During the migration of gas in the annulus while the well is shut in, what happens to the gas bubble pressure?

In the context of well control during the migration of gas in the annulus when the well is shut in, the gas bubble pressure remains constant. This is based on the principle of an ideal gas under conditions where volume and temperature do not change significantly. When a well is shut in, there are no additional influences acting on the gas, such as pressure changes from fluid influx or changes due to temperature fluctuations.

Under constant conditions and assuming that there is no flow of gas or pressure variations in the surrounding formation, the pressure exerted by the gas bubble in the annulus is determined primarily by its initial state. Therefore, it retains a stable pressure until influenced by external factors, such as changes in hydrostatic pressure caused by fluid movement or reservoir pressure variations.

Understanding this concept is vital for well control and managing potential risks associated with gas influx scenarios. Ensuring a proper grasp of gas behavior under these conditions is crucial for effective risk assessment and response planning during well operations.