What action should be taken immediately after significant changes in mud properties?

After significant changes in mud properties, the appropriate action is to record Slow Circulation Rate (SCR) pressures. This step is crucial because significant changes in the mud properties can affect downhole pressures, which in turn influence wellbore stability and overall drilling operations. By recording SCR pressures, the team can assess how these changes impact the hydraulic conditions within the well.

Monitoring SCR pressures helps identify whether the current mud properties are maintaining sufficient hydrostatic pressure to prevent well control issues such as kick or loss of circulation. It allows drillers to make informed decisions based on pressure readings that reflect the conditions of the hole with minimal disturbances. This practice supports the safe and effective management of the wellbore.

The other actions listed would not provide the necessary immediate insight into how the well is responding to the changes in mud properties. For instance, increasing drilling speed before evaluating pressures could lead to unforeseen complications, while switching mud types might not address the current state effectively without an initial assessment of the pressures. Reducing annular pressure without prior analysis could also risk well control situations.