Recyclable surface-functionalized Fe3O4 particles for heavy oil viscosity reduction

Abstract

The main objective of this study is to design and apply surface-functionalized Fe3O4 particles to reduce the viscosity of heavy oil from Shengli Oilfield and to study the mechanism of viscosity reduction. Fe3O4 particles were synthesized by the co-precipitation method and modified with 3-propyl trimethoxysilane (KH570), oleic acid (OA), and triethoxyvinylsilane (A151) to obtain Fe3O4–KH570, Fe3O4-OA, and Fe3O4-A151, respectively. The particles were characterized through Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), and Dynamic Light Scattering (DLS). The contact angle and dispersion stability in kerosene were evaluated. The average net degree of viscosity reduction (%DVR) of Fe3O4–KH570, Fe3O4-OA, and Fe3O4-A151 on Chenping heavy oil at 50 °C is 27.91%, 51.27%, and 29.44%, respectively. The surface functionalization of asphaltene aggregates, the improvement of lipophilicity, and dispersion stability after destruction are the main reasons for the decrease of heavy oil viscosity. Particle size and the ability to adsorb asphaltenes have no direct relationship with DVR. It was also confirmed that the modified Fe3O4 particles can effectively recycle from the oil under a magnetic field. This work developed a kind of recyclable Fe3O4 particles for heavy oil viscosity reduction, which was beneficial to lower the cost in heavy oil recovery.