Date:

Monday, October 14, 2002

Speaker:

Todd Arbogast

Affiliation:

TICAM, University of Texas at Austin

e-mail:

arbogast@ticam.utexas.edu

Title:

Modeling of flow through vugular porous media

Abstract:

Sedimentary rocks sometimes contain void regions called vugs that are much larger than the usual inter-granular pores. We consider the problem of large-scale simulation of flow through vugular carbonate reservoirs. We address the question of determining the effective permeability of single-phase flow at the grid-block scale, using the theory of homogenization and direct multiphysics computations. At the micro-scale, the system is governed by Darcy's law in the rock matrix and Stokes' equations in the vugs, with the Beavers-Joseph-Saffman boundary condition on the interface between the two regions. Homogenization predicts that on the macro-scale, Darcy's law holds everywhere with an effective permeability that can be readily computed. To assess the validity of this prediction, we test it computationally. We first develop a numerical method and code capable of simulating the Darcy-Stokes system in a medium with irregular and ubiquitous vugs. We then obtain micro-scale computations of flow in such vugular media on very fine grids that resolve the geometry of the vugs. In the future, we will finally compare these results to macro-scale Darcy simulations that use our effective permeability on coarser grids with grid blocks that contain many vugs.