Study And Evaluation Of Oil Pipeline Service Performance In Permafrost Area

In the paper, the service performance of pipeline is studied for the China-Russia oil pipeline "Mohe-DaQing" through field investigation, theoretical research, numerical simulation method, etc. The main conclusions are as follows:The change rule of soil temperature distribution around the pipeline is study based on the monitoring data of "Mohe-DaQing" oil pipeline. The pipeline effect on frozen soil temperature around the pipeline under different conditions is summarizes.The frozen soil temperature change in next50years is studied by numerical simulation. The different types of frozen soil, heat preservation measures, the depth of pipeline buried, oil temperature are all considered in simulation. And the change rule of the permafrost table, high temperature zone around pipeline is got.A coupled heat-fluid transport mode for frozen soil is established based on the water flow in unsaturated soil. The model is proven to be reasonable through the comparison of the real test and the model simulation. The adaptive time step method which greatly improves the computing efficiency of the program was proposed. The model is used in preliminary analysis of temperature, water, and stress change around the pipeline.In the direction of parallel the pipe, stress and deformation of the pipeline is studied based on the elastic foundation beam method. The stress and deformation change rule are got under different length of frozen heave zone, the maximum frozen heave value. And two service performance evaluation methods based on the pipe stress are comparison.The main factors which influence the pipeline service performance are put forward. A service performance evaluation system of pipeline is established based on the factors. The AHP method is applied to get the evaluation result. The final score of service performance is got by using the weighted average method. The evaluation steps above are used in China-Russia Crude Oil Pipeline. The result shows that the service performance evaluation system and the AHP method with it can describe the service condition well and give a warning when the pipeline is in a danger condition.