Patent ID: 6609568
Filing Date: 2003-08-26
Classification: E21B,G01V

Abstract:
A method for determining at least one parameter of interest of a formation comprising:(a) conveying a tool into a borehole on a work string, the borehole traversing a subterranean formation containing formation fluid under pressure, the borehole and work string having an annulus between the borehole wall and work string, the annulus being filled with a pressurized fluid containing the formation fluid; (b) sealing a portion of the annulus by extending at least one selectively extendable device disposed on the tool; (c) exposing a port to the sealed portion of the annulus, the port being in fluid communication with a test volume created by (a) and (b), the test volume containing a fluid including the formation fluid; (d) increasing the test volume at a first rate with a volume control device until the test volume pressure falls below formation pressure; (e) sensing at least one characteristic of the fluid using a test device at least twice while the test volume is being increased at the first rate; (f) increasing the test volume at an at least one second rate with the volume control device, the at least one second rate being a non-zero rate; (g) sensing the at least one characteristic of the test volume using the test device at least twice while the test volume is being increased at the at least one second rate; and (h) determining the at least one parameter of interest of the formation using the at least one characteristic sensed during the first rate and at least one second rate.