Fremgangsmåte for måling av formasjonsegenskaper med tidsbegrenset formasjonstest

摘要

A method for determining mud compressibility is disclosed. The method comprises capturing wellbore fluid in the formation tester, the wellbore fluid being in fluid communication with a pretest chamber containing a movable piston. The piston is selectively moved in the pretest chamber to alter the volume of captured fluid in the downhole tool, and the pressure of the captured fluid is measured. Mud compressibility is then estimated from the measured pressure.