Halliburton Energy Services, Inc.

Halliburton Company

Ronald Lee Hinkie

Roger Lynn Schultz

Paul David Ringgenberg

H Kent Beck

Jason P Poullard

A pressure responsive well tool is provided of the general type including a housing having a flow conducting passage therethrough, a pressure conducting channel formed in the housing, and a spring assembly in the housing for storing potential energy in response to an increase in fluid pressure within the pressure conducting channel and releasing the stored potential energy into the pressure conducting channel in response to a decrease in fluid pressure within the pressure conducting channel. A staged latching assembly is operatively connected to the spring assembly for providing at least one intermediate stage pressure position for the spring assembly. The staged latching assembly preferably includes interfering structures on a mandrel and a collet for providing the intermediate stage pressure position. The intermediate stage pressure position of the spring assembly can be used as a stage for selectively directing the spring assembly in either direction, thereby providing better control over the tool. The staged latching assembly can be incorporated into a multi-mode well tool having a ball valve assembly and a circulating assembly to assist in selectively controlling the operation of the tool between a well test mode, a blank mode, any a fluid circulating mode. A method of operating a well tool is also provided.

Pressure responsive well tool with intermediate stage pressure position

Early evaluation testing of a subsurface formation is provided by monitoring pressure fall-off in the formation. This is accomplished by providing a column of fluid in the well having an overbalanced, hydrostatic pressure at the subsurface formation greater than a natural formation pressure of the subsurface formation. A testing string is run into the well, and the testing string includes a packer, a pressure monitor and a closure tool arranged to close a bore of the testing string. The formation is shut in by setting the packer and closing the bore of the testing string with the closure tool and thereby initially trapping the overbalanced hydrostatic pressure of the column of fluid in the well below the packer. Then the pressure in the well below the packer is monitored as it falls off toward the natural formation pressure. This data can be extrapolated to estimate the natural formation pressure based upon a relatively short actual test interval on the order of ten to fifteen minutes.

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Marlow, OK, United States of America

Ronald Lee Hinkie