摘要
现今地应力状态(大小和方向)和煤储层渗透率是影响煤层气勘探开发的重要地质因素。基于震源机制解反演、水力压裂等方法确定了滇东-黔西地区现今地应力状态,揭示了二叠系煤层地应力大小垂向变化规律,并在此基础上剖析了滇东-黔西地区二叠系煤储层渗透率发育特征及其控制因素。研究结果表明:滇东-黔西地区水平最大主应力(S_(H,max))方向总体为WNW-ESE向;水平最大主应力为2.67~29.84 MPa,平均为14.10 MPa,水平最小主应力(S_(h,min))为1.85~23.76 MPa,平均为10.36 MPa,垂向应力(S_(v))为0.86~31.93 MPa,平均为14.49 MPa。现今地应力大小随煤层埋深的增加而增大,在垂向分布上呈现出分带性,在600 m以浅,地应力分布整体表现为S_(H,max)>S_(v)>S_(h,min),水平最大主应力起主导作用,为大地动力场型,而在700 m以深之后,地应力机制转换为S_(v)>S_(H,max)>S_(h,min),垂向应力起主导作用,为大地静力场型,地应力垂向转换深度为600~700 m。滇东-黔西地区二叠系煤储层渗透率的变化受多种因素的综合影响,天然裂隙发育特征与现今地应力状态耦合对该区煤储层渗透性具有重要的控制作用。
The present-day in-situ stress state(magnitude and orientation)and coal reservoir permeability are extremely important factors for the coalbed methane(CBM)exploration and development.In the present study,methods including focal mechanism solution,hydrau⁃lic fracturing were adopted to analyze the present-day in-situ stress state in the eastern Yunnan and western Guizhou regions.The correla⁃tion between the present-day in-situ stress magnitude and burial depth was established through statistical analysis.Furthermore,the vari⁃ation characteristics of Permian coal reservoir permeability in the eastern Yunnan and western Guizhou regions,and the controlling factors were analyzed.The results indicated that the orientation of horizontal maximum principal stress(S_(H,max))was in a dominant NWW-SEEtrending.In the study area,the magnitudes of S_(H,max),S_(h,min) and S_(v) were 2.67-29.84 MPa(averaged 14.10 MPa),1.85-23.76 MPa(av⁃eraged 10.36 MPa),and 0.86-31.93 MPa(averaged 14.49 MPa),respectively.The in-situ stress magnitudes became larger with in⁃creased burial depth and could be divided into several belts.The in-situ stress regime was a dominant of S_(H,max)>S_(v)>S_(h,min) in layers shallo⁃wer than 600 m.Coal seams were under the strike-slip stress regime.Whereas it was a dominant normal stress regime(S_(v)>S_(H,max)>S_(h,min))in layers deeper than 700 m.Coal seams were under the strike-slip stress regime.The vertical transformation depth of the in-situ stress re⁃gime in the eastern Yunnan and western Guizhou regions was approximately 600-700 m.Many factors together influenced the variations of Permian coal reservoir permeability in the study area.The coupling effect between natural fracture characteristics and in-situ stress field showed great controls on the Permian coal reservoir permeability in the eastern Yunnan and western Guizhou regions.
作者
鞠玮
王胜宇
姜波
苗琦
李明
黄沛铭
JU Wei;WANG Shengyu;JIANG Bo;MIAO Qi;LI Ming;HUANG Peiming(Key Laboratory of Coalbed Methane Resources and Reservoir Formation Process,Ministry of Education,China University of Mining and Technology,Xuzhou 221008,China;School of Resources and Geosciences,China University of Mining and Technology,Xuzhou 221116,China;No.198 Coalfield Geology Prospecting Team of Yunan Province,Kunming 650208,China)
出处
《煤炭科学技术》
CAS
CSCD
北大核心
2022年第2期179-186,共8页
Coal Science and Technology
基金
国家科技重大专项资助项目(2016ZX05044001)
国家自然科学基金资助项目(41702130)
江苏高校优势学科建设工程资助项目联合资助项目。
关键词
现今地应力场
煤储层渗透率
二叠系煤层
滇东-黔西地区
present-day in-situ stress field
coal reservoir permeability
fracture
stress regime
Permian coal seams
eastern Yunnan and western Guizhou regions
