Discussion: Gulf of Mexico an oil well minefield?

The Deepwater Horizon, as is fairly well known, was in the middle of a procedure designed to plu the hole with cement when the blowout occured. This procedure was part of an operation which would render this test well ‘temporarily inactive’. A recent article by the Associated Press has, however, highlighted yet another area of concern related to the Gulf. That not only is the Deepwater Horizon one of the thousands of oil wells in the region, but it was infact about the join the 27,000 abandoned gas and oil rigs in the area.

Detail of a map showing geology, oil (in red) and gas (green) fields, in the Gulf of Mexico Region Illustration: U.S. Geological Survey US Geological Survey. From the Guardian website.

This may not seem to be an issue, but the fact is that these abandoned wells are pretty much forgotten. They’re not routinely checked to assess the seals, and they’re *. Some of them are under the heading ‘temporarily abandoned’ which just seems to mean the oilcompany has to less rigorously plug them... and some them have been like this since the 1950s.... that’s over half a century. Similarly, many were plugged before the relatively stringent safety conditions were applied, so even the original condition of the plugs comes into question.

Changing geological conditions can alter the pressure within the boreholes and cause the cement to fail, or the oil and gas to force its way through. As a result, both fully and temporarily abandoned wells found on land have been regularly found to leak, and it stands to reason those under the sea would too, especially with the added negative conditions of water and pressure. Spokespeople for various oil companies seem to maintain the dubious notion that plugged wells ‘do not normally degrade’ and even the Government regulators in America say abandoned wells are ‘presumed to be properly plugged and expected to last indefinitely without leaking’. This seems unlikely, and the fact oil companies don’t seem to want to even consider this notion publically is fairly worrying. ‘Me thinks the lady doth protest too much’ or words to that effect...