Biosurfactants Produced From Agriculture Process Waste Streams To Improve Oil Recovery in Fractured Carbonate Reservoirs

摘要

We examined the ability of surfactin, an anionic lipopeptide surfactant produced by Bacillus subtilis, to mediate wettability changes that positively affect oil recovery in fractured carbonate rock. On both a weight for weight and a molar basis, surfactin has a greater ability to alter a carbonate rock to a more water-wet state than does sodium laureth sulfate (SLS). Surfactin, was produced by growing Bacillus subtilis on high-starch medium to represent agricultural effluent, and a suitable benchmark chemical surfactant was selected for comparative study. Cores and crushed samples of Lansing-Kansas City (LKC) carbonate reservoir material were cleaned and characterized. Crushed rock was aged in crude oil to ensure that it was strongly oil-wet and rapid wettability tests were performed to assess the wettability change mediated by low concentrations of surfactin and SLS. Static adsorption of surfactants on LKC rock was assessed and dynamic adsorption in intact cores was measured. Surfactin exhibits higher specific adsorption onto crushed LKC.