GAS DISPLACED CHAMBER LIFT SYSTEM WITH CLOSED LOOP/MULTI-STAGE VENTS - Patent 1328704

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EP 1 328 704 A1

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(43)	Date of publication:
	23.07.2003 Bulletin 2003/30

(21)	Application number: 00973812.1

(22)	Date of filing: 23.10.2000

(51)	International Patent Classification (IPC)⁷: E21B 43/00

(86)	International application number:
	PCT/US0029/305

(87)	International publication number:
	WO 0203/5057 (02.05.2002 Gazette 2002/18)

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

(71)	Applicant: Valence Operating Company
	Kingwood, TX 77339 (US)

(72)	Inventor:
	AVERHOFF, Jon R. Kingwood, TX 77339 (US)

(74)	Representative: Frankland, Nigel Howard et al
	FORRESTER & BOEHMERTPettenkoferstrasse 20-22 80336 München 80336 München (DE)

(54)	GAS DISPLACED CHAMBER LIFT SYSTEM WITH CLOSED LOOP/MULTI-STAGE VENTS