Integrated Analysis of Mooring and Riser Systems for FPSO’s in Harsh Shallow Water Environments

Volume 4: Pipeline and Riser Technology ◽

10.1115/omae2011-50007 ◽

2011 ◽

Author(s):

M. Martens ◽

J. R. Whelan ◽

Y. Drobyshevski

Keyword(s):

Shallow Water ◽

Time Domain ◽

Integrated Approach ◽

Integrated Analysis ◽

Mooring System ◽

South East Asia ◽

Riser Design ◽

Design Case ◽

East Asia Region ◽

Design Challenges

Shallow water mooring and riser systems for permanently turret moored FPSOs present significant design challenges. Many FPSOs, in particular in the South-East Asia region, are required to remain on-station in 100-year return period tropical revolving storm (typhoon) conditions. Extreme sea states combined with the restricted height of the water column generate large mooring loads and make it difficult to accommodate conventional riser configurations. Metocean conditions in such areas can be highly directional. This directionality can be exploited by undertaking an integrated mooring and riser design analysis. The critical interface between the mooring and riser systems is the turret offset and the associated turret heave. The conventional approach is to identify a single offset envelope for each design case, comprising the mooring system (intact or damaged) and FPSO condition (loaded or ballasted), which is then used in riser design. This paper presents a more developed approach, the integrated approach, which is based on conducting the mooring and riser analyses simultaneously for a common set of design cases. To exploit the directionality of the metocean conditions, an offset envelope for each governing metocean condition is calculated from time domain mooring simulations, followed by a parameterisation scheme. As a result, multiple turret offsets and associated metocean conditions and FPSO headings are identified which form a family of offsets for each compass octant of the environment. The integrated approach is applied to an example FPSO with an external turret supporting seven risers arranged in double wave tethered configuration. The drivers and advantages for selecting a particular riser configuration are discussed. It is shown how application of an integrated analysis approach leads to less conservative combinations for use in the riser design, and enables the development of a feasible riser system. An optimal mooring pattern, both leg make-up and orientation for riser layout, is also developed.

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Motion Responses of a Catenary-Taut-Hybrid Moored Single Module of a Semisubmersible Very Large Floating Structure in Multisloped Seabed

Journal of Offshore Mechanics and Arctic Engineering ◽

10.1115/1.4038501 ◽

2017 ◽

Vol 140 (3) ◽

Cited By ~ 1

Author(s):

Yiting Wang ◽

Xuefeng Wang ◽

Shengwen Xu ◽

Lei Wang

Keyword(s):

Shallow Water ◽

Time Domain ◽

Large Scale ◽

Bottom Topography ◽

Three Dimensional ◽

Low Frequency ◽

Mooring System ◽

Floating Structure ◽

Mooring Lines ◽

Motion Responses

Motion responses of moored very large floating structures (VLFSs) in coastal regions are remarkably influenced by shallow water, seabed topography, and mooring system, which were given particular focus in this paper. A three-dimensional (3D) numerical model of a moored semisubmersible single module (SMOD) was described, and time domain simulated and experimentally validated. A catenary-taut-hybrid mooring system was adopted considering coastal space limitations. Large-scale catenary mooring lines were deployed on the deep water side, while taut chains were used on the shore side to decrease the anchor radius. Although the mooring system may induce a stiffness difference between the two sides, the effectiveness of the mooring system was demonstrated by time-domain simulation and model tests. The moored semisubmersible SMOD in shallow water exhibits significant low frequency characteristics. Water depth, asymmetric stiffness, and bottom topography effects were investigated by a series of sensitivity studies. The results show that these factors play an important role in motion responses of the moored SMOD, which can further conduce to better understandings on the hydrodynamic of the semisubmersible-type VLFSs.

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Design and Automated Optimization of an Internal Turret Mooring System in the Frequency and Time Domain

Journal of Marine Science and Engineering ◽

10.3390/jmse9060581 ◽

2021 ◽

Vol 9 (6) ◽

pp. 581

Author(s):

Hongrae Park ◽

Sungjun Jung

Keyword(s):

System Design ◽

Time Domain ◽

Initial Conditions ◽

Minimum Weight ◽

Optimization Algorithms ◽

Local Optimization ◽

Mooring System ◽

Floating Offshore Wind Turbines ◽

Global And Local Optimization ◽

Global And Local

A cost-effective mooring system design has been emphasized for traditional offshore industry applications and in the design of floating offshore wind turbines. The industry consensus regarding mooring system design is mainly inhibited by previous project experience. The design of the mooring system also requires a significant number of design cycles. To take aim at these challenges, this paper studies the application of an optimization algorithm to the Floating Production Storage and Offloading (FPSO) mooring system design with an internal turret system at deep-water locations. The goal is to minimize mooring system costs by satisfying constraints, and an objective function is defined as the minimum weight of the mooring system. Anchor loads, a floating body offset and mooring line tensions are defined as constraints. In the process of optimization, the mooring system is analyzed in terms of the frequency domain and time domain, and global and local optimization algorithms are also deployed towards reaching the optimum solution. Three cases are studied with the same initial conditions. The global and local optimization algorithms successfully find a feasible mooring system by reducing the mooring system cost by up to 52%.

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Development of Diabetic retinopathy screening guidelines in South-East Asia region using the context, challenges, and future technology

Seminars in Ophthalmology ◽

10.1080/08820538.2021.1925308 ◽

2021 ◽

pp. 1-8

Author(s):

Brijesh Takkar ◽

Taraprasad Das ◽

Thaksaphon Thamarangsi ◽

Padmaja K Rani ◽

Raba Thapa ◽

...

Keyword(s):

Diabetic Retinopathy ◽

East Asia ◽

South East Asia ◽

Screening Guidelines ◽

Future Technology ◽

Diabetic Retinopathy Screening ◽

East Asia Region ◽

Retinopathy Screening

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Capacity building on global health diplomacy (GHD): Experience from the South East Asia region

Annals of Global Health ◽

10.1016/j.aogh.2014.08.027 ◽

2014 ◽

Vol 80 (3) ◽

pp. 164

Author(s):

C. Kanchanachitra

Keyword(s):

Global Health ◽

East Asia ◽

Capacity Building ◽

South East Asia ◽

The South ◽

Global Health Diplomacy ◽

Health Diplomacy ◽

East Asia Region

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An integrated approach to identifying and characterising resilient urban food systems to promote population health in a changing climate

Public Health Nutrition ◽

10.1017/s1368980015000610 ◽

2015 ◽

Vol 18 (13) ◽

pp. 2498-2508 ◽

Cited By ~ 21

Author(s):

Sarah W James ◽

Sharon Friel

Keyword(s):

Population Health ◽

Environmental Sustainability ◽

Mixed Methods Research ◽

Food Systems ◽

Food System ◽

Production Systems ◽

Integrated Approach ◽

Integrated Analysis ◽

Climate Resilience ◽

Urban Food Systems

AbstractObjectiveTo determine key points of intervention in urban food systems to improve the climate resilience, equity and healthfulness of the whole system.DesignThe paper brings together evidence from a 3-year, Australia-based mixed-methods research project focused on climate change adaptation, cities, food systems and health. In an integrated analysis of the three research domains – encompassing the production, distribution and consumption sectors of the food chain – the paper examines the efficacy of various food subsystems (industrial, alternative commercial and civic) in achieving climate resilience and good nutrition.SettingGreater Western Sydney, Australia.SubjectsPrimary producers, retailers and consumers in Western Sydney.ResultsThis overarching analysis of the tripartite study found that: (i) industrial food production systems can be more environmentally sustainable than alternative systems, indicating the importance of multiple food subsystems for food security; (ii) a variety of food distributors stocking healthy and sustainable items is required to ensure that these items are accessible, affordable and available to all; and (iii) it is not enough that healthy and sustainable foods are produced or sold, consumers must also want to consume them. In summary, a resilient urban food system requires that healthy and sustainable food items are produced, that consumers can attain them and that they actually wish to purchase them.ConclusionsThis capstone paper found that the interconnected nature of the different sectors in the food system means that to improve environmental sustainability, equity and population health outcomes, action should focus on the system as a whole and not just on any one sector.

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A Quasi-three-dimensional Finite-volume Shallow Water Model for Green Water on Deck

Journal of Ship Research ◽

10.5957/jsr.2013.57.3.125 ◽

2013 ◽

Vol 57 (03) ◽

pp. 125-140

Author(s):

Daniel A. Liut ◽

Kenneth M. Weems ◽

Tin-Guen Yen

Keyword(s):

Shallow Water ◽

Finite Volume ◽

Time Domain ◽

Degrees Of Freedom ◽

Initial Conditions ◽

Three Dimensional ◽

Green Water ◽

Water Model ◽

Ship Motions ◽

Shallow Water Model

A quasi-three-dimensional hydrodynamic model is presented to simulate shallow water phenomena. The method is based on a finite-volume approach designed to solve shallow water equations in the time domain. The nonlinearities of the governing equations are considered. The methodology can be used to compute green water effects on a variety of platforms with six-degrees-of-freedom motions. Different boundary and initial conditions can be applied for multiple types of moving platforms, like a ship's deck, tanks, etc. Comparisons with experimental data are discussed. The shallow water model has been integrated with the Large Amplitude Motions Program to compute the effects of green water flow over decks within a time-domain simulation of ship motions in waves. Results associated to this implementation are presented.

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