A method of monitoring a reservoir comprising: - in a well with a cross-section, setting at least one barrier (22a, 22b) in the well, such that pressure and fluid communication are resisted across the entire cross-section of the well thus separating the well into a lower isolated section below the at least one barrier and an upper section above the at least one barrier; wherein there is provided an apparatus in the lower isolated section, including: a perforating device; a control mechanism (52, 152) to control the perforating device, and comprising a wireless communication device configured to receive a wireless control signal for activating the perforating device; a pressure sensor; - at any time, sending a wireless control signal to the wireless communication device to activate the perforating device, the wireless control signal transmitted in at least one of the following forms: electromagnetic, acoustic, inductively coupled tubulars and coded pressure pulsing; - after the at least one barrier is set, activating the perforating device, in order to create at least one perforation between the well and a surrounding reservoir; - during or after the at least one barrier is set, suspending or abandoning at least a zone adjacent said lower isolated section; - after the perforating device has been activated and after said zone has been suspended or abandoned: (i) monitoring the pressure in the lower isolated section below the at least one barrier using the pressure sensor; and - (ii) sending a wireless data signal including pressure data from below the at least one barrier to above the at least one barrier, using at least one of electromagnetic communication, acoustic communication and inductively coupled tubulars. - in a well with a cross-section, setting at least one barrier (22a, 22b) in the well, such that pressure and fluid communication are resisted across the entire cross-section of the well thus separating the well into a lower isolated section below the at least one barrier and an upper section above the at least one barrier; wherein there is provided an apparatus in the lower isolated section, including: a perforating device; a control mechanism (52, 152) to control the perforating device, and comprising a wireless communication device configured to receive a wireless control signal for activating the perforating device; a pressure sensor; a perforating device; a control mechanism (52, 152) to control the perforating device, and comprising a wireless communication device configured to receive a wireless control signal for activating the perforating device; a pressure sensor; - at any time, sending a wireless control signal to the wireless communication device to activate the perforating device, the wireless control signal transmitted in at least one of the following forms: electromagnetic, acoustic, inductively coupled tubulars and coded pressure pulsing; - after the at least one barrier is set, activating the perforating device, in order to create at least one perforation between the well and a surrounding reservoir; - during or after the at least one barrier is set, suspending or abandoning at least a zone adjacent said lower isolated section; - after the perforating device has been activated and after said zone has been suspended or abandoned: (i) monitoring the pressure in the lower isolated section below the at least one barrier using the pressure sensor; and (i) monitoring the pressure in the lower isolated section below the at least one barrier using the pressure sensor; and - (ii) sending a wireless data signal including pressure data from below the at least one barrier to above the at least one barrier, using at least one of electromagnetic communication, acoustic communication and inductively coupled tubulars.