That's always been my take also - the ocean basins are basalt and the channel/cavern thesis doesn't compute. But then again there's a hell of a lot of oil coming from way down there, there is indeed a lot of outrageous pressure, and my wife says I've been wrong before.
WHAT "outrageous pressure"?? We know what the reservoir pressure is.....11,000psi (0r 13000 psi depending on whether you add or subtract the backpressure of the seawater column). This is MEASURED pressure, taken IN the reservoir, and the measurement was taken BEFORE the system crashed and burned, when BP was still ecstatic about the new find.....so there is absolutely no reason for BP to have lied about it.
it could burst. there is more than oil coming out from under the mantle. there are rocks plus sand that act as abrasives and the pressures of oil leak is tremendous.