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Numerical Simulations of Invasion of 3D Porous Media
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, ECMOR XIV - 14th European Conference on the Mathematics of Oil Recovery, Sep 2014, Volume 2014, p.1 - 22
Abstract
Pore-scale modeling of multiphase flow of petroleum reservoir fluids through real natural porous media is a true challenge for both engineering and academic societies. Due to the fundamental aspect of pore-scale description in hydrodynamics it is widely considered in order to improve our knowledge of flow and transport phenomena. Another interest of such an approach is to derive macro-scale constitutive equations, to provide multiphase flow properties for large scale models,etc.
One of the important aspects of this problem is the construction of adequate 3D numerical models of multiphase flow through pore space. With the recent development of computed micro-tomography technique, it seems obvious that direct numerical simulations at pore-scale will be widely used in the porous medium modeling and particularly in petroleum applications.
We report 3D pore-scale simulations of invasion of porous media motivated by the analysis of waterflooding experiments of extra-heavy oils in quasi-2D square slab geometries of Bentheimer sanstone. For a simulation of fluid distribution inside pores a model based on incompressible Navier-Stokes equations is used. We thus use a Volume-of-Fluid (VOF) method to model two-phase Stokes flows with sharp interface between the two fluids. The height function method is used to model surface tension. Accuracy and precision are tested using several levels of refinement, and comparing to reference simulations in the literature.
We focus on brine imbibition (or drainage) in an initially oil-filled porous medium (obtained by micro-tomography) at very unfavourable mobility ratio. Transient flow patterns at various viscosity ratios and capillary numbers are presented and discussed in some detail. The problems of computational speed at low capillary numbers are also addressed.
The reported methodology of a porous medium properties computation is a valuable tool for both fundamental porous media studies and applied petroleum applications.