Performance evaluation of a novel CO2-induced clean fracturing fluid in low permeability formations

Abstract

After the limitations of polymer-based fracturing due to poor clean-up property during flowback after fracturing treatment, viscoelastic surfactant (VES) received very huge attention in the last three decades, especially in low permeability reservoirs. In this study, a Novel CO 2 -induced clean fracturing fluid (SDS-TMTAD-CO 2 ) is formulated with simulated formation water (23,003 mg L −1 ) after optimization experiments according to the proposed parameters (i.e., 70 °C, economical, easily preparation, and environment-friendly). The results of rheological experiments show that the apparent viscosity of the fracturing fluid system increases to a certain extent under high salt conditions and possesses sufficient self-healing property against high shear tolerance. At different temperatures (25, 50, and 70 °C), the thermodynamic properties, fluid viscoelasticity, and proppant carrying capacity meet the requirements of the fracturing fluid industry standards. After adding kerosene (0.02 mol L −1 ); the gel breaking fluid viscosity (3.2 mPa s), anti-swelling rate (91.3%), and interfacial tension (2.3 × 10 −2 mN m −1 ) are holding promising conditions during the flowback period, clay swelling, and residual oil saturation, respectively. The filtration and core damage experimental results meet the national industry standard for fracturing fluids. The SEM results show that the fluid system after reaction forms a unified adsorption film on the core surface. Hopefully, this fluid system will be proved as a good candidate by means of excellent proppant transportation ability, anti-swelling, easy gel structure breaking, low filtration, and less formation damage in low permeable formations with an increase in productivity. • Easy preparation of an economical and environment-friendly CO 2 -induced clean fracturing fluid system (SDS-TMTAD-CO 2 ). • Rheological and functional performances of the system meet the “SY/T 6376-2008, SY/T 5107-2016, and SY/T 5971-2016” standards. • Can fracture the low permeable formations with less filtration and low formation damage.