WAVE MOTION COMPENSATION SYSTEM FOR SUSPENDING WELL EQUIPMENT FROM A FLOATING VESSEL

摘要

A reversible hydraulic motor and a high pressure-low pressure hydraulic reservoir system are used to counterbalance the weight of a drill string or other well equipment suspended from a line wound on a draw works positioned on a floating vessel. A load cell controls the torque output and the direction of the output drive of the hydraulic motor and in turn torque on and the direction of rotation of the draw works. On downward movement of the floating vessel high pressure hydraulic fluid from an accumulator moves through the hydraulic motor into a low pressure hydraulic fluid reservoir to provide increased torque to the draw works as the draw works spools up line and upward movement of the floating vessel the hydraulic motor reverses and becomes a pump and moves low pressure fluid from the low pressure reservoir to the high pressure accumulator to provide decreased torque and reverse direction to the draw works as the draw works spools off line.