基于孔隙弹性的水力压裂耦合方法与压裂状态参数数值研究

本文系统地阐述基于多孔介质渗流-损伤耦合原理，进行水力压裂FEM的数值实现方法。基本架构为：(1)引入孔隙流体压力膨胀系数将孔隙流体压力与应力场进行耦合；(2)基于损伤局部化模型，提出裂缝张开度表达式; (3)提出水力压裂引起的多孔介质水-力学属性的各向异性表达式; (4)提出全流量加载的耦合分析方案。最后作为实例，模拟三维地层水压裂缝扩展形态，通过比较模型的数值解和经典理论解，验证该方法的正确性。

The coupling method of hydraulic fracturing base on poroelasticity concepts and numerical research of fracturing state parameters

In the paper we completely and systematically elaborate the controlling equations and FEM coupling methods for numeric simulation of hydraulic fracturing. The framework is consist of: (1) The concept of poroexpansibility is employed to couple the fluid pore pressure with the stress field; (2) An formula of hydraulic fracture opening is proposed based on the concepts of damage localization;(3) Deduce the formula for calculation of anisotropic properties such as damage, permeability, poroelasticity, etc; (4) Propose a coupling loading scheme using full flow rate. As a validation, a three-Dimensional hydraulic fracturing simulation is performed. The comparison of numeric solution and analytical solution of the state parameters of the hydraulic fracture is performed and proved the validation and correction of the numeric simulation.