UPSTREAM PUMPING SOLUTIONS • Spring 2011

Mud Pump Vibration Analysis
Online condition monitoring for hard-to-reach or hazardous places
A mud pump is a reciprocating piston/plunger device designed to circulate drilling fluid under high pressure down the drill string and back up the annulus.
Mud pumps come in a variety of sizes and configurations, but for the typical petroleum drilling rig, the triplex (three piston/plunger) mud pump is the pump of choice. Duplex mud pumps (two piston/plungers) have generally been replaced by the triplex pump, but are still common in developing countries. A later development is the hex pump with six pistons/plungers.
The normal mud pump consists of two main sub-assemblies—the fluid end and the power end. The fluid end produces the pumping process with valves, pistons, and liners. Because these components are high-wear items, modern pumps are designed to allow for quick replacement.

Vibration Reduction on a Six-Pump Rig
To reduce severe vibration caused by the pumping process, mud pumps incorporate both suction and discharge pulsation dampeners. These are connected to the inlet and outlet of the fluid end.
The number of mud pumps varies per drilling rig depending on the size of the drilling rig. The larger the rig the more mud pumps that will be needed. The mud pumps are considered vital to the operation of the drilling rig. If the mud pumps fail it affects production and can be very costly to repair due to the downtime in production.
Six mud pumps were running on a drilling ocean rig.

The Monitoring System
To avoid any failures of the pumps, an online monitoring system was selected to collect and transmit vibration data back to a software system for analysis. This online monitoring and diagnostic system can also be expanded by a series of program modules (MUXs) that are specific to the application:

• Band analysis module for the automatic evaluation of complex vibration processes in rolling element bearings, gears, or special   machines
• Cepstrum analysis
• Orbit analysis
• Data server for the automatic or event-controlled readout of data and for transferring this data to higher systems

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