Up-scaling relative permeability for stratified reservoir waterflooding

Abstract

This research presents an improved procedure for generating pseudo relative permeability curves for stratified waterflooding using either constant pressure or constant flux at the reservoir boundaries. Pseudo relative permeability reflects the generation of a relative permeability curve that can be used to represent the entire reservoir thickness, rather than a specific layer during reservoir simulation, thus saving computational time. In this project, Fractional Flow Theory is applied to the generation of pseudo relative permeability curves for i) constant flow rate condition, and ii) constant pressure boundary condition. Previously pseudo relative permeability curves were generated for the constant flow rate condition only. The method differs from previous methodologies and studies, which are all based on a piston-like displacement for water flooding. Instead, this new model uses fractional flow theory to generate a pseudo relative permeability curve that is physically more realistic. The solution is extended to generate pseudo relative permeability curves for simulating the waterflood of a reservoir under the constant pressure boundaries which is a more realistic assumption in compared to constant flow rate. The generated pseudo relative permeability curve is used in a 2D areal reservoir model in an ECLIPSE simulator to predict the behavior of the full layered 3D reservoir model. It was found that there is good agreement between the results corresponding to this new method and the full layered reservoir model, which is very important.