The distribution of in-situ stress has a significant effect on fracture development direction so as to affect the selection of the fluid backflow. Analysis of the influences on the longitudinal cracks in fracture development direction, caused by vertical stress distribution of the reservoir interlayer reservoir layer, was firstly carried out;Then, settling rule of proppants within the fractures was analyzed during the flowing back process. Meanwhile, the bottom pressure curve after stopping pumping was obtained by the volume balance principle with different nozzle diameters of open flow. Therefore, the closing time of factures and the longest settling distance of proppants were worked out;Finally combined with the well instance, fracturing and flowing back processe was optimized given in-situ stress effects. Calculation shows that, location of oil layer in the in-situ stress area and settling distance of proppants have close relations with the selection of fracturing fluid backflow process. Hence, the optimization of fracturing fluid backflow process needs to consider the above key factors.%油藏地应力的分布情况对裂缝发育方向有重大影响，进而会影响压裂液返排工艺的选择。首先分析隔层-油层的垂向应力分布对压裂裂缝纵向发育方向产生的影响；然后对返排期间裂缝内支撑剂的沉降规律进行分析，同时由体积平衡原理求解出在不同放喷油嘴直径下，停泵以后的井底压力变化曲线，进而求出裂缝的闭合时间和支撑剂在裂缝中的最大沉降距离；最后结合现场实例井，对考虑油藏地应力影响后的压裂液返排方式进行了优选。计算结果表明，返排工艺的选择与油层在应力区所处的位置和支撑剂的沉降距离密切相关，需要根据油藏的地应力分布和支撑剂沉降规律来选择合理的返排方式。
展开▼
