稠油降黏减阻及其流变学性质

Viscosity/drag reduction and rheological properties of heavy crude oil

针对稠油的管道输送问题,从降黏减阻的角度开展研究工作。采用管流实验和流变仪测试相结合的方法,探讨了升温、充气和掺混稀油对稠油降黏减阻的作用效果。结果表明:对于具有牛顿流体本构关系的稠油,升温和掺混稀油均具有明显的降黏减阻作用,其减阻效果呈指数关系衰减;充气减阻仅在大流量、低温度的条件下发生,且黏度的降低幅度不大。针对掺稀油减阻,提出了一个指数关系式对混合黏度进行预测,该公式是稠油黏度、稀油黏度及稀油体积含率的函数,通过与实验数据进行对比,证明了其预测精度较高。

In this paper, research is conducted in respect of viscosity/drag reduction to solve the problems in heavy oil pipeline transportation. Pipe flow experiment and rheometer test are used together to reveal effects of heating, gas injection and dilution on heavy oil viscosity/drag reduction. Research results show that, for the heavy crude oil with Newtonian fluid constitutive relation, both heating and dilution have significant impacts on viscosity/drag reduction, which may decrease exponentially. For gas injection, drag reduction only happens under the condition of large flowrates or at low temperatures, but viscosity does not decrease greatly. Furthermore, for the dilution, an exponential equation is developed to predict viscosity of heavy crude oil and light oil mixture. The equation is a function of heavy oil viscosity, light oil viscosity and volumetric content of light oil. Comparison with test data may confirm accuracy of the prediction deducted by using the equation.