Study On The Influence Factors Of Emulsifying Ability And Stability Of Heavy Oil

In the thermal recovery process,stable emulsion is formed under the action of shear force.Because of the high density,high viscosity,high content of gum and asphaltene of heavy oil,it is difficult to treat heavy oil later.Therefore,the study of complex oil-water relationship and formation mechanism of heavy oil has important enlightenment for solving the difficult problem of demulsification and dehydration of heavy oil.This paper takes four groups of heavy oil samples provided by J oilfield as the research object,and studies the factors affecting the emulsifying ability and stability of heavy oil from two aspects of water phase and oil phase.At the same time,a method for determining the HLB value of heavy oil emulsion in J oilfield was explored.The HLB value was used to determine the number of polar functional groups and asphaltene aggregates on the oil water interfacial film,and the real reason for the difficulty of dehydration of emulsion was explained from the microscopic point of view.The emulsifying ability of heavy oil emulsion was studied by water content inversion point and HLB value.The higher the HLB value,the bigger the water content inversion point,the stronger the emulsifying ability of heavy oil.The emulsifying ability of ordinary heavy oil is higher than that of super heavy oil,and the stability of super heavy oil is higher than that of ordinary heavy oil.It shows that the emulsifying ability of heavy oil is not related to stability.The influence of active substances?gum and asphaltene?in heavy oil on the stability of heavy oil emulsion was studied.It was found that Mg²⁺and Ca²⁺in cations in water phase had a positive effect on the demulsification of heavy oil emulsion.The ability of Mg²⁺to reduce the overall stability of heavy oil emulsion was slightly higher than Ca²⁺.The promotion effect of anions on the stability of heavy oil emulsion was from large to small:HCO₃^->Cl^->Br^-.At the same time,water had a positive effect on the stability of heavy oil emulsion.When the phase tends to be acidic or alkaline,the stability of heavy oil decreases,which is conducive to demulsification.With the increase of the content of colloid and asphaltene in the system,the wetting angle of oil and water decreases,the wettability of oil-water interface is enhanced,the surface tension and strength of oil water interfacial film increase significantly,the time of single droplet breakage of emulsion reaches 100%,and the stability of heavy oil emulsion increases.Based on the study of the influencing factors of the stability and emulsification performance of heavy oil,the bubble equilibrium model of heavy oil under the condition of heavy oil boiling is established from the point of view of thermodynamic equilibrium.The critical temperature of heating demulsification of heavy oil samples is explored.The method of closed heating is used to help the water phase in heavy oil break through the polar covalent bond of active substance in oil phase,and achieve the effect of dehydration demulsification.The method is convenient,effective,green and environmentally friendly,and it has enlightening effect on the development of green dehydration technology for heavy oil in the future.