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Method for measuring formation properties with a time-limited formation test

  • US 7,263,880 B2
  • Filed: 05/09/2003
  • Issued: 09/04/2007
  • Est. Priority Date: 09/09/2002
  • Status: Expired due to Fees
First Claim
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1. A method for determining downhole parameters using a downhole tool positioned in a wellbore adjacent a subterranean formation, comprising:

  • (a) establishing fluid communication between a pretest chamber in the downhole tool and the formation via a flowline,(b) establishing an initial pressure in the flowline;

    (c) moving a pretest piston positioned in the pretest chamber in a controlled manner to reduce the initial pressure to a drawdown pressure;

    (d) terminating movement of the piston to permit the drawdown pressure to adjust to a stabilized pressure;

    (e) repeating steps b–

    d until a difference between sequential stabilized pressures is substantially smaller than a predetermined pressure drop; and

    (f) determining one or more downhole parameters from an analysis of one or more of the pressures.

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