Understanding aqueous foam with novel CO2-soluble surfactants for controlling CO2 vertical sweep in sandstone reservoirs

• Main Authors: Guangwei Ren, Quoc P. Nguyen
• Format: Article
• Language: English
• Published: SpringerOpen 2017-03-01
• Series: Petroleum Science
• Subjects: Foam; CO2-soluble surfactant; Sweep efficiency; Gravity segregation; Optimal injection strategy
• Online Access: http://link.springer.com/article/10.1007/s12182-017-0149-2

Abstract The ability of a novel nonionic CO2-soluble surfactant to propagate foam in porous media was compared with that of a conventional anionic surfactant (aqueous soluble only) through core floods with Berea sandstone cores. Both simultaneous and alternating injections have been tested. The novel foam outperforms the conventional one with respect to faster foam propagation and higher desaturation rate. Furthermore, the novel injection strategy, CO2 continuous injection with dissolved CO2-soluble surfactant, has been tested in the laboratory. Strong foam presented without delay. It is the first time the measured surfactant properties have been used to model foam transport on a field scale to extend our findings with the presence of gravity segregation. Different injection strategies have been tested under both constant rate and pressure constraints. It was showed that novel foam outperforms the conventional one in every scenario with much higher sweep efficiency and injectivity as well as more even pressure redistribution. Also, for this novel foam, it is not necessary that constant pressure injection is better, which has been concluded in previous literature for conventional foam. Furthermore, the novel injection strategy, CO2 continuous injection with dissolved CO2-soluble surfactant, gave the best performance, which could lower the injection and water treatment cost.