Dynamic propagation behaviors of hydraulic fracture networks considering hydro-mechanical coupling effects in tight oil and gas reservoirs: A multi-thread parallel computation method

Abstract

Hydrofracturing is a remarkable technology for unconventional oil and gas exploitation in tight reservoirs, in which the fluid-driven propagation of hydraulic fractures in a porous medium rock reservoir is an extremely complex physical process, for which there are great challenges in numerical simulation, such as multiphysical field coupling, multiple field evolution on engineering-scale reservoirs, and multi-scale fracture propagation processes. This complex physical process renders it difficult to obtain reliable solutions rapidly and efficiently. Understanding the behavior and mechanism of hydrofracturing is complicated. A multi-thread parallel computation scheme for solid and fluid analysis was developed to improve computational efficiency in large-scale models and multi-physical field coupling (hydro-mechanical) problems, and fracture criteria via a dual bilinear cohesive zone model was introduced. Considering the hydro-mechanical coupling and leak-off effects, the combined finite element-discrete element-finite volume approach was introduced and implemented successfully, and a multi-thread parallel computation method and global procedure was proposed. This study provides valuable results for parallel computation of dynamic fluid-driven propagation of hydraulic fractures in porous elastic rock mass and lays the foundation for further development of efficient and reliable simulations for dynamic multiscale complex fractures under multiphysical field coupling.