Delineating and Quantifying the Hydraulic Fracturing Energy System

Current hydraulic fracturing strategies require a significant investment of resources, time, and capital to warrant well productivity. As a result, it has become the crux of asset development in unconventional formations. Given that this technique has been in full force for almost two decades, the optimization strategies couldn't be more varied than they are today. Part of the problem exists in completion teams discretizing and optimizing individual facets while ignoring their impact on the entire system. To the authors’ knowledge, this paper is the first to present a comprehensive energy analysis of the hydraulic fracturing process. During hydraulic fracturing, energy transfer originates from the horsepower equipment used to inject a unit volume of fluid, containing a certain volume fraction of proppant, into the wellhead. Surface energy consumption is defined as the horsepower deployment integrated over time. As this unit volume traverses down the wellbore and into the formation, it is assisted by gravitational potential energy, which supplements its energy budget but must overcome the friction from the pipe, perforations, and tortuous near-wellbore zone, which act as energy losses. Subtracting energy losses from the total energy input results in the effective energy delivered to formation. With the tools outlined here to calculate the effective energy and energy efficiency, teams can vet and optimize their completion strategies to maximize energy delivered to the formation and/or improve capital efficiency. These metrics are sensitive to most of the variables involved in well completions and provide an understanding of the influence every decision has on the complete hydraulic fracturing system.