倾斜海底及瞬态潮汐流对单点系泊系统的影响

发布时间：2018-04-13 20:38

本文选题：单点系泊 + 系泊缆　；参考：《大连理工大学》2014年硕士论文

【摘要】：单点系泊系统因其具有良好的风向标效应以及低成本等优势被广泛的应用于海洋油气开发生产之中。随着海洋环境的变化以及探索领域的扩大,单点系泊系统在应用海洋油气生产的过程中出现新的问题和考验,在进行系泊设计过程中,越来越多的新的因素需要被考虑。本文主要针对系泊缆索与浮体的耦合计算方法,研究了单点系泊系统在随机海况下的运动和受力特点。着重分析了倾斜海底条件以及瞬态潮汐流两种因素对单点系泊系统运动和受力的影响。单点系泊系统会受到海底地形的影响,为了便于分析,将海底简化为带有一定坡度的平面。在研究倾斜海底对系泊缆的影响时,首先介绍了任意海底形态下系泊缆张力计算模型。然后据此分析了海底地形对单根系泊缆张力和内转塔系泊系统性能的影响。分析的结果表明,系缆低频运动是造成倾斜海底对系缆张力产生影响的最主要因素。当海底存在小角度倾斜时,通过调整系缆长度,使预张力水平分力相等的方式能够有效降低倾角对系泊性能的影响,但是当海底倾角较大时,海底倾角对系泊系统的影响是不可忽略的。为了研究单点系泊系统在潮汐流作用下的大回转问题,以渤海湾一处单锚摇臂系泊系统为例,通过对水动力软件AQWA进行二次开发,使用Fortran语言编写子程序,实时获取FPSO的位置以速度,从而实现了流载荷的计算。并在稳态流以及瞬态流的条件下,验证了方法的正确性。在此基础上,根据给定的潮流表,模拟了系泊系统24小时的运动。从结果中发现FPSO在潮汐流作用下发生大角度回转的同时会伴随小幅往复运动,这种小角度回转过程在总行程计算中具有重要的作用,通过数值模拟方法,能够准确地计算出回转的总行程。从而弥补了传统工程分析方法的不足,具有一定的工程应用价值。
[Abstract]:Single point mooring system is widely used in offshore oil and gas production because of its good wind vane effect and low cost.With the change of marine environment and the expansion of exploration field, new problems and tests appear in the process of application of single point mooring system in offshore oil and gas production. In the process of mooring design, more and more new factors need to be considered.In this paper, the motion and force characteristics of a single point mooring system under random sea conditions are studied, aiming at the coupled calculation method of mooring cable and floating body.The effects of inclined seabed conditions and transient tidal flow on the motion and force of a single point mooring system are emphatically analyzed.The single point mooring system is affected by the submarine topography. In order to be easy to analyze, the seabed is simplified to a plane with a certain slope.In order to study the influence of inclined seabed on mooring cable, the calculation model of mooring cable tension under arbitrary submarine configuration is introduced.Then the influence of submarine topography on the tension of single mooring cable and the performance of mooring system of inner turret is analyzed.The results show that the low frequency motion of mooring cable is the most important factor which causes the cable tension to be affected by inclined seabed.When the seabed is inclined at a small angle, the influence of dip angle on mooring performance can be effectively reduced by adjusting the length of mooring cable so that the pretension horizontal component is equal, but when the submarine dip angle is large,The influence of submarine inclination on mooring system can not be ignored.In order to study the large slalom problem of single point mooring system under tidal current, taking a single anchor rocker arm mooring system in Bohai Bay as an example, through the secondary development of hydrodynamic software AQWA, the subprogram is written in Fortran language.The position of the FPSO is obtained in real time at the speed, thus the calculation of the flow load is realized.The correctness of the method is verified under the condition of steady flow and transient flow.On this basis, the 24-hour mooring system motion is simulated according to the given power flow table.From the results, it is found that the large angle rotation of FPSO occurs under the action of tidal flow and accompanied by small reciprocating motion. This small angle rotation process plays an important role in the calculation of the total stroke, and the numerical simulation method is used.The total stroke of rotation can be calculated accurately.Therefore, it makes up for the deficiency of traditional engineering analysis method and has certain engineering application value.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U674.38;U661

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