Thursday, January 24, 2008

Oozing mud overtops barriers, no blame found

We may never know what triggered the Indonesian Mud Volcano, but sure-as-shootin', you know the mud won't stick to the richest family! Now, it is overtopping the feeble barriers, and stands poised to engulf more land.

I'm still not clear on the mechanics of large mud volcanoes, but the essential ingredient is oil and gas. The gas is probably the driving mechanism for the mud, which must involved ancient unconsolidated oceanic sediment. Normally, once rock is hardened by time (lithification), it can't be 'melted' again by heat. But it is possible to have a high-pressure gas pocket that survived a considerable time.

So, what we had here was a high-pressure pocket of mud, capped by some thin volcanics. Oil companies have blow-outs all the time when they drill, so now they are smart enough to make some attempt at blow-out prevention. This involves a heavy casing of steel and concrete, and a blow-out valve which can pinch off the drill stem. In most cases it works.

It is possible that the drilling in Indonesia did not have adequate blow-out prevention, but I find it hard to believe that the thick mud could have forced its way up an 8 inch hole. Then, there would have to have been a high enough flow to erode the hole to a larger size.

It is also quite likely that this was a disaster waiting to happen, as it has happened spontaneously before. That would have required a large crack developing, and the mud oozing out the rupture. I find this easier to contemplate.

Who knows? The point is that this mud is not going to stop. In that area of the world, it could have been just as likely that a real volcano could have started. Then there would be no question of running like hell!

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