Friday, June 18, 2010
BP denies it. But this video confirms it: oil is leaking from cracks in the sea floor. It could spell the beginning of a far worse catastrophe than anyone expected. If the sea bed fissures and collapses around the well bore, the flood of oil will be of an order of magnitude that the world has never experienced.
The sea floor in this area of the Gulf of Mexico is not solid rock, but rather sand held together by a substance called methane clathrate, or "fire ice", in which methane is trapped within ice crystals. It's the same substance that fouled the "top hat" containment dome BP tried, and forms when methane and water combine under high pressure. It's not exactly dense or stable.
We now learn via Bloomberg that BP was dealing with surging natural gas coming through fissures around the well shaft as early as February -- two months before the explosion of the Deepwater Horizon. They tried three different types of cement to seal the leaks over the course of a week, which is highly unusual, and ultimately the seal broke down causing the explosion of the rig.
"While gas surges are common in oil drilling, companies have abandoned wells if they determine the risk is too high. When a Gulf well known as Blackbeard threatened to blow out in 2006, Exxon Mobil Corp. shut the project down."
So, what happens if there's a collapse of the unstable seabed over the existing gusher? That depends on the extent of the collapse. As the bore hole continues to erode, eventually the casing will detach and relief wells will become irrelevant. At that point, the entire reservoir of oil -- approximately 2 billion barrels -- could empty over the course of the next few decades.
Various people have been crunching the numbers on this, but mostly they use total volumes of water and assume uniform distribution, and that is not what will happen in the short term.
Initially the oil will move into and concentrate in the ocean currents, which is exactly the same place marine life tends to congregate. We may soon be longing for the simplicity of Exxon Valdez.
See also BP's Spill Plan: what they knew and when they knew it and my post of yesterday: BP's nightmare scenario.
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