Study On The Thawing Risk Prevention And Treatment Of The Oil Pipeline Buried In Permafrost Region

Since the operation, the operating temperature of the Mo-Da pipeline was keeping positive for the whole year instead of alternatively positive and negative which it was designed to be. The average value of the oil temperature was about 6.2℃, and it is 6.7℃ warmer than the prediction. The warmer oil accelerated the thaw of the permafrost around the pipeline and increased the risk of thaw settlement. Responding to the situation, this project was developed to explore the prevent measures of permafrost thaw settlement and offer the support techniques for the safety operation of Mo-Da pipeline. The project focused on the feasibility research and technology design of the control technique of the thaw settlement in the swamp areas. The research contents included pipeline thermodynamic calculation and force analysis, pipeline thaw settlement control measure design, anchor span calculation and numerical modeling, and related construction techniques. Based the researches, a demonstration of thaw settle ment control technique for the swamp areas was established at 97# in Mo-Da pipeline, and also the related pipeline displacement and soil temperature monitoring systems were installed. The effect of the control technique was assessed based on the monitoring data.