Applying the technology and lessons learned from field developments in west Africa and the North Sea to help unlock Australia's more complex gas discoveries

2008 ◽  
Vol 48 (2) ◽  
pp. 467
Author(s):  
Marin Abélanet
Keyword(s):  
West Africa ◽  
North Sea ◽  
Lessons Learned ◽  
The North ◽  
The North Sea

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.

Challenges of Deepwater Developments

2011 ◽  
Vol 367 ◽  
pp. 367-373
Author(s):  
Babs Mufutau Oyeneyin
Keyword(s):  
North Sea ◽  
Production Systems ◽  
Lessons Learned ◽  
Gulf Of Guinea ◽  
The North ◽  
The United Kingdom ◽  
Keynote Paper ◽  
Depth Analysis ◽  
The North Sea ◽  
Technical Issues

This keynote paper attempts to catalogue the key business drivers for deepwater developments especially for the Mediterranean, Gulf of Guinea, Gulf of Mexico and other deepwater environments and the challenges arising thereof. The paper goes further to provide some in-depth analysis of the key technical issues such as subsea production systems integrity, multiphase flow assurance management, lessons learned from the shallow water as well as the deepwater areas like the North Sea before addressing some of the technology developments and competency required to take the new regions forward. . The paper ends with a presentation of what the new National Subsea Research Institute [NSRI] in the United Kingdom is doing and can do to support future deepwater developments.

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.

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