裂缝转向对低渗地层水平井压裂的影响

水力裂缝转向作为压裂过程中的一种重要现象,可造成近井筒裂缝的弯曲,对于裂缝中支撑剂的传输和流体的流动规律具有很大影响,可最终影响水力压裂的成败和人工裂缝的导流能力。统计了长庆油田水平井压裂施工的部分资料,分析了长庆油田水平井压裂的特点。结合二维裂缝的平面应变模型,建立了裂缝转向的曲率半径与地层物性参数和压裂施工参数的关系,并针对性地分析了不同参数对于裂缝曲率半径的影响。结果表明,水平应力差对裂缝的转向距离有决定性的影响,压裂施工排量对水力裂缝高度的增长贡献显著,控制排量、延长注液时间能有效增加裂缝长度。结论对于压裂参数优化设计和水力压裂施工具有参考意义。

Effect of Fracture Reorientation on Horizontal Well Fracturing in Low Permeability Reservoirs

Hydraulic pressure was an important phenomenon in the fracturing process,it would induce the bending in fractures on near wellbore.It had great influence on the proppant transportation and fluid flow in fractures,which would ultimately affected the success of hydraulic fracturing and artificial fracture conductivity.Based on the statistics of part of the information of horizontal well fracturing in Changqing Oilfield,the data of horizontal well fracturing in Changqing Oilfield and its fracturing characters were analyzed.Two dimensional fracture model(plane strain) was used to study the relationship between the fracture radius of curvature and formation physical parameters and formation fracturing operation parameters.The effect of different parameters to the fracture radius was studied specifically.The results show that the horizontal stress difference has a decisive influence on the total reorientation length and controls charging rate,expands the injection intervals,and effectively increases the fracture length.It provides valuable reference for optimizing fracturing parameters and hydraulic fracturing.