基于PHF-LSM-MT的非均质岩石细观界面与水力压裂数值建模

基于PHF(permeability-based hydraulic fracture)模型，采用水平集方法(level set method，LSM)描述材料边界分布，并用多尺度方法MT模型，对材料有效参数进行均匀化，建立适用于考虑非均质岩石材料细观界面特征分布与水力裂缝动态发展过程的PHF-LSM-MT数值计算模型.该模型解决了已有PHF-LSM模型无法精确描述积分点作用范围内细观尺度材料分布特征的问题.通过比较包裹体几何分布和体积分数影响下的有效弹性参数，验证了采用MT模型均匀化细观特征的可行性;在此基础上，对非均质岩石水力裂缝发展过程进行研究，得到了考虑细观界面特征情况下的裂缝发展过程，探讨了等效开裂区域影响范围内关键位置的水压力变化特征和应力路径发展过程.

Numerical Modeling for the Material Interface of Heterogeneous Rock at Mesoscale and Hydraulic Fracturing Based on the PHF-LSM-MT

The permeability-based hydraulic fracture(PHF) method is integrated with the level set method(LSM) and Mori-Tanaka(MT) model to study the hydraulic fracture propagation in heterogeneous rock(HR)with the mesoscale material interface being considered. In the proposed method， the PHF method is for simulating the hydraulic fracture propagation， and the LSM is for capturing the material interface with the mesoscale material properties of integration points being homogenized by MT model. To verify the mesoscale homogenization modeling procedure for HR， numerical simulations were carried out to estimate the effective elastic properties of HR with the volume fraction and inclusions’ dimension being taken into account， and the results indicate that the proposed method is capable of homogenizing the material properties at mesoscale. Numerical simulations of hydraulic fracture propagation in HR with the mesoscale material interface show the characteristics of hydraulic fracture development， the features of pore pressures and stress paths of the equivalent fracture zone.