Small Core Flood Experiments for Foam EOR - Screening Surfactant Applications

Aqueous foams are a means of increasing the sweep efficiency of enhanced oil recovery processes. An understanding of how a foam behaves in the presence of oil is therefore of great importance when selecting suitable surfactants for EOR processes. The consensus is currently that the most reliable method for determining the foam behavior in the presence of oil is to inject foam through a rock core. Coreflood tests, however, are typically carried out using large rock cores (e.g. diameter = 4 cm, length = 40 cm or longer), and hence foam flow tests can take days or weeks to achieve steady-state flow. In this study, we present the preliminary results for a core-flood system where the rock core is pen-sized (diameter = 1 cm, length = 17 cm). These small cores allow for short-duration foam flow tests, where steady-state flow is achieved in a few hours. Using this system, the foam quality/effective viscosity response curves can be plotted, both with and without oil in the system. These small size cores then enable rapid screening of surfactants and foam properties in different rocks and with different oils. Benefits and limitations of these small coreflood experiments are discussed.