The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 21, 1976
Filed:
Jul. 31, 1975
Robert N Healy, Houston, TX (US);
Exxon Production Research Company, Houston, TX (US);
Abstract
Disclosed herein is a method for recovering oil from subterranean formations using microemulsions. The microemulsion is compounded from an oil, an aqueous medium, and a surfactant, and its parameters are varied to form volumetric ratios of oil to surfactant in the microemulsion and/or water to surfactant in the microemulsion greater than 0.5. Preferably, the volumetric ratios will be greater than 2.0. Among the parameters which can be adjusted to change these volumetric ratios include the salinity of the aqueous medium, the temperature of the microemulsion system, the chemical structure of the surfactant, the chemical structure of any cosurfactant included in the microemulsion, the degree of aromaticity of the oil, and composition of dissolved solids in the aqueous medium. In one preferred embodiment of the invention an oil is chosen which has physical and chemical characteristics substantially the same as the formation oil. The aqueous medium has physical and chemical characteristics substantially the same as the formation water. A surfactant which has a chemical structure which will form a microemulsion having volumetric ratios of oil to surfactant and/or of water to surfactant greater than 0.5 is selected for inclusion in the microemulsion system. The oil; aqueous medium; and surfactant, determined in accordance with the teachings of this invention, form a class of microemulsions which is effective in recovering oil from subterranean formations of interest. All microemulsions within the class will be effective for recovering oil from the formation. Oil is recovered by compounding a microemulsion within the class and injecting this microemulsion into the formation.