The Methods And Mechanism For Reducing Viscosity Of Heavy Oil By Emulsifying

With conventional oil reserves that can be found less and less,heavy oil will become the important energy resources in the 21st century .Due to high colloid and asphaltene content, the viscosity of heavy oil is high.So it is much more difficult to drill for heavy oil than regular oil.The viscosity reduction by emulsifying of heavy oil is researched and used the most widely in chemical visbreaking.First in this paper, through lab experiments,the optimum formula is obtained by orthogonal tests, and emulsifier concentrations, oil-water ratio, salinity, temperature on the effect of emulsified heavy oil are studied systematically.Then CaoQiao and GuDao heavy oil is chosen to reduce the viscosity, using three common methods,including heating,solvent, emulsification .After that effects of the viscosity reducer on oil-water interfacial tension , and synergistic enhancement of the mixture of surfactants is studied ;micro photos of the emulsion is also observed. At last the homogeneous cores are flooded by water dissolved with viscosity reducer.The experimental results show that: the viscosity of heavy oil is depressed by more than 90% , and dehydration rate of the emulsion is also more than 90% at 50℃. The higher viscosity reducer concentration is ,the lower emulsion viscosity is ;but when the concentration increases to a certain extent, emulsion viscosity becomes no longer change; the higher viscosity reducer concentration is ,the more stable the emulsion is ; the bigger the oil-water ratio is, the higher emulsion viscosity is ; the salinity is bigger ,the effect of viscosity reducer for heavy oil becomes worse and the emulsion is less stable ; while increasing temperature , the emulsion viscosity is slightly lower. Compared to heating and solvent , the emulsification can effctively reduce viscosity of heavy oil, the viscosity is depressed by more than 90% . Viscosity breaker can reduce water/crude oil interfacial tension to 10-2mN/m,which is in favor of emulsifying heavy oil and impoves the stability, the mixture of surfactants has the effect of synergistic enhancement,which improves the surface activity on the whole ; through micro observation ,heavy oil is clearly emulsifyed to form a number of small O/W emulsion droplets.When adding the active water dissolved with viscosity reducer to heavy oil,the oil recovery could be higher.