Numerical Study of Nonlinear Unsteady Percolation for Shale Gas Reservoir and Productivity Analysis

Abstract

Multi-stage fracturing of horizontal well is crucial for economic production of shale gas. The distribution of porosity and permeability in shale formation are not clearly understood. In this paper, the inhomogeneous distribution models of porosity and permeability are proposed which can be applied in the whole simulated reservoir volume as well as all four flow regimes. Considering the nonlinear pressure-dependent effects of slip, diffusion and desorption, the unified mathematical model is established. Also, a new and general semi-analytic approach is developed to simulate the unsteady nonlinear seepage process. The numerical simulation results match well with the field data in reference.