沁水盆地南部煤层气井压裂失败原因分析

依据煤层气井压裂施工的工艺参数,以沁水盆地南部12口煤层气井压裂施工失败为例,分析了沁水盆地南部煤层气井压裂失败的主要控制因素,研究认为：井口刺漏、高压停泵和煤储层力学性质是沁水盆地南部煤层气井压裂施工失败的主要控制因素;井口刺漏主要是由施工压力过高、井口老化造成的;高压停泵主要是由砂堵引起的,井口刺漏、高压停泵与砂堵之间相互影响及促进;砂堵受施工工艺及地质因素的影响;研究区煤储层具有低弹性模量、高泊松比的特点,地层开启难度大且裂缝难以延伸;压裂施工前,应做好煤储层特征的研究、压裂设备的选择、压裂工艺的设计等,减少工程事故的发生。

Analysis on Fracturing Failure Cause of Coal Bed Methane Well in South Part of Qinshui Basin

Taking the technical parameters of the fracturing operations in the coal bed methane well as the basis and taking the fracturing failures of the 12 coal bed methane wells in south part of Qinshui Basin as an example,the paper analyzed the main control factors of the fracturing failures of the coal bed methane wells in south part of Qinshui Basin.The study held that the tabbing leakage of mine shaft head,the stop of the high pressure pump and the mechanics property of the coal seam would be the main control factors of the fracturing failure in the coal bed methane wells of the south part of Qinshi Basin.The stabbing leakage of the mine shaft head was caused by the construction pressure too high and the aging of the mine shaft head.The stop of the high pressure was mainly caused by the sand jammed.There were mutual influences and promotion between the stabbing leakage of the mine shaft head,the stop of the high pressure pump and the sand jammed.The sand jammed would be affected by the construction technology and the geological factors.The coal seams in the study area would have the features of the low elastic modules and high Poissons ratio.The strata would have high difficult in excavation and the crack would be difficult to be expanded.Before the fracturing construction,the study on the coal seam features,the selection of the fracturing equipment and the design of the fracturing technology should be well done to reduce the project accident occurred.