浅水采油树防落物保护框架结构设计优化

Structural design optimization of shallow water Christmas tree protective frame against falling object

采油树保护框架具有防落物撞击能力,结合某浅水采油树防落物保护框架结构,基于标准DNV-U-001和DNV-RP-R107,采用5 kJ和50 kJ两种不同能量的物体分别撞击框架进行有限元分析,而后对框架薄弱部位进行优化。有限元分析结果表明:保护框架薄弱部分位于两片树帽外罩的中间区域,50 kJ的冲击造成了最大变形和应力。对树帽外罩分别采用壁厚优化和局部加强优化两种保护思路,优化结果表明:在壁厚优化思路下,随着厚度增加,树帽外罩变形量和应力减小,但增大到一定厚度后,减小趋势变缓;在局部加强优化思路下,优化后树帽外罩的垂直方向变形减小明显,结构的应力和塑性变形满足标准DNV-U-001,局部加强优化更适用于采油树保护框架的优化。

Christmas tree protective frame has the capability against falling object impact.Combined with the structure of a shallow water Christmas tree protective frame and based on standards of DNV-U-001 and DNV-RP-R107,two objects with different energies of 5 kJ and 50 kJ are used to impact the frame in the finite element analysis,and then the weak parts of the frame are optimized.The results show that the weak part of the protective frame was located in the middle zone of the two pieces of the tree cap covers,and the 50 kJ impact caused the greatest deformation and stress.Two protection ideas,i.e.the wall thickness optimization and the local reinforcement,ware respectively used for the tree cap covers.The optimization results show that as the thickness increases,the tree cap cover deformation and stress decrease,but decreasing trend then slows down as the thickness increases to a certain extent.As adopting the local strengthening optimization,the vertical direction deformation of the tree cap cover is significantly reduced,and the stress and plastic deformation of the structure meet standard DNV-U-001.So,the local strengthening optimization is more suitable for the optimization of the Christmas tree protective frame.