Superactive Surfactant for Enhanced Oil Recovery

Abstract

After primary and secondary oil recovery, a large amount of oil is left behind in the reservoir. Enhanced oil recovery (EOR) techniques are introduced to recover additional oil from the reservoir. Chemical EOR is one of the commonly used EOR techniques. It involves the use of chemical substances such as surfactants. Surfactants are commonly used in the petroleum industry because they have the ability to change the water-oil interface as well as the properties of the rock surface. The use of such surfactants depends on technical, financial, and environmental factors. In this study, the performance of a new superactive surfactant is evaluated for use as an oil recovery agent for carbonate and sandstone formations. The surfactant showed high stability in deionized water and seawater, with strong ability to lower the interfacial tension of different crude oils (light, medium, and heavy) at a very low concentration (i.e., 0.05 wt%). The maximum reduction in interfacial tension reached 99.5%. The surfactant also showed significant surface wettability alteration toward water-wet at the tested concentration, with maximum reduction of 87%. From the interfacial tension and wettability experiment results, the optimum system was obtained for the medium crude oil and seawater at surfactant concentration of 0.05 wt%. Therefore, the coreflooding experiments on carbonate and sandstone samples were carried out using this system. Results showed a significant additional oil recovery by the surfactant injection. Additional oil of 43% was recovered from the carbonate core samples, while 16% recovered from the sandstone sample. With these results, this new surfactant can be potentially considered as a new agent for enhancing oil recovery from carbonate and sandstone formations.