Gas Kick Behaviour, Migration & Expansion
In well control, the gas kick is simply to be detected once enter wellbore in water base mud as once driller (driller job description) shut in the well, the SICP & SIDP start to increase slowly with the same values due to gas migration. Of course, it may be difficult to notice such migration in oil-base mud as the gas solubility is higher in such medium.
https://www.drillingmanual.com/gas-kick-behavior-expansion-migration-well-control/