Fluid driven fracturing of rocks using interface pore pressure cohesive element technique

Abstract

Fluid-driven fracturing is a phenomenon observed in numerous engineering problems, with hydrocarbon recovery being one of the most significant applications. Analyzing this type of fracture is complex due to the involvement of hydro-mechanical coupling. Among various FEM-based numerical techniques, the intrinsic interface pore pressure cohesive element (PPCE) method is straightforward to implement. However, this method requires pre-positioning the PPCEs into the mesh along the anticipated fracture path, reducing its flexibility for models with complex scenarios where the fracture path cannot be predicted a priori. To address this issue, a mesh post-processing technique is needed, where PPCEs are placed around the bulk elements of the mesh, allowing the fracture to pass through these PPCEs as it evolves. This research presents such a technique with a new mesh post-processing algorithm. To better analyze the fracture and hydro-mechanical coupling, higher-order triangular element discretization is adopted for the domain, while the PPCEs are considered linear. Several validation analyses have been conducted. The results indicate that this technique is robust and capable of accurately representing fracture propagation. Through comprehensive validation analyses, the method has demonstrated its effectiveness in capturing the intricate details of fracture evolution. The mesh post processing ability to place PPCEs around bulk elements ensures that the technique remains flexible and applicable in complex scenarios. This enhanced flexibility highlights the technique’s reliability and precision in modeling fluid-driven fracturing in saturated rock mass.