Design Of Deep Water Pipeline Inner Occluder And Reliability Study Of Anchoring Device

Submarine pipelines are indispensable in the development and production systems of offshore oil and gas fields and are the lifeline in the development of deep water oil and gas.Due to the complexity of the marine environment,it is difficult to reduce the submarine pipelines damaged and destructed.In order to reduce the unnecessary loss caused by pipeline damaged and the pollution caused by pipeline leakage to the marine environment in the oil exploitation process,it is necessary to temporarily plug the pipeline and transfer the oil to achieve rapid recovery.In this paper,a deep water pipeline inner occluder is designed.Based on the analysis of subsea pipeline maintenance related technology,for the underwater working environment and technical requirements of 1500 m deep,the overall program of deep water pipeline inner occluder is determined and modular design is carries out,including force applying system,anchoring and sealing system,the separation system,the guiding system and the transfer assist system,especially the integrated design of hydraulic cylinders,and the working process of the device is determined.Through the mechanical properties analysis of the inlaid briquetting,the shape of the inlaid briquetting is determined,and the intersecting linear inlaid briquetting is designed for the problem that the inlaid briquetting do not fit the pipelines.The embedding depth calculation model is determined by plastic mechanics,and the embedding depth of the intersecting linear inlaid briquetting and the ordinary inlaid briquetting are compared by the finite element contact analysis,compared with the theoretical values.The force analysis of the inlaid briquetting in the same column is carried out to determine the inlaid briquetting for anchoring and embedding depth with different number of inlaid briquetting,and the in-line inlaid briquetting is evenly stressed by optimizing the design of the inlaid briquetting.According to the working condition of deep water pipeline inner occluder,the environmental load is analyzed,and the dangerous part is determined.Through the fatigue analysis of the inlaid briquetting,the life and safety factor are determined,and the influencing factors affecting the safety factor are clearly defined,providing a basis for improving the fatigue safety factor.The reliability is calculated by using First Order Second Moment method and Monte Carlo method.Through the reliability analysis,the factors that have the greatest influence on the reliability of the inlaid briquetting is determined.By simulating the force-carrying process of the deep water pipeline inner occluder,experiments were carried out on different inlaid briquetting to verify the design rationality of the inlaid briquetting.The embedding depth and indentation of the intersecting linear inlaid briquetting and the ordinary inlaid briquetting are compared,and compared with theoretical analysis.The overload test was carried out on the intersecting linear inlaid briquetting to verify the anchoring reliability of the inlaid briquetting.The experimental comparison between two in-situ inlaid briquetting and three in-situ inlaid briquetting was carried out to analyze the influence of the number of different inlaid briquetting on the embedding depth.