射孔水平井分段压裂破裂点优化方法

Fracture Rupture Point Optimization for Staged Fracturing of Perforated Horizontal Well

为确定水平井裂缝破裂点位置,指导射孔位置的优选,建立了综合考虑多条人工裂缝诱导应力、井筒内压、原地应力、热应力、压裂液渗流效应和射孔联合作用下的水平井分段压裂应力场模型,模型重点考虑了先压开裂缝产生的诱导应力场影响,更符合水平井分段压裂的实际特点,在此基础上结合岩石破裂准则从降低破裂压力角度形成了破裂点优化方法。研究结果表明先压开裂缝产生的诱导应力场影响使得水平井筒周围应力场更为复杂,研究裂缝起裂问题时必须考虑这一因素。对川西水平井分段压裂的破裂点进行了优化,压裂后输气求产,实际破裂压力梯度低于邻井同层的破裂压力梯度,大大降低了施工风险。该破裂点优化方法对水平井分段压裂优化设计有一定的指导意义。

To determine the location of fracture rupture point for horizontal wells and to guide the choice of pre-ferred perforation location,a horizontal well fracturing stress field model has been established,which takes in-duced stress interference caused by open cracks and fitting the actual characteristics of horizontal well fracturing into account.On this basis,a rupture point optimization methods has be established combined with rock frac-ture criterion from an angle of lowering fracture pressure.The results show that the induced stress interference caused by cracks makes stress field around the horizontal wellbore more complex,so studying on the problem of fracture initiation this factor must be considered.This method was applied to staged fracturing for horizontal wells in western Sichuan.According to the result,the actual fracture gradient is lower than those of adjacent wells,which greatly reduced the construction risk.The breaking point optimization method has some guiding significance for the design of horizontal well fracturing.