Oil recovery process by in situ emulsification

Abstract

Petroleum may be recovered from subterranean, petroleum-containing formations by injecting into the formation an organic liquid having dispersed therein, an alkali metal in very fine, preferably colloidal size range, particular form. The organic liquid containing the alkali metal dispersion is followed by injecting an aqueous fluid to react with the alkali metal, generating alkali metal hydroxide, hydrogen gas and heat in the formation which stimulates displacement of the petroleum by encouraging formation of low viscosity oil-in-water emulsions, as well as by thermal viscosity reduction effects, and dissolution of hydrogen gas in the viscous petroleum. The organic liquid having alkali metal dispersed therein may be preceded or followed by injecting crude petroleum from another formation which is prone to emulsify spontaneously and aid in the formation of low viscosity oil-in-water emulsions. Liquids containing emulsifying agents may also be used in combination with the present process, injected either in advance of or after injection of the organic liquid having alkali metal particles dispersed therein. Alkali metals suitable for use in this invention include sodium, potassium and lithium. This process may be used in combination with thermal stimulation processes including steam and/or hot water injection.