[QUOTE=Careener;31913]Company man. Thanks for your good comments. However, could you or someone else clarify a couple of things because I don’t understand how casing could run in dry.
- The shoe has a one-way check valve preventing mud back-flow into the bottom of the casing as it is lowered. so, when you say it plugged, what do you mean? It is plugged in one direction on purpose.
- The casing is periodically filled with mud as it is lowered (otherwise, it wouldn’t sink because of buoyancy). The mud would prevent any bubble from forming in the bottom of the casing unless perhaps the float collar was defective and blocked flow, which could cause air between the float collar and shoe. However, that would only be as much air as could fit in one 40-foot casing joint.
Really appreciate your help.[/QUOTE]
If fill ups weren’t right or there was a plug formed while RIH then it is quite possible under balance conditions that the well could have come in on the backside while pumping the cement due to a bubble. I spoke to someone just a few minutes ago who is a very reliable source to me & is close to a couple of people who were on the rig. He said the casing was filled every joint & circulated 4 times while RIH & that the rig circulated bottoms up before pumping cement. The only other scenario I can come up with is somehow it is possible that while pumping cement a frac could have formed into another zone with a much higher bottom hole pressure causing the well to come in them. The biggest part of this situation that bothers me is that this well somehow magically blew out at surface. I have been on many wlell control situations & it doesn’t happen that way.
The riser held somewhere in the neighborhood of 1900 Bbls. If the well blew out @ 20,000 Bbls./day it would have taken 1/10 day or over 2 hours to come in with that much hydrocarbon to cause an explosion. I also don’t understand how they were just circulating the rise & finished with the job & there is flow coming up the work string.