Surfactant and Friction Reducer Interaction in High Salinity Slickwater Fracturing

Abstract

Slickwater fracturing has been phenomenally successful in unconventional shale formations due to their unique geomechanical properties. Nevertheless, these treatments consume large volumes of water. On average, hydraulic fracturing treatments use up to 13,000,000 gallons of water in unconventional wells. In an effort to reduce the use of freshwater, research has focused on developing friction reducers (FR) that can be used in high salinity brines such as seawater and produced water. However, commonly used friction reducers precipitate in high salinity brine, lose their friction reduction properties, and cause severe formation damage to the proppant pack. Consequently, this work proposes the use of common surfactants to aid the FR system and achieve salt tolerance at water salinity up to 230,000 ppm. This paper will (a) evaluate five surfactants for use in high salinity FR systems, (b) evaluate the rheological properties of these systems, and (c) evaluate the damage generated from using these systems. Four types of tests were conducted to analyze the performance of the new FR at high salinity brine. These are (a) rheology, (b) static proppant settling, (c) breakability, and (d) coreflood tests. Surfactants with ethylene oxide chain lengths ranging from 6 to 12 were incorporated in the tests. Rheology tests were done at temperatures up to 150°F to evaluate the FR at shear rates between 40-1000 s-1. Proppant settling tests were performed to investigate the proppant carrying capacity of the new FR system. Breakability and coreflood tests were conducted to study the potential damage caused by the proposed systems. Rheology tests showed that using surfactants with high ethylene oxide chain length (>8) improved the performance of the FR at water salinity up to 230,000 ppm. Anionic surfactants performed better than cationic surfactants in improving FR performance. The ammonium persulfate was used as a breaker and showed effectiveness with the proposed formula. Finally, the retained permeability after 12 hours of injecting the FR was over 95%. This shows that after using this system, the productivity of the formation is minimally affected by the new FR system. This research provides the first guide on studying the impact of using different ethylene oxide chain lengths of surfactants in developing new FR systems that can perform well in a high salinity environment. Given the economic and environmental benefits of reusing produced water, this new system can save costs that were previously spent on water treatments.

Review on High-Temperature-Resistant Viscoelastic Surfactant Fracturing Fluids: State-of-the-Art and Perspectives

“…Multistage hydraulic fracturing measures can even consume up to 16 million gallons of water. 80 The transportation and on-site treatment costs of water are very high. In addition, due to the low viscosity of the fluid (close to the viscosity of water), its proppant-suspension capacity is not as good as that of traditional fracturing fluids, severely limiting the delivery of proppant to the fracture tip.…”

“…But 40000 to 60000 gallons of water for fracturing treatment are required due to the high pumping speed. Multistage hydraulic fracturing measures can even consume up to 16 million gallons of water . The transportation and on-site treatment costs of water are very high.…”

“…But the cationic FRs are usually more expensive than anions. The viscosity and salt resistance of HVFR fluids are improved by adding cross-linking agents and surfactants. ,, The FRs are not suitable for high-temperature reservoirs. According to the research of Biheri et al, the anionic FRs decreased their viscosity to 5 mPa·s at 95 °C and a shear rate of 100 s –1 .…”

Fracturing Fluid Polymer Thickener with Superior Temperature, Salt and Shear Resistance Properties from the Synergistic Effect of Double-Tail Hydrophobic Monomer and Nonionic Polymerizable Surfactant

“…In general, water-based fracturing fluids such as guar gum, synthetic polymers and viscoelastic surfactants are the most commonly used types [ 3 , 4 ]. Nevertheless, guar gum lacks thermal stability and produces a large amount of residue upon breaking, which has a negative impact on productivity [ 5 , 6 ].…”

Preparation and Performance Evaluation of a Variable Viscosity Friction Reducer Suspension with High Salt Tolerance and Low Damage

“…Polymer friction reducers can be categorized into powder friction reducers and emulsion friction reducers based on their morphology. Due to their convenient storage, low production cost, high temperature and salt resistance, and small dosage, powder friction reducers are preferentially used in oilfield applications. − Emulsion friction reducers also have unique advantages such as a fast dissolution rate, strong dispersibility, and continuous in-line mixing. − However, these two kinds of friction reducers also exhibit some problems to be solved in the application process. For example, powder friction reducers suffer from slow dissolution, long mixing time, and complex mixing equipment, which restrict the supply capacity of slickwater and even affect the process of fracturing.…”