RIG FLOOR EQUIPMENT

Quintuplex mud pump enables efficient transfer to hydraulic horsepower

The Ellis Williams Engineering Company (EWECO) is on the verge of showcasing its next generation of pumps in the 2008 OTC show. Their expanded offering is for a “Quintuplex” (five cylinder) high-horsepower (1,700, 2,200 and 3,000) continuous-duty mud pump with their patent-pending design of a crankshaft driven by internal herringbone gears. As is the norm with all of the company’s designs, roller bearings are in every position with a true eccentric-type, fully balanced, crankshaft. The crankshaft will have a piston firing order of 1-3-5-2-4 with four main bearings, which isolates all crankshaft loads, unlike a typical triplex, where two eccentrics are always fully loaded between two mains at any given time. The pinion shaft will be driven from both sides by electric motors much like a conventional triplex pump, which allows for true interchangeability on every drilling rig.

Fig. 1. Instantaneous flow rate curves for Triplex and Quintuplex pumps (one cycle of operation).

The pump design innovation provides for a more efficient transfer to hydraulic horsepower by spreading the piston rod loads evenly over five as opposed to three cylinders. This provides for a reduction in piston rod loads approaching 40% compared to equivalent horsepower triplex pumps. This reduction in piston rod loads significantly increases the life of all load components. An additional benefit produced is the reduction of flow variation (proportional to pressure variation) approaching 70% compared to the conventional triplex pump (figure 1), which appreciably reduces the stress and strain on the drill string and its associated MWD and LWD tools. This alleviates the down time of tripping out of the hole to replace damaged measurement tools and improves signal telemetry.

Fig. 2. Schematic drawing of the Quintuplex high-horsepower, continuous-duty mud pump.

All of these benefits are achieved in a pump package that provides a weight reduction of approximately 30% in comparison to an equivalent-horsepower triplex pump, while maintaining a similar or smaller footprint. Additionally, the parts making up the power and fluid ends of the “Quintuplex” pump are all conventional parts used in modern triplex pumps. Therefore, the maintenance aspects for this pump are no different than those associated with triplex pumps with no special tools or training required.