Well with pressure activated acoustic or electromagnetic transmitter

Abstract

A well comprising a pressure activated device exposed to pressure in an annulus above a barrier between an upper tubular and the borehole. An acoustic or electromagnetic (EM) transmitter is coupled to the pressure activated device and configured to transmit a control signal to a respective receiver below the barrier for controlling a valve. In the event of an emergency, certain embodiments allow the pressure in the annulus to be quickly dropped, activating the transmitter to close the valve below the barrier, thus isolating the well below the barrier. A variety of default states may be programmed into the transmitter, such as transmitting a 'stay-open' signal to the receiver controlling the valve, which is configured to close if this signal is not received. A further EM or acoustic transmitter may be coupled to the valve to send information from below the barrier to above the barrier, such as pressure data or valve status.