Research On The Damage Of The Submarine Pipeline Based On ABAQUS

The Bohai Sea is the main offshore oil production area of our country. With the rapid development of China’s economy, the problem of energy scarcity has become increasingly prominent, and the exploitation and utilization of oil and natural gas resources is an indispensable part of China’s modernization. Submarine pipeline is an important part of the development of offshore oil and gas resources, and is the lifeline of the offshore oil and gas engineering. Recent years, the damage of anchoring to submarine pipelines is more and more frequent.Once the submarine pipeline leakage occurs, the consequences are very serious, and these are mostly due to the anchoring operation.In order to prevent the occurrence of leakage in the submarine pipelines, it is necessary to conduct a study on the damage probability and the damage of submarine pipelines and the protective measures.Firstly, this paper is based on the risk assessment of pipeline protection of Det Norske Veritas.This thesis investigates on two forms of submarine pipeline danage: the impact damage and dragging damage. There are many factors that affect the extent of the damage of submarine pipelines. The atmospheric hydrology and soil geology of the Bohai sea area are introduced, which provide the basis for the calculation. A detailed introduction and selection of the anchor which directly impacts the submarine pipeline is introduced, and the related knowledge of the contact problem in ABAQUS is introduced.Secondly, the impact damage due to anchoring operation is studied in this paper. The first is the impact probability, using the probability theory to assume that the drift obeys the normal distribution, setting up mathematical models, and the probability of collision is obtained; As to the impact energy, according to the kinetic energy theorem,velocity and energy of the anchor fall into the bottom of the sea are calculated; Finally, using the soil absorption energy formula, the depth of the anchor in the protective layer is calculated.In the initial impact analysis, this paper discusses the influence of the pipe wall thickness, pipeline length, anchor sizes on the dent depth.And compared with other impact form, DNV specification, the reliability of the DNV standard is obtained.All the results are based on ABAQUS finite elements analysis.Then, this paper studies the dragging damage. Firstly, the drag behavior of the anchor and the pipeline in the specification are introduced. Secondly, the drag force in dragging operations is calculated. We also establish the dragging model, using ABAQUS to simulate the size under different soil conditions of the drag force.Drag anchor force includes anchor chain holding power and anchor holding power.And the security checks of pipelines are made according to the calculating result.At the same time, the shipping distance is calculated, and the setting of the anchor area is obtained.Finally, on the basis of the existing research, the design of the pipeline buried depth and the method of setting up the anchorage prohibited area is put forward, and the theoretical method of the pile rock protection layer is introduced in detail, which has certain significance to the design of the pile rock protection layer. At the same time, it also puts forward some other measures for the protection of submarine pipelines and submarine cables, which have positive significance to guide construction.