Engineering news
A well capping device developed by the British oil and gas industry in response to last year's Deepwater Horizon disaster is ready for deployment if needed, the UK Oil Spill Prevention and Response Advisory Group (Osprag) has said.
The “major piece of new equipment”, intended to be a key element of the industry’s oil spill response capability, was unveiled by energy minister Charles Hendry MP at the SPE Offshore Europe 2011 conference, which is taking place in Aberdeen.
The decision to construct the cap came as a result of a recommendation by Osprag, the body set up by the UK oil and gas industry, its regulators and trade unions in response to the disaster in the Gulf of Mexico in April last year. The well capping device was built in order to seal off an uncontrolled subsea well in the event of a major well control incident, minimising environmental damage and buying time for engineers to develop a permanent solution to seal the well.
The cap works by shutting in and holding pressure on an uncontrolled well and uses a choke and a series of valves which close down and stop the flow of hydrocarbons into the marine environment.
The device was constructed specifically for subsea wells in the UK Continental Shelf (UKCS). Its modular design means it can be attached to various points of subsea equipment and deployed to the widest possible range of subsea well types and oil spill scenarios which could occur – including in the deep waters and harsh conditions west of Shetland.
The cap is rated for deployment in water depths up to 10,000 feet on wells flowing up to 75,000 barrels per day at 15,000 psi. This is a much greater depth than any of the deepest wells in the UKCS, Osprag said.
Its portable size and weight also makes it relatively easy to deploy quickly from a wide range of vessels, even during short weather windows.
The capping device was designed and manufactured in seven months. “This was achieved through access to pre-existing equipment systems, a streamlined project management approach and close collaboration with the industry’s global supply chain,” Osprag said.
The device has completed factory acceptance and system integration testing and will be handed over to Oil Spill Response, which will store it in readiness at an operational base in the north east of Scotland with deployment capabilities in the event it should ever be called upon.
James House, chair of Osprag and regional vice president and managing director of Apache North Sea, said: “I’m pleased to say that the successful completion and availability of this cap marks a significant step forward in industry preparedness and significantly bolsters our capability to deal with a major loss of well control.
“Despite the fact that there has not been a major loss of well control in the UK in over 20 years of offshore operations, we believe that having such a contingency device here in the UK is essential, as it allows a quick response no matter how unlikely a scenario this is.
“Our long-term focus remains, however, to prevent such incidents from occurring in the first place and the cap complements other work being carried out by Osprag in spill prevention. Osprag's work demonstrates the industry’s determination to learn from experience and continuously improve the safety of operations so that risks to people and the environment are minimised or eliminated.”
Archie Smith, chief executive of Oil Spill Response, said: “[It is] an important piece of equipment which would minimise marine pollution should a major loss of well control ever occur subsea in UK waters.
“The cap will be held on standby and will form part of our suite of response measures which have kept us at the forefront of oil spill response services for 25 years.”
The design development was overseen by Osprag's technical review group, working with BP, which agreed to project manage the detailed design, procurement and construction phases, with support from engineering services firm Wood Group Kenny. The device was commissioned by the industry’s specialist organisation, Oil Spill Response, and was built by oil, gas and process engineering firm Cameron in Leeds.
Capping device: key facts
It can quickly be deployed:
- At the widest possible range of wells and oil spill scenarios which could occur in the UKCS, including West of Shetland
- To various points of the subsea stack
- At water depths of between 100 metres and 3,048 metres (328 feet to 10,000feet)
- In wave heights of up to 5 metres (16feet) depending on the vessel/rig used
- From a wide variety of multi-service vessels or drilling rigs
- To wells flowing up to 1,034 bar (15,000 psi) in pressure and 121°C (250°F) in temperature
- Even where there is a high content of hydrogen sulphide present
- On to a well flowing up to 75,000 barrels a day
Dimensions:
- Length – 4.26 metres
- Width – 3.97 metres
- Height – 7.14 metres (can be adjusted for transportation)
- Footprint – 15.8m² if frame fully plated
- Weight – approximately 40 tonnes