Oilfield services company Expro reported the first wireless transmission of reservoir pressure data to the surface from an abandoned subsea appraisal well with a rock-to-rock cement plug.

Expro offers an explanation of the transmission process from the well:

The Expro cableless telemetry system (CaTS) with wireless gauges using electromagnetic (EM) technology was installed in the reservoir of the main bore, and casings were cut below the side-track kickoff point to install the cap rock cement plug. CaTS repeaters placed in the side-track enabled data transmission across the open-hole section and to the seabed transceiver for storage and transmission to an overhead vessel. The system provided continuous reservoir data, which began immediately after the drill stem test, allowing extended pressure build-up analysis without rig support.

Read more at Expro.