A successive gas and water displacement process involves recovering oil from a carbonate reservoir having a low connate water saturation of less than about 15% pore volume by displacement of the oil with gas such that the residual oil content is less t han about 25% pore volume and the gas saturation is in the range of from about 60 to 80% pore volume. The reservoir is then water-flooded by a natural water drive from an underlying aquifer and/or by water injection. Oil recovery is enhanced by up to 5 to 15% OOIP.
