China United Coalbed Methane Corporation Limited MOE Key Lab of Petroleum Engineering,China University of Petroleum(Beijing)

为对煤层顶底板水平井穿层压裂技术提供理论支撑,以煤层顶底板水平井穿层压裂技术为模拟对象,应用大尺寸真三轴测试系统对天然岩样制得的试件进行了水平井压裂模拟试验,研究了地应力、天然裂缝及弹性模量对水力裂缝扩展的影响规律。结果表明:在采用水平井穿层压裂技术开发煤层气时,应优选垂向应力与最大水平应力差较大(5 MPa)的含煤地层;高弹性模量层中水力裂缝内压力较高,可进一步促进裂缝扩展;天然裂缝对水力裂缝扩展的影响不仅与逼近角有关,更与天然裂缝宽度、水力裂缝内注入压力相关。水力裂缝内注入压力较低(10 MPa)、天然裂缝较宽时(0.05 mm),水力裂缝易受天然裂缝影响,与天然裂缝相交后沿天然裂缝扩展;水力裂缝内注入压力较高时(30MPa),天然裂缝对水力裂缝扩展的影响减弱。

in order to provide theoretical support to the through stata fracturing technology of horizontal l in the roof and foo of sean.taking through strata fracturing technology of horizontal ell in the roof and foo of seam as th simulation objct a large size rue triaxil test systemn was aplied tothe racturing simulation test of horizontal ell n the sample prepared with the naural rock samples,and a study was conducted on the in titu sress,natural crack and elastic modulus affected tothe expansion of the hydraulic cracking. The resuts shcwed that when the through stat fracturing technocgy of the horizontal vell as aplied todeveloag the coaltedmethane ,a coal beaing stratum with a max high stress difference betwee the verical stress and horzonal tress( 5 MPaj should be optimally seleced.n the high elastic moduus stratum,the pressure in the lhydraulic fractured cracks would be high and the cracks could be frther expanded.The natural racks wouldinfuence the hyraulic cracking expansion,which would not only related to the approximate ang e but would be related to the with ofthe naturl crack and the iniecion pressure in the ydrauli fractured cracks.The injction pressure in the hydraulic cracks would be low(10 MPa.When the with of the natural crack was wide( 0.05 m),.the hydraulic cracking would be eily afced by the natural cracking and would be expanded along the natural cracking when the natura cracking interaced. 晶hen the injecionpressure in the hydraulic cracks was high( 30 MPa)the natural cracks would reduce the infuences to the expansion of the hydraulic cracks.

国家科技重大专项资助项目(2011ZX05042)；