"Damn. Bob, can you speak to the procedures and times it would have taken the Driller to shut it in?"
I’m sorry I cannot. I do seem to recall there was a post addressing that Q earlier.
Alf, I would certainly agree that there could have been confusion during those last 20 minutes of the log. On the other hand the Jr. TP was also on the floor at the time and had earlier agreed to call Ezell at the first sign of any trouble. His presence would have made driller’s life easier if there was indeed panic.
Here is what I think happened. During normal circulating ops you have a closed loop system, pumping mud down inside DP and recovering it across the shakers before it re-enters the pits. There, pit level is more or less stable except for give and take from the formation and volume of drill cuttings that have to be replaced with mud as hole is made. Pit gain is Unusual.
But there was no circulation going on here. Sea water was being picked up and pumped down while mud returns were being pumped (or poured) overboard to the Bankston.
In this case there would be no expectation of a constant pit level so pit gain (or loss) could reasonably be ignored.
But the reasonableness of that expectation changed the moment the rig pump(s) were turned off. At that moment pit gain became hugely important because the difference in rate of sea water in and pit level could no longer be attributed to differences in pump rates. But after 1 1/2 hours of reasonably ignoring pit gain, human nature prevented them from making the shift to changing it’s status once pumps were turned off (pumps may have been turned off because displacement was complete?). I believe this whole thing came as a complete surprise to them and that the Jr. TP did make the trouble call to Ezell around 10 of 10.