Gravity Segregation in Gas IOR in Heterogeneous Reservoirs

Vertical segregation of gas to a thin override zone is a major limitation on sweep efficiency and oil<br>recovery in gas improved oil recovery (IOR), including CO2 sequestration in oil reservoirs. Stone (SPE<br>11130, 1982) and Jenkins (SPE 12632, 1984) present an elegant and powerful model for gravity<br>segregation for co-injection of gas and liquid in homogeneous reservoirs. They contend that the model<br>applies also to WAG. In this study we extend the model of Stone and Jenkins to heterogeneous (layered or<br>checkerboard) reservoirs, as representatives of reservoirs with long- or short-range lateral autocorrelation<br>of permeability, and test the extension with simulation.