After a surface sheen was spotted in the immediate vicinity of the Macondo well site, BP has reported that there are no signs of a fresh leak from the well. The company has proposed that the oil may have come from the disused cofferdam that was deployed in an unsuccessful attempt to cap the well during the five month long leak.
The cofferdam is an 86 ton, 40 ft tall steel containment device, lowered over the well in an attempt to funnel oil to the surface. The device was abandoned after it was found that highly flammable methane hydrates had begun to form on the inside of the dome. Once the hydrate build-up had been discovered, the cofferdam was no longer considered fit for use and was deposited some 500 m from the site of the well.
BP has released a statement saying that, “On 17 October, Remotely Operated Vehicle video inspection observed small, intermittent drops of oil coming from an opening at the top and another on one side of the cofferdam.”
“Samples of the droplets have been collected from the opening at the top, known as the stovepipe and will be analyzed to confirm a match with the sheen.”
In addition to checking the actual well, BP also examined the relief well and the 4500 ft riser and was unable to find any oil leaks there. The US Coast Guard has also confirmed that the sheen poses no risk to the shoreline.
Edited from various sources by David Bizley
Read the article online at: https://www.oilfieldtechnology.com/drilling-and-production/19102012/bp_reports_that_new_sheen_is_not_from_a_fresh_leak/