石壕煤矿煤层气水力压裂微地震监测技术及应用

Microseismic Monitoring Technology and Application to Hydraulic Fracturing in Shihao Coal Mine

论文以重庆市石壕煤矿煤层气水力压裂为依托,现场压裂7个孔,其中1#孔的稳定压力19.5 MPa,压入水量489 m3,压裂时间670 min,2#孔的稳定压力为21.8 MPa,压裂时间430 min,压入水量251 m3。基于微地震技术,现场监测了1#、2#孔水力压裂的微地震信号,通过分析,得到了水力压裂煤层破裂点的三维损伤定位,其损伤点主要集中在M6-3煤层,煤层顶板、底板未发生破裂,煤层破裂的方向性不明显,水力压裂1#增渗半径约90 m、2#增渗半径约110 m,平均影响半径约为100 m,此次试验结果,为石壕煤矿煤层气开采水力压裂钻孔优化布置、增渗效果提供参考。

This paper is based on hydraulic fracturing engineering for CBM in Chongqing Shihao coal mine, 7 holes were drilled for hydraulic fracturing on site, the stable pressure in 1# hole is 19.5 Mpa with 489 m3 injected water volume and 670 min fracturing time span;meanwhile the stable pressure in 2# hole is 21.8 Mpa with 251 m3 injected water volume and 430 min fracturing time span. The microseismic signals are monitored in 1#&2# holes on sites during hydraulic fracturing using microseismic monitoring technology. 3-D damage locations of failure points in coal bed are obtained through data analysis, the failure points are mostly happens in M6-3 coal bed, and there is no failure in both coal seam roof and floor;also the orientation of failure in coal seam is not obvious. The practice shows that anatonosis radii in 1# &2# hole is 90 m and 110 m, respectively;the mean influence radius is 100 m. This experiment results can provide a practical experience and technical support for drilling layout optimization and anatonosis in hydraulic fracturing for CBM exploitation.