【摘要】 介绍了井温测试法、放射性同位素法、大地电位测试法和微地震测试法监测煤层水力压裂裂缝的基本原理。使用上述4种方法对华北地区施工的煤层气井压裂裂缝进行测量,得到了大量压裂井的裂缝方位和高度的监测数据。通过统计分析发现:压裂后的煤层裂缝一般都穿越其上下隔层,最大裂缝高度是压裂层厚度的6倍,裂缝长度大部分为50~90 m,裂缝形状基本以垂直裂缝为主,裂缝方向存在着随机性,扩展方向受地应力、局部地层构造和煤层割理共同作用。更多还原

【Abstract】 Four fundamental methods are introduced,namely well temperature,ground potential survey,microearthquake and radioactivity isotope,which were used to monitor the fracture geometry of fractured coalbed methane wells in North China.Many monitoring data of fracture height and azimuth were obtained.The statistical and analytical results show that the coalbed fractures generally grow into the over and underlying coal seam,the maximum fracture height is five times higher than the thickness of fractured layer,most of the fractures are between 50 m and 90 m long,fracture shape is mainly vertical and fracture orientation exists randomness,and the extension orientation is decided by the ground stress,local structure and coal cleat together.更多还原