砂砾岩储层压裂地应力差影响探究

Study on influence of in-situ stress difference in sandy gravel reservoir fracturing

在水力压裂过程中,水平地应力差对裂缝扩展趋势影响最为显著,此外由于砂砾岩储层含有砾石,裂纹与砾石相互作用会对水力压裂施工产生影响。因此,本文利用泰森多边形对砾石随机分布进行表征,采用全局插入的有限元方法建立数值模型,对砂砾岩储层裂缝扩展进行分析。结果表明,压裂裂缝沿着最大水平主应力方向延伸,且延伸距离也呈增大趋势;井眼压裂液注入附近,水力裂缝将产生穿砾现象,相比绕砾将消耗更多能量;砾石对水力裂缝有吸附作用。

In the process of hydraulic fracturing,the horizontal in-situ stress difference has the most significant influence on the fracture propagation trend,in addition,because the sand and gravel reservoir contains gravel,the interaction between the crack and the gravel will have an impact on the hydraulic fracturing construction.So this paper uses the Tyson polygon to characterize the random distribution of gravel,and uses the global insertion finite element method to establish a numerical model to analyze the fracture propagation of sand and gravel reservoir.The results show that the fracture extends along the direction of the maximum horizontal principal stress,and the extension distance also shows an increasing trend.Near the injection of fracturing fluid in the well,the hydraulic fracturing will produce the phenomenon of gravel penetration,which will consume more energy than the gravel.The gravel has an adsorption effect on the hydraulic fracturing.