Towards Freshwater Conservation: Seawater Based Dry Friction Reducer for Slickwater Fracturing

Abstract

Abstract Hydraulic fracturing with slickwater has been widely used in development of unconventional reservoirs. One of the key components in slickwater formulation is friction reducer (FR). Regular slickwater fracturing operation requires huge amount of low-salinity water, which poses great challenges in areas with freshwater shortage. This study aims to develop slickwater formulation using high performance dry friction reducer (DFR) that can be fast dissolved in seawater to reduce freshwater usage. The DFR products were evaluated in several key aspects, including hydration time, viscosity, friction reduction, and flow-back performance. Hydration time of the DFRs in synthetic brine was measured by viscosity monitoring. The viscosity was measured using rheometer at 160°F. Friction reduction of DFR samples was characterized by industry standard friction flow loop system. Formation damage evaluation was conducted by measuring permeability of core plug before and after slickwater injection at 270°F. The DFRs are cost effective and easy for logistic handling under harsh environmental conditions comparing to liquid and emulsified FRs. To ensure the successful use of DFR with seawater, the evaluation on polymer hydration time was conducted. Viscosity measurements were used to quantitatively compare the hydration time for different DFR samples. An optimum DFR candidate was able to totally dissolve in seawater in 1 minutes, and similar hydration performance in brines with salinity range from 58,000 ppm to 315,000 ppm. The friction reduction can reach 74% in 2 minutes, at low concentration around 2 pounds per thousand gallons (pptg). The relatively high viscosity of slickwater solution ensures the proppant carrying during hydraulic fracturing. A slickwater formulation containing several components was also developed using seawater. Because of the high salinity, the compatibility of different components was investigated, the formulation was able to reach high retained permeability ratio over 85%, The excellent performance of the slickwater makes it promising for field trial. The seawater suitable DFR based slickwater was developed to perform properly under unique environmental conditions. The excellent performance of DFR based chemicals makes this slickwater fracturing technology available for field operations and assist the conservation of freshwater.