A method for enhancing oil recovery from a sandstone reservoir through optimized brine salinity

Abstract

The present invention relates to a method for enhancing oil recovery from a sandstone reservoir by optimizing the salinity and composition of injection brines based on relative permeability and fractional flow analysis. The method involves collecting core and crude oil samples from multiple wells, preparing a series of injection brines containing calcium chloride, magnesium chloride, and potassium chloride at varying concentrations, and conducting core flooding experiments on aged crude oil-saturated core plugs. The process includes precise determination of porosity, permeability, and relative permeability under controlled flow and pressure conditions. Fractional Flow Curves are constructed to evaluate the effect of brine composition on wettability alteration and oil displacement efficiency. The optimized brine formulation effectively enhances oil recovery while minimizing clay swelling and permeability impairment, providing an improved approach for implementing low-salinity water flooding in sandstone reservoirs.