What happens to BHP during a connection gas event?

During a connection gas event, the Bottom Hole Pressure (BHP) typically decreases. This phenomenon occurs because, during the connection process, the flow path is disrupted, which can lead to a temporary drop in pressure. When the annulus experiences an influx of gas, the hydrostatic pressure exerted by the fluid column in the wellbore can be reduced, particularly if there is a significant volume of gas introduced. This reduction in BHP is critical for well control because it can impact the balance between formation pressure and the hydrostatic pressure of the fluid in the well. Understanding this behavior is essential for maintaining control of the well and preventing possible blowouts or other hazardous situations during operations.