Production model of fractured horizontal wells in shale gas reservoirs considering different gas diffusion mode

Because of the complexity of the shale gas seepage mechanism, the establishment of a fractured horizontal well model of shale gas reservoirs based on multiple migration mechanisms is helpful to the development of shale gas reservoirs. In this study, different matrix diffusion modes in different regions are considered. The fractured horizontal well model of the shale gas reservoir can be divided into a fracture network region (SRV region) and a shale matrix region. The quasi-steady-state matrix diffusion in the fracture network region is described by Fick's first law, the non-steady diffusion in the matrix region is described by Fick's second law, and seepage of the fracture system is described by Darcy's law. Based on the above ideas, a fractured horizontal well production model of fractured horizontal wells in shale gas reservoir is established. The Laplace transformation, Duhamel principle, and Stehfest numerical inversion are used to solve the mathematical models of seepage flow, and a sensitivity analysis of the dimensionless production curve is performed. [Received: January 22, 2023; Accepted: February 13, 2024]