关键词: 井口装置, 隔水套管, 海冰, 有限元, 有限差分法

Abstract: Design of wellhead protector system against ice loading is an important problem in oil development in shallow waters in Liaodongwan, Bohai Gulf. To investigate the stress state of the developed protector system using the riser to directly resist ice loading, types of joint three dimension finite elements and many boundary elements are used to model the layers of steel pipes and cement or concrete to establish the FE structural model of the system. The constraint conditions of the soil deposits to the structures are modeled by finite difference method. An ice sheet of 60mm thickness in extreme conditions is supposed to act on the thickened riser. The detailed analysis of stresses and displacements of the structure shows that the maximum displacement is at the top of the structure and the maximum stress in the top round plate connecting the riser and the outermost casing, with all the displacements and stresses in the system being in the allowed ranges. It is seen that the cemented concrete layers between the casings take very active part in increasing the strength of the structure.

Key words: wellhead protector system, riser, sea ice, finite element, boundary element, finite difference method