Molecular dynamics simulation of magnetic field influence on waxy crude oil

Magnetic treatment is a widely used physical treatment technique in oilfields. The influencing mechanism of magnetic field on waxy crude oil has drew much attention in recent years. Molecular dynamics simulation was employed in this paper to study the influence of magnetic field on waxy crude oil. The waxy crude oil model consists of light oil and 24.9% by weight of paraffin. The simulation results showed that the density of waxy crude oil model firstly decreased and then increased with the strengthening of magnetic field intensity, while the diffusion coefficient increased in low magnetic field intensity and decreased in high intensity. Viscosity was calculated by Rouse Model. The reduction of viscosity only appeared within a specific range of magnetic field intensities, mainly concentrated on the low intensities. The viscosity increases when the range is overstepped, which is supposed to be the reason of the unstable effects of magnetic treatment. The aggregation of paraffin molecules in magnetic field was proved by analysing the radial distribution function. The analysis of energy represented that the magnetic field had greater influence on molecular morphology than distances between molecules. The simulation results provide micro-perspective of waxy crude oil in the presence of magnetic field, which help to offer the mechanism explanation of magnetic treatment effects. (C) 2017 Elsevier B.V. All rights reserved.