Letters of intent for the removal of two redundant North Sea platforms, H7 and 2/4-S, have been awarded by Statoil on behalf of operator Gassco. AF Decom Offshore will remove and sell H7, while Saipem UK will remove 2/4-S. Both installations are to be removed by the end of 2014. The conditional contracts are subject to sanction of the decommissioning projects by the Gassled joint venture.
The H7 booster platform is located in the German sector of the North Sea. From 1977-99 it was used to maintain pressure in the pipeline transporting gas from the Ekofisk Centre to the terminal in Emden, Germany. The platform was disconnected from the pipeline four years ago. AF Decom Offshore's contract, with an estimated value of NKr420 million, involves removal of the whole installation and transportation to its Vats yard north of Stavanger for disassembly and scrapping.
AF Decom's letter of intent also includes an option to decommission a similar platform, B11.
The 2/4-S riser platform is located in the Norwegian sector and came onstream in 1985. It was used to transport gas from Statpipe to the Ekofisk Centre. From 1998, 2/4-S became superfluous as the Statpipe gas was sent directly into Norpipe through the Ekofisk Bypass pipeline. The 2/4-S topside was removed in 2001. Saipem UK's contract, with an estimated value of NKr400 million, is for the removal of the jacket and its transport to shore. A separate contract for scrapping the 2/4-S jacket will be awarded later.
H7 and 2/4-S are owned by the joint company partnership Gassled. Gassco is the operator, with Statoil as the technical service provider for 2/4-S and ConocoPhillips as the technical service provider for H-7. Statoil is carrying out the removal projects on assignment from Gassco. MC
Testing times
Cutting Underwater Technologies (Cut) is looking to complete both functional tests and in-water trials on its SBC 58 – hailed as the first industrial sub bottom cutter – by the end of the year.
The SBC 58 (so called because it can cut up to a diameter of 58in) is described by the division as. The SBC 58 is a much bigger and more powerful machine than the prototype successfully tested a few years ago by Cut, a division of Tecnospamec. It was recently put through a severe assessment trials programme.
Following in-air function testing in Aberdeen, the system was shipped to the company's Houma, Louisiana, facility to undergo in-water deployment, positioning, dredging, cutting and control system trials.
The trials, in 10m of water, aimed to perform diamond wire cutting of a 48inOD x 2in WT pile 15ft below the mud level. Positioning of the system in this shallow-water and inshore deployment was problematic from the start and, Cut believes, contributed greatly to the mechanical breakdown of a dredging system component and early curtailment of the trials programme.
The company says it now has a dedicated team investigating the problems encountered, adding: ‘Based on our review of the information gathered, our engineers are now working on solutions that will drastically simplify the SBC operational deployment, positioning and engagement onto the target. The new configuration is already provided by our SBC patent, and includes an almost vertical deployment of the dredging/ cutting units connected directly to the target leg/pile just above the seabed.'MC
DIVERLESS DECOM: Aberdeen-based specialist subsea service company DOF Subsea UK has been contracted by Hess to provide diverless decommissioning services from its new multipurpose support vessel, the Skandi Skansen (pictured left), in the UKCS Ivanhoe/Rob Roy field. The £5 million contract, hailed by DOF Subsea UK managing director Garry Millard as ‘one of the first diverless decommissioning projects in the North Sea' with an anticipated duration of 21 days and is scheduled to start in 3Q 2011. The scope of work includes the engineering and recovery of four mid-water arches, eight flexible risers and associated structures and umbilicals.
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