Effects of Alternative Water Sources on Formation and Proppant Pack Damage Reduction Properties of Near-residue-free Fracturing Fluid

Abstract

This paper examines how the use of high-salt-content waters (i.e., produced and flowback water) in conjunction with a recently developed, virtually residue-free (res-free) hydraulic fracturing fluid affects the cleanup properties of the system. The res-free fluid system is designed based on a naturally low residue polymer that, when breaking, causes significantly less damage to the formation and proppant pack compared to conventional guar-based fracturing fluids.Since its introduction, guar-based fluid technology has grown to dominate the hydraulic fracturing industry because of its reliability and cost-effectiveness. However, guar gum contains a significant amount of insoluble residue that is not removed during its processing. The residue can cause damage to both the proppant pack and hydrocarbon-bearing formation when the broken fluid is flowed back following the fracturing treatment. This damage can impair hydrocarbon flow from the formation and through the propped fracture, resulting in lower production over time. The res-free fluid offers better cleanup when breaking than guar-based fluids; therefore, it offers significantly higher proppant pack conductivity and formation permeability in laboratory testing.The res-free polymer exhibits sensitivity to certain ions present in the solution, both in terms of gel hydration and crosslinking behavior. Depending on the ions present in the water and their respective concentrations, manipulation of the crosslinked res-free fluid system chemical formulation can mitigate these effects and achieve a stable, highly viscous fluid suitable for hydraulic fracturing. This paper investigates whether the necessary reformulations impact the regained permeability and conductivity of the fluid system. Rheological data demonstrating how the reformulated fluid compares to standard formulations is presented. Additionally, test results are presented highlighting the effects of alternative water sources on res-free fluid regained permeability and conductivity data.The use of produced and flowback waters for fracturing operations can substantially reduce both the economic and environmental impact of fracturing operations. The combination of the res-free fluid's ability to use these water sources and its excellent damage-reducing properties provides a system with significant advantages compared to conventional technologies in many applications.