Horizontal Installation of TLP Tendons

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.

Technical and Economic Evaluation of a Gulf of Mexico PlatForm for Reuse in the North Sea

1998 ◽  
Author(s):  
S. DeFranco ◽  
J. Gebara ◽  
P. O'Connor ◽  
W. Hamilton ◽  
F. Puskar ◽  
...  
Keyword(s):  
Economic Evaluation ◽  
Gulf Of Mexico ◽  
North Sea ◽  
The North ◽  
The North Sea

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

2010 ◽  
Vol 50 (2) ◽  
pp. 737
Author(s):  
Per A. Nesje
Keyword(s):  
North Sea ◽  
State Of The Art ◽  
Cost Savings ◽  
Repair System ◽  
Design Phase ◽  
Significant Cost ◽  
Local Repair ◽  
The North ◽  
The North Sea ◽  
Vertical System

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.

Hydrographic Survey in the North Sea and English Channel

1984 ◽  
Vol 37 (3) ◽  
pp. 407-419
Author(s):  
D. W. Haslam ◽  
F. A. Pielou
Keyword(s):  
North Sea ◽  
English Channel ◽  
Hostile Environment ◽  
Trade Routes ◽  
The North ◽  
Hydrographic Survey ◽  
The Pacific ◽  
The World ◽  
The North Sea ◽  
Tidal Streams

Ever since man first ventured to sea, he has needed to know not only where he was in relation to the land but also what dangers lay hidden below the surface, and what courses to steer in order to avoid these unseen dangers so as to arrive safely and speedily at his destination – making due allowances for the effects of tidal streams and currents.Because his sea-maps were working documents, usually exposed to a hostile environment, fewer such old records have survived than is the case with old land maps. Undoubtedly, whilst many early voyages of exploration emanated from Europe, it should not be forgotten that in the – to European eyes – ‘unexplored’ parts of Asia and the Pacific, similar voyages were being made. However, as trade developed between Europe and the rest of the world, hydrographic surveyors from Europe began to record the information needed along the various trade routes.

scholarly journals Decommissioning Plans for Fixed Offshore Platforms: A Brief Revision

2021 ◽  
Vol 9 (3) ◽  
Author(s):  
Marcio Soares Pinheiro ◽  
Paulo Roberto Duailibe Monteiro
Keyword(s):  
North Sea ◽  
Rio De Janeiro ◽  
The State ◽  
Oil Field ◽  
Offshore Platforms ◽  
The North ◽  
Campos Basin ◽  
Heavy Lift ◽  
Long Time ◽  
The North Sea

Brazil began to explore its seas in the 60’s of the XX Century looking for petroleum. This journey began in the Northeast and the first oil field produced offshore was the Guaricema Field, in the State of Sergipe. During the 70’s, Petrobrás found oil in the Campos Basin, between the States of Espírito Santo and Rio de Janeiro, that became the most important oil province in Brazil until the discovery of the Pre-Salt province, in the Santos Basin. As these fields are producing for a long time, many of them are already completely depleted or their production is in way of to be not commercial anymore, and their facilities need to be decommissioned. This review of decommissioning practices of fixed offshore platforms carried out worldwide has focus on the removal of topside with special vessels designed for this purpose or with conventional methods (crane vessels + barge). It will show the benefits of using specialised heavy lift vessels to remove the topsides and move it to shore for dismantling / recycling / reuse / disposal. The cases for study were the successful decommissioning projects in the North Sea: Brent B/D, Valhall QP, Viking, Curlew, Eider A, Golden Eye and Leman, Iwaki-Oki, Halfweg Q1, Yme and Ninian North.

1300 Tons Grouted Integrity Support Installation Case Study

2020 ◽  
Author(s):  
Beatriz Alonso Castro ◽  
Roland Daly ◽  
Francisco Javier Becerro ◽  
Petter Vabø
Keyword(s):  
North Sea ◽  
Structural Integrity ◽  
High Strength ◽  
Regulatory Compliance ◽  
Lessons Learned ◽  
Oil Field ◽  
The North ◽  
Future Production ◽  
Heavy Lift ◽  
The North Sea

Abstract The North sea Yme oil field was discovered in 1987, production started in 1996 and ceased after 6 years when it was considered no longer profitable to operate. In 2007 a new development was approved, being Yme the first field re-opened in the Norwegian Continental Shelf. The concept selected was a MOPUStor: comprising a jack-up unit grouted to a subsea storage tank. Due to compromised structural integrity and lack of regulatory compliance that came to light shortly after installation, the platform was required to be removed [1]. The remaining riser caisson and the future 1050 t wellhead module required a support to allow the re-use of the facilities and tap the remaining oil reserves. The innovative tubular frame support was designed as a braced unit, secured to the existing MOPUstor leg receptacles and holding a grouted clamp larger than typical offshore clamps for which design guidance in ISO is available. The existing facilities had to be modified to receive the new structure and to guide it in place within the small clearances available. The aim of this paper is to describe the solutions developed to prepare and verify the substructure for installation; to predict the dynamic behavior of a subsea heavy lift operation with small clearances around existing assets (down to 150 mm); and to place large volume high strength grouted connections, exceeding the height and thickness values from any project ever done before. In order to avoid early age degradation of the grout, a 1 mm maximum relative movement requirement was the operation design philosophy. A reliable system to stabilize the caisson, which displacements were up to 150 mm, was developed to meet the criteria during grouting and curing. In the stabilizer system design, as well as the plan for contingencies with divers to restart grouting in the event of a breakdown, the lessons learned from latest wind turbine industry practices and from the first attempt to re-develop the field using grouted connections were incorporated. Currently the substructure is secured to provide the long term integrity of the structure the next 20 years of future production in the North Sea environment.

The Gjøa Semi: a North Sea project relevant for Western Australia

2011 ◽  
Vol 51 (1) ◽  
pp. 589
Author(s):  
Kristian Aas ◽  
Lars Bjørheim
Keyword(s):  
North Sea ◽  
Western Australia ◽  
Oil And Gas ◽  
Development Project ◽  
Conceptual Level ◽  
Field Development ◽  
The North ◽  
Heavy Lift ◽  
The North Sea ◽  
Field Location

Gjøa was the largest field development project in Norway in 2010. Gjøa was proven in 1989 and are now being developed together with nearby Vega satellites. The combined reserves are estiThe recent Gjøa field development in the North Sea has many features that are relevant for the oil and gas developments north of Western Australia. While the field location is not very similar to the north of Western Australia, the field development solution is very relevant. Several subsea clusters are tied back to a semi-submersible platform with export of gas and condensate via pipelines to shore. Other aspects to the project that are relevant to Western Australia are split location engineering between Norway and India, fabrication of the hull in Korea and subsequent heavy lift transport to the assembly yard, pre-installation of the mooring system, and tow to field with ocean going tug boats. The semi concept, which was used for the Gjøa development, is a mature technology with few technical challenges on a conceptual level. On the other hand the building of an oil and gas platform for A$2 billion has many challenges, both economical and technical, that have to be solved to have a successful project for both the client and the contractor.

scholarly journals From a DC-3 to BOSB: The Road to a Breakthrough in Military Safety Measures Against the Risks of Historic, Explosive Ordnance

2011 ◽  
Vol 45 (6) ◽  
pp. 26-34 ◽  
Author(s):  
Gunnar Möller
Keyword(s):  
Baltic Sea ◽  
North Sea ◽  
The Baltic Sea ◽  
Safety Measures ◽  
The Road ◽  
The North ◽  
The World ◽  
The North Sea ◽  
The Baltic ◽  
Real Danger

AbstractApproximately 175,000 mines were laid in the Baltic Sea during the world wars, and in former mined areas in general, 10‐30% of the mines remain sunken on the seabed. The search for a Swedish aircraft downed in 1952 led to the finding of previously unknown minefields in the Baltic Sea. Subsequent historic research has identified approximately 1,985 minefields in the Baltic Sea and 4,400 minefields in the North Sea. These historic minefields present an impediment to the use of the Baltic and North Seas and are a real danger to the increasing shipping, fishery, and exploration of the seabed. The Baltic Ordnance Safety Board (BOSB) was established in 2006 to assemble information on mines and other explosives in the Baltic Sea, to prioritize areas for mine clearance, and to coordinate multinational mine clearance efforts across the Baltic Sea. The BOSB has improved the efficiency of mine clearance and the safety of seafarers and all those who have the seabed as their working ground.

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