Oilfield services company Expro has conducted he world’s first proven wireless transmission of reservoir pressure data from a recently abandoned subsea appraisal well – which incorporated a rock-to-rock cement plug – to a surface ship.
The system was installed in the North Sea and will be used to improve understanding of the reservoir and to optimise future development planning of the field, while ensuring full compliance with local well abandonment regulations.
This achievement provides operators with a more cost-effective option for well abandonment design and consideration of wider well barrier techniques, while maintaining the ability to monitor the reservoir or plug integrity.
Expro’s cable-less telemetry system (using electromagnetic 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 (illustrated above).
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 (DST), allowing extended pressure build-up analysis without rig support.
Alistair Geddes, Expro’s Executive Vice-President, commented: “This latest downhole telemetry allows us to instrument more wells with casing breaks or longer open-hole sections, partnering with customers to develop the most effective plug and abandonment strategies.”
26 Oct 2017