Managing Friction Pressures to Reduce Fuel Consumption and Emissions for a Fracturing Fleet

Abstract

Friction pressure has always been a limiting factor for placing water and proppant during a hydraulic fracture treatment. Mitigating friction pressure has relied heavily upon using chemicals to reduce the friction and ultimately the hydraulic horsepower required to complete the job. Costs to reduce friction pressure have always been associated with the type and amount of friction reducer (FR) used. Best practices being associated with using as little as necessary to achieve the treatment. On the contrary, utilizing the minimum amount of FR can increase overall costs for treatment due to increased fuel usage which leads to increased emissions. As the industry strengthens focus surrounding Environmental, Social, and Governance (ESG) and optimizing costs for well completions, this paper discusses a unique approach to decrease friction pressures, reduce fuel usage, and ultimately optimize the completions treatment and associated cost. Using friction models based on laboratory data and fuel consumption models built from flowmeter measurement during treatment, various pumping scenarios can be combined to estimate fuel consumption for diesel and dual fuel engines at varying FR set points. Incorporating a friction pressure model allows for treating pressure to be estimated and used within the fuel consumption model. Providing commodity costs and emissions factors allows for understanding of total cost and emissions changes with increased FR usage. Varying FR usage, treatment rate, and number of pumps gives room for optimization and understanding of the variables that demonstrate the greatest effect on total costs and emissions. Increasing FR leads to decreased treating pressure and required hydraulic horsepower which reduces fuel consumption and generated emissions. The cost reductions depend on commodity prices as well as the types of fuel used (diesel or a blend of diesel and natural gas). Utilizing current market pricing, an increase in FR concentration from 0.4 gal per thousand to 0.6 gal per thousand resulted in a decrease in overall costs of nearly 5% per pumping hour and emissions reductions of up to 15.9%. By changing the conventional wisdom of lowering costs by reducing chemical concentrations to optimizing based on the bigger picture, emissions, treatment costs, and equipment utilized are reduced. Additional horsepower can be utilized for backup and further reduce non-productive time and increase efficiency. With proper planning and understanding, this solution will provide a more efficient environment for completions.