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Holden John C, Wray Gary Q: Improved annulus pressure operated well testing apparatus and its method of operation. Halliburton Company, Tregoning John H, Cockfield James E, Gonzalez Floyd A, December 24, 1974: US3856085 (90 worldwide citation)

A full opening, annulus pressure responsive, formation testing method and apparatus wherein both valve closing and valve opening biasing forces are generated in response to annulus pressure and wherein a full opening, formation fluid flow passage is provided by the testing valve. A disabling mechani ...


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Holden John C, Wray Gary Q: Wellbore circulating valve. Halliburton Company, Tregoning John H, Gonzalez Floyd A, Cockfield James E, November 26, 1974: US3850250 (53 worldwide citation)

A wellbore circulating valve especially useful in a string of testing tools ultilizes a sequentially ratcheted inner mandrel which covers a series of flow ports and is opened by a predetermined sequence of operations which move the mandrel away from the flow ports thereby communicating the annulus w ...


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Wray Gary Q, Holden John C: Apparatus for testing oil wells using annulus pressure. Halliburton Company, Tregoning John H, Gonzales Floyd A, January 7, 1975: US3858649 (47 worldwide citation)

An annulus pressure operated oil well testing and sampling apparatus utilizes hydrostatic pressure to supplement spring means which biases against valve means to hold the valve means closed until application of sufficient hydraulic pressure to the annular fluid opens the tool to the formation and al ...


4
Wray Gary Q, Holden John C: Method for testing oil wells. Tregoning John H, Gonzalez Floyd A, January 14, 1975: US3860069 (27 worldwide citation)

An annulus pressure operated oil well testing and sampling apparatus utilizes hydrostatic pressure to supplement spring means which biases against valve means to hold the valve means closed until application of sufficient hydraulic pressure to the annular fluid opens the tool to the formation and al ...


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