沁水盆地煤岩力学特征及其压裂裂缝的控制  

Coal/Rock Mechanics Features of Qinshui Basin and Fracturing Crack Control

作　　者：冯晴[1,2] 吴财芳[1,2] 雷波[1,2] 

机构地区：[1]中国矿业大学资源与地球科学学院,江苏徐州221116 [2]中国矿业大学煤层气资源与成藏过程教育部重点实验室,江苏徐州221116

出　　处：《煤炭科学技术》2011年第3期100-103,共4页Coal Science and Technology

基　　金：国家重点基础研究发展计划(973计划)资助项目(2009CB219605);国家重大科技专项资助项目(2011ZX05034;2011ZX05063);国家自然科学基金重点项目(40730422);国家青年科学基金资助项目(40802032)

摘　　要：以沁水盆地煤层气水力压裂井为研究对象,结合实验室煤样测试分析资料和煤层气井实际压裂数据,深入分析了煤层气井压裂效果,并进一步阐明了研究区煤岩力学特征对煤层压裂裂缝的影响。结果表明:研究区煤岩体弹性模量在2～5 GPa,且煤岩体弹性模量越小,压开的裂缝宽度越大;随着裂缝宽度的增加,裂缝长度将受到限制,其长度50～70 m;在对研究区煤层压裂过程中,压裂裂缝均不同程度地延入煤层顶底板,裂缝高度9～20 m,最大时裂缝的高度超过压裂层厚度的4倍;煤层压裂裂缝的形态特征没有固定的深度界限。煤层压裂裂缝的形成除受地应力影响外,还受局部构造应力及先存裂隙的控制,存在着在某一方向裂缝出现概率相对较大的现象。Taking the hydraulic fracturing of the coal bed methane wells in Qinshui Basin as the research object,in combination with the analysis information on the coal sample measurement and test in the lab and the actual fracturing data of the coal bed methane well,the paper in detail analyzed the fracturing effect of the coal bed methane wells and further stated the coal and rock mechanics features in the research zone affected to the fracturing of the coal seam.The results showed that the elastic modulus of coal and rock in the research zone would be distributed ranging from 2~5 GPa.When the elastic modulus of coal was lower,the crack width fractured would be higher.With the crack width increased,the crack length would be restricted and the length would be distributed at 50~70 m.During the seam fracturing process in the research zone,the cracks fractured in different degree would be expanded into the seam roof and floor,the crack height would be 9~20 m and the max crack height could be 4 times over the thickness of the fractured seam.The pattern features of the cracks fractured in seam would not have a fixed depth limitation.The crack formation fractured in seam would not be only affected by the ground stress,but would be controlled by the local structural stress and the previous existed cracks.There would be a relative high phenomenon to have cracks occurred along a certain direction in a probability.

关 键 词：沁水盆地 煤层气 水力压裂 煤岩力学特性 裂缝 

分 类 号：P618.11[天文地球—矿床学]