Magnetic field effect on apparent viscosity reducing of different crude oils at low temperature

The viscosity of crude oil is extremely high at low temperature and transporting crude oil through pipelines consumes a lot of energy. Reducing the viscosity of crude oil can save a large amount of energy and have significant economic benefits. In this study, the viscosity reduction effects of four types of crude oils by applying an external magnetic field at 5 degrees C was studied. Experimental results show that at low temperature, high intensity magnetic field can not only reduce the viscosity of high waxy crude oil, but also decrease the viscosity of heavy oil with high content of heavy components. When the maximum magnetic flux density is 1T, the maximum viscosity reduction rates of the four crude oils was 13.29%, 26.88%, 14.44% and 18.72%, respectively. An empirical formula was proposed to describe the variation of crude oil viscosity with magnetic field and to predict the existence of viscosity reduction limit. The mechanism of viscosity change is ascribed to the change of microscopic aggregation of suspended particles in oil. The thickening phenomenon of some crude oils under magnetic field is due to the polarized chains of aggregation crosses the upper and lower plates. This research shows that it has great potentials of utilize magnetic field viscosity reduction to help crude oil pipelines transportation at low temperature.