Aqueous displacement fluid injection for enhancing oil recovery from an oil bearing formation

摘要

A method for enhancing recovery of crude oil from a porous subterranean formation of which the pore spaces contain crude oil and connate water comprises:—determining the Ionic Strength (Mol/l) of the connate water; and—injecting an aqueous displacement fluid having a lower Ionic Strength (Mol/l) than the connate water into the formation, which aqueous displacement fluid furthermore has an Ionic Strength below 0.15 Mol/l. FIGS. 13 and 16 and Table 4 demonstrate that injection of an aqueous displacement fluid with lower Ionic Strength than the connate water improves oil recovery (IOR).