfang,Hebei065007,China;3.InstituteofPetroleumExplorationandDevelopment,DaqingOilfieldCompany,Daqing,Heilongjiang163712,China)Abstract:Permeability-stresssensitivityofcomplexvolcanicreservoirhasbeenstudiedusingthevariableporepressure-constantconfiningpressur
6、emethod.Meanwhile,permeabilitystress-sensitivityobtainedfromtwodifferentexperimentalmethodsalsohasbeencompared.Theexperimentalresultsindicatethatthevolcanicreservoirpermeabilitydeclineswiththedecreaseofreservoirporepressure.Decreaseofreservoirpermeabilitymainl
7、yoccursintheporepressurefrom40MPato25MPa.Thereisnogoodrelationshipbetweenrockinitialpermeabilityanditslossrate,whichisdifferentfromthatofthesedimentarysandstonereservoir.Permeability-stresssensitivityoftightvolcanicgasreservoirobtainedfromvariableporepressure-
8、constantconfiningpressureismuchstrongerthanthatobtainedfromconstantporepressure-variableconfiningpressure.Andthisdifferencebecomeslargerduringtheactualgasreservoireffectivestressra