The Dual-Porosity Vertical-Well Model for Transient Pressure Analysis of Naturally Fractured Shale Gas Reservoirs

During the process of development for shale gas reservoirs, the permeability of fractures will decrease due to stress-sensitive effect. Adsorption is also an important mechanism which determines the production of shale gas reservoirs. Therefore, the effect of stress sensitivity and adsorption must be considered in the numerical model for pressure transient analysis. In this paper, a dual-porosity model was established considering both mechanisms, and finite-difference method was used for discretizing fluid equations. Then Newton method was applied for solving the resulting algebraic equations, and the typical curves in terms of dimensionless pseudopressure and time were drawn with different sets of parameters. The numerical well-testing model provides theoretical basis for interpreting production data of shale gas reservoirs.