The Thermal Simulation of Restoration Segment of Buried Hot Oil Pipeline during the Periods of Shut Down and Restart

The hot oil pipeline of northeast has been worked for 30 years, and it´s using life has exceed the designing life. Corrosion protective covering breakage and oil scattering are very common appearance, so it urgent needs to be repaired in the operational mode of shut down. When hot oil pipeline is repaired in the operational mode of shut down, the bared pipe of excavation segment directly contact with air, heat loss and temperature drop are very great, which affect the changing of oil viscosity and restart. For the whole buried oil pipeline, the segment of maximal temperature range is the excavation segment. Now the researches about temperature drop in shut down all focus on the temperature variation of the whole buried pipeline. This paper established the astable computation module of oil temperature in excavation segment during the periods of shut down and restart for the first time based on the research of the run in stable state, and simulated the curve of temperature variation, at last analysed the alternation regularity of oil temperature in excavation segment during the period of shut down with different repair parameters. The research of this paper can decline the energy consumption of service in oil field.