Containment capability in the cross-hairs

December 31, 2010

Post-Macondo efforts to improve well containment capabilities on both sides of the Atlantic moved into higher gear last month.

In the US it was confirmed that Technip will handle front- end engineering and design of a proposed subsea well containment system that could be used to respond to another blowout in the deepwater Gulf of Mexico.

ExxonMobil, which is responsible for the engineering, procurement and construction of the system on behalf of the Marine Well Containment Company, did not disclose the value of the Technip contract in a 7 October announcement.

The organization’s founding members – ExxonMobil, Chevron, ConocoPhillips and Shell – have pledged an initial investment of $1 billion to develop the rapid-response system (OE August). The four founding companies collectively have dedicated 100 employees to work full-time on the project.

BP said last month it would join the group and make available the equipment used in its effort to contain and cap the Mississippi Canyon block 252 Macondo well following the 20 April explosion of the Deepwater Horizon. The equipment will be available to respond to a potential blowout while the new containment system is in development, ExxonMobil said.

The scope of the Technip contract includes engineering and design of a containment assembly, manifold, control umbilicals, accumulator, dispersant injection equipment, risers and flowlines. Scheduled for a 2012 completion, the containment system will be 10,000ft water depth rated and capable of capturing up to 10,000b/d of oil.

containment graphic

Learning lessons

Meanwhile the UK oil spill prevention and response and advisory group (Osprag), set up in May to bring Macondo incident learnings back to the UKCS, is commissioning detailed designs for a full/ partial pressure capping device.

After evaluating three design concepts put forward by Wood Group Kenny, the group opted to progress with a modular device it considered best suited to typical UK continental shelf metocean constraints, particularly the severe wind and sea conditions encountered West of Shetland. The detailed design and procurement phase will be project-led by BP, working closely with Osprag and other UK operators. Manufacturing time is currently estimated at around 11 months.

‘The design allows installation at various points of the subsea wellhead, the blowout preventer or lower marine riser assembly to stop the flow of oil and buy valuable time for engineers to develop a permanent solution for killing the well,’ said Osprag chairman Mark McAllister, chief executive of Fairfield Energy.

‘Time is of the essence for minimising environmental impacts when bringing a well under control,’ stressed Oil & Gas UK’s Brian Kinkead, who leads the Osprag technical review group responsible for developing the capping concepts. ‘The cap design therefore needs to be compact, relatively low weight and flexible for ease of handling and installation in short operational weather windows.’

Short windows

According to Kinkead, the approach is likely to utilise a variety of adapters, connectors, a main body incorporating two gate valves, choke and kill manifolds and a variable flow ported sub/cap with an overall system rating for 15,000psi working pressure.

Such a device could be deployed in sea states of up to 5m, depending on the vessel used, and capping could be achieved within 20-30 days of the incident, depending on weather and well site conditions.

McAllister added: ‘This work can also help inform the development of a longer-term regional or global (non-US) response which is being co-ordinated by the Global Industry Response Group under OGP [the International Association of Oil & Gas Producers].’ Russell McCulley & Jennifer Pallanich

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