[QUOTE=alcor;38026]My understanding of reservoirs is that they contain the high pressure zone. I know of no other zone below. The pressure charts will show if they encountered any higher pressure zone while drilling. I have no idea where you would find the drilling data.
As to whether the casing floated, there’s no evidence of this while running and cementing.[/QUOTE]
The geology shows a high pressure zone blow the resevoir.
The caing was designed to (almost) to handle the production zone. Somebody (help) can calculate what it would take to float a 9 5/8 * 7" string of casing with 16# mud on the outside and a decresing weight on the inside. (while they were displacing).