A Novel and Cost-Effective Dry Friction Reducer Based Slickwater for Unconventional Reservoir Stimulation

Abstract

Abstract Slickwater has been the most widely used fracturing fluid in stimulation of unconventional reservoirs. Friction reducers (FRs) are one of the key components in a slickwater formulation, while dry FRs (DFRs) are gaining more attention because of logistical and operational benefits. This study aims to develop a cost-effective DFR based slickwater that dissolves quickly with low chemical dosage for slickwater fracturing. Hydration time of the DFRs in synthetic brine was measured by viscosity monitoring. The rheological properties were measured using rheometer. Friction reduction performances of the DFR samples were characterized by an industry standard flow loop apparatus. The breakability experiments were conducted at 82°C by mixing breakers with DFR solution, and broken fluid was tested on rheometer and gel permeation chromatography (GPC). Flow-back performance of slickwater was estimated using proppant packed chromatographic column. Formation damage evaluation was characterized by measuring core permeability before and after slickwater injection at high temperature. DFR powder usually contains two times more effective content than liquid friction reducer with same weight, which significantly reduces logistical costs in operation. To tackle the possible lumping of DFR during hydration, a comprehensive evaluation on polymer hydration time was conducted. Viscosity measurements were used to quantitatively compare the hydration time of different DFR samples. An optimum DFR candidate was able to totally dissolve in synthetic brine in less than 2 minutes. The friction reduction can reach up to 75% in 2 minutes for the DFR solutions, and even at a concentration as low as one pound per thousand gallons (pptg). With the addition of flow-back enhancer and polymer breaker, the formation damage of slickwater to core plug is reduced to less than 12%. In the end, one slickwater formulation was developed, with excellent performance in compatibility, viscosity, flow-back percentage, formation damage restoration and friction reduction, which was recommended for field operation. A novel DFR based slickwater was developed to overcome DFR's hydration and compatibility issues. Analysis on the performance of DFR based chemicals makes this cost-effective slickwater fracturing technology available for field operations.