METHOD AND APPARATUS FOR DETERMINING DOWNHOLE PRESSURES DURING A DRILLING OPERATION.

摘要

A method and apparatus is provided to collect downhole data during a drilli ng operation via a downhole tool. A differential pressure is created by the difference between internal pressure of fluid passing through the downhole tool and the annular pressure in the wellbore. The apparatus includes a drill collar connectable to the downhole drilling, and has an opening extending into a chamber therein. A piston is positioned in the chamber and has a rod extending into the opening. The piston is movable between a closed position with the rod filling the opening, and an open position with the rod retracted into the chamber to form a cavity for receiving downhole fluid. A sensor is positioned in the rod for collecting data from fluid in the cavity. The apparatus may also be provided with a probe and/or hydraulic circuitry to facilitate the collection of data.