Evidence, mechanisms and improved understanding of controlled salinity waterflooding part 1: Sandstones

A common feature of all three proposed mechanisms for the LSE is that they lead to changes in zeta potential at mineral surfaces, either through changes in mineral surface charge (MIE, ΔpH) or changes in the thickness of the double layer (DLE). Thus they change the magnitude of the electrostatic forces acting between mineral surfaces and polar organic species. Experiments that can probe this effect at conditions appropriate to reservoir displacements, whilst also measuring oil recovery, oil and brine composition and pH, and (if possible) the in-situ distribution of the fluids, are required to understand the LSE and predict the optimum injection brine composition for a given COBR system.