In this paper, a novel computational framework is introduced for simulation of multiphase flow, geomechanics, and fracture propagation in porous media based on Biot’s model for poroelasticity by focusing on interactions between hydraulic and natural fractures. Since realistic porous media contain many natural fractures, it is important not only to stimulate hydraulic fractures but also to study the interaction between natural and hydraulic fractures. Here, state-of-the-art numerical modeling of natural and hydraulic fractures using a diffusive adaptive finite element phase field approach is employed. The locally mass conservative enriched Galerkin finite element methods (EG) are utilized to model two-phase flow in propagating fractures with relative permeability and capillary pressure. Geomechanics approximated by a continuous Galerkin finite element method is coupled to multiphase flow by applying an iteratively coupled scheme. Numerical examples are presented that demonstrate the effectiveness of this framework for different propagation scenarios by varying the degrees of physics. In addition, the capabilities to perform high-fidelity simulations on complex fracture networks, with randomly joined diffusive natural fractures, are illustrated.

本文介绍了一种新颖的计算框架，该模型基于Biot的多孔弹性模型，重点研究了水力裂缝和自然裂缝之间的相互作用，从而模拟了多孔介质中的多相流动，地质力学和裂缝传播。由于实际的多孔介质包含许多天然裂缝，因此不仅要激发水力裂缝，而且研究天然裂缝和水力裂缝之间的相互作用也很重要。在此，采用了使用扩散自适应有限元相场方法进行的自然裂缝和水力裂缝的最新数值模拟。利用局部质量保守富集Galerkin有限元方法（EG）来模拟具有相对渗透率和毛细管压力的传播裂缝中的两相流。通过应用迭代耦合方案，将通过连续Galerkin有限元方法近似的地质力学耦合到多相流。数值示例通过改变物理程度证明了该框架对于不同传播场景的有效性。此外，还展示了在复杂的裂缝网络上执行高保真模拟的能力，该网络具有随机连接的扩散自然裂缝。