04860581 is referenced by 281 patents and cites 17 patents.

The apparatus of the present invention relates to a down hole tool capable of extraction of valid samples and making pressure measurements useful in calculating formation permeability. The tool incorporates the features of a staddle packing to allow formation fluid specimens to be taken at large flow rates without depressing the pressure below the formation fluid bubble point. When used in combination with a pressure probe the tool is used to obtain meaningful permeability readings in a larger radius area than previously permitted with known dsigns. Additionally, the apparatus of the present invention allows flow control during the creation of the pressure pulse which enhances extraction of valid samples and the permeability determination. The apparatus may be modularly constructed so that in a single descent of the tool, a pressure profile of the zone of interest can be made, a fluid analysis can be made at each station, multiple uncontaminated fluid samples can be withdrawn at pressures above the bubble point, local vertical and horizontal permeability measurements can be made at each station, a packer module can be set at a location dictated by previous measurements and a large scale pressure build up test can be performed.

Title
Down hole tool for determination of formation properties
Application Number
7/248867
Publication Number
4860581
Application Date
September 23, 1988
Publication Date
August 29, 1989
Inventor
Joseph L Perkins
Sugar Land
TX, US
Julian J Pop
Houston
TX, US
Thomas H Zimmerman
Houston
TX, US
Agent
John H Bouchard
Henry N Garrana
Assignee
Schlumberger Technology Corporation
TX, US
IPC
E21B 49/08
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