Multi-stage enhanced oil recovery process

摘要

Multi-stage methods for the enhanced recovery of high viscosity oil deposits from low temperature, shallow subterranean formations. The methods may include the steps of heating potentially extractable hydrocarbons, such as high viscosity oil, by injecting a sufficient amount of a heating fluid having a temperature and viscosity sufficiently high to minimize channeling and to permit penetration into regions of the reservoir containing the potentially extractable hydrocarbons. Thereafter, there is injected an extraction fluid that forms a mobile emulsion with the oil, without need for a co-solvent. The extraction fluid may include either a surfactant-polymer formulation or an alkaline-surfactant-polymer formulation. This is followed by injecting a polymer drive medium into the reservoir to displace and drive hydrocarbons and fluids comprising oil to a production well. An aqueous driving medium is then injected into the reservoir to also drive hydrocarbons and fluids comprising oil to a production well.

主权项

1. A method for increasing oil recovery from a subterranean formation having a low temperature reservoir containing hydrocarbons, the method comprising the steps of:
injecting a sufficient amount of a heating fluid having a viscosity sufficient to minimize channeling of the heating fluid through the reservoir and to permit penetration of the heating fluid into regions of the reservoir containing hydrocarbons; injecting into the reservoir an extraction fluid formulation comprising a surfactant and a polymer, the extraction fluid formulation in an amount sufficient to extract oil from the reservoir; injecting into the reservoir a polymer drive fluid formulation comprising a polymer, the polymer drive fluid formulation in an amount sufficient to displace and sweep oil and fluids from the reservoir; and recovering hydrocarbons from the reservoir.