Anatomy of the Mud Pump Pulse

Mud Pumps with pulse reducing pulsation dampeners have been in existence for more than half a century. Until now, the market has been dominated with 40-year-old triplex pump designs that have rough discharges and excessive vibration. During the last four decades, the drilling industry has acceptedthe difficulties of mud pump pulses and the problems they cause. Some of these problems are poor telemetry for direction drilling and rig vibration/harmonics in offshore environments.

Mud pump pulses can be minimized using pulsation dampeners or syncing the pumps when more than one electric drive pump is used in parallel. Syncing pumps is a process in which multiple pumps’ strokes are controlled to synchronize their pulses and reduce the combined effect of the pulse’s by dispatching a peak in the other pumps’ trough. However, syncing the pumps still leaves a tremendous amount of pulse in the mud flow and vibration offshore. Traditional triplex mud pumps have proven ineffective in adequately delivering a smooth flow, despite counter measures.


Figure 1. Triplex Mud Pump

To reduce the many causes of pulses in single acting reciprocating triplex pumps, one needs to first consider the source or sources of the these pulsations before they can truly be minimized in any significant way.

Pulsation at the Mud Inlet

One of the first places that pulse can occur is at the suction or mud inlet to the pump. The mud enters the suction manifold and fills the liners. It is critical that the inlet valve open and close quickly to allow the liner to fully fill up during the suction stroke. The term suction can be misleading because the pump would be supercharged by an impeller pump, so as the piston moves back, the charge pump pushes the mud into the cylinder cavity. As the cylinder retreats on the back stroke and the mud flows in, the piston moves back at a nonlinear speed, starting at zero velocity, building up to maximum velocity near the middle of the stroke and back down to zero at the end of the stroke when the liner is filled with mud.