PARIS, April 3 Total plans to send
eight experts to its leaking Elgin oil and gas platform on
Wednesday afternoon or Thursday morning to assess the steps
needed to stop the potentially explosive gas leak, a spokesman
said on Tuesday.
Here is a timeline of events at the stricken platform:
--2001: The Elgin gas field starts production. The Elgin
well head is connected to 8 production wells and 3 exploration
wells. Six wells are still in production mode.
--January 2011: Total stops production at G4 well, the
leaking well, after the group detects production problems. As a
result, the French oil major plugs the well 5,500 metres below
ground level to isolate it from its reservoir.
--February 25, 2012: While the well is no longer producing,
Total detects pressure and temperature problems in the A, B and
C annuli, the outer layers of the well's pipe casing.
--March 4: Total decides to "kill" the well, which involves
injecting drilling mud into the well head to cap it
indefinitely. In the following days, the group proceeds to carry
out a risk assessment for the operation, mobilises the required
equipment and brings it on site.
- Total proceeds to "kill" the well. The company uses the
Rowan Vicking drilling rig to carry out the operation.
- Total detects a gas leak during the works and proceeds to
evacuate the platform's all 238 staff in early afternoon.
- A flare on the Process, Utilities and Quarter (PUQ)
platform, 100 metres away from the gas leak, is left alight to
burn off excess gas in the platform, raising fears the gas cloud
could ignite and cause a major explosion.
--March 29: Total says the source of the leak is a
calcareous rock formation (hod) 4,000 metres below ground level.
--March 30: Total says the likely cause of the leak is high
pressure that would have moved the ground and the pipe, creating
some small cracks in the annuli A of the outer pipe casing.
--Total says it has decided to carry out two rescue
operations in parallel: the first is the most risky one but is
considered to be the fastest. It consists of sending experts by
helicopter to land on the PUQ platform. The experts will then go
to the production platform and plug a pump into the well from a
nearby ship to inject drilling mud to shut the well.
The second option consists of drilling two relief wells to
ease the pressure inside the G4 well. But this could take up to
6 months and be more costly.
-A senior union official says Total repeatedly assured
workers on the Elgin platform that a leak was impossible until
just hours before evacuating them.
--March 31: Total says the flare extinguished itself without
human intervention on March 30, reducing the risk of a blast.
--April 2: Total says the leak is costing it $1.5 million
per day in lost earnings and $1 million daily in response costs.
Source: Reuters News
(Compiled by Muriel Boselli; editing by James Jukwey)