Those wells were on land, and there was a rather simple solution to cap them.
Massive gushers a mile beneath the sea are unprecedented.
A wrecked wellhead is a wrecked wellhead, and those wells had the casing integrity to be capped.
If need be, the sea bottom can be excavated and a new wellhead attached.
It is unlikely however, with an apparently compromised casing string, that that would be effective.
The best bet in this instance is the relief wells being drilled. It should be possible, if the casing program in the relief wells is right, to frac into the old wellbore from close proximity, to kill the well from the relief well(s)--and plug off the producing zone.
We set plugs in open hole all the time, no casing is required. Even if the casing in the hole has 'mechanical problems', the kill mud and cement are liquid and will go anywhere the oil would in the wellbore (and beyond if the casing is compromised).
The question is one of giving the rigs drilling the two relief wells time to get the job done. In the meantime, BP is recovering unprecedented amounts of oil from the well, before it gets away in the gulf.
While the BP disaster is a disaster, I think these guys talking of collapsing bubbles, tsunamis, etc. are over-the-top. These types of large leaks have occured before. The Ixtoc 1 spill in the Gulf is the obvious one. I have another article with marine biologists from American universities saying things about the Ixtoc spill like “We went out a year later to monitor the devastation on the shrimp grounds. We were amazed to find very little - after only one year. We were baffled. However, the types of oil and other products are all a factor, so this BP spill may take years to clean up, we just don’t know”.
Here’s some basic information on some other huge blowouts:
http://www.first-draft.com/2010/05/the-ixtoc-1-spill.html
Excerpt:
It Came From Mexico: The Ixtoc I Oil Spill
We in the United States of Amnesia have short memories:
The exploratory oil well two miles below the surface of the Gulf of Mexico exploded in a ball of fire, spurting millions of gallons of crude into the sea. As weeks turned to months, oil executives grappled with capping the well. The growing slick turned into an immediate ecological nightmare.
The year was 1979. The blowout of the Ixtoc I, drilled by the Mexican-run Pemex, retains the dubious record of causing the world’s largest accidental oil spill, dumping an estimated 138 million gallons over nine months. Eventually, Pemex cut off Ixtoc I with two relief wells and a cement seal.
With top BP executives, scientists and Obama administration officials searching for a solution to capping the Deepwater Horizon blowout off the Louisiana coast, perhaps they could find a blueprint in the Ixtoc I experience, observers say. They also may find lessons from the Montara oil spill last August off the northern coast of Australia, where it took five tries and nearly three months to stop the flow of as many as 84,000 gallons a day into the Timor Sea.
If some scientists, who say BP and the U.S. Coast Guard are underestimating how much oil is leaking now, are right, the current gusher could easily eclipse the demise of Ixtoc I in the Bay of Campeche. By their count, instead of the 210,000 gallons leaking per day, it’s more like 4 million ``Everybody keeps saying the spill in the Gulf is unprecedented,’’ said geologist John Amos, president and founder of SkyTruth, a nonprofit that investigates environmental issues using satellite images. ``That is such bull——t. We had perfect precedence.’’