动力水力压裂的相场模拟方法  

A phase-field description of dynamic hydraulic fracturing

作　　者：刘国威[1] 李庆斌[1] 梁国贺[1] 

机构地区：[1]清华大学水沙科学与水利水电工程国家重点实验室,北京100084

出　　处：《岩石力学与工程学报》2017年第6期1400-1412,共13页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(51339003;51579134);国家重点基础研究发展计划(973)项目(2013CB035902)~~

摘　　要：水力压裂计算对页岩气开采至关重要,将岩体等效为均匀多孔介质,以动力达西–毕奥流描述岩体内的渗流过程,以相场方法追踪裂缝扩展,将压裂裂缝内流体近似为泊肃叶流,并通过修正渗流方程予以实现,从而提出了动力水力压裂的相场模拟方法,并基于显式有限元框架进行数值求解。通过与一维解析解对比说明所提方法计算位移和动水压的准确性。一系列数值算例表明,提出的压裂相场模拟方法能够模拟动力水力压裂作用下裂缝动态扩展的典型特征,且能够计算水力压裂裂缝的相交、分叉和三维扩展等复杂裂缝扩展形态,为动力水力压裂设计提供了强有力的数值计算工具。Calculations of hydraulic fracturing are very essential for the exploration of shale gas. In this paper,the shale is approximated by a homogeneous porous medium. The seepage process in rock mass and the fluid motion in cracks are described by the dynamic Darcy-Biot and Poiseuille flows respectively. The crack propagation is tracked with the phase-field method and the simulation method for the dynamic hydraulic model is proposed. The method is implemented under an explicit finite element scheme. The accuracy of the method to calculate the dynamic displacement and pressure fields is illustrated by comparing the output with the one-dimensional analytical solution. A series of numerical examples indicate that the proposed method can not only simulate the typical characteristics of dynamic hydraulic fracturing,can also calculate the crack intersection,bifurcation and three-dimensional propagation.

关 键 词：岩石力学 水力压裂 相场方法 达西–毕奥流 显式有限元 

分 类 号：TU45[建筑科学—岩土工程]