基于PHF-SFM非均质岩石材料水力压裂数值计算模型研究  

Study on Numerical Calculation Model of Hydraulic Fracture for Heterogeneous Rock Materials Based on PHF-SFM

作　　者：李明[1] 周世康 刘士乙 梁力[1] LI Ming;ZHOU Shi-kang;LIU Shi-yi;LIANG Li(School of Resources&Civil Engineering,Northeastern University,Shenyang 110819,China)

机构地区：[1]东北大学资源与土木工程学院,辽宁沈阳110819

出　　处：《东北大学学报（自然科学版）》2023年第8期1160-1167,共8页Journal of Northeastern University(Natural Science)

基　　金：中央高校基本科研业务费专项资金资助项目(N2001015,N2101009);国家留学基金资助项目(201906085065).

摘　　要：在基于渗透率修正的水力压裂(permeability-based hydraulic fracture,PHF)模型基础上引入概率破坏模型(statistical fracture model,SFM),采用Weibull概率模型描述岩石材料微观的非均匀分布对宏观水力裂缝特征离散性的影响.PHF-SFM模型假设岩石材料的渗透率是平均有效应力的函数,基于Biot固结理论,采用摩尔-库伦弹塑性本构模型和达西定律分别描述岩石材料固体骨架和孔隙流体开裂前后的力学特征.通过与KGD模型对比验证该模型的可行性,并通过数值模拟分析了模型中Weibull模量和尺度参数以及岩石材料性质对起裂压力、裂缝高度和裂缝宽度等的影响.结果表明,概率破坏模型的引入不会影响起裂压力,但会影响裂缝的几何特征.当Weibull模量降低或尺度参数增加时,裂缝的几何特征离散性呈增大趋势.Based on the permeability-based hydraulic fracture(PHF)model,a statistical fracture model(SFM)is introduced to capture the influence of the micro non-uniform distribution of rock materials on the macroscale characteristics of hydraulic fracture.The Weibull probability model is adopted to account for the discreteness of characteristics of these characteristics.By assuming that the permeability of rock material is a function of the mean effective stress,the PHF-SFM model is proposed based on the Biot consolidation theory.The model incorporates the Mohr-Coulomb elastoplastic constitutive model and Darcy’s law to represent mechanical behaviors for the solid and liquid phase of rock material in pre-and post-failure part.The verification is carried out by comparing the simulated results with those of the KGD model.Breakdown pressure,equivalent fracture height and fracture width were studied by varying the Weibull modulus and scale parameters in the SFM model and material properties of rock.The simulation results indicate that including the SFM model does not affect the breakdown pressure,but does vary the fracture geometry.When the Weibull modulus decreases or the scale parameter increases,the discreteness of fracture geometry features increases.

关 键 词：水力压裂 非均匀岩石 PHF-SFM 概率破坏 韦伯分布 

分 类 号：TU443[建筑科学—岩土工程]