Research Into Rheological Behaviour And Adding Deprssant Pipeline Transportation Technical Program For Waxy Crude Of Liaohe

Over 80% of the crude in China is waxy crude, of which the rheological behaviour and the corresponding pipelinepipeline technology are being the subjects in domestic researches on oil & gas storage and transportation for a long time. Being of poor fluidity at the normal temperature, heating transporting technique is commonly adopted. This technique, however, is of deficiencies in throughput, energy dissipation, facility cost, management expenses as well as safty etc. Adding depressant into the crude can effectively solve these problems, as the wax crystal morphology of soilid hydrocarbon is changed from the priginal spatial network structure to low the pour point and the viscosity and further improve the rheological behaviour at lower temperature. However, with the effects of high-speed shearing and repeated heating during long-distance pipe conveying, the rheological behaviour is redegraded. In addition, since the waxes condensate near the pour point as the temperature dorp caused by the shutdown and a gelling netted texture is formed, the crude is of complex thixotrophy. According to the energy saving and consumption reduction that initiated in the 11th Five-year Plan for Oil Industry as well as the Oil-Gas exploration and development of Huabei Oilfield, the researches in this paper is not only can offer basic datum for the optimization of pipeline transport design, but also of great theoretical and practical significance for waxy crude production.Based on the theories of rheology, Non-Newtonian Fluid Mechanics, petroleum chemistry, crystallography and pipeline technology etc. and sampling Huabei crudes, experimental indexes and programmes are drew out, integrating the oil properties and parameter analysis; in terms of the macro analysis of continuum mechanics, substantial experiments are conducted with HAAKE RS600 rotational rheometer and the rheological equation as well as the viscosity-temperature equation are further developed with tested rhrogramme and viscosity-temperature curve, respectively. Beased on the researches on thixotropic mechanism and thixotropy fluid property, hysteresis loop curve, structure failure and viscosity build-up curve as well as shear stress decrement curve for one type oil are first present in this paper. According to the theoretical researches and testing results, a novel thixotropy equation withτ=τ_∞e^b/(t+c) pattern, which is of hi-accuracy, few parameter and simplicity, is developed. Considering the influence of various parameters on rheological behaviour, depressant adding condition is optimized and experimental evaluation on BEM-5P is conducted, which further unrip its mechanism on the Huabei crude. A corresponding viable pipe transportion programmel is also recommended.