Patent ID: 9581019
Date: 2017-02-28
CPC Classifications: E21B

Claim:
1. A method, comprising: contacting a fluid communication device of a formation testing tool with a wall of a borehole extending into a subterranean formation; performing a first drawdown to draw fluid into the fluid communication device from a starting pressure of the first drawdown to a final pressure of the first drawdown via continuous expansion of a first volume of fluid within the formation testing tool, wherein the final pressure of the first drawdown is lower than a pressure of the subterranean formation; detecting a breach of a mudcake on the borehole wall during the first drawdown and, in response to detecting the mudcake breach, performing a second drawdown to draw fluid into the fluid communication device via incremental expansion of a second volume of fluid within the formation testing tool, wherein the second volume of fluid is less than the first volume of fluid, wherein a starting pressure of the second drawdown is lower than the starting pressure of the first drawdown, and wherein performing the second drawdown includes performing a plurality of step-wise expansions of the second volume of fluid or other volumes of fluid, including: confirming the mudcake breach during the second drawdown; estimating the pressure of the subterranean formation based on at least one of: confirming the estimated pressure of the subterranean formation by performing a measurement phase comprising: