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Gordon N.,Subsea
Hart's E and P | Year: 2012

A commitment to developing and embracing new technology is critical to achieving advances in subsea technology. Longer tiebacks, deepwater construction, increased production, and integrity issues on aging assets are just a few of the challenges facing the subsea sector as it matures and exploits deepwater and ultra-deepwater fields. Since the late 1990s, flow assurance and the challenges associated with the move to deep water have dominated the subsea umbilicals, risers, and flowlines industry. These challenges have led to new technologies such as Technip's electrically trace-heated pipe-inpipe (ETHPiP) design, which provides a low-power solution that compliments reel-lay installation. As many pipelines and subsea wells reach the end of their planned lifespan or even exceed it, they require regular servicing. New and innovative technologies to lower the cost of pipelines over their lifetime could offer significant savings. Pipelines made of composite material and coatings that will not corrode and are less prone to blockage should offer increased pipeline and riser reliability. Source

Juluri N.,Subsea | Dib E.,Intecsea | El-Gebaly S.,Intecsea | Cooper P.,Intecsea
Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE | Year: 2013

Long spools are often required to absorb the end expansion of deep water high pressure and high temperature flowlines. These spools typically have significant metrology and fabrication tolerances. Metrology and spool fabrication tolerances lead to misalignments at the connector hub face. Residual loads then arise from spool deformation due to the installation forces that are required to match-up the connector faces. It is a current industry practice to design the spools for multiple independent tolerances at extreme limits in all directions. Previous project experience shows that the Algebraic Sum (AS) combination of multiple independent tolerances at extreme limits may result in large spools where the probability of occurrence of these tolerances at extreme limits is quite low. The use of less conservative SRSS (square root of sum of squares) combination has been suggested in this paper as an alternative to the Algebraic Sum combination. Due to the large number of misalignment components, the probability of exceeding the loads in the spool and at the connector obtained by the SRSS method is small and is within the applicable failure probabilities defined in DNV-OS-F101. The SRSS method is demonstrated in this paper by using a Monte Carlo simulation. Five different spools have been analysed to demonstrate the suitability of using SRSS misalignments when the spools are designed to DNV-OS-F101. The spools considered include 10", 16" and 20" outside diameter spools to represent different sizes at different loading combinations. Maximum bending moments in the spool and maximum moments at the connector have been considered to check the SRSS feasibility. The results indicate that it is acceptable to use SRSS misalignments as an alternative to AS misalignments. Considering SRSS misalignments in preference to AS leads to reduced spool size and reduced loadings on connectors. Copyright © 2013 by ASME. Source

Kahlstrom M.,Subsea | Frossard R.,Subsea | Mattsson H.,Lulea University of Technology
Frontiers in Offshore Geotechnics III - Proceedings of the 3rd International Symposium on Frontiers in Offshore Geotechnics, ISFOG 2015 | Year: 2015

In this paper, a study is presented on the possibility to numerically simulate observed settlements of an offshore subsea rock foundation installed on normally consolidated clay. Settlements were monitored at 31 days and 200 days after installation and compared against predictions computed by means of finite element analysis. The results highlight that computations with a material model incorporating a logarithmic stress-strain relationship can accurately predict the consolidation settlements of normally consolidated clay. For long-term settlements, a material model that includes a creep factor is likely to increase the prediction accuracy of the total settlements. This study was performed in order to improve the prediction of soft clay settlements, as this phenomenon may have a large impact on design for sensitive subsea infrastructure installed on the seabed. © 2015 Taylor & Francis Group, London. Source

Faugstadmo J.E.,Subsea | Pettersen M.,Subsea | Hovem J.M.,Sintef | Lie A.,Sintef | Reinen T.A.,Sintef
Proceedings - 4th International Conference on Sensor Technologies and Applications, SENSORCOMM 2010 | Year: 2010

The NNN-UTS project (Nordområdenes Nye Nervesystem - Undervanns Trådløst Sensornettverk) has aimed to develop wireless network technology for underwater sensor networks, employing acoustic communication to realize wireless functionality in water. Research and development has been carried out in 2006-2009. A final sea test/demonstration of the system was carried out at Breiangen in the Oslo fjord, on December 3-4 2009. The result is a fully operative network system available for water depths down to 4000m. © 2010 IEEE. Source

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