Study On The Techniques And Theories Of Gathering And Transportation Viscous Oils As Emulsion

It is one of the effective methods to solve the problems of viscous oils transportation for the oils to be transported by viscosity reduction with emulsification. A viscosity reduction method of reversed phase emulsification was presented for the characteristic of water-in-oil emulsion with high vosicosity formed easily by the viscous oil in Xintan oil field. The rheological properties, stability, microstructures and their main effect factors were analyzed, and a very efficient viscosity reducer VRXT01 fitting Xintan's water-in-oil emulsion was developed and the mechanism of viscosity reduction of viscous oil emulsification and drag reduction of the emulsion pipeline were discussed by means of rheological test, dynamic and static stability evaluation and image analysis. Based on the laboratory experiments, the simulating test in loop pipe and field test of viscous oil transportation as emulsion were conducted. The results show that: (1)there is a certain match law between emulsifiers and the components of oil and water, and the major factors affecting emulsion stability and apparent viscosity include the properties and ratio of oil and water, the type and content of emulsifiers, temperature and the mixing mode and so on; (2)Xintan's water-in-oil emulsion and its reversed phase emulsion have non-Newtonian behavior within the investigated temperature and obey the power law mode; (3)the apparent viscosity of Xintan's water-in-oil emulsion can be reduced from about 8000mpa.sto below 100mpa.s at 50℃ and 51s-1 under a certain emulsifying conditions andthe viscosity reduction rate is more than 99 percent; (4)the apparent viscosity of the emulsion is less than 50mPa.s at 30℃ and can successfully realize the viscous oil transportation as emulsion under the simulated operation conditions of the pipeline from the gathering station Kendong 451 to the processing stationGudong 4 and there is no any difficulty for the static emulsion lasting 8 hours at 30℃ to be restarted; (5)the viscous oils transportation as emulsion was successfully realized in the production pipeline without two middle heating and bumping stations about 24km long from Kendong 451 to Gudong 4, and the mean total pressure drop is reduced from 1.397Mpa to 1.051Mpa and the drag reduction rate is 59.7 percent under the conditions of 300ppm additive and outlet temperature from 50℃ to 57℃ and there is no any difficulty for the emulsion to be demulsified and dehydrated; (6)the viscosity reduction of water-in-oil emulsion and the drag reduction of its transportation are mainly attributed to VRXT01 changing the inside and outside phase of the emulsion and the wetting properties of pipeline wall.