Formation testing apparatus and method for smooth draw down
First Claim
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1. A method of determining in situ a desired formation parameter of interest comprising:
- a) conveying a tool into a well borehole traversing a formation;
b) establishing fluid communication between the tool and the formation, the tool having a test volume for accepting fluid from the formation;
c) drawing fluid into the test volume, the drawing including a first draw portion and a second draw portion;
d) controlling a draw rate during at least one of the first draw portion and the second draw portion, the draw rate being controlled according to one or more of i) increasing the draw rate a plurality of times during the first draw portion, and ii) decreasing the draw rate a plurality of times during the second draw portion; and
e) determining at least one characteristic of the test volume during one or more of the first draw portion and the second draw portion, the determined characteristic being indicative of the formation parameter of interest.
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Abstract
A method and apparatus for of determining a formation parameter of interest. The method includes placing a tool into communication with the formation to test the formation and drawing down a test volume at an increasing draw rate during a first draw period and decreasing the draw rate during a second draw period to create a smooth draw down cycle. The draw down can be step-wise or continuous. The formation parameter is determined using formation rate analyis and characteristics determined during the draw down cycle.
53 Citations
45 Claims
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1. A method of determining in situ a desired formation parameter of interest comprising:
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a) conveying a tool into a well borehole traversing a formation;
b) establishing fluid communication between the tool and the formation, the tool having a test volume for accepting fluid from the formation;
c) drawing fluid into the test volume, the drawing including a first draw portion and a second draw portion;
d) controlling a draw rate during at least one of the first draw portion and the second draw portion, the draw rate being controlled according to one or more of i) increasing the draw rate a plurality of times during the first draw portion, and ii) decreasing the draw rate a plurality of times during the second draw portion; and
e) determining at least one characteristic of the test volume during one or more of the first draw portion and the second draw portion, the determined characteristic being indicative of the formation parameter of interest. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. An apparatus for determining in situ a desired formation parameter of interest comprising:
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a) a tool conveyable into a well borehole traversing a formation;
b) a test unit in the tool, the test unit being adapted for fluid communication with the formation, the test unit including a test volume for receiving fluid from the formation;
c) a control device associated with the test volume for controlling a draw rate of the fluid being drawn into in the test volume, the control device being operable to control the draw rate according to one or more of i) increasing the draw rate a plurality of times during a first draw portion, and ii) decreasing the draw rate a plurality of times during a second draw portion; and
d) a sensing device for determining at least one characteristic of the test volume during one or more of the first draw portion and the second draw portion, the determined characteristic being indicative of the formation parameter of interest. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
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31. A system for determining in situ a desired formation parameter of interest comprising:
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a) a work string for conveying a tool into a well borehole traversing a formation;
b) a test unit in the tool, the test unit being adapted for fluid communication with the formation, the test unit including a test volume for receiving fluid from the formation;
c) a control device associated with the test volume for controlling a draw rate of the fluid being drawn into in the test volume, the control device being operable to control the draw rate according to one or more of i) increasing the draw rate a plurality of times during a first draw portion, and ii) decreasing the draw rate a plurality of times during a second draw portion;
d) a sensing device for determining at least one characteristic of the test volume during one or more of the first draw portion and the second draw portion;
e) a processor receiving an output of the sensing device, the processor processing the received output according to programmed instructions, the formation parameter of interest being determined at least in part by the processed output. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45)
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Specification