Study On Transportation Technology Of Viscosity-Reducing Of Heavy Crude Oil With Supercritical CO₂

When the temperature of CO₂ higher than 31.26℃and the pressure of it higher than 7.29MPa, CO₂ can reach supercritical state. It has the property of liquid and gas which has the capacity of high diffusion coefficient and strong dissolving power. When certain range concentration of supercritical CO₂ was injured into heavy crude oil, It can permeate into heavy crude oil quickly, and decrease the viscosity of heavy crude oil heavily. This technique has important meaning for reducing viscosity and transportation of heavy crude oil.At first, the feature of heavy crude oil and the viscosity-reducing mechanism of supercritical CO₂ were studied in the article.The writer studied dissolving features of CO₂ that was into heavy crude oil in different of pressure and temperature. It has been discovered that when the temperature reach 80℃and the pressure reach 20MPa, the viscosity-reducing result of heavy crude oil is best. Take advantage of circle experiment device, the flowing deformation features of heavy crude oil was studied when the supercritical CO₂ was dissolved into heavy crude oil. Also mathematical models with flowing regular pattem of supercritical CO₂ that dissolved into heavy crude oil was builded. The actual measurement and calculation pressure-reducing results are analyzed and the mean relative error is 3.38%, So the pressure drop of pipeline can be obtained by calculation.Taking account of the influence of transferring press and transferring temperature, Under the conditions of the experiment, The optimum decision of the viscosity-reducing of supercritical CO₂ is temperature 90℃,pressure 20MPa.