Reports: AC9
45175-AC9 Unstable Miscible Displacements: Influence of Non-Vertical Wells, Reservoir Inclination, and Permeability Anisotropy and Stratification
Over the last year, our research has focused on high-resolution numerical simulations of miscible displacements in porous media for horizontally oriented injection wells. In this context, we have considered both homogeneous and heterogeneous, isotropic porous media.
Horizontal wellbores have been employed only very recently for the purpose of miscible flooding of a petroleum reservoir. In support of this novel practice, coarse grid numerical simulations have been reported in the literature, with little rigorous testing as to their ability to provide reliable long-term information. Specifically, the literature does not contain long-term studies that analyze mature horizontal floods beyond the point of breakthrough at the production well. We can assume that coarse-grain simulations are insufficient for investigating the detailed mechanisms at work in miscible floods. Hence, we employ fine-grain simulations to analyze such flows.
Our results indicate that flows from horizontal injection sources in a homogeneous porous medium result in very different displacement mechanics as compared to vertical injection sources. Depending on the ratio of buoyancy to viscous forces, the development of gravity tongues has been observed, along with fingering phenomena that exhibit dendritic growth. Frequently, horizontal sources are found to perform better than vertical sources.
