Enhanced oil recovery method using CO2 injection

(19)

(11)

EP 1 258 595 A3

(12)	EUROPEAN PATENT APPLICATION

(88)	Date of publication A3:
	03.03.2004 Bulletin 2004/10

(43)	Date of publication A2:
	20.11.2002 Bulletin 2002/47

(21)	Application number: 02253397.0

(22)	Date of filing: 15.05.2002

(51)	International Patent Classification (IPC)⁷: E21B 43/16

(84)	Designated Contracting States:
	AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE TR
	Designated Extension States:
	AL LT LV MK RO SI

(30)

Priority:

16.05.2001 US 858363

(71)	Applicant: THE BOC GROUP, INC.
	Murray Hill, New Providence, New Jersey 07974-2082 (US)

(72)	Inventors:
	Ramachandran, Ramakrishnan Allendale, NJ 07401 (US) Limbach, Kirk Walton Dresher, PA 19025 (US) Hwang, Shuen-Cheng Chester, NJ 07930 (US)

(74)	Representative: Wickham, Michael et al
	c/o Patent and Trademark Department The BOC Group plc Chertsey Road Windlesham Surrey GU20 6HJ Windlesham Surrey GU20 6HJ (GB)

(54)	Enhanced oil recovery method using CO2 injection

(57) A method for enhancing the recovery of oil from underground formations is disclosed. A gas mixture which contains greater than 50% by volume carbon dioxide, the remainder typically being an inert gas, is injected in the underground formation to lower the oil viscosity and surface tension and increase the oil swelling. Preferably, the gas mixture contains greater than 60% by volume carbon dioxide with a gas mixture containing greater than 70% by volume carbon dioxide preferred.

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