Switched-Field Surface NMR for Enhanced Detection and Resolution of Shallow Groundwater

This proposal addresses the challenge of mapping groundwater and hydrogeologic parameters in the subsurface, with a focus on improving sensitivity and spatial resolution for shallow groundwater targets. We will apply imaging methodologies at the core of medical MRI to efficiently map shallow groundwater and hydrogeologic properties at improved resolution. Conventional surface NMR has been proven as a powerful non-invasive technique for coarse groundwater imaging. The method is limited, however, by simplistic imaging protocols. To enhance sensitivity and spatial resolution, we will introduce “switched-field” NMR. This new paradigm combines gradient and prepolarization fields to allow localization of signals based on their frequency and phase response and will increase the signal-to-noise ratio for shallow water. In addition to improving resolution, these approaches will also accelerate measurement speed allowing the technology to be applied in a wider range of environments and markets. Having established feasibility in Phase 1, the Phase 2 work will fully develop and commercialize the use of switched fields for groundwater imaging. In the first task, we will complete a comprehensive framework for the forward modelling, processing, and interpretation of switched field data. These simulations will also be used to evaluate novel acquisition and processing methodologies improving upon those explored in Phase 1. In the second task, a complete system will be developed for commercial sale, including robust, modular, and lower cost power electronics, next-generation data acquisition interfacing and control, as well as customer-facing software for user-friendly survey planning, data acquisition, and data interpretation. In the final task, the developed technology will be validated and demonstrated in a large number of field project, including local test sites, government environmental research projects, and commercial geotechnical projects. Completion of this technology will deliver a powerful groundwater imaging product for commercial sale, rental, and/or services in the environmental, geotechnical, and subsurface research markets. This technology will be of value to companies, governments, and public agencies facing problems such as groundwater contamination, dewatering for geotechnical engineering, and permafrost mapping. The ability to image at high-resolution in with reduced survey times will improve the reliability of subsurface models, reduce site characterization costs, support informed decision making. In turn, this technology will improve project efficiency, reduce risk, and result in improved outcomes