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Houston, TX, United States

Pistani F.,MCS Kenny | Thiagarajan K.,University of Western Australia
Ocean Engineering | Year: 2012

A sloshing experiment has been setup in order to carry out analysis on the behaviour of LNG (Liquefied Natural Gas) tanks on board of marine vessels. The experiment aimed to measure with accuracy the high pressure generated during the impacts of the fluid in the case of rectilinear sinusoidal motion in the direction of sway. A two-dimensional tank model has been used for this purpose. The pressures due to fluid sloshing are measured at several locations along the tank boundaries together with the position of the tank and acquisition of images of the flow. This paper describes the experimental procedures that have been put in place to acquire the data and ensure its quality. The problems encountered during the activity are illustrated in detail in order to provide useful indications to other researchers. The different types of impact observed during the experiment, the characteristics of the measured pressures and the implementation of an algorithm for their correct identification are discussed in detail. © 2012 Elsevier Ltd. Source

Williams D.,MCS Kenny
Proceedings of the Annual Offshore Technology Conference | Year: 2010

As exploration activity in deepwater and harsh environment regions, and associated vessel costs, increase so too does pressure on drilling contractors and operators to accurately assess the limitations of vessels and drilling equipment. As a result there is a requirement for more refined methodologies and finite element models to verify the operability of drilling riser systems in these environments. The efficiency of a drilling riser system for connected operations will generally be most influenced by the current regime onsite as this will influence the vessel offsets and nominal flex joint angles. However, as vessel offset from the nominal position increases, the vessel dynamics become increasingly important in the determination of operability limits. Likewise for the storm hang-off, deployment (including both conductor and casing deployment) and retrieval scenarios the accurate assessment of system response is critical to identifying operability windows. For harsh environment operations the operability and efficiency of the system is a function of both riser component limitations and vessel response characteristics. As a result detailed analysis considering both system response screening (involving estimation of downtime due to extreme weather events) and irregular sea analysis of riser response is required. In addition, an iterative design approach is required in order to balance the competing design drivers associated with connected operations, storm hang-off, riser recoil, deployment and vessel drift-off and resultant weak point response. This operability assessment requires a detailed model of the riser system to accurately predict the response. This model needs to account for the nonlinear response of riser tensioners, influence of wellhead, conductor and casing, nonlinear soil interaction, detailed storm hang-off arrangements and associated clashing and interference issues. In addition to refined FE models, a detailed knowledge of the metocean data for the region of interest is required. This metocean data includes detailed seastate scatter diagrams and current profiles accounting for seasonal directional variation. This paper outlines the key issues associated with the modeling and analysis techniques for drilling riser systems intended for deepwater and harsh environment locations such as Atlantic Margin, offshore Norway and Offshore Canada. In addition a number of conservatisms in current practice are identified and optimizations are outlined. Copyright 2010, Offshore Technology Conference. Source

Abdalla B.,J P Kenny Pty Ltd. | Mei H.,MCS Kenny
Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE | Year: 2013

For deep water pipeline end manifold (PLEM) subject to complex loading conditions, a combined 3D finite element (FE) model has been developed by the authors to determine the foundation bearing capacity by studying the interaction between individual parts, including the PLEM structure, flowline, mudmat and soil. The advanced numerical techniques have proven that the resulting factor of safety against bearing failure is higher when compared to the classical approach given in API-RP-2A/2GEO. However, the minimum required safety factor of 2.0 is not reached. Therefore, risk assessment using reliability analysis becomes mandatory to assess the probability of failure of the mudmat. As an input to the risk assessment, this paper presents an investigation of the system's modes of failure and failure consequences on the environment and project cost. Using the developed 3D FE model, plausible excessive loads beyond design considerations are applied until a failure in soil foundation occurs. Then, loads are increased until the capacity of structural and mechanical components in the system is reached putting the containment of carried hydrocarbons at risk. A direct relationship between the hydrocarbon temperature and the capacity of structural/mechanical components is developed to evaluate the system flexibility and resistance to induced excessive deformations. The paper demonstrates the advantages of numerical techniques in evaluating the ultimate capacity of a PLEM structure and foundation soil system. The methodology can be used in the design of a new system or to assess the stability of an existing system under future loadings. Copyright © 2013 by ASME. Source

Connolly A.,MCS Kenny
Hart's E and P | Year: 2011

MCS Kenny has developed a new advanced software called Flexcom 8 specifically for oil and gas operations. Flexcom 8 is the company's next-generation riser design and analysis software that delivers a step change in how riser engineering design and analysis is performed. The enhancements provided by this new version lead to a better design that supports the industry's increasing focus on improved process safety, better predictability, and greater knowledge of utilization and integrity during operations. The new user interface has been created using the latest software development technologies, including .NET Framework and Windows Presentation Foundation (WPF). Flexcom 8 represents a fully integrated engineering environment, with all of the necessary tools available in one box. A structural preview facility is available while model creation is in progress, which continually updates to reflect alterations and augmentations to the model. The software is designed to simplify the quality assurance process. Source

Francis K.,MCS Kenny
Proceedings of the International Offshore and Polar Engineering Conference | Year: 2011

This paper presents a comparison of the various methods for combining bimodal wave fatigue damage for flexible risers attached to floating production platforms. Finite Element Analysis is used to determine the riser response, stress ranges, and fatigue damage. The resulting stress ranges or damages are then combined via the various methods outlined in DNV-RP-F204 [2] and the RealLife JIP [3]. A base case of the fatigue damage with swell and sea analyzed together is compared against each method for summation of the damages to determine the level of conservatism in each method. A recommendation of the most appropriate method of combining swell and sea wave damages is presented in this paper. Copyright © 2011 by the International Society of Offshore and Polar Engineers (ISOPE). Source

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