Investigation on Foam Self‐Generation Using <italic>In Situ</italic> Carbon Dioxide (CO2) for Enhancing Oil Recovery.

Abstract: <italic>In situ</italic> carbon dioxide (CO₂) foam flooding has proved to be economically feasible in the oil field, but its self‐generation behavior in the bulk scale/porous media is far from understood. In this study, the optimum <italic>in situ</italic> CO₂‐foaming agent was first screened, and then <italic>in situ</italic> foam was investigated in the bulk. <italic>In situ</italic> foam flooding was conducted to evaluate the displacement characteristics and enhanced oil recovery of this system. The results showed that the foaming agent comprising 0.5% sodium dodecyl sulfonate (SDS) + 0.5% lauramido propyl hydroxyl sultaine (LHSB) gave the best foam properties and that the <italic>in situ</italic> CO₂ foam with a slow releasing rate is effective both in bulk scale and in porous media, allowing a considerable enhancement of oil recovery in sand packs with different permeabilities. [ABSTRACT FROM AUTHOR]