Nowadays, deepwater drilling is one of the important parts of drilling in the world and there are a lot of ongoing deepwater operations. Our team will start focus on subsea well control and this topic is about hard shut in procedure while drilling with a subsea stack. This is quite similar to surface stack but it is quite tricky how you space out the well properly because the BOP is way down below approximately thousand feet from sea surface.
There are 3 steps which are space out, shut down and shut in and the details for the procedure are below.
1st step: Space Out
- Stop drilling, pick up off bottom and space out to ensure that the tool joint will not be located across the BOP. Personnel need to pre calculate where to space out because the position on the rig floor will affect where the tool joint down hole.
2nd step: Space shut down
- Shut down pumps
3rd step: Shut-in the well
- Shut the well in on the top most BOP as annular preventer first and then open the upper choke valve against a fully closed choke manifold valve.
- Confirm well is properly shut in and double check line up. Check the accumulator unit to ensure that there is no leakage after closure of the BOP.
- Inform rig supervisors and start record data as pit gain, Shut In Casing Pressure, Shut In Drill Pipe Pressure.
Reference books: Well Control Books