Development and performance evaluation of a novel SiO2-enhanced seawater-based temperature-resistant clean fracturing fluid

Hydraulic fracturing has been proposed as a potential technology for the development of low-permeability oil reservoirs and also has promising application prospects offshore. In this study, a novel SiO 2 -enhanced seawater-based temperature-resistant clean fracturing fluid was formulated. The fracturing fluid main agents, additives and reducing agents were screened. Besides, the physical and chemical properties (rheology) as well as application (i.e., sand-carrying, gel-breaking, dynamic fluid loss, dynamic damage and anti-swelling) performance of the proposed SiO 2 -enhanced seawater-based temperature-resistant clean fracturing fluid were systematically investigated. It was revealed that 3.2 wt% AASB-17+1.92 wt% NaSal+0.1 wt% SC-107+0.1 wt% TS3 was the optimal SiO 2 -enhanced seawater-based clean fracturing fluid system formula. The SiO 2 -enhanced seawater-based temperature-resistant clean fracturing fluid exhibited remarkable rheological characteristics , the temperature and shear resistance was increased by 28 %, with a maximum temperature resistance of 90ºC. This system can be applied to the fracturing development of most oil reservoirs in the Bohai Bay. In addition, the presence of SiO 2 nanoparticles significantly improved the sand-carrying properties of the proposed clean fractuirng fluid system. The experimental results also suggested that the SiO 2 -enhanced seawater-based temperature-resistant clean fracturing fluid showed excellent performance of shear recovery (fixed shear viscosity recovery rate was 100 %), gel breaking (30 min,1 mPa·s), filter loss ( C w =4.75×10 −4 m/min 1/2 ), anti-swelling (anti-swelling rate was 77.78 %) and salt tolerance. This study provides fundamental technical support for the application of SiO 2 -enhanced seawater-based temperature-resistant clean fracturing fluid in offshore fracturing.