【摘要】 水力压裂裂隙扩展形态对于深部岩体油气开采和地热能开采具有重要意义。针对深部地层岩体水力压裂裂隙扩展问题，基于相场法理论、Biot多孔弹性介质力学理论和渗流力学理论建立了相场法应力-渗流耦合模型。该模型采用有限元方法对方程组进行离散化处理，运用牛顿迭代法（Newton-Raphson method，简称NR法）和分离式耦合方法求解方程组以提高计算精度。对比了该模型数值解与室内试验模拟结果和基于数值流形法（numerical manifold method，简称NMM）的数值解，并将数值解与理论解析解进行比较，验证了模型的可靠性。基于该模型，研究了地应力差、裂隙间距和注入流量等因素对垂直于最大主应力方向的双裂隙水力压裂裂隙扩展的影响规律。研究结果表明：随着地应力差的增大，裂隙扩展路径的偏转角度增大，扩展分支路径相应增多；较小的裂隙间距使裂隙更易贯通，且裂隙扩展的偏转程度和扩展长度均随着裂隙间距的增大而逐渐增大；较大的注入流量更有利于裂隙扩展长度和扩展速度的增加。通过探讨不同因素对裂隙扩展的影响，为深部岩体水力压裂优化复杂裂隙网络提供了理论依据。更多还原

【Abstract】 The morphology of fracture propagation in hydraulic fracturing plays a crucial for exploiting oil, gas, and geothermal energy in deep rock formations. To address fracture propagation in hydraulic fracturing in deep rock formations, this article establishes a stress-seepage coupling model based on the phase field method theory, Biot’s porous elastic medium mechanics theory,and seepage mechanics theory. The equations were discretized using the finite element method, and the Newton-Raphson(NR) and the separated coupling methods were employed to enhance calculation accuracy. The reliability of the model was verified by comparing the numerical simulation results with indoor test simulations and numerical simulations based on the numerical manifold method(NMM), and comparing numerical solution with the theoretical analytical solution. In this study, we utilize the established model to investigate the effects of in-situ stress difference, fracture spacing, and injection flow rate on the propagation of double fractures perpendicular to the direction of maximum principal stress in hydraulic fracturing. The results demonstrate that an increase in in-situ stress difference leads to a higher deflection angle of the fracture propagation path and more propagation branches. Smaller fracture spacing facilitates easier fracture penetration, while larger spacing increases the deflection angle and propagation length.Additionally, a larger injection flow rate increases fracture propagation length and speed. Understanding the impact of different factors on fracture propagation establishes valuable theoretical foundations for optimizing complex fracture networks in deep rock formations through hydraulic fracturing.更多还原