[null and void]

Dropped down or was blown up.

Anyway I agree that the BOP probably isn’t designed to shear two pipes to close off the well.

There are also reports that bits of rubber were coming up in the mud before the well blew.

The roughnecks interpreted this as evidence that the seals on the BOP’s hydraulics were damaged.

They were, of course, ignored.

[Smokin' Joe]

Circumfrence=pi*the diameter, and squashed, divide the circumfrence in half for the width. If the riser is 22 inches, for instance, it would be 3.14*22/2 or about 33 inches wide squashed flat. The two sections of pipe inside are less than half of that, just eyeballing them, Each of them would be the same formula (3.14*the diameter of the pipe)/2

Five inch drill pipe would squash down to about 7 1/2 inches wide, twice that would be about half the width of the riser at 22 inches diameter.

That's just an example, but production casing, the smallest at 7 inches, would squash down to just about 11 inches wide, much larger than the drill pipe.

This looks more like someone dropped a joint or stand (three ~31 ft. joints of drill pipe screwed together) down the hole while all hell was breaking loose on deck. Without the numbers, I can't say for certain, but that could help indicate whether the pipe in the riser was casing (from downhole) or not.