professional explanation needed

As most have, I have been watching this disaster unfold and hope/pray that the gulf will be able to be saved in a relatively quick time frame. But I don't understand the mechanics involved in the well having so much pressure in it inherently. And I am a bit fuzzy on how the sea floor could be damaged because of whatever happened. If a resident expert could explain it for the simple folks, it would be super.

Thanks in advance for any help.