A heterogeneous model for simulating fluid flow in naturally fractured-vuggy carbonate reservoirs

Abstract

In this paper, a heterogeneous model named matrix-fracture-vug (MFV), which considers the interactions of flow regimes in matrix, discrete natural fractures, large-scale fractures and vugs, is developed for simulating fluid flow in fractured-vuggy reservoirs. In the MFV model, coupling Darcy-Stokes equations are used to describe flow regime in matrix and vugs. Fluid flow follows the cubic law in each discrete natural fracture. An equivalent method is put forward in large-scale fractures. The flow mechanisms in fractured-vuggy reservoirs are analyzed, and the oil well productivity is demonstrated by investigating the influences of the matrix, fractures and vugs. The matrix permeability controls the production rate in the whole production process, and the conductivity of fracture network is another main influence factor. The cumulative production will increase due to the storage capacity of vugs in later period. This model can provide insights into the history matching and the production prediction for fractured-vuggy. [Received: August 4, 2016; Accepted: September 20, 2017]