the volume calc is a SWAG due to the thickness thing.
But, it's probably more in the ballpark than calculating 5,000 bpd for 11 days. I always wondered about the 5,000 bpd figure, because while that's a very good oil well almost anywhere in the world, it's not worth a multi-billion dollar investment for further development, and it wouldn't be worth it to BP to run production casing in it.
It will, no doubt, be a bigger deal than the Valdez.
And. no, oil companies will not be able to write it off as business as usual. There will be serious consequences as a result of this.