Abstract: A pumping system includes a plurality of pumps, each having an inlet and an outlet. The inlet is fluidly coupled to a hydraulic fluid reservoir. The outlet is fluidly coupled to a control pod having a valve and a pair of sensors monitoring upstream and downstream pressures of the valve. The control pod is fluidly coupled to a subsea blowout preventer. A first motor is coupled to a first pump of the plurality of pumps and sets the first pump at a first predetermined pressure. A controller is coupled to and configured to control the first motor, thereby controlling the first pump. The pumping system is configured to: engage and disengage each pump independently; and de-stroke each pump to limit pressure to the valve, when a predetermined pressure for each pump is attained, thereby reducing fluid hammer at the control pod.

Abstract: Cement plugs used in the cementing of casing in a borehole drilled into a subterranean formation are restrained from rotation by being forced into a portion of the casing and check valve apparatus which includes a reduced diameter section formed as a continuous annular liner of material having a coefficient of friction. Compression of the plug against the high-friction liner avoids rotation of the plugs when they are drilled subsequent to the cementing operation.