Objectives/Scope: High-viscosity or high-efficiency friction reducers have become increasingly popular in North American unconventional plays over the past years as operators recognize the operational and economic advantages that the fluid system offers. Benefits associated with HVFR usage vary depending on the need and application. They range from improving operational performance by reducing equipment footprint and chemicals needed to meet job design specs; reducing treatment pressure, stage duration and horsepower; reducing the risk of screen-outs; reducing water consumption; mitigating frac bashing; improving proppant pack conductivity, which is linked to production enhancement; and the list goes on.
Methods, Procedures, Process: More than a dozen HVFR products were evaluated for effectiveness by merging lab testing with operational field trial results to provide a recommendation on product usability to deliver the best value to the operator. Extensive lab test results were used to guide the design of the HVFR loading and usage, primarily depending on treatment rate and proppant concentration to ensure sufficient suspension and optimal placement without over-capitalizing. Treatment pressure response is considered the best real-time driver to guide HVFR loading when the guidelines based on slurry rate and proppant concentration prove to be insufficient.
Results, Observations, Conclusions: Delaware Basin case studies are presented to highlight the effect that the selected HVFR fluid system has had on improving operational performance and reducing completion costs. The case studies highlight the fluid system's effect on well productivity, offering additional guidance on preferred well development scenarios.
Novel/Additive Information: This paper showcases a systematic workflow for bridging the gap between extensive lab testing and field trials of HVFR fluid systems to present the operator with an improved scientific methodology of applying HVFR fluid systems depending on well development needs.
High-Viscosity Friction Reducers (HVFR) are polyacrylamide-based additives that are capable of providing a greater reduction in pipe friction at lower chemical concentrations than slickwater, linear, and crosslinked gel fluid systems, primarily because of their higher molecular weight. They also provide improved proppant transport at higher proppant loadings, also known as PPA (pounds of proppant added per gallon of clean fluid volume) during hydraulic fracturing treatments compared with conventional slickwater fluid systems. The effectiveness of the HVFR fluid systems is a result of the concentration of the polyacrylamide, with improved performance with increased molecular weight. The improved viscoelasticity results from a reduction in shear, so the polymer chain entanglement enhances proppant transport into the fracture. Two of the most critical variables in hydraulic fracturing design, pipe friction and proppant concentration, are addressed with a single product solution, which when utilized effectively, can bring about significant technical, operational, and economic improvements to the fracturing job.