浸没式可移动外输终端系泊系统优化研究

我国的边际油田大多年产量小且开发年限短,周围没有可依托设施的油田。针对此情况,可采用“蜜蜂式”开发模式。针对浸没式可移动外输终端这一新型概念设计,选取关键工况开展了时域耦合分析,研究了系泊系统参数对可移动外输终端最大水平位移和系泊缆最大张力的影响。以可移动外输终端最大水平位移和系泊缆最大张力最小为优化目标,以系泊缆结构安全为约束条件,构建了系泊系统多目标优化模型。分别建立了基于NSGA-Ⅱ和多目标粒子群算法的系泊系统优化框架,并应用这两种算法对系泊系统进行了优化设计。结果表明,NSGA-Ⅱ和多目标粒子群算法均可以解决系泊系统多目标优化问题,粒子群算法优化速度快,但通过NSGA-Ⅱ得到的Pareto前沿优化性能更好,因此更适合开展浸没式可移动外输终端的系泊系统优化。

Research on optimization method of mooring system of submerged mobile offloading terminal

There are many marginal oil fields in China, which have small annual output with short service life, and are not surrounded by oilfields with supporting facilities. As for this situation, the "bee-style" development model can be adopted. For a submersible mobile offloading terminal designed newly in concept, the critical scenario is selected to carry out coupled analyses in time-domain, and the influence of mooring system parameters on the maximum horizontal displacement of the mobile offloading terminal and the maximum tension of the mooring line are studied. A multi-objective optimization model of the mooring system is established with the minimum of the maximum horizontal displacement of the mobile offloading terminal and the maximum tension of the mooring line as the optimization objectives, and with the structural safety of the mooring line as the constraint. The mooring system optimization frameworks based on NSGA-II and multi-objective PSO are established respectively, and are used to optimize the design of the mooring system. The results show that both NSGA-II and multi-objective PSO can successfully solve the multi-objective optimization problem of the mooring system. The optimization speed of PSO is fast, however, NSGA-II is more suitable for the optimization of the mooring system of the submersible mobile offloading terminal because of the better optimization performance of the obtained Pareto front.