Numerical study on the thermal characteristics and its influence factors of crude oil pipeline after restart

Mathematical models and numerical approaches are used to understand thermal system coupling by the crude oil, pipeline, and soil during the pipeline restart process. Eighteen simulation cases were used to investigate the heat transfer characteristics of a crude oil pipeline. It is concluded that, after restart, the pipeline can be divided into three regions with temperature profiles and dominant mechanisms varying in each region. Two stages have been presented after restart with different temperature evolution features. In addition, the effects of flow rate, outlet temperature, as well as the burial depth and the thickness of the insulating layer on the thermal characteristics of oil pipeline are analyzed in detail after restart. The impact of flow rate on the flow assurance of a pipeline after restart is substantial and much larger than that of the outlet temperature, which has generally received more attention.