Abstract: A heavy crude oil with high salt content is due to the high mineralization of its associated water. This crude oil also has high density, viscosity, asphaltene content, and solid particle content, which cause dehydration difficulties. As a result, the low-salinity water injected during the electric desalination process cannot be separated effectively, leading to high salt and water contents in the oil after electric desalination, which affects the enterprise's safe production.By analyzing the properties of this heavy crude oil, it was found that the high condensation degree of asphaltene and the existence of solid particles are the main factors hindering desalination. Accordingly, two demulsifiers, RPD-73X and RPD-73Y, were developed. Their industrial application reduced the salt and water contents in the oil after electric desalination. Industrial test results indicate that after three-stage electric desalination, the average salt mass concentration of the treated crude oil is 28.5 mgNaCl/L, a 41.4% decrease from the pre-test level, while the water mass fraction decreases by 20.1%. These results show that the developed demulsifiers are effective for desalination and dehydration.

Key words: high salt crude oil, desalination, demulsification, demulsifier