海上退役平台改作鱼礁体的稳定性及流场效应研究

Research on the stability and flow field effect of the decommissioned offshore platform converted into artificial reefs

海洋油气平台在达到作业寿命后必须进行废弃处置,将海上退役平台改作人工鱼礁投放,对优化渔业资源、促进海洋经济持续发展具有重要意义。基于平台拆卸结构,共制作了箱状、管状、柱状、网状4种典型鱼礁实物模型,通过室内模拟试验和数值模拟研究,分析了不同鱼礁类型单体的稳定性和流场效应。结果表明:开口率0.1至0.8的箱状礁的稳定性均能满足要求,但开口率高于0.6的箱状礁难以形成连续的背涡流区域,设计时应使开口率低于0.6;管状礁应选择堆叠放置方式投放,且堆叠层数与稳定性和流场造成能力均呈正相关,在设计时尽量提高管状礁的堆叠层数;柱状礁设计时应尽量降低其重心,并减小迎流投影面的中空面积投放;基于平台的钻井架、火炬臂、栈桥设计的3种网状礁,均满足礁体稳定条件,且均能形成大范围的背涡流区域,可作为人工鱼礁投放。研究成果为平台造礁礁体结构设计提供了理论依据与实践基础,对海上退役平台的废弃处置具有一定的参考价值。

Offshore oil and gas platforms must be disposed after reaching their operating life.It is of great significance to optimize fishery resources and promote the sustainable development of marine economy to convert offshore decommissioned platforms into artificial reefs.Based on the dismantled structure of the platform,four typical fish reef physical models were made,including box,tube,column,and mesh.Through laboratory simulation experiments and numerical simulation studies,the stability and flow field effects of different reef types were analyzed.The results show that the stability of box reefs with an opening ratio of 0.1 to 0.8 can meet the requirements,but it is difficult for a box reef with an opening ratio higher than 0.6 to form a continuous back vortex area,and the opening ratio should be designed to be lower than 0.6.Tubular reefs should be placed in a stacking mode,and the number of stacked layers is positively correlated with stability and flow field generation capacity.The number of stacked layers of tubular reefs should be maximized in design.In the design of columnar reef,the center of gravity should be reduced as much as possible,and the hollow area of the oncoming projection plane should be reduced.The three network reefs designed based on platform drilling rig,torch arm and trestle all meet the reef stability conditions and can form a large-scale back vortex area,which can be used as artificial reefs.The results of this research provide a theoretical basis and practical basis for the structural design of reefs converted from decommissioned platforms,and have certain reference value for the disposal of decommissioned offshore platforms.