Novel green surfactant made from L-aspartic acid as enhancer of oil production from sandstone reservoirs: Wettability, IFT, microfluidic, and core flooding assessments

Abstract

Surfactant flooding is a proven chemical Enhanced Oil Recovery (cEOR) method. Commonly/commercially available surfactants impose adverse impacts on the environment and even human health. Thus, finding green surfactants is of interest to petroleum engineers to implement cleaner EOR processes. In the current study, a novel surfactant, namely (S)-2-Dodecanamido-Aminobutanedioic acid was synthesized from L-Aspartic acid (an amino acid). After confirming its successful synthesis by FT-IR and 1H NMR spectrometry, its first petroleum engineering application was investigated. To do so, the effect of the surfactant on oil-water IFT, oil-sandstone rock contact angle and oil recovery from glass micromodel and sandstone core plugs was reviewed. In the presence of the surfactant, at different water salinities, oil-water IFT and the oil-wetting tendency of sandstone rock is decreased. At the surfactant's critical micelle concentration, minimum IFT is 9.8 mN/m, and minimum contact angle is 92.40°, which respectively are obtained in the salinities of 40,000 and 20,000 ppm. These two salinities were selected for oil recovery tests. Microfluidic evaluation visually showed that chemical fluids made from the surfactant compared to saline water flooding push more oil out of the micromodel, i.e., increase the volumetric sweep efficiency. Furthermore, four sandstone core plugs were subjected to water and surfactant flooding, respectively, to review the dominant mechanism of oil recovery by the surfactant. Surfactant EOR, with the mechanism of IFT reduction enhances oil recovery by 1.5%. However, considering both the IFT reduction and wettability alteration mechanisms, in the presence of 20,000 and 40,000 ppm salinities, 11.19 and 6.04% more oil volume is produced, respectively. Therefore, it is evident that wettability alteration is the prevailing mechanism for cEOR by the surfactant. In a sentence, the cEOR application of the amino-acid-based surfactant is confirmed.