Novel and Rugged Electromagnetic Wireless System for Long-Term Subsurface CO2 Plume Monitoring and Saturation Mapping

Carbon capture and storage (CCS) is a key technological approach to slow down the CO2 accumulation in the atmosphere and marine and mitigate global climate and environmental change. The sequestrated CO2 needs to be safely stored in the underground geological structure for at least thousands of years. The leaked CO2 will affect the environment and even endanger human lives. Therefore, measuring and detection of CO2 leaks at sequestration sites are extremely important. Compared to seismic methods for subsurface monitoring, electromagnetic techniques have the potential to provide a more precise measure of CO2 saturation, which is a key index for evaluating CO2 migration and leakage. However, electromagnetic methods usually have much heavier signal attenuation and thus shallower depth of detection in underground formation, and the highly conductive metallic well casings will greatly affect electromagnetic subsurface sensing, oftentimes in a negative way. Besides, most current subsurface monitoring solutions require cables placed either inside or outside of the well casing. The first method may need perforation on the casing to connect sensors outside of casing, which will impair well integrity, and for the second method the cable outside of the casing in the cement annulus can potentially be a pathway to CO2 leakage. We propose to develop a rugged and low-cost electromagnetic wireless monitoring system for long-term CO2 monitoring. A set of novel electromagnetic modules will be mounted on the outside of metallic casing for wireless sensing and communication. Each electromagnetic module has multi-turn loop antenna for deep sensing, toroidal antenna for wireless communication and power transfer, supercapacitors for power storage, and embedded electronics for wireless control. The goal of the Phase I proposal is to demonstrate the feasibility of building an electromagnetic wireless sensing, charging, and communication system for long-term monitoring of carbon storage site. In Phase I, Cyentech Consulting, in collaboration with the University of Houston and Innovotive Downhole Solutions, will 1) design the multi-turn loop antenna and conduct sensitivity study; 2) develop and optimize the toroidal antenna for long-distance wireless communication; 3) verify the feasibility of utilizing energized casing, toroidal antennas, and supercapacitors to wirelessly transmit power to deep electromagnetic modules; and 4) develop control electronics for the wireless system. Lab-scale tests will be conducted for each task. The success of this project will pave the way to produce a powerful, robust, and cost-effective CO2 sequestration monitoring system for deep subsurface sensing. This system can be applied to detect and characterize CO2 plumes for long-term and real-time monitoring. In addition, the proposed technology and product can find many commercial applications in other areas such as enhanced geothermal systems and deep borehole disposal of nuclear waste.