New Oil Slick In Gulf Waters Linked To BP Well 98
An anonymous reader writes "A new oil sheen appeared in the Gulf of Mexico last week, and now scientists have confirmed that the oil bubbling up to the surface matches the type released by BP's Deepwater Horizon oil well last summer. Ed Overton, a chemist at Louisiana State University, examined samples of the oil and said, 'After examining the data, I think it's a dead ringer for the MC252 oil, as good a match as I've seen. My guess is that it is probably coming from the broken riser pipe or sunken platform.'"
Plausible other sources (Score:4, Interesting)
I can think of at least one plausible (and very unwelcome) scenario that could have Macondo reservoir oil coming up to the surface, but not from the original well. Actually, now I can think of three ways.
There could be a leak from one of the two relief wells. Which would be unwelcome in the extreme, but at least they're known quantities, and re-entering a well in good condition for an "intervention" is a pretty routine operation. That's the nice option that has Macondo oil coming to surface but not from the MC252 well.
Alternatively, with all the high-pressure operations happening on the MC252 well and on the relief wells, then it's possible to have fractured the cap rock over the HPHT (high pressure high temperature) reservoir, allowing oil and gas to start to migrate up to the surface, in exactly the same way that natural oil seeps occur all over the Gulf (and other oil provinces). That could be the start of a long-drawn out process of draining the reservoir to surface. Which shouldn't take more than a few centuries.
Actually, there is a third plausible option : searching for naturally occurring oil seeps is a well-established technique for exploration. I've had several satellite imagery companies trying to convince me of the value of their imagery and analysis tools for finding precisely this sort of oil seep, as a guide to where to put your seismic boats, then your seabed samplers, then your drilling rigs, then your production platforms. I don't know if BP/Andarko used seep-tracking in their prospecting in this area, but it's certainly possible. In which case, this may just be a "normal" seep that is being noticed because of the intense scrutiny of the area.
Anyway, with those several possibilities, the chemist is being correctly cautious about attributing the origin of the oil. He can be confident that the oil has the same characteristics as the ones that he's measured from the main flow, and that suggests but does not prove the point of origin, or the reason for the oil coming to the surface.
Oil from the rig?
It's not impossible that there was enough crude in storage on the Deepwater Horizon for it to have started seeping now. But it's fairly unlikely. By the stage they'd got to in the well, they should have finished testing the well, and the testing equipment spread would have been being stripped down for return to shore (and taken OFF RENTAL, as the encouragement to get it done NOW). You don't ship separators, chicksans, production chokes etc full of anything other than thin air, let alone full of flammables. So there is unlikely to have been more than a few gallons of Macondo crude onboard. Plenty of diesel, lube oils, gas bottles for the galley or the welder, certainly helicopter fuel ... but Macondo crude itself is unlikely to have been present in more than sample quantities. And all of those hydrocarbons have very different chemical signatures, so should be easily distinguished.