Estimation of permeability heterogeneity in limestone outcrop by pressure measurements: Experiments and numerical simulation

Abstract

This paper presents the experimental and numerical simulation study of waterflooding of a very low permeability limestone outcrop. Continuous pressure measurements during waterflooding is carried out to estimate the permeability heterogeneity. Waterflooding experiments have been performed with vertical injection–vertical production (VI–VP) and vertical injection–horizontal production (VI–HP) well configurations. Relative permeability and permeability heterogeneity characteristics have been obtained for the limestone outcrop using pressure and oil recovery profiles obtained for VI–VP well configuration. These characteristics have further been used for simulation of VI–HP well configuration. The experimental and simulation recoveries are in good agreement whereas pressure profiles match qualitatively. For the outcrop under investigation, the experimental and simulated pressure profiles indicated the presence of permeability heterogeneity. The pressure measurements and numerical simulations provided the qualitative estimation of permeability heterogeneities of the studied outcrop. The nature of pressure profiles remained the same during waterflooding for both the well configurations.