On October 21, 2020, Vista Clara CEO, Dave Walsh presented an extensive webinar on “Magnetic Resonance for Groundwater Investigations” for the South African Geophysical Association (SAGA). The webinar abstract includes the following description:
The NMR measurement technique has been adapted in several forms for geophysical applications, and in recent years has been used more widely in groundwater investigations. Compared to other geophysical measurements, NMR offers the unique ability to directly detect and quantitatively measure water content in native earth formations and sediments. NMR measurements also provide the ability to unambiguously differentiate moveable groundwater that resides in large pores (sands, gravels and large fractures) from immovable water in small pores (silts, clays and small pore structures in rock matrices).
This webinar will provide a high-level review of how the basic NMR measurement works, and how the amplitude and time decay properties of the detected NMR signal relate to water content, porosity and hydraulic conductivity. We will then review and explain the two most widely used NMR geophysical methods: borehole NMR logging and non-invasive surface NMR. We will include example applications and case studies for both methods. Finally, we review other smaller-scale NMR instruments that are useful for measuring soil moisture content and the hydrogeological properties of rock cores and sediment samples.
Click below to watch the entire webinar: