UK-based BP has completed a three day survey to identify potential sources of a surface sheen near Mississippi Canyon block 252 in the Gulf of Mexico.
The company said the area has been visually inspected at the sea floor and they can confirm there is no leakage, thereby attesting to the integrity of the Macondo well, which was permanently sealed in September 2010.
The survey was conducted jointly by BP and Transocean, with Coast Guard BP confirming an 86-ton steel cofferdam, a piece of containment equipment used during the Deepwater Horizon response, as the probable source of the surface sheen.
A remotely operated vehicle (ROV) undertook 70 hours of video inspection from October 15 through to October 17 and observed that small oil drops were coming out of a small connection port on one side of the cofferdam.
The Coast Guard has determined the sheen is not feasible to recover and does not pose a risk to the shoreline.
In May 2010, the cofferdam was lowered over a leaking drill pipe at the Macondo well to capture the oil and send it to the surface; during the response programme, oil and slushy methane hydrates were trapped inside the cofferdam.
On 15 July 2010, the Macondo well was capped and permanently sealed with the approval from the US Government, while the well’s integrity was also confirmed.
Previously BP confirmed the integrity of the Macondo well and the two associated relief wells with an ROV inspection, which came after a separate surface sheen was reported near the well site on 25 August 2011.
Image: BP’s world headquarters in London, UK. Photo courtesy of WhisperToMe.