由于大型天然裂缝、水力裂缝延伸单一等原因,多平台压裂时容易发生井间窜扰现象,邻井瞬时产气量最高降低93 %,井口压力最高上涨12 MPa,严重影响页岩气压裂开发效果。针对该类复杂情况,提出了一种页岩气水平井控缝防窜技术,主要包含多裂缝控缝长技术与转向控缝长技术。通过增加水力裂缝条数,降低净压力,或者利用暂堵材料控制水力裂缝远端延伸转向等措施,控制水力裂缝延伸,增加裂缝复杂程度,避免与邻井发生窜扰现象,最终实现井控泄气区域内有效开发页岩气。数值模拟表明,运用该技术有效缝长缩短了11.9 % ~ 24.8 %,且现场应用效果明显,微地震实时监测缝长同比降低24 %,邻井压力实时监测压力未上涨。页岩气水平井控缝防窜技术不仅为现场施工提供了理论支撑,同时降低了复杂情况发生概率,提高了单井产量。

Due to the large natural fractures and the single extension of hydraulic fractures, gas channeling occurs easily during fracturing of multi-platform, as a result the instantaneous gas production of adjacent wells is reduced by at most 93 %, and the wellhead pressure is increased by at most 12 MPa, which seriously affects the fracturing development effect of shale gas. For this complex situation, a fracture control and channeling prevention technology for horizontal wells of shale gas is proposed, which mainly includes fracture-length control of multiple fracture and steering fracture. By the measures of increasing the number of hydraulic fractures to reduce the net pressure, or using temporary plugging materials to steer hydraulic fractures, the extension direction of hydraulic fractures has been controlled and the fracture complexity has been increased to reduce the interacting of adjacent wells, and finally make the shale gas effectively develops in the well controlled gas drainage area. The numerical simulation shows that after applying this technology, the effective fracture length is shortened by 11.9 %~24.8 % The field application effect is obvious, the fracture length monitored by real-time micro seismic is reduced by 24 %, and the real-time monitoring pressure of adjacent wells does not change. The fracture control and channeling prevention technology in horizontal wells of shale gas does not only provides theoretical support for field application, but also reduces the probability of complex situations and improves the production of single well.