Abstract
It is found that the mineralogical composition of conglomerate oil reservoirs in the Junggar Basin in northwest China is complex compared to conglomerate oil reservoirs in other regions. Among them, the most active physicochemical properties are zeolite minerals and clay minerals, which have the largest specific surface, the highest zeta potential, and they readily interact with surfactants used in chemical oil recovery. Experiments were conducted according to the actual surfactant/polymer binary composite drive chemical oil recovery model at the production site, and the interfacial tensions of 17 surfactants were measured, and the anionic surfactant KPS petroleum sulfonate, the nonionic surfactant coconut oil fatty acid diethanolamide 6501, and the amphoteric surfactant octadecyl betaine, which achieved ultra-low interfacial tensions, were screened out. Using the core of conglomerate reservoir, the contained minerals and oil and water, three surfactants were tested for adsorption performance, wettability test, emulsification performance evaluation, and finally, after the oil drive validation experiments, it was concluded that the specific surface of the minerals, zeta potential and the amount of adsorption of the chemical agent are positively correlated, and the amount of adsorption affects the recovery rate of chemical drive in conglomerate reservoirs, so that the 6501 was recommended to be the preferred surfactant. The research methodology adopted in the paper can be applied to chemical drive in reservoirs of different types and rock mineral compositions, and is also constructive for the promotion of chemical drive in similar reservoirs.