Flow Control, Flow Control November 2017

Cover Series Pump Efficiency Increasing pump durability in the oil field A new design for continuous duty By Bryan Wagner Weir Pressure Pumping T he oil field is an incredibly demanding and hazardous environment that is notoriously tough on equipment Todays hydraulic fracturing operations present even greater challenges with longer laterals multi well pads and harsher environmental restrictions As required operating hours and increasing rod loads exceed the capabilities of traditional intermittent duty frac pumps durable and cost effective solutions become imperative to achieve success Historically frac pump designs and the resulting technology have been slow to change in the industry Typically frac pump manufacturers make only incremental improvements to existing designs and those improvements are often limited because of the constraints inherently imposed by the existing footprint they must stay within These limitations translate to performance constraints and greater costs of ownership in the field while rarely addressing customers needs Achieving continuous duty The goal in creating a continuous duty pump was to develop a frac pump that would provide the best durability costefficiency reduced downtime and full rod load operation 100 percent of the time by challenging all previously imposed restrictions When evaluating how to achieve 100 percent runtime understanding the weaknesses of existing equipment was essential The three most common failure modes experienced with frac pumps include lubrication structural rigidity and undersized components Lubrication is of significant concern because lubrication contaminants inherent to mechanical systems affect the life of the power end especially the bearings Lubrication oil becomes contaminated in two primary ways These include contaminants that are generated from internal wearable components through typical wear and tear within the power end and airborne particles and sand that enter the pump on location With respect to structural rigidity the majority of frame failures typically start at the weld Failure occurs for a multitude of reasons including a poor quality weld that is either difficult to reach or does not have the correct weld geometry and design a weld located in a highstress area or a weld that does not follow established industry best practices We found that structural rigidity and alignment could be greatly improved to protect the power end by optimizing the frame design to place welds in low stress areas and to utilize an engineered skid to reduce pump deflection under load Additionally doubling the mounting feet from four to eight created more structural stability Alignment was also improved by stabilizing the gearbox enhancing dimensioning and Continuous duty pump on a trailer All images courtesy of Weir Pressure Pumping 12 November 2017 Flow Control