So the rupture in the well pipe is where? In the rock or above where the rock starts or both? You said the trouble is below the soft stuff. I’ve read conflicting info on that so I don’t know.
There’s also the issue of how much support is being provided now to the well pipe. Seems to me that the answer there would be not enough until you get to the rock so everything above it is not stable. Is that correct?
I’m not exactly clear on the orginal cement operation. But it was at depth. It would have been to seal the oil producing zone off from the annulus (outside) of the hole above the oil zone. The well is double-cased, so this would include between the outer casing and the rock, and between the inner pipe and the outer casing.
I believe that the idea was once this deep cement job had “set up”, then they would remove the heavy mud from the well and replace it with seawater. And once that was done, put a shallower cement plug into the inner well pipe.
But yes, if there is a breach at depth of the well, which there obviously is, the oil under pressure may be working its way up along the outside of the outer casing - between the rock and the casing.
When it reaches the soft mud at the bottom of the gulf, I would imagine that it will both disperse into the mud, and start creating a subsidence near the well., which could cause further harm to the shallow portion of the well I suppose.
Okay - here’s one last article that I found awhile ago on the Ixtoc (Mexican) well that blew out in 1979. I am not sure on the rate per day that it gushed, but I think it is in the ballpark of the BP “spill”. But it was not some minor spill.
http://www.guardian.co.uk/environment/2010/jun/01/gulf-oil-spill-ixtoc-ecological-tipping-point
But although Ixtoc was a big disaster, it did not develop into the long-term catastrophe that scientists initially thought was inevitable.
“This is not to say there were no consequences. Just that the evidence is that these are not as dramatic as we feared,” says Luis Soto, a marine biologist from the National Autonomous University of Mexico. “After about two years the recuperation was well on the way.”
Wes Tunnell, now at the Texas Harte Research Institute, took samples before and after the oil arrived in Texas that showed an immediate 80% drop in the number of organisms living between the grains of sand that provide food for shore birds and crabs.
“Sampling a couple of years after the spill indicated the populations were back to normal,” he says. Six years after Ixtoc 1 exploded it was hard to find any evidence of the oil, he says. “It is rather baffling to us all. We don’t really know where it went.”
But although their message is hopeful, those who studied the Ixtoc disaster warn against assuming the gulf is automatically heading for another quick comeback.
Ixtoc 1 stood in just 50 metres (165ft) of water, while Deepwater Horizon was drilling 1,500 metres below the surface. It is also likely that the quantity of chemical dispersants being used today is significantly larger, potentially blocking the work of the oil-eating micro-organisms.
But what worries Tunnell most is that over-fishing may have reduced the ability of the gulf to bounce back. “It was much more resilient 30 years ago than today. My fear is it is reaching a tipping point.”