基于扩展有限元的径向井压裂技术

Research of Radial Well Fracturing Based On Extended Finite Element Method (XFEM)

基于储层特征,利用ABAQUS扩展有限元建立了径向井模型,开展了不同条件下径向井力学特征及储层应力分布研究,分析了径向井压裂时裂缝扩展形态及规律,并通过物模试验验证了数值模拟结果的准确性。结果表明,径向井具有引导裂缝扩展、形成多裂缝的能力;径向井对压裂裂缝的引导效果与径向井方位角、水平地应力差、储层弹性模量、压裂液黏度等参数呈负相关,与径向井井径、储层泊松比、储层渗透率、施工排量等参数呈正相关;在双径向井夹角内形成的干扰应力场内可形成复杂的多裂缝;在低油价的形势下,通过径向井压裂技术实现低产低效井的有效利用,为老区低效井的挖潜提供参考。

Based on the reservoir characteristics and the application of XFEM for establishing the radial wells model by using ABAQUS,the research on stress distribution in reservoir and the mechanical characteristics of radial wells are studied under different conditions. The rules of radial wells fracturing and propagation are analyzed, the accuracy of the numerical simulation results is verified by the physical model test. The results show that the radial well is able to guide the propagation direction of fracture during fracturing, and it is possible to form multiple fractures. The effect of radial well on fracturing is negatively correlated with the parameters of its azimuth, horizontal ground stress difference, elastic modulus of reservoirs and viscosity of fracturing fluid, and it is positively correlated with the parameters of radial well diameter, reservoir Poisson's ratio, reservoir permeability and operation displacement. Complex multiple fractures can be formed in the interference stress field formed in the angle between two radial wells. In the situation of low oil prices, the technology of radial well fracturing can be use for an effective utilization of oil wells with low production and low efficiency to provide reference for tapping the potential of low efficiency wells.