Patent ID: 7395703

Claim:
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, wherein increasing the draw rate includes at least one of i) increasing the draw rate continuously during the first draw portion and ii) increasing the draw rate in a step-wise manner during the first 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.