Application of a new bio-ASP for enhancement of oil recovery: Mechanism study and core displacement test

The evaluations of Alkaline-Biosurfactant-Biopolymer (ABsBp) flooding for enhancement of oil recovery applications were explored. A lipopeptide biosurfactant (surfactin) and a biopolymer (schizophyllan) in combination with alkali (Na₂CO₃) were experimentally investigated to evaluate the possibility for EOR studies using native Omani reservoir cores and Berea core plugs. The selected oil reservoir was high permeability (500–1000 mD) sandstone type, the reservoir temperature of 50 °C, and less than 80% water cut. The crude oil was also procured from the selected Omani reservoir, having 27.15 API. The interfacial tension (IFT) values of 0.02–0.1mN/m were observed at comparatively lower biosurfactant and alkali concentrations. The effect of other chemicals and biosurfactant on biopolymer was also studied on its viscosity at reservoir temperature, and no adverse effect was observed on biopolymer performance in the presence of alkali and biosurfactant. The injection of a 0.5 PV slug of 1.1% (w/v) Na₂CO₃, 20% (v/v) biosurfactant (400 ppm) and 20% (v/v) biopolymer (600 ppm), followed by 3 PV of biopolymer (600 ppm) drive showed 14% and 32% of additional oil recovery from reservoir cores and Berea cores respectively. This is the first report of Alkali-Biosurfactant-Biopolymer application using surfactin and schizophyllan, showing additional oil recovery from Omani reservoir cores and Berea sandstone cores.