In the recent literature, much attention has been given to the simulation of naturally fractured reservoirs. The most prevalent approach is a dual-porosity formulation with computational blocks that may represent the system of fracture network by the noncontinuous matrix blocks. In models of this type, proper formulation of the matrix/fracture fluid transfer by gas/oil drainage and water/oil imbibition is requisite. The conventional description of this transfer function uses a matrix/fracture transmissibility and capillary and gravity gradients based upon the averaged values of matrix saturation assuming a simplified saturation distribution in the matrix, or is obtained by "history-matching" using a fine grid model of a single matrix block.

In this paper. the author presents a matrix/fracture transfer model which is consistent with the experimental data. Using vertical equilibrium to define the transition zone in the matrix blocks, the effects of the viscous, capillary and gravity forces on the fluid transfer between matrix and fracture are integrated. The fluid transfer calculated from this approach includes the effects of a varying Pc through the transition zone, the changing gravity potential with the relation between the segregated oil- water contact level in the fracture and the bottom level of the transition zone in the matrix, and the changing matrix block surface area which contributes to the fluid transfer. This approach has been successful in matching laboratory results of fractured systems that could not be matched by the conventional dual-porosity formulations.

You can access this article if you purchase or spend a download.