Oil recovery by sequential waterflooding with oil reinjection and oil relocation

摘要

A method for enhancing oil recovery from reservoirs is described. The method includes partially recharging zones of pore space in a reservoir that has been previously waterflooded to extract oil, in order to obtain increased ultimate oil recovery by re-waterflooding the recharged zones. The recharging may be achieved by either reinjection of oil or by change in injection scheme, such as changing an oil producing well to a water injection well. This procedure of recharging with oil followed by waterflooding may be repeated. Application of the present method to increase recovery from reservoirs producing dry (water-free) oil to mature reservoirs which produce at high water-to-oil ratios is anticipated.