* During '''shut-in periods''', the packer(s) is still inflated and the tester valve is closed. Ideally, pressure in the closed tool gradually builds up until it reaches equilibrium with the pressure of the isolated formation. | * During '''shut-in periods''', the packer(s) is still inflated and the tester valve is closed. Ideally, pressure in the closed tool gradually builds up until it reaches equilibrium with the pressure of the isolated formation. |