Test on Bitter Leaf Sap as a Surfactant for Wettability Alterations in Enhanced Oil Recovery from Sand Aggregates

Alteration of reservoir-wettability is very important during Enhanced Oil Recovery (EOR) process since it helps to mobilize hydrocarbon and thus increase its recovery from the reservoirs. However, conventional wettability alteration agents used in the industry are inorganic chemicals which are expensive, constitute and have been found to be harmful to the environment. Hence, there was need for cheaper and environmentally-friendly alternative. Also, there was need to find more use for abundant local materials which have are under-utilized. In this article, bitter leaf sap (BLS) was studied to ascertain its possibilities as bio-surfactant for wettability alteration. In order to establish its phytochemical composition, BLS was analyzed using SEM, FT-IR, XRD, and XRF in accordance with ASTM standards. Wettability alteration capacity of three different concentrations of BLS solution on three sand aggregates was investigated. Active compounds which qualified BLS as bio-surfactant were identified from phytochemical analyses. Phytochemical analyses of BLS do not reveal any compounds that could be dangerous to the environment. The results from wettability tests obtained showed that core Sample A, (grain-size 0.118 cm) gave highest degree of wettability alteration with wettability index change from - 0.3030 to - 0.2020. Degree of wettability alteration increased as grain size of sand increased. It was also found that the degree of wettability alteration increased as concentration of BLS increased. Although, BLS could cause wettability alteration, its degree of alteration was lower than the degree of alteration of industrial wettability alteration agent.