Patent ID: 6568487
Filing Date: 2003-05-27
Classification: E21B

Abstract:
A method for determining at least one parameter of interest of a formation while drilling, the method comprising:(a) conveying a tool on a drill string into a borehole traversing the formation; (b) extending at least one selectively extendable probe disposed on the tool to make sealing engagement with a portion of the formation; (c) exposing a port to the sealed portion of the formation, the port providing fluid communication between the formation and a first volume within the tool; (d) varying the first volume with a volume control device using a plurality of volume change rates; (e) determining at least one characteristic of the first volume using a test device at least twice during each of the plurality of volume change rates; and (f) using multiple regression analysis to determine the at least one parameter of interest of the formation using the at least one characteristic determined during the plurality of volume change rates.