Response Analysis Of Submarine Pipeline In The Landing Section Under Sea Ice

Nowadays,the increasing demand for energy results in rapid development of marine petrochemical industry.As the global oil and industry moves into the ocean,the submarine pipeline has become an important part of marine oil and gas transportation.The submarine pipeline is the key connecting offshore oil field and onshore storage facility.Due to the exploitation of offshore oil and gas projects in China,more and more submarine pipelines need to land directly,The coastal area around Bohai Bay freezes in winter.The ice load acting on offshore structures will induce serious damage.The submarine pipeline in the landing section is located near shallow water.Ice load will impose on the covered soil of the submarine pipeline or exposed pipeline directly,which is hazard for the safety and integrity of submarine pipeline.Therefore,the submarine pipeline in the landing section has to face the challenge of sea ice.In this thesis,the submarine pipeline at Chengdao offshore oil field is selected as the research background.The submarine pipeline in the slope landing section is studied and analyzed under the action of sea ice.The contents of this research include:(1)The literatures related to response induced by ice force are summarized.Meanwhile,reasonable ice load calculation methods are selected.(2)Using the finite element software ANSYS Workbench,according to the actual project,the three-dimensional nonlinear finite element(FE)models of the submarine pipeline in the landing section is established,considering the interaction between pipeline and oil.(3)Based on ocean environment data,the calculation cases are determined.Then,modal analysis of the the submarine pipeline is carried out.By FE analysis,the deformation and stress analysis of buried pipeline under the action of ice load is conducted.The effects of buried depth and structure inclination on the stress and deformation of buried pipeline is studied.(4)The FE models of the exposed pipeline and the suspended pipeline are established.Under the same loading cases,the deformation and stress analysis of the exposed and suspended pipelines are performed and compared.