Modelling of Hydraulic Fracture Growth in Multiphase Porous Media Using Enriched EFG Method

In this study, the propagation of hydraulically driven fractures in deformable porous media is numerically investigated. The media is assumed to be containing two fluid phases. Across mesh-less methods, the extended element free Galerkin method is used in order to discretize and solve the governing equations in terms of fully coupled hydro-mechanical system. In the numerical model, an initial crack is defined and it is being injected with wetting fluid. The pores of problem domain are filled with both wetting and non-wetting fluid phases. Enforcement of essential boundary conditions are done using the penalty method. Discontinuities of field variables are modeled with employment of extrinsic enrichment strategy. In order to model and introduce weak and strong discontinuities, the Ridge and Heaviside enrichment functions are utilized, respectively, and as an important part, the crack tip is defined by means of a cohesive crack model which is assumed to show a nonlinear behavior in front of the crack. The effecting items associated with hydraulic fracturing process are fully modeled throw this investigation. Cubic and Darcy’s laws are used in order to express continuity equations of two fluid phases through the fracture domain. The mass transfer among the fracture and the surrounding area and the fluid leak-off phenomenon are considered in model and besides, the fluid lag zone is assumed in model. These considerations are strongly affected by the coupling terms of both fluids. The results demonstrate the delicacy of the proposed framework in order to simulate the complex aspects of the hydraulic fracture propagation process.

کلیدواژه ها:

Enriched EFG method ، Multiphase porous media ، Extrinsic enrichment method ، Hydraulic fracture ، Cohesive crack