Method for measuring formation properties

摘要

A method for evaluating a subterranean formation comprises positioning a downhole tool in a wellbore adjacent the subterranean formation, the downhole tool having a pretest piston therein adapted to perform a pretest of the formation. The first pretest of the formation is used to determine an initial estimate of the formation parameters, and pretest criteria for performing a second pretest are designed based on the initial estimate of the formation parameters. The second pretest of the formation is then performed according to the designed pretest criteria, to determine a refined estimate of the formation parameters.