State of the art technology for subsea tie-in and repair systems in the North Sea

The new design of subsea structures such as riser bases (RB), pipeline end terminations (PLET) and pipeline end manifolds (PLEM) has resulted in lighter and more installation-friendly solutions. PLETs and PLEMs can be installed together with the pipeline, avoiding separate installation campaigns. The RB is designed to slide on the seabed, hence it can be connected directly to the pipeline, avoiding the need for expansion spools. If dropped object and/or trawl protection is required, a range of standardised GRP protection covers is available for the protection of structures, inline/hot-tap tees and spools. A new remote controlled tie-in system—THOR—has been developed for general use. The concept offers significant cost savings when measured against the existing conventional tie-in tool based systems. The system will be available for all pipeline sizes and will be independent of connector manufacturer.A vertical system for hot-tapping and tie-in onto a hot-tap tee has been developed and installed on the Ormen Lange field. The system includes a contingency isolation plug for recovery of the isolation valve module.Active pipeline supports (APS) have been introduced to the market and are now installed on several projects. This type of structure will enable the adjustment of pipelines during and after installation, and will therefore ensure more flexibility during the design phase. The pipeline repair system developed for the North Sea has been used for 20 years and is definitively field proven through a large number of repair operations and planned work. Many repair components and their associated installation systems have been made and used over these years. Based on this knowledge we can now better recommend, to a new repair market such as Australia, which type of repair items to purchase for the local repair system. This evaluation will also identify the items or components that should be partly prepared, either on a design level only, or up until storage of forged material or completion of particular long lead items.

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State-of-the-Art Fracturing in the North Sea

10.4043/7890-ms ◽

1995 ◽

Author(s):

M.S. Van Domelen ◽

R.C. Jacquier ◽

M.W. Sanders

Keyword(s):

North Sea ◽

State Of The Art ◽

The North ◽

The North Sea

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Bonhomme Richard: Connecting the Past With the Future

Marine Technology Society Journal ◽

10.4031/mtsj.47.2.1 ◽

2013 ◽

Vol 47 (2) ◽

pp. 8-13

Author(s):

Melissa S. Ryan ◽

Jonathan W. White

Keyword(s):

Stem Education ◽

North Sea ◽

International Organizations ◽

State Of The Art ◽

The Past ◽

Partnership Model ◽

The North ◽

Ocean Science ◽

The North Sea ◽

Ocean Environment

AbstractA unique team of personnel from federal, private, and international organizations has worked together over the past seven years to locate the remains of the Bonhomme Richard (BHR), one of the original ships of the U.S. Continental Navy commanded by Captain John Paul Jones and lost in the North Sea in 1779. While the team has yet to discover the wreckage, it has demonstrated the effective capabilities and value of state-of-the-art technology to image and survey objects on the bottom of the North Sea. Perhaps, more importantly, it has demonstrated that people from disparate organizations and militaries can work together effectively and efficiently with minimal overhead and bureaucracy. The work to date has paved the way toward eventual location and recovery of the BHR, but it has also demonstrated a partnership model that should be explored in other venues as we seek to increase our knowledge of the changing ocean environment. This paper describes the partnerships, challenges, and value of the search; its applications to STEM education; and its role in advancing the fields of ocean science and exploration.

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Horizontal Installation of TLP Tendons

Volume 1: Offshore Technology ◽

10.1115/omae2012-83013 ◽

2012 ◽

Author(s):

Guang (George) Li ◽

Robert Kipp ◽

Steve Leverette

Keyword(s):

West Africa ◽

Gulf Of Mexico ◽

North Sea ◽

Significant Cost ◽

Bottom Part ◽

The North ◽

The World ◽

Heavy Lift ◽

The North Sea ◽

Foundation Pile

Tension Leg Platforms (TLPs) are ideal supports for dry-tree top tension riser systems because their tendons exhibit high tensile stiffness and significantly reduce the heave, pitch, and roll motions of the platforms. Since the first TLP (Hutton) was installed in the North Sea in 1984, a total of 24 TLPs have been installed throughout the world with 16 of them installed in the Gulf of Mexico. Currently there are new TLP projects proposed in regions off the coast of Malaysia, West Africa, Brazil and Western Australia. Heavy-lift vessels were used to install tendons for most of these TLP’s. Tendon joints were assembled vertically from bottom part to top part. Using a heavy-lift vessel introduces significant cost and schedule challenge to TLP projects, especially ones located in remote regions. A horizontal tendon installation methodology is presented in this paper. This innovative approach involves horizontal assembly of TLP tendon segments on a construction barge. The partially assembled tendon is then incrementally pulled out through a stinger at the barge stern and secured with a hold back clamp so that the next tendon joint can be connected. The process repeats itself until the whole tendon is assembled and deployed. The tendon is then upended to a vertical configuration and connected to a TLP or a foundation pile. In this paper, we examine the alternative equipment and configuration options in the horizontal installation methodology. We outline rationales to select the appropriate options and measures to reduce project cost and risks.

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Evaluation of high-resolution reanalyses for wind energy application in the North Sea and Baltic Sea

10.5194/ems2021-241 ◽

2021 ◽

Author(s):

Thomas Spangehl ◽

Michael Borsche ◽

Deborah Niermann ◽

Frank Kaspar ◽

Birger Tinz

Keyword(s):

High Resolution ◽

Baltic Sea ◽

North Sea ◽

State Of The Art ◽

Wind Farms ◽

Horizontal Resolution ◽

Offshore Wind ◽

The North ◽

Hourly Data ◽

The North Sea

The exploitation of offshore wind energy is an essential part of the German energy transition (Energiewende). The planning of new offshore wind farms demands detailed information on wind conditions at turbine hub heights in the North Sea and Baltic Sea. High-resolution reanalyses which are based on state-of-the-art numerical weather prediction (NWP) models combined with data assimilation systems offer the required meteorological data which are suitable for climatological assessment.The regional reanalysis COSMO-REA6 operated by Germany&#8217;s national meteorological service (Deutscher Wetterdienst, DWD) provides hourly data of 6 km horizontal resolution for 1995-2019/08 (Kaspar et al., 2020). Moreover, hourly data of 31 km horizontal resolution for 1950 to present are available from the global reanalysis ERA5 produced by the European Centre for Medium-Range Weather Forecasts (ECMWF). DWD delivers reanalysis data and statistical evaluation results to Bundesamt f&#252;r Seeschifffahrt und Hydrographie (BSH) in order to facilitate offshore site tenders. Data and a report were recently published as part of the tenders for 2021 (https://pinta.bsh.de/).Here we present an evaluation of the 100 m wind speed and direction from COSMO-REA6 and ERA5 based on a comprehensive statistical analysis. On the reference side the FINO measurements (Research platforms in the North Sea and Baltic Sea, https://www.fino-offshore.de/en/index.html) from FINO1 and FINO2 are used. The FINO measurements are not used by the data assimilation schemes of the two reanalyses and therefore constitute independent reference data. The focus is on episodes prior to the installation of wind farms in the direct vicinity of the FINO platforms to avoid wake effects. The quality of the two reanalyses is compared to other state-of-the-art reanalyses and wind atlas data.Reference:Kaspar et al. (2020): Regional atmospheric reanalysis activities at Deutscher Wetterdienst: review of evaluation results and application examples with a focus on renewable energy, Adv. Sci. Res., 17, 115&#8211;128, https://doi.org/10.5194/asr-17-115-2020.

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On the Installation Planning of a Self-Floating Offshore Platform

Marine Technology and SNAME News ◽

10.5957/mt1.1979.16.3.279 ◽

1979 ◽

Vol 16 (03) ◽

pp. 279-293

Author(s):

Michael F. Metcalf ◽

Michael W. Praught ◽

Wayne O. MacDonell

Keyword(s):

North Sea ◽

State Of The Art ◽

The State ◽

Offshore Platform ◽

Scale Model ◽

Offshore Platforms ◽

Analysis And Design ◽

The North ◽

Field Activity ◽

The North Sea

This paper describes the installation planning for a major self-floating offshore platform that recently has been installed in the North Sea. Attention is given to the naval architectural aspects of the installation planning with particular emphasis on three phases: analysis and design, scale-model testing, and field activity preceding and during the actual installation operation. The paper describes the state-of-the-art in the installation planning of major self-floating offshore platforms of the kind being designed and built worldwide, and demonstrates the close coordination of many diverse disciplines in planning such installation operations.

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