Description

Mud pressure penetration, the infiltration of drilling mud into shale formations due to rising pore pressure, poses a greater concern in water-based mud (WBM) systems with lower capillary entry pressures, potentially leading to shear failure. The PTT 700 is specifically engineered to ascertain the tendency of a fluid filtrate, subjected to overbalance pressure, to invade the shale matrix and elevate the near wellbore pore pressure. Its configuration encompasses a hydrostatic core holder, a pore fluid injection pump, a test fluid piston accumulator, upstream and downstream pressure transducers, and automated valves, all contained within a meticulously controlled temperature airbath. To regulate the confining pressure of the core sample, an automated syringe pump is employed. The computer-controlled system is furnished with bespoke software that facilitates both manual and automated operation, affording precise management over pumps, valves, pressure sensors, and data acquisition.