Effect Of Microstructure On Wax Deposition Of Water-in-oil Emulsion

Water-in-oil emulsion is a two-phase dispersion system whose wax deposition process is more complex than single-phase crude oil.The presence of dispersed water droplets will affect the diffusion of wax molecules and wax crystal particles deposition process.Therefore,it is very important to study the wax deposition law of water-in-oil emulsion.The microstructures of emulsions are quantitatively characterized by the microstructure parameters such as Shad average diameter,dipersity and particle size distribution index(PDI).The quantitative relationship between micro-characteristics and rheological properties(such as yield stress,viscosity and gelation)of Daqing oil emulsion is studied.The influence of water content,oil-wall temperature difference and stirring speed on wax deposition is studied by cold finger device.Wax deposition rate and wax diffusion coefficient decrease with the increase of water content and stirring speed,and increase with the increase of oil-wall temperature difference.Based on the micro-parameters of the emulsion,the formula for calculating the diffusion coefficient of water-in-oil emulsion is proposed,which involves crude oil viscosity,emulsion viscosity and particle size distribution index.The average deviation is 4.75% compared with the experimental values.The results of comparison with the data in literature is good,the average deviation is 12.42%.