Any thing is possible with these globalist freaks. The global warming hoax showed us how a large conspiracy could be pulled off. In this case however, there are additional aspects that should be considered. This well also contained a large amount of methane. One of the strongest green house gases. We have the drill pipe and inner casing of the well bore cemented, but that is only half the picture. Still need to cement the outer casing area to completely close the well. And we only will have BPs word that the Relief Well has worked. They could just declare victory and leave this well seeping large amounts of methane and oil through the loose sediments. Who could prove them wrong ? The environmentalists that are in Obama/BPs back pocket ? Over a few years the additional methane could have a global effect. In fact, here is an interesting wiki page talking about the Clathrate Gun Hypothesis. They could be implementing a very minor version of this theory. Not a planetary killer, but a planetary global warmer. Might explain all the skipping stone clathrates we see on the sea floor.
Clathrate gun hypothesis
BTW - Only posted this because you were asking for conspiratorial thoughts.