Applications In Drilling

Both high-pressure mud pumps are utilized on rigs to circulate the drilling fluid around. Each type, however, has its operating limits, which are:

• Duplex pumps: the cranks are at 90°, and the pump can be run at a maximum of 70 spm.

• Triplex pumps: the cranks are at 120° and can be run at a maximum of 150 – 170 spm.

In practice, triplex pumps have the following advantages:

• The triplex pump provides a more even delivery so that discharge variations are about half those of a duplex pump. This provides a longer life for pump parts, hoses, etc.

• The total weight of a triplex  pump is approximately 70 % of that of a duplex pump with the same capacity, and it also requires less space.

• Triplex  pumps are more accessible than duplex pumps; consequently, maintenance is faster and cheaper.

Downtime incurred due to pump repair is expensive and should be prevented. Frequent pump overhauls are demanding in terms of labor. Therefore, purchasing a generously sized pump is often preferred as this reduces the wear on parts and the required maintenance.

Common operational requirements may vary between 5.4 – 6.7 m3/min at 7,000 kPa (1,200 – 1,500 GPM at 1,000 psi) and 1.35 – 2.25 m3/min at 31,500 kPa (300 – 500 GPM at 4,500 psi). However, from experience, it has been found that the wear of mud pump parts sharply increases when operating the pump at pressures exceeding 21,000 kPa (3,000 psi).

Liner changes can be necessary when the flow rate ranges required during the course of the well cannot be covered by the same liner size, even when several pumps are run simultaneously.