Lateral Vibration Behavior Analysis and TLD Vibration Absorption Design of the Soft Yoke Single-Point Mooring System

Mooring system is the key equipment of FPSO safe operation. The soft yoke mooring system is regarded as one of the best shallow water mooring strategies and widely applied to the oil exploitation in the Bohai Bay in China and the Gulf of Mexico. Based on the analysis of numerous monitoring data obtained by the prototype monitoring system of one FPSO in the Bohai Bay, the on-site lateral vibration behaviors found on the site of the soft yoke subject to wave load were analyzed. ADAMS simulation and model experiment were utilized to analyze the soft yoke lateral vibration and it was determined that lateral vibration was resonance behaviors caused by wave excitation. On the basis of the soft yoke longitudinal restoring force being guaranteed, a TLD-based vibration damper system was constructed and the vibration reduction experiments with multi-tank space and multi-load conditions were developed. The experimental results demonstrated that the proposed TLD vibration reduction system can effectively reduce lateral vibration of soft yoke structures.

Analysis for the Deployment of Single-Point Mooring Buoy System Based on Multi-Body Dynamics Method

Deployment of buoy systems is one of the most important procedures for the operation of buoy system. In the present study, a single-point mooring buoy system which contains surface buoy, cable segments with components, anchor and so on is modeled by applying multi-body dynamics method. The motion equations are developed in discrete node description and fully Cartesian coordinates. Then numerical method is used to solve the ordinary differential equations and dynamics simulations are achieved while anchor is casting from board. The trajectories and velocities of different nodes without current and with current in buoy system are obtained. The transient tension force of each part of the cable is analyzed in the process of deployment. Numerical results indicate that the transient payload increases to a peak value when the anchor is touching the seabed and the maximum tension force will vary with different floating configuration. This work is helpful for design and deployment planning of buoy system.

基于毕达哥拉斯模糊概率Petri网的FPSO单点关键部件风险评估

为准确对FPSO单点系泊系统关键部件进行风险评估,通过产生式规则建立概率Petri网络模型,基于德尔菲法的结构熵权法确定专家权重,并引入毕达哥拉斯模糊集理论收集、聚合专家意见得到基本事件的模糊可能性得分和模糊失效概率,利用概率推理算法迭代出最终的失效概率,并进行基本事件重要度分析。实例分析结果表明,引起单点系泊系统发生失效的主要因素有电滑环电刷磨损、电滑环负载电流较高、液滑环结构物晃动冲击、液滑环润滑不充分、电滑环电压过高击穿等。针对主要风险因素提出预防和控制措施,能够保障系统安全正常地运转。

Shallow Water Effects on Surge Motion and Load of Soft Yoke Moored FPSO

Much attention should be paid to a large FPSO moored permanently in an oil field with water depth of only about 20 m, since shallow water effects on the hydrodynamics may bring about collision and damage. A 160kDWT FPSO with a permanent soft yoke mooring system is investigated with various shallow water depths and focuses are the low frequency surge motion and mooring load. Computation for the FPSO system is made based on linear 3-D potential fluid theory and time-domain numerical simulation method. Corresponding model test is carried out in the ocean engineering basin of Shanghai Jiao Tong University. It is shown that, in the surge natural period, low frequency surge motion and mooring force increase remarkably with the decrease of water depth. Especially, the smaller the ratio of water depth and draught is, the quicker the increase is. The shallow water effects should be taken into account carefully for determining the design load of a single point mooring system.

Theoretical Model and Dynamic Analysis of Soft Yoke Mooring System

As a popular solution for mooring an FPSO （Floating Production, Storage and Offloading） permanently in shallow water, the soft yoke mooring system has been widely used in ocean oil production activities in the Bohai Bay of China. In order to simulate the interaction mechanism and conduct dynamic analysis of the soft yoke mooring system, a theoretical model with basic dynamic equations is established. A numerical iteration algorithm based on error estimation is developed to solve the equations and calculate the dynanfic response of the mooring system due to FPSO motions. Validation is conducted by wave basin experimentation. It is shown that the numerical simulation takes only a few iteration times and the final errors are small. Furthermore, the calculated results of both the static and dynamic responses agree well with those ones obtained by the model test. It indicates that the efficiency, the precision, the reliability and the validity of the developed numerical algorithm and program are rather good. It is proposed to develop a real-time monitoring system to further monitor the dynamic performance of the FPSO with a soft yoke mooring system under various real sea environments.

3-D computational method of wave loads on turret moored FPSO tankers

A three-dimensional method of calculating wave loads of turret moored FPSO (Flo ating Production Storage and Offloading) tankers is presented. The linearized restoring forces acting on the ship hull by the mooring system are calculated according to the catenary theory, which are expressed as the function of linear stiffness coefficients and the displacements of the upper ends of mooring chains. The hydrodynamic coefficients of the ship are calculated by the three-dimensional potential flow theory of the linear hydrodynamic problem for ships with a low forward speed. The equations of ship motions are established with the effect of the restoring forces from the mooring system included as linear stiffness coefficients. The equations of motions are solved in frequency domain, and the responses of wave-induced motions and loads on the ship can be obtained. A computer pro gram based on this method has been developed,and some calculation examples are illustrated. Analysis results show that the method can give satisfying prediction of wave loads.

基于CART决策树的FPSO单点系泊系统电滑环故障诊断

为了保障FPSO单点系泊系统电滑环运行安全,有必要开展电滑环故障诊断方法的研究,为单点系泊系统电滑环故障预警与排查提供依据。本文针对FPSO单点电滑环故障的诊断问题,采用了一种基于CART决策树算法的故障诊断模型;进一步利用有限元制作样本数据集,并通过该数据集训练得到了电滑环故障诊断模型;最后,通过后剪枝法完成了诊断模型的简化,实现了对电滑环的故障诊断。分析结果可以得到,该模型具有较高的准确率和较快的诊断速度,能够对电滑环进行有效的诊断,以便工作人员及时采取措施修复或更换电滑环,保证FPSO的安全运行。

Dynamic Analysis of Turret-Moored FPSO System in Freak Wave

Freak wave is the common wave which has significant wave height and irregular wave shape, and it is easy to damage offshore structure extremely. The FPSOs（Floating Production Storage and Offloading） suffer from the environment loads, including the freak wave. The freak waves were generated based on the improved phase modulation model, and the coupling model of FPSO-SPM（Single Point Mooring） was established by considering internal-turret FPSO and its mooring system. The dynamic response characteristics of both FPSO and SPM affected by the freak wave were analyzed in the time domain. According to the results, the freak waves generated by original phase modulation model mainly affect the 2nd-order wave loads. However, the freak waves which are generated by random frequencies phase modulation model affect both 1st-order and 2nd-order wave loads on FPSO. What is more, compared with the irregular waves, the dynamic responses of mooring system are larger in the freak waves, but its amplitude lags behind the peak of the freak wave.

南海油气田在位FPSO限位方案设计

南海海上浮式生产储油轮(FPSO)定位型式均采用单点系泊系统,近年来偶尔出现系泊锚缆零件损坏,为了消除安全隐患,需要对FPSO限位情况下进行海上维修。以更换海洋石油 118FPSO的单点锚缆零件为例,基于限位作业条件,计算分析限位载荷,确定限位拖轮,设计了动态限位方案,并提出风险控制的提升措施,实践证明限位方案的可靠性和安全性。

在位FPSO限位维修方案设计和作业风险监控

南海浮式生产储卸油装置(FPSO)均采用单点系泊系统,基于生产和维修需要,为消除安全隐患,在海上维修FPSO。以更换海洋石油118FPSO的单点锚缆零件为例,基于限位作业条件,计算限位荷载,确定限位拖轮,设计动态限位方案,提出风险控制的提升措施。实践证明,限位方案具有可靠性和安全性。

FPSO跨海域移位单点系统适应性研究——以“南海奋进号”FPSO为例

根据油田开发需要,“南海奋进号”FPSO拟由南海西部文昌油田群移位至南海东部惠州油田群。为实现该FPSO单点系统的顺利移位,移位选址综合考虑了FPSO在位安全性、外输安全距离、管缆投资等因素,最终选址在惠州油田群所有设施外围的HZ32-5平台西南侧。以单点移位结构和设备利旧最大化为目标,新建系泊系统设计将4×3锚腿方案优化为3×3锚腿方案,降低了项目成本;在此基础上,对单点转塔浮筒、锥形对接模块结构强度以及锁紧机构锁紧能力和浮筒抗旋转能力进行了全面校核,并分析了新建单点构件与原保留结构的匹配性。结果表明,原单点的对接结构、浮筒锁紧机构、浮筒提升绞车、滑环堆栈结构等可保留使用,对浮筒与锥形对接结构支撑环的精密测量和加工,使得锁紧后的浮筒与船体对接椎体匹配度达80%,提升了单点浮筒与船体连接的可靠性。“南海奋进号”FPSO新建单点浮筒和系泊系统于2023年8月顺利完成海上移位安装,目前已安全稳定运行近1年,验证了跨海域移位单点系统适应性改造技术的工程可行性及可靠性。研究成果为FPSO单点移位改造再投用项目提供了参考和借鉴。

FPSO锚桩海上安装作业流程的优化

阐述浮式生产储卸油装置(FPSO)单点系泊系统锚桩的海上安装程序,通过优化作业步骤、改进作业工具等,统筹兼顾,提高锚桩海上施工效率,为今后类似锚桩海上安装作业流程的优化提供借鉴。

缆绳破断条件下FPSO码头系泊系统安全性分析

为研究浮式生产储卸油船(Floating Production Storage and Offloading, FPSO)在码头舾装期间系泊系统的安全性,对某30万吨级FPSO的码头系泊系统在台风条件下单系泊缆破断后的安全性进行分析。基于模拟结果,分别计算了受力最大和受力第二大的缆绳破断后,码头系泊系统中剩余缆绳的张力和安全系数。结果表明:缆绳破断后,剩余缆绳的安全系数总体是减小的,但有部分剩余缆绳的最小安全系数有明显的上升;在系泊系统完整和破断条件下,安全系数最小的缆绳均为同一组缆绳;在一根缆绳破断后,码头系泊系统仍具有足够安全性。研究成果可为FPSO码头系泊系统安全评估提供一定参考。

FPSO软刚臂单点系泊系统动力分析

本文针对渤海油田浅水FPSO软刚臂单点系泊系统，利用多刚体动力学的分析方法，建立软刚臂系泊系统动力方程进行受力分析，得到FPSO在风浪流中运动时转塔上的系泊力，并与模型试验实测得到的系泊力进行对比，以验证动力方程与计算程序的正确性。二者对比的结果吻合良好，动力分析方法正确，故可应用于对系泊系统的模拟和对FPSO运动中系泊系统的受力预测。

多点系泊FPSO系泊结构局部强度研究

多点系泊是浮式生产储油船(FPSO)的一种特殊的系泊方式,适用于较好的海况环境.采用有限元分析方法,对多点系泊FPSO系泊结构的局部强度进行了研究.建立三维有限元模型,合理施加计算载荷,对导向装置和导链装置结构强度进行了计算,分析结构的应力状况,得出的结论对于设计类似结构具有一定的参考意义.

FPSO系泊系统载荷计算与分析——基于南海“奋进号”FPSO运动特性实船测量结果

通过实船测量获得了"天鹅"和"彩虹"台风过境过程中南海"奋进号"FPSO运动响应数据。根据实船测量数据,对业界普遍采用的FPSO水动力性能分析数值模型进行了修正。利用修正后的模型,将实船测量获得的船体运动响应数据作为输入项,采用非耦合数值分析技术对南海"奋进号"FPSO系泊系统在实际海况下的载荷进行了计算,并对其在恶劣海况下的定位能力进行了评估。

FPSO系泊系统参数的动力效应影响分析

利用水动力分析软件AQWA研究了内转塔式单点系泊参数对海上浮式生产储油船FPSO(floating production,storage and affcoading system)系统动力效应的影响特性,定量分析了内转塔位置、系泊缆材料分布、系泊缆预张力、系泊缆数量、系泊缆布置形式等参数对FPSO系统动力效应的影响,对每个系泊参数采取多个特征量进行比较分析,计算结果表明:转塔位置距船艏柱25%Lpp时风标效应及定位效果最好,多成分系泊缆材料分布采取下端钢链9%、聚酯缆90%、上端钢链1%时,系泊缆数量取9根且为3组×3根/组布置时定位效果最好,缆绳受力最小.以FPSO水平偏移量与系泊缆的安全系数为目标,提出了一套系泊系统的优选方案,计算结果表明系泊性能优良,与初步设计方案相比有了显著地提高.文中的计算及分析结果对内转塔式FPSO系泊系统的设计具有一定指导意义.

塔架式单点系泊FPSO的监测与预警系统开发

系统介绍了一种针对塔架式单点系泊FPSO的监测与预警系统的开发方案,方案集成软硬件设施于一体,除可以监测FPSO的运动与系泊系统的载荷外,还首次集成了风险评估和预警功能。基于此套系统,可以弥补FPSO作业过程中人为判断的不足,实现生产与安全的有机结合。

南海某FPSO STP单点系泊系统的再评估

对一艘中国南海北部服役的内转塔单点FPSO在新环境条件下的系泊系统载荷变化及其对STP浮筒静密封的潜在影响进行分析,结果显示,在新环境条件作用下,FPSO系泊系统最大张力、系泊系统平面内载荷增加30%以上,系泊系统垂向载荷增加12%。同时,对该FPSO在200年一遇极端环境作用下的系泊系统响应进行分析发现,此时FPSO的系泊系统已不能满足系泊完整状态的安全系数要求。研究结果表明:该FPSO的STP静密封系统在新环境条件下存在较大失效风险,有必要对液压锁紧装置、浮筒及舱壁重新进行优化设计及结构强度评估。

转塔式FPSO单点系泊系统受力计算方法

依据国家有关标准及相关规范,计算了影响FPSO单点系泊系统的风作用力、流作用力和波浪作用力,分析了系泊系统各锚链的受力情况;建立了锚链受力计算模型,将动态锚链受力问题通过静态的计算方法予以核算,为转塔式FPSO单点系泊系统提供了一种简单有效的核算方法。以"南海开拓"号FPSO为例进行验算,计算结果与实际情况基本相符。