ABERDEEN, UK – Expro has achieved what it claims is the world’s first proven wireless transmission of reservoir pressure data to surface, from a recently abandoned subsea appraisal well that incorporated a rock-to-rock cement plug.
The system, installed in the North Sea, should assist understanding of the reservoir and help optimize future development planning for the field, the company said.
It claimed that the technique also provides operators with a more cost-effective option for well abandonment design and a consideration of wider well barrier techniques, while maintaining the ability to monitor the reservoir or plug integrity.
The cable-less telemetry system (CaTS) wireless gauges, employing electromagnetic (EM) technology, were 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 allowed 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 started immediately after the drillstem test, allowing extended pressure build-up analysis without rig support.
CaTS gauges can also cut costs of side tracked wells with appropriate well barriers, the company said, as long-term interference testing can be completed from the main bore to side track, without the need to drill a separate appraisal well.