Kacewicz, Marek¹, Wenlong Xu¹, Dan Carruthers², Thomas Hantschel³ 
(1) Unocal Corporation, Sugar Land, TX 
(2) The Permedia Research Group Inc, Ottawa 
(3) IES GmbH, 52428 Juelich, Germany

ABSTRACT: Darcy Vs. Invasion Percolation – Do they Complement Each Other?

Latest trends in basin modeling include better utilization of 3-D seismic data by building models at seismic data resolution. Typical seismic inversion cubes are from tens of MB to GB in size and contain an enormous amount of information about distribution of lithofacies in the subsurface. Any up-scaling of subsurface data results in a loss of potentially important information and may lead to missed exploration opportunities. 
Classical approaches in basin modeling are based on Navier-Stokes equations and have been extensively tested over many years since their introduction. Darcy based approaches are computationally intensive which is their big disadvantage. Resulting models are relatively small and require a significant amount of up-scaling. 
Invasion percolation based approaches provide a computationally faster alternative (Carruthers, 1998; Wagner, 1997). One of their key assumptions is that viscosity can be neglected at very slow flow rates and capillary forces control the flow. 
Our paper compares theoretical aspects of the two approaches and tests them on a single 3D data set representing a well defined petroleum system where known oil vs. gas distribution patterns allow us to demonstrate where the two methods generate similar results and in which geologic conditions the results are different.

AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004.