A Novel Wireless Power Transfer System for Long-term and Real-time Monitoring of Subsurface CO2 Storage

The data and power transfer systems for long term underground CO2 sequestration monitoring are normally based on wire-line cable, which will lead to a potential leakage path way through the casing and cement annulus in high-temperature, high-pressure, and hash underground environments. In this paper, a novel wireless power transfer system has been developed for real-time underground CO2 monitoring. The system includes an array of toroidal transceivers winding around the highly conductive casing string for wireless power transfer to deep subsurface. This design helps to maintain well integrity and reduce potential leakage by eliminating the need to perforate the casing or an umbilical in the cement annulus. The metal casing’s amplification effect significantly enhances the wireless power transfer efficiency, which provides a highly conductive power/electric current’s pathway instead of omnidirectional wireless radiation loss in the subsurface. Toroidal transceiver’s design has been optimized to improve the received signal, and our results show significant improvements in wireless power transfer efficiency. Using the optimized design, we can receive 1 to 10 % power transfer efficiency at 800 meters deep using only one toroidal transceiver with 1A current as input. Compared with other wireless antenna designs, such as the helix coil antenna, our system has shown 26,000 times power transfer efficiency improvement. In the end, a lab-scale power transfer system is built, and our experimental measurements support the simulation results.