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开发了一种新型的深吃水干树式半潜生产平台(TCDD-Semi),该平台可用于中国南海深水区域的油气田开发。它的一个显著特点是立柱的截面形状呈现为渐变形式,而非传统的等截面形式。立柱的底部最大,向上逐渐变小,再结合适当的下浮体设计,能够为平台在服役前期及在位状态时提供足够的浮力以及稳性。最重要的是这种新型立柱的设计能够明显地减小平台在恶劣海况时的垂向运动,从而使在平台上布置具有干式采油树的TTR立管系统成为可能。此外,这种渐变式的立柱设计也有利于减弱平台在流作用下的涡激诱导运动(VIM)。分析结果表明这种渐变式立柱半潜平台可以明显降低平台的垂向运动,也可以在码头组装时提供足够的浮力以及在平台下沉过程中提供足够的稳性。平台优越的垂向运动性能可以使顶部张紧式立管的行程范围限制在10.5 m之内(包括平台偏移、垂荡运动、潮汐影响、海床沉降、热膨胀等因素)。分析结果表明平台的垂荡范围、水平偏移、倾侧角度、上部模块重心处的加速度等可以满足设计要求,证明了这种新型干树式半潜平台的可行性。 相似文献
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This paper presents a novel semi-submersible(SEMI) platform concept, called the multiple small columns(MSC) SEMI that improves upon the hydrodynamic performance of the conventional SEMI. Unlike the conventional SEMI, the proposed MSC SEMI utilizes multiple small circular columns to support the deck and a large pontoon that increases the structural displacement. The novelty of the MSC SEMI is its reduction of the hydrodynamic load on the structure and suppression of its motion response, particularly in the heave direction. The MSC SEMI has the advantages of increasing the added mass, radiation damping, and natural period of the structure. A comprehensive investigation of the hydrodynamic performance of the novel MSC SEMI is conducted in both the time and frequency domains with a special focus on the resulting hydrodynamic load and motion response. Numerical simulation results demonstrate that the MSC SEMI concept can reduce the hydrodynamic load and motion response and improve the hydrodynamic performance of SEMIs as expected. 相似文献
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The Multiple Column Platform (MCP) semi-submersible is a newly proposed concept, which differs from the conventional semi-submersibles, featuring centre column and middle pontoon. It is paramount to ensure its structural reliability and safe operation at sea, and a rigorous investigation is conducted to examine the hydrodynamic and structural performance for the novel structure concept. In this paper, the numerical and experimental studies on the hydrodynamic performance of MCP are performed. Numerical simulations are conducted in both the frequency and time domains based on 3D potential theory. The numerical models are validated by experimental measurements obtained from extensive sets of model tests under both regular wave and irregular wave conditions. Moreover, a comparative study on MCP and two conventional semi-submersibles are carried out using numerical simulation. Specifically, the hydrodynamic characteristics, including hydrodynamic coefficients, natural periods and motion response amplitude operators (RAOs), mooring line tension are fully examined. The present study proves the feasibility of the novel MCP and demonstrates the potential possibility of optimization in the future study. 相似文献
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针对深水半潜式平台在极端工况下张拉锚泊系统失效情况,基于板锚失效上拔过程中位移与承载力的关系曲线,提出在AQWA软件中用非线性锚缆模拟板锚走锚过程的方法,对深水半潜式平台张拉锚泊系统在百年一遇工况下断锚、走锚情况的平台响应、锚缆拉锚力及最大缆张力进行分析。研究表明:断锚时各锚链拉力瞬变,平台迅速发生大距离偏移;走锚时随着板锚的拔出各锚链上的拉力逐渐增大,平台位置逐渐偏移,最后达到平衡状态。单缆断锚时,迎浪向5号锚缆拉力最大;单缆断锚且单锚走锚时,3、6号锚缆拉锚力最大。失效缆超过一根时,平台偏移和单缆最大缆张力均超出规范要求,同时其它锚缆最大拉锚力极有可能出现超过板锚极限承载力的情况,最终造成整个锚泊系统破坏。 相似文献
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This paper numerically and experimentally investigates the hydrodynamic interaction between two semi-submersible type VLFS modules in the frequency domain. Model tests were conducted to investigate the relationship between interactions and wave headings. Numerical studies were performed by solving the radiation-diffraction problem and were validated against the experimental results. Motion Response Amplitude Operators (RAOs) were obtained from numerical and experimental studies. The dependency of the hydrodynamic interaction effect on wave headings is clarified. The influence of different wave periods on the motion responses of two-module VLFS and wave elevations in the gap is studied. The results indicate that the hydrodynamic interactions of the two modules are directly related to the wave headings and the periods of the incident wave. The shielding effect plays an important role in short wave, and the influence decreases with the increase of the incident wavelength. The numerical results based on the diffraction-radiation code can give a relatively good estimation to the responses in short wave while for long wave, it would over-predict the response. 相似文献
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The main challenge in predicting global responses of floating vessels in deepwater and ultra-deepwater areas comes from the system's coupled effect.In this paper,the coupled approach is used to analyze effects of riser on floating system in deepwater.The analysis results show that the coupling effects of risers will mainly affect the low frequency (LF) motions of the system.That is because risers will provide the system with a significant low frequency (LF) damping which will vary with the sea states.Under ... 相似文献
27.
Using frequency and time domain analysis, the authors analyzed the hydrodynamics and motion behavior of a Truss Spar platform at a water depth of 1500 m in the Liwan 3-1 area of the South China Sea. Firstly, the seakeeping ability is acquired in the frequency domain by calculating the hull’s hydrodynamics and comparing with a semi-submersible platform. The random wave analysis for 100-year, 10-year and 1-year return periods in Liwan 3-1 distinctly shows lower heave but larger surge and pitch re-sponses of the Truss Spar than those of a semi-submersible. Secondly, 3-hour motions of the Truss Spar are predicted and compared in the time domain under 100-year return period conditions in Liwan 3-1 and the Gulf of Mexico. Thirdly, the hull/mooring line cou-pled and uncoupled models are compared. Finally, the responses of the Truss Spar under 10-year and 1-year return period conditions are assessed. The results reveal that the mooring line damping reflected by the coupled model distinctly decreases the low frequency motion. The maximum heave response for 100-year return period waves is 1.23m and below 0.1m for the case of 1-year return period. 相似文献
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我国南海海域海洋环境条件复杂且海水密度垂直层化现象显著,内孤立波活动频繁,因内孤立波而造成海洋开采平台破坏的案例屡见不鲜。依托水动力计算软件AQWA二次开发功能,采用Kdv方程,借助Fortran语言将深水半潜式平台立柱、浮箱、系泊系统3部分的内孤立波作用力叠加到外力项中,联合求解半潜式平台的6自由度动力响应特性。数值模拟结果表明,在内孤立波作用下,半潜式平台的运动及系泊线张力均受到了显著的影响。在不考虑系泊系统受内孤立波作用时,平台在纵荡和横荡方向上产生较大的漂移运动,最大偏移量较无内孤立波情况下增加了8倍;系泊线最大张力提高了17%,增加了系泊线断裂的风险。在考虑系泊系统受内孤立波作用时,平台的纵荡和横荡运动响应在原响应基础上继续提高15%,但是系泊线张力变化不大。内孤立波不同浪向下的平台纵荡和横荡响应相差也很明显;系泊系统合力在不同方向上的大小决定了平台不同方向上运动的大小。 相似文献
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Based on the principle of turned mass damper(TMD) systems,the conceptual design of semi-submersible platform with a moveable heave-plate(MHS) has been put forward.The heave motion response amplitude operator(RAO) and viscous damping of the MHS platform are calculated by iteration,and the coupling stiffness between the MHS hull and the heave-plate is optimized to decrease the maximum heave motion response of the MHS hull under 10-year survival conditions in the South China Sea.The nu-merical results indicate that the heave motion RAO of the MHS hull can be decreased in the range of predominant wave frequencies,which may provide some reference to the heave motion control of offshore platforms. 相似文献