页岩储层压裂流固耦合数值模拟及裂缝扩展研究进展

A REVIEW ON HYDRO-MECHANICAL COUPLING SIMULATIONS OF HYDRAULIC FRACTURE NETWORK IN SHALE RESERVOIRS

页岩储层岩体结构复杂,天然裂缝网络发育,储层压裂改造过程中大量天然裂缝激活,形成复杂的水力裂缝网络,大幅增加储层渗流能力。因此,储层压裂改造技术是实现页岩油气商业开发的关键技术之一。页岩储层压裂涉及到多个物理过程的相互作用及大量裂缝的动态拓展,是一个典型的流固耦合力学问题。其中:数值模拟是研究压裂裂缝扩展机制、缝网动态演化过程及压裂优化设计的重要手段之一,是近些年油气开发领域的研究热点。针对该问题,本文首先分析了页岩储层压裂的特点及主要流固耦合力学过程,并对主流数值模拟方法的特点进行了总结;其次,从复杂压裂缝网动态演化模拟和储层尺度压裂模拟两个角度对近些年取得的主要进展进行了总结;最后,依据压裂模拟的研究现状及实际工程需求,对页岩储层压裂数值模拟的发展趋势进行了展望。

Shale reservoir fracturing involves the interaction of multiple physical processes and is a typical hydro-mechanical coupling problem.The fracturing process is influenced by the heterogeneity of shale and the complex structure of the rock mass,leading to the formation of dense fracture networks in the reservoir.Numerical simulation is an important tool for investigating the mechanisms of fracture propagation,the evolution processes of fracture networks,and the optimization of fracturing designs.Thus,fracturing simulation remains a hot topic in the field of oil and gas development in recent years.This paper first analyzes the formation characteristics of fracture networks and the hydro-mechanical coupling processes of hydraulic fracturing.The main numerical simulation methods for hydraulic fracturing are summarized here.Secondly,recent advances in fracturing simulations are provided from two perspectives:dynamic evolution simulation of complex fracture networks and reservoir-scale fracturing simulation.Finally,based on the current research status of fracturing simulation and actual engineering requirements,future prospects for fracturing simulation are discussed.