Deepwater Technology (DWT) | Awarded on 07 Apr 2014

Projects awarded:

• Hydrodynamic Characteristics in the Moonpool of Drillships
  

  Deepwater Technology (DWT) | Awarded on 07 Apr 2014
  Hydrodynamic Characteristics in the Moonpool of Drillships

  To meet the increasing demands of the global society for the oil and gas production, it is clear that the exploratory drilling of new oil or gas wells will be carried out more in deeper water. Due to their large deck load capacity and time saved sailing between oilfields worldwide, drillships become the most frequent choice for this activity. However, many problems associated with drillships need to be well understood, and the hydrodynamic characteristic in the moonpool is one of them.

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  Involved Researcher(s): Bai Wei

• Dynamic Positioning Capability Simulation of Marine and Offshore Operations
  

  Deepwater Technology (DWT) | Awarded on 07 Apr 2014
  Dynamic Positioning Capability Simulation of Marine and Offshore Operations

  The overall aim of the project is to develop a tool/code for DP capability simulation in time domain.

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  Involved Researcher(s): Capt Gopala Krishnan

• Contrast Enhanced Vision for Deepwater Monitoring System
  

  Deepwater Technology (DWT) | Awarded on 07 Apr 2014
  Contrast Enhanced Vision for Deepwater Monitoring System

  Deepwater video suffers from poor visibility due to the scattering and light distortion. With the correct physical concept of the property of light transmission and statistical information of image/video in deepwater, it is possible to produce a clear and good contrast image with state-of-the-art enhancement method. The project proposes the usage of scattering to model the depth as visual degradation is usually a function of the depth. The project will investigate the assumption and feasibility of applying the concept of Dark Channel Prior for deepwater images.

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  Involved Researcher(s): Chau Lap Pui

• Experimental and numerical investigation of scour due to vibration of a steel catenary riser
  

  Deepwater Technology (DWT) | Awarded on 07 Apr 2014
  Experimental and numerical investigation of scour due to vibration of a steel catenary riser

  The project aims to

  1. enhance the understanding of scour under Steel Catenary Riser (SCR); and
  2. study the influence of the dynamic motion of SCR on scour and its effect on the fatigue life of the structure.

  The project will be the first comprehensive study on scour hole development due to the vibration of a SCR. Innovative experimental technique and numerical software on SCR vibration on scour.

  The project adopts the following approach

  1. Physical modelling;
  2. Numerical modelling of fluid structure-sediment interactions; and
  3. Analysis of the dynamics of SCR and fatigue life prediction.

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  Involved Researcher(s): Chiew Yee Meng

• Numerical and Experimental Investigations on Hydrodynamic Interactions and Operational Risks of Adjacent Vessels During Side-by-Side Operations
  

  Deepwater Technology (DWT) | Awarded on 07 Apr 2014
  Numerical and Experimental Investigations on Hydrodynamic Interactions and Operational Risks of Adjacent Vessels During Side-by-Side Operations

  The physics of flow between adjacent structures is a complex interaction of various viscous effects.  To date, investigations into the flow and its influence on motions of the adjacent structures have been limited to model tests, and numerical analysis with correction factors dependent on calibration with experimental data of similar hull configurations.   Given the dependence of hydrodynamic behaviour prediction on model tests, reliable risk assessment of side-by-side operations can thus only be carried out after preliminary hull configurations have been determined.  This imposes a constraint in terms of design optimization – should the tests or risk assessments reveal undesirable motions or risk levels, design changes would mean high cost implications on the overall project. The proposed research thus seeks to address the above issues by:

  • Developing a methodology to carry out reliable numerical modelling of hydrodynamic interaction between side-by-side floating structures, by incorporating viscous effects, and applying the methodology on analysis of side-by-side operations of LNG-FPSOs with shuttle tankers.  The methodology is based on the coupling of inviscid potential flow and viscous regions.  To date, such approaches have only been carried out in two-dimensions in the academia and the development of a three-dimensional model is of academic significance and will benefit the industry in its design practices.
  • Investigating the hydrodynamic interactions between adjacent vessels via experimental tests.  These tests are designed to provide benchmark data for identifying the various effects of viscosity between the two vessels, thus providing insights into the fundamental physics of flow.  The collaborators from University of Sao Paulo (USP) are recognised experts in offshore model testing and numerical simulation with their Numerical Offshore Tank (TPN). The close collaboration with USP experts will greatly benefit Singapore’s offshore research efforts.
  • Assessment of operational risks associated with side-by-side vessels at the concept design stage.  As discussed above, the current state of engineering practice means that reliable risk assessments are dependent on accurate hydrodynamic prediction, which at this stage is accepted to be model testing.  By developing a risk assessment approach that is coupled with accurate numerical hydrodynamic modelling and integrated into the design cycle, better hull optimization can be carried out earlier in the design cycle, thus reducing any cost implications on the overall project.

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  Involved Researcher(s): Choo Yoo Sang

• Development of Robust and Efficient Methodology for Simulation of Catamaran Float-over Integrated Deck Installation
  

  Deepwater Technology (DWT) | Awarded on 07 Apr 2014
  Development of Robust and Efficient Methodology for Simulation of Catamaran Float-over Integrated Deck Installation

  Exploration & production of oil and gas in deep waters has promoted the development of floating platforms such as SPAR, which offers advantages of intrinsic stability, large storage capacity, low motions and dry tree production system. It is a challenge to install an integrated and heavy deck onto a SPAR due to relative motions between the deck and the floating SPAR hull. While SPARs are well-suited to long-term operations within a harsh environment in deep waters, the installation of the integrated deck is critical to successful integration of the deck-hull system.
  The proposed research aims to address technical issues arising from installation of deep water floating platform by developing a robust and efficient methodology for the simulation and modeling of catamaran float-over integrated deck installation, with emphasis on the development of SPAR and related designs in deep waters. Catamaran float-over deck installation embraces a number of technical challenges such as multi-body hydrodynamic interaction, complex multi-body mechanical interactions and deck flexibility. Existing analysis methods do not address the above challenges adequately. In addition, current engineering practice lacks a generic analysis method for evaluating the performance of catamaran float-over installations based on specific inputs such as sea-states and model properties.
  The proposed research will develop a robust and efficient methodology by coupling hydrodynamic and dynamical analysis of multiple structures with the deck being modeled as a flexible body. For analyzing nonlinear problems such as mechanical impacts between the deck and the SPAR hull during the mating stage, time-domain modeling of the catamaran float-over system will be carried out based on the constant parameter time-domain model established from the Cummins equation. The developed methodology will help to enhance the understanding of this novel installation technology and improve its workability and operability in deep waters.

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  Involved Researcher(s): Choo Yoo Sang

• Extreme Wave Impact on Floating Structures: A Novel Particle Method with Experimental Validation
  

  Deepwater Technology (DWT) | Awarded on 07 Apr 2014
  Extreme Wave Impact on Floating Structures: A Novel Particle Method with Experimental Validation

  Extreme waves have tremendous destructive power when they impact on offshore and floating structures such as semi-submersible and tension leg platforms. The impact of extreme waves can lead to serious damage and instability of these structures. Most studies on extreme wave impacts have been based on mainly experimental observation, as the complex and highly non-linear waves are still poorly understood and cannot be well predicted by existing numerical methods, particularly in terms of impact pressure. In solving the Navier-Stokes equations, the investigators of this proposal have recently developed a new particle method called Consistent Particle Method (CPM) which incorporates several novel ideas and is shown to be able to predict such effects well. In particular, the method eliminates the need of introducing any fudge factor such as artificial viscosity or defining an arbitrary kernel function. A 3-dimensional flow model has been developed in predicting pressure histories for flow phenomena pertaining to large-amplitude liquid sloshing, green water impacts and wave run-up.

  A two-phase (water-air) model is also in the early development stage so as to include the significant effects of entrapped air. Of practical significance is the experimental validation carried out in laboratory using a linear shake table and a 2-degree rotational simulator. The CPM has thus far shown great performance in modelling violent sloshing with wave breaking. This novel method has tremendous potential for wave impact on floating structures and marine vessels when extended to model extreme waves in deep sea and addressing the computational challenges for large-scale problems. The research will focus on the nonlinear discontinuous nature of extreme waves upon impact on structures and the efficient numerical implementation (including parallelization) for 3D and 2-phase modelling. Experimental studies on small-scaled models will also be conducted by using wave basin and rotational simulators available in the NUS laboratories. The numerical-experimental approach will ensure that key features of the highly nonlinear wave impact-breaking be captured and the numerical methodology be physically validated. The collaboration with Sembcorp Marine (a global leader in the offshore and marine industry) would provide invaluable industry input to the research.

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  Involved Researcher(s): Koh Chan Ghee

• Pipeline-Soil-Water Interaction Effects for Realistic Deepwater Pipeline Design
  

  Deepwater Technology (DWT) | Awarded on 07 Apr 2014
  Pipeline-Soil-Water Interaction Effects for Realistic Deepwater Pipeline Design

  With the increasing exploitation of deepwater production fields, there has been increasing research interest in deepwater pipelines behaviour. In contrast to shallow water pipelines which are often buried in shallow trenches, deepwater pipelines are commonly just laid on the seabed. As the pipelines are unrestrained, pipeline lengthening and expansion due to changing temperature and pressure during start-ups and shutdowns can often lead to buckling and axial movement (known as pipeline walking); which, if uncontrolled, can be very damaging to the pipeline. In order to devise strategies to control pipeline buckling and walking, effects of pipeline-soil interaction must be accounted for, including the effects of changing pore pressure in the soil. Although there have been substantial volume of research into pipeline-soil interaction, much of these works are based on total stress. Hence, pore pressure effects are not considered.

  The objective of this proposal is to examine the effects of pipeline-soil-water interaction, especially, excess pore pressure generation and dissipation, effects on pipeline behaviour in working conditions, so as to develop design guidelines which can realistically account for effects arising from changes in pore water pressure in the soil. The proposed research approach involves a combination of laboratory testing to examine pipe-soil interface behaviour, centrifuge modeling to shed light on pipeline-soil system behaviour and numerical modeling using effective stress coupled analysis to replicate the effects of pore pressure on pipeline buckling and walking.
  The research team has already garnered significant experience in centrifuge modeling of offshore foundations and numerical modeling of pore pressure effects in spudcans and torpedo piles, having generated several cutting edge developments and publications in this direction. The partnership of ABS also ensures that the work done has strong industry relevance and that the research team is kept abreast of developments in this area, even as the research work progresses.

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  Involved Researcher(s): Lee Fook Hou

• Fracture Assessment of Flawed Girth Welds in Clad Pipelines with Under/Over-mismatch Weld Strengths
  

  Deepwater Technology (DWT) | Awarded on 07 Apr 2014
  Fracture Assessment of Flawed Girth Welds in Clad Pipelines with Under/Over-mismatch Weld Strengths

  Pipelines containing external surface crack at the weld toe of a girth weld. It provides a new procedure to access flawed girth welds of clad pipelines, which is to fill up the gap in current standards. The project will be adopting the Failure Assessment Diagram (FAD) approach.

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  Involved Researcher(s): Lie Seng Tjhen

• A practical method to evaluate highly-nonlinear wave runup on columns and air-gap for semi-submersible platforms in harsh wave environments
  

  Deepwater Technology (DWT) | Awarded on 07 Apr 2014
  A practical method to evaluate highly-nonlinear wave runup on columns and air-gap for semi-submersible platforms in harsh wave environments

  A practical methodology to improve the evaluation of the impacts of large wave runup on columns and negative air-gap on semi-submersible platforms in harsh wave environments.

  The novelty of it is that it improves the runup and air-gap predictions using potential solvers.

  The project will be adopting the the following approach:

  1. Wave flume model tests;
  2. CFD simulations; and
  3. Simulations using potential solvers.

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  Involved Researcher(s): Lo Yat-Man, Edmond

• Numerical Modeling of Strong Wave Impact on Deep-sea Semi-Submersible (WID-Sea)
  

  Deepwater Technology (DWT) | Awarded on 07 Apr 2014
  Numerical Modeling of Strong Wave Impact on Deep-sea Semi-Submersible (WID-Sea)

  The objective of this research is to develop advanced CFD modeling methodologies/tools to improve the prediction of wave impact for semi-submersibles under extreme weather conditions, evaluation of instantaneous air gap for extreme events by leveraging on the existing OpenFOAM platform. The investigation would focus on:

  • Air-gap and pressure load analysis and
  • Sea keeping performance of deep-sea semi-submersible.

  Statistical and dynamic nonlinearities in ocean waves and wave-structure interaction will be considered. Emphasis will be placed on prediction of extreme air-gap events for semi-submersibles and tension leg platforms (TLP).

  To perform the research with OpenFOAM, following key activities will be conducted:

  • Extreme wave generator
  • Numerical wave-current interaction with reflection absorption
  • Enhanced structural solver for floating body under extreme conditions
  • Mooring line system simulator
  • A coupled hybrid near-field and far-field formulation for numerical wave tank
  • Model bench mark and verification

  The proposed framework will provide an efficient and accurate CFD tool for wave run-up and impact loads analysis of a floating structure under harsh environment. This tool has not only academic importance, but most importantly, it will equip Singapore companies, such as our collaborator, Keppel with an advanced modeling technique, which will greatly enhance Singapore industries’ competiveness and productivity leading to even higher value chain.

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  Involved Researcher(s): Lou Jing

• Energy efficient wireless communication techniques and components for autonomous sensors in off-shore and marine application
  

  Deepwater Technology (DWT) | Awarded on 07 Apr 2014
  Energy efficient wireless communication techniques and components for autonomous sensors in off-shore and marine application

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  Involved Researcher(s): M. Annamalai Arasu

• Fatigue Life Prediction Methodology for Offshore Structures, Risers and Pipelines starting from multiple small surface cracks relevant to Welded Structures
  

  Deepwater Technology (DWT) | Awarded on 07 Apr 2014
  Fatigue Life Prediction Methodology for Offshore Structures, Risers and Pipelines starting from multiple small surface cracks relevant to Welded Structures

  The project aims to:

  1. develop a methodology for predicting the fatigue crack growth behaviour of multiple surface cracks in welded structures; and
  2. develop an algorithm to model the growth and coalescence of multiple surface cracks, by modelling multiple surface cracks coalescing and small surface cracks at weld toes.

  The project will develop finite element and fatigue crack growth modelling methods and fatigue tests for validation of surface cracks.

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  Involved Researcher(s): Pang Hock Lye, John

• Analysis of High Voltage AC/DC Power Transmission and Penetration of Renewables for Subsea Power System Distribution Network
  

  Deepwater Technology (DWT) | Awarded on 07 Apr 2014
  Analysis of High Voltage AC/DC Power Transmission and Penetration of Renewables for Subsea Power System Distribution Network

  As the difference between the energy demand and supply gets larger and larger due to the rapid economic development of various developing countries worldwide the quest for natural energy resources becomes very important. Along with the development of marine oil-gas fields and the increased depth of water, the subsea production system has gained the attention of big oil companies due to considerable economic benefits. The subsea electric power system equipment technology addressed in this proposal deals with the analysis of suitable electric power transmission schemes from onshore facilities, their efficiency comparisons, harmonic analysis with accurate medium/long transmission line models, reactive power compensations, real-time monitoring, fault identification as well as location and control along with data analytics for predictive maintenance of the subsea electrical equipment. This proposal consists of a combination of interrelated studies since high interconnectivity of components in the electrical network demands the collective study of such issues. This project also proposes the novel idea of using intermittent and limited renewable energy sources for meeting the harmonic power requirements of loads through their intelligent power management, and mitigation of harmonics in the transmission line thereby keeping the transmitted power as “clean” as possible as well as more efficient thereby providing CAPEX savings. This multifarious project focuses on the effective operation of the subsea power system (both transmission and distribution), their energy efficiency and increment in reliability. Coupled with condition monitoring of the electrical equipment, data analytics generated helps to exercise predictive estimation of the system states that could possibly be used for advanced control of the electrical equipment. This calls for incorporation of advanced information processing of continual sensor outputs and embedded intelligence in the monitoring devices. The most desired “low-maintenance-equipment” objective could be achieved through accurate understanding of the relations between transmission, distribution and terminal power consumptions and their real-time monitoring. Enhanced life-time of the equipment would be an implicit benefit. Such a holistic study could take Singapore to the next step of technological advancements in understanding and designing subsea power system technologies.

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  Involved Researcher(s): Sanjib Kumar Panda