An efficient coupled fluid flow-geomechanics model for capturing the dynamic behavior of fracture systems in tight porous media

Abstract

This paper introduces an efficient hybrid numerical discretization method designed to address the coupled mechanical challenges of geomechanics and fluid flow during pressure depletion in tight reservoirs. Utilizing the extended finite element method, this approach solves the elastic deformation of rock, while the mixed boundary element method precisely calculates the unsteady fluid exchange between the matrix and fractures. These numerical schemes are integrated fully, with temporal dynamics managed through a fully implicit method that effectively characterizes fracture deformation and fluid flow in hydrocarbon development. Furthermore, this model incorporates embedded pre-treatment to represent hydraulic macro-fractures and considers the effects of proppant. It captures dynamic information regarding the matrix and minor natural fractures through the double-porosity effective stress principle and a dual-medium implicit fracture characterization method. Thus, the proposed hybrid model provides a comprehensive depiction of the complex interplay between the matrix, natural fractures, and hydraulic fractures. The model's accuracy is validated through various examples, highlighting its reliability. This research offers valuable theoretical insights for advancing the development of unconventional hydrocarbon resources.