Nano-SiO₂/hydroxyethyl cellulose nanocomposite used for 210 °c sedimentation control of petroleum drilling fluid

Cellulose derivatives are widely applied in the field of oil and gas exploration. However, this kind of natural polymers always shows poor temperature resistance due to their organic nature. To improve the temperature resistance of hydroxyethyl cellulose (HEC), inorganic nano-SiO2 was introduced onto HEC polymer chains through the silylation coupling technique. And Fourier transform infrared spectrum (FTIR), X-ray photoelectron spectrum (XPS), and thermogravimetic analysis (TGA) were used to analyze the nanocomposite. As a result, nano-SiO2 particle is chemically coupled onto hydroxyethyl cellulose molecule, and nano-SiO2/hydroxyethyl cellulose nanocomposite (RJ-HEC) shows excellent thermal stability comparing with HEC polymer. In experiment, thermal aging tests were utilized, and test results suggest that nano-SiO2/hydroxyethyl cellulose (RJ-HEC) nanocomposite can be utilized as thickening agent of water-based drilling fluid, which shows improved rheology stability at 210 °C and excellent salt (NaCl) tolerance.