Concept of Gravity Drainage in Layered Porous Media

Abstract

Abstract Gas-oil gravity drainage in layered porous media is, under certain conditions, an unstable process. Even for two layers, gas could finger through a less permeable top layer to reach a more permeable bottom layer. This paper provides a criterion for instantaneous gas fingering towards the more permeable layer. A non-linear form of the diffusivity equation is used to study gas-oil drainage in layered systems. Numerical examples show that recovery performance of layered systems, unlike homogeneous media, is sensitive to capillary pressure.