Kais Gzara

Real-Time Formation Integrity Tests Using Downhole Data

Accurate leakoff/formation-integrity tests are essential for efficient management of equivalent circulating density within the safe pressure window. Traditionally, the rate of downhole buildup is estimated from the standpipe pressure but now can be monitored directly with a downhole annular-pressure measurement. Low flow rates used during a leakoff/formation-integrity test preclude use of traditional measurement-while-drilling (MWD) systems to transmit data to the surface. However, by use of a wireline coupling tool, downhole pressure can be transmitted to surface in real time, allowing the operator to view the surface and downhole pressure buildup simultaneously and evaluate both formation integrity and mud compressibility.