Towards the Integration of Analysis and Design of Mooring Systems and Risers: Part I — Studies on a Semisubmersible Platform

2002 ◽  
Author(s):  
Stael Ferreira Senra ◽  
Fabricio Nogueira Correa ◽  
Breno Pinheiro Jacob ◽  
Ma´rcio Martins Mourelle ◽  
Isai´as Quaresma Masetti
Keyword(s):  
Motion Analysis ◽  
Production Systems ◽  
Companion Paper ◽  
Coupled Analysis ◽  
Mooring Line ◽  
Mooring System ◽  
Analysis And Design ◽  
Design Methodologies ◽  
Campos Basin ◽  
Fully Coupled

The objective of this paper is to study different analysis methodologies for the design of floating production systems. The main issues are the use of uncoupled and coupled analysis methods, and the integration in the analysis and design of the mooring system and the risers. This paper is a companion to another paper also presented in the OMAE2002 Conference [1] The present paper begins describing a “basic” classic, uncoupled methodology, and proceeds with comments on some refinements in the representation of the behavior of the lines in the motion analysis of the vessel. Comments regarding the introduction of some level of integration between mooring line and riser behavior are also presented. These issues are illustrated with studies applying some of the considered design methodologies to the P-18 semi-submersible platform in Campos basin. The companion paper [1] proceeds describing a fully coupled methodology, and some hybrid methodologies that combine coupled and uncoupled analysis tools, and illustrates their application to a DICAS system for deepwater applications in Campos basin.

Towards the Integration of Analysis and Design of Mooring Systems and Risers: Part II — Studies on a DICAS System

2002 ◽  
Author(s):  
Fabri´cio Nogueira Correa ◽  
Stael Ferreira Senra ◽  
Breno Pinheiro Jacob ◽  
Isai´as Quaresma Masetti ◽  
Ma´rcio Martins Mourelle
Keyword(s):  
Motion Analysis ◽  
Production Systems ◽  
Companion Paper ◽  
Coupled Analysis ◽  
Mooring Line ◽  
Mooring System ◽  
Analysis And Design ◽  
Design Methodologies ◽  
Analysis Methods ◽  
Campos Basin

The objective of this paper is to study different analysis methodologies for the design of floating production systems. The main issues are the use of uncoupled and coupled analysis methods, and the integration in the analysis and design of the mooring system and the risers. This paper is a companion to another paper also presented in the OMAE2002 Conference [1]. That paper describes a “basic” classic, uncoupled methodology, and comments on some refinements in the representation of the behavior of the lines in the motion analysis of the vessel. Comments regarding the introduction of some level of integration between mooring line and riser behavior are also presented in the companion paper [1], and these issues are illustrated with studies applying some of the considered design methodologies to the P-18 semi-submersible platform in Campos basin. The present paper proceeds describing some hybrid methodologies that combine coupled and uncoupled analysis tools, and illustrates their application to a DICAS system for deepwater applications in Campos basin.

Reliability Analysis of Short Term Mooring Tension of a Semi-Submersible System

2018 ◽  
Author(s):  
Sheng Xu ◽  
C. Guedes Soares ◽  
Ângelo P. Teixeira
Keyword(s):  
Reliability Analysis ◽  
Line Strength ◽  
Coupled Analysis ◽  
Mooring Line ◽  
Global Maximum ◽  
Hydrodynamic Drag ◽  
Sampling Point ◽  
Wave Condition ◽  
Drag Coefficients ◽  
Fully Coupled

A detail procedure to study mooring line strength reliability is presented. A fully coupled analysis is carried out to get the mooring tensions of a deep water semi-submersible floating systems operated in 100 year wave condition in South China Sea. The ACER method is applied to predict the 3h extreme mooring tension, and the results are validated by global maximum method. The hydrodynamic sampling points are generated by Latin Hypercube Sampling technique. The 3h extreme mooring tension is calculated by the ACER method with 10 minutes fully coupled dynamic simulation for each sampling point. The Kriging meta model method is trained to predict 3h mooring extreme tension under the effects of random hydrodynamic drag coefficients. A reliability analysis is carried out by implementing Monte Carlo simulation with the random hydrodynamic drag coefficients and mooring breaking strength considered.

An enhanced semi-coupled methodology for the analysis and design of floating production systems

2020 ◽  
pp. 1-33
Author(s):  
Aldo Roberto Cruces Giron ◽  
William Steven Mendez Rodriguez ◽  
Fabrício Nogueira Correa ◽  
Breno P Jacob
Keyword(s):  
Equilibrium Position ◽  
Production Systems ◽  
Equations Of Motion ◽  
Coupled Analysis ◽  
Mooring Lines ◽  
Analysis And Design ◽  
Stiffness Matrices ◽  
Linear Effects ◽  
The Mean ◽  
Nonlinear Static

Abstract This work presents an enhanced hybrid methodology for the analysis and design of floating production systems (FPS). The semi-coupled (S-C) procedure exploits advantages of coupled and uncoupled models, incorporated into a three-stage sequence of analyses that can be fully automated within a single analysis program, presenting striking reductions of computational costs. The procedure begins by determining, through a full nonlinear static coupled analysis, the mean equilibrium position of the FPS with its mooring lines and risers. Then, it automatically evaluates equivalent 6-DOF stiffness matrices and force vectors representing the whole array of lines. Finally, these matrices/vectors are transferred to the dynamic analysis, solving the global 6-DOF equations of motion restarted from the static equilibrium position. This way, the S-C methodology represents all non-linear effects associated to the lines and consider their influence on the dynamic behavior of the hull. However, in some situations it could still overestimate dynamic amplitudes of LF motions, and/or underestimate amplitudes of line tensions. Thus, to improve the overall accuracy, enhanced procedures are incorporated to better represent damping and inertial contribution of the lines. Results of case studies confirm that this methodology provides results adequate for preliminary or intermediary design stages.

An Integrated Methodology for the Design of Mooring Systems and Risers of Floating Production Platforms

2012 ◽  
Author(s):  
Aldo Roberto Cruces Girón ◽  
Fabricio Nogueira Corrêa ◽  
Breno Pinheiro Jacob ◽  
Stael Ferreira Senra
Keyword(s):  
Production Systems ◽  
Coupled Analysis ◽  
Mooring Line ◽  
Design Practice ◽  
Structural Behaviour ◽  
Coupled Models ◽  
Mooring Lines ◽  
Hydrodynamic Behaviour ◽  
Integrated Methodology ◽  
Analysis Tools

Nowadays, coupled analysis tools that allow the simultaneous modelling of the hydrodynamic behaviour of the hull and the structural behaviour of the lines of floating production platforms have been increasingly used. The use of such tools is gradually allowing the introduction of some feedback between the design of risers and mooring systems. In the current practice, that comprises the so-called “hybrid” methodologies, mooring designers have been using these tools to consider the influence of the risers on the platform motions. On the other hand, riser designers can use motions that result from coupled simulations for the analysis of each riser. Such integration is already being implemented in the design practice of Petrobras; however, elsewhere the design of risers and mooring systems may still be performed separately, by different teams, therefore not fully exploiting the benefits that the coupled analysis tools can provide. In this context, this work describes an innovative, fully integrated methodology for the design of mooring systems and risers of floating production systems (FPS). This methodology considers different design stages (from preliminary to advanced), integrating the design activities of mooring lines and risers in a single spiral, allowing gains in efficiency and cost reduction. The initial design stages already include a feedback between riser and mooring analyses. The integrity of the risers can be considered in the mooring design by determining their safe operational zones, and therefore, mooring line pretensions can be modified to improve its structural performance. Then, in advanced stages critical design cases for both mooring and risers systems can be identified and rigorously verified by using fully coupled models. The application of the proposed methodology is illustrated with a case study of a typical FPS, representative of the platforms that have been recently considered for deepwater applications. It should be stressed that the methodology described here does not reflect the current design practice of Petrobras. Presently it is merely a proposal that is being studied and assessed; this work comprises the first draft of the methodology, which will be enhanced and consolidated as the result of current and future studies.

Study on Weight Control Methods of Single Point Mooring System of FPSO in Deepwater

2015 ◽  
Author(s):  
Yuan Hongtao ◽  
Zeng Ji ◽  
Chen Gang ◽  
Mo Jian ◽  
Zhao Nan
Keyword(s):  
Weight Control ◽  
Linear Time ◽  
Single Point ◽  
Line Tension ◽  
Coupled Analysis ◽  
Mooring Line ◽  
Mooring System ◽  
Control Methods ◽  
Analysis Method ◽  
Mooring Lines

This paper applies 3D potential theory and non-linear time domain coupled analysis method to analyze motion response of FPSO and dynamic response of mooring line of single mooring system. In addition, respectively to calculate mooring line tension of tension type and composite mooring line type and added buoy in mooring line. There the paper analyze different mooring lines to affect on the weight of single point mooring system of deepwater FPSO. Which expects to provide a theoretical basis for single point mooring system design and weight control.

scholarly journals STRUCTURAL BEHAVIOUR OF FULLY COUPLED SPAR–MOORING SYSTEM UNDER EXTREME WAVE LOADING

2014 ◽  
Vol 19 (Supplement_1) ◽  
pp. S69-S77 ◽  
Author(s):  
A. B. M. Saiful Islam ◽  
Mohammed Jameel ◽  
Suhail Ahmad ◽  
Mohd Zamin Jumaat ◽  
V. John Kurian
Keyword(s):  
Response Time ◽  
Deep Water ◽  
Mooring Line ◽  
Mooring System ◽  
Wave Loading ◽  
Extreme Wave ◽  
Spar Platform ◽  
Mooring Lines ◽  
Time Histories ◽  
Fully Coupled

Floating spar platform has been proven to be an economical and efficient type of offshore oil and gas exploration structure in deep and ultra-deep seas. Associated nonlinearities, coupled action, damping effect and extreme sea environments may modify its structural responses. In this study, fully coupled spar–mooring system is modelled integrating mooring lines with the cylindrical spar hull. Rigid beam element simulates large cylindrical spar hull and catenary mooring lines are configured by hybrid beam elements. Nonlinear finite element analysis is performed under extreme wave loading at severe deep sea. Morison's equation has been used to calculate the wave forces. Spar responses and mooring line tensions have been evaluated. Though the maximum mooring line tensions are larger at severe sea-state, it becomes regular after one hour of wave loading. The response time histories in surge, heave, pitch and the maximum mooring tension gradually decreases even after attaining steady state. It is because of damping due to heavier and longer mooring lines in coupled spar–mooring system under deep water conditions. The relatively lesser values of response time histories in surge, heave, pitch and the maximum mooring tension under extreme wave loading shows the suitability of a spar platform for deep water harsh and uncertain environmental conditions.

Conditional Reliability Analysis of a Semi-Submersible Mooring Line With Random Hydrodynamic Coefficients

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Sheng Xu ◽  
A. P. Teixeira ◽  
C. Guedes Soares
Keyword(s):  
Reliability Analysis ◽  
Line Tension ◽  
Coupled Analysis ◽  
Mooring Line ◽  
Global Maximum ◽  
Hydrodynamic Drag ◽  
Dynamic Simulations ◽  
Wave Condition ◽  
Drag Coefficients ◽  
Fully Coupled

Abstract In this paper, a detailed procedure to study the mooring line conditional strength reliability of a semi-submersible platform in a 100-year sea state is presented. A fully coupled analysis is conducted to calculate the mooring line tension of a deepwater semi-submersible floating system operated in the 100-year wave condition in South China Sea. 3-h extreme mooring line tensions are estimated by the average conditional exceedance rate (ACER) method from the data obtained by 10 and 20 min fully coupled dynamic simulations, and the results are validated by the global maximum method. A kriging metamodel is trained to predict the 3-h mooring line extreme tension taking into account the effect of random hydrodynamic drag coefficients. The hydrodynamic sampling points are generated by Latin hypercube sampling technique. A reliability analysis is carried out by Monte Carlo simulation considering the random hydrodynamic drag coefficients and mooring line breaking strength.

Model Testing of Ultra-Deepwater Floater Systems: Truncation and Software Verification Methodology

2006 ◽  
Author(s):  
Rolf Baarholm ◽  
Ivar Fylling ◽  
Carl Trygve Stansberg ◽  
Ola Oritsland
Keyword(s):  
Time Domain ◽  
Software Verification ◽  
Production Systems ◽  
Coupled Analysis ◽  
Mooring Line ◽  
Test Results ◽  
Set Up ◽  
Verification Methodology ◽  
Good Agreement

Model tests for global design verification of floating production systems in depths beyond 1000m–1500m cannot be made directly at reasonable scales. Truncation of mooring line and riser models, software calibration, as well as extrapolation and transformation to full depth and full scale, are required. Here, the first two of the above three items are addressed. The paper emphasizes the important matters to be taken into account. The choice of proper procedures for the set-up and the interpretation, and consistent and well documented methods, are essential. A case study with a deep-water semisubmersible is presented. In general, good agreement between model test results and analytical results from time-domain coupled analysis of the floater system responses is found.

scholarly journals Transient Responses Evaluation of FPSO with Different Failure Scenarios of Mooring Lines

2021 ◽  
Vol 9 (2) ◽  
pp. 103
Author(s):  
Dongsheng Qiao ◽  
Binbin Li ◽  
Jun Yan ◽  
Yu Qin ◽  
Haizhi Liang ◽  
...  
Keyword(s):  
Service Condition ◽  
Mooring Line ◽  
Mooring System ◽  
Transient Effects ◽  
Floating Platform ◽  
Transient Responses ◽  
Mooring Lines ◽  
Performance Deterioration ◽  
Steady State Responses ◽  
Influence Process

During the long-term service condition, the mooring line of the deep-water floating platform may fail due to various reasons, such as overloading caused by an accidental condition or performance deterioration. Therefore, the safety performance under the transient responses process should be evaluated in advance, during the design phase. A series of time-domain numerical simulations for evaluating the performance changes of a Floating Production Storage and Offloading (FPSO) with different broken modes of mooring lines was carried out. The broken conditions include the single mooring line or two mooring lines failure under ipsilateral, opposite, and adjacent sides. The resulting transient and following steady-state responses of the vessel and the mooring line tensions were analyzed, and the corresponding influence mechanism was investigated. The accidental failure of a single or two mooring lines changes the watch circle of the vessel and the tension redistribution of the remaining mooring lines. The results indicated that the failure of mooring lines mainly influences the responses of sway, surge, and yaw, and the change rule is closely related to the stiffness and symmetry of the mooring system. The simulation results could give a profound understanding of the transient-effects influence process of mooring line failure, and the suggestions are given to account for the transient effects in the design of the mooring system.

Object-oriented and conventional analysis and design methodologies

Computer ◽  
1992 ◽  
Vol 25 (10) ◽  
pp. 22-39 ◽  
Author(s):  
R.G. Fichman ◽  
C.F. Kemerer
Keyword(s):  
Object Oriented ◽  
Analysis And Design ◽  
Design Methodologies ◽  
Conventional Analysis
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