Development of a Laboratory Methodology for Core Flooding Experiments to Evaluate Gravity Segregation in Oil–Water Saturated Porous Media

A laboratory methodology was developed to investigate gravity segregation in oil–water saturated cores. The approach is based on the fabrication of epoxy-sealed cores placed and fixed inside a steel sleeve, providing a cost-effective and practical solution. The design of the core holder also allows the installation of pressure ports along the core length.

Two experimental scenarios are considered. In the first case, an unfavorable mobility ratio leads to early water breakthrough caused by viscous fingering. In the second case, premature breakthrough is induced by introducing an artificial high-permeability channel. Following water breakthrough, the flooding process is suspended, and the core is aged in a vertical position. Subsequent resumption of water injection allows evaluation of fluid redistribution due to gravity segregation.

An additional methodological feature includes a simple and reproducible technique for oil–water separation in effluent samples, based on preferential adhesion of oil to the walls of polyethylene containers.

The methodology enables qualitative and quantitative assessment of oil and water redistribution within the porous medium due to gravity effects. The approach can serve as a laboratory basis for field technologies involving shut-in periods in highly watered wells, where gravity-driven phase segregation may reduce water cut and improve oil production.