There are several figures that must be recorded after the well has been properly shut in in case of a well control situation.
Shut-In Casing Pressure (SICP): Read and record the shut-in casing pressure (casing gauge).
In order to get the proper pressure reading, the casing gauge should be installed upstream of the closed choke.
Shut-In Drillpipe Pressure (SIDP): Read and record the shut-in drillpipe pressure. You must remember that whether you have a float in drilling string or not.
If there is no a float is in the drillstring, the shut in drill pipe pressure can be read directly from the standpipe manifold.
If there is a float in the drillstring, you need to bump the float in order to determine the correct shut in drill pipe pressure. I will write about how to bump float to record the shut in drill pipe pressure later.
Time: Record the time that the well control situation is occurred and keep an accurate time log for the entire well kill operation
Closing Pressure: Record the closing pressure of BOP. In order to prevent well bore fluid leaking through BOP elements, the closing pressure should be high enough.
Pit Gain: Read and record the pit gain. Pit volume gained is very critical for the maximum casing pressure calculation. You should check the volume gained from mud logger and driller in order to get the accurate figure. I don’t recommend you to ask only one person to get this figure. It is better to have another data source to compare with.
After the well is properly secured and all information is gathered, the supervisor on the rig should inform his supervisor to find the proper method to kill the well.
Reference book: Well Control Books