AN EVALUATION OF THE IMPROVED DUAL POROSITY MODEL FOR THE SIMULATION OF GRAVITY EFFECTS IN NATURALLY FRACTURED RESERVOIRS

The accurate representation of the interactions between matrix and fracture in the dual porosity model is crucial to the proper prediction of recovery from fractured petroleum reservoirs. In the standard dual porosity model, matrix-fracture transfer is represented by a single term in the mass balance equations, and the matrix-matrix flow is assumed to be negligible. This was found to be inadequate when gravity effects are important. Various methods were reported in the recent literature which account for the gravity drainage process. These include the gravity segregated model, the subdomain method, and the dual permeability model. In this paper, we will examine the gas-oil gravity drainage process and evaluate the different approaches for solving this problem.