NUMERICAL SIMULATION OF NATURALLY FRACTURED SHALE GAS RESERVOIRS APPLYING THE LAYER MODEL

Abstract

Typically, hydrocarbon reservoirs have heterogeneities that influence pressure variation in producing wells. In the case of natural fractures, the layer model has been widely applied to obtain analytical and numerical solutions. In this model, we superimpose the porous media layers representing the porous matrix and fractures. In this work, the layer model is used in the numerical simulation, using cylindrical geometry and finite differences, to determine the pressure in natural gas producing wells. We consider shale gas reservoirs, and obtain the numerical results investigating the effects resulting from the presence of fractures and non-Darcy flow due to slip and adsorption phenomena. This work studies grid refinement and performs numerical verification, as well as a sensitivity analysis varying the main physical parameters that directly influence the reservoir and well pressures, such as permeability, porosity, and thickness of the fracture, reservoir temperature, and the Langmuir pressure and volume. As expected, from specialized and diagnostic plots, we can visualize how fractures favor the flow while capturing typical flow regimes of fractured reservoirs described in the literature.