Thermal characteristics study on the gathering and transportation process of crude oil by mixing with hot water

This paper takes the part from actual wellhead production tree to the front end of the gathering pipeline, including the water blending part, as the research object, and constructs physical and mathematical models for simulation calculation. Taking the oil-gas-water three phases as research medium, based on VOF (Volume of Fluid), porous medium is used to describe transformation of waxy crude oil from sol state to gel state, and to explore the influence of water blending on law of flow-heat transfer and solidified oil adhesion during gathering and transportation process. The results show that the water blending can effectively improve crude oil fluidity and reduce phenomenon of solidified oil adhesion (23.83 %–4.49 %) by increasing the temperature (35–44 °C) and flow rate of produced fluid (0.3–0.9 m 3 /h). The increase in water blending temperature and flow rate has a more significant effect on improving the fluidity of crude oil and reducing the solidified oil adhesion. For every 1 °C increase in water blending temperature, the average temperature of produced fluid will increase by about 0.3 °C, and for every 1 m 3 /h increase in water blending flow, the average temperature will increase by about 0.75 °C. However, the increase in water blending temperature and flow rate will also lead to an increase in energy consumption losses (5.83–12.38 W/m 2 ).