混合压裂在苏里格致密气藏水平井的应用

苏里格致密砂岩气资源量巨大,压裂水平井是重要的开采手段之一。常规水力压裂形成的高导流短裂缝对于致密砂岩储层或低渗砂岩储层Ⅲ,Ⅳ类井增产效果较差,另外,高黏度交联冻胶压裂液对储层伤害较大。通过借鉴混合压裂工艺在国外致密气田的成功案例,结合苏里格致密砂岩气藏的地质特征,使用StimPlan软件模拟常规压裂和混合压裂裂缝形态,并借助井下微地震监测结果,分析了2种压裂工艺井的裂缝展布特征,验证了压裂施工效果。最后,通过苏里格东区致密气藏60余口水平井的试气和生产产量对比,得知混合压裂比常规压裂增产效果明显,且降低了施工成本。混合压裂工艺由于"低伤害、控缝高、造缝长、低成本"等特点,是苏里格致密砂岩气藏开发中的有效增产手段之一。

Application of hybrid fracturing in horizontal well of tight gas reservoir in Sulige Gas Field

Sulige Gas Filed has huge resources of tight gas sand, fractured horizontal well is one of important means of exploitation. However, conventional hydraulic fracturing can form high conductivity and short fracture, which leads to the poor yield-increasing effect for Class Ⅲ/Ⅳ wells of tight sandstone gas reservoir or low permeability sandstone reservoirs. In addition, the fracturing fluids with high viscosity crosslinked gel damage greatly the reservoir. This paper takes example by the successful application cases of hybrid fracturing in foreign tight gas field, combines with the geology characteristics of Sulige tight sandstone gas reservoir and uses stimplan 3D software to model the fracture shapes of conventional hydraulic fracturing and hybrid fracturing. With the help of the monitoring results of downhole microseism, the fracture distribution characteristics of fracturing wells are analyzed, verifying the effect of fracturing operation. Finally, the comparison of testing and production from 60 horizontal wells shows that the effect of hybrid fracturing is more obvious than that of conventional hydraulic fracturing and operation cost reduces. Therefore, hybrid fracturing is one of the effective means to increase the yield of Sulige tight gas reservoirs due to its characteristics of low damage, high fracture controlling, long making fracture and low cost.