www.sagaonline...
Abstract:
Nuclear Magnetic Resonance (also known as Magnetic Resonance or NMR) is a powerful physical measurement that enables direct, non-invasive measurement of hydrogen protons. NMR is the physical basis for medical MRI, where it is used in medicine as an essential non-invasive means of diagnosing many types of disease and injury. 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.
Presenter Bio:
Dave Walsh is President of Vista Clara Inc., a business focused on developing and manufacturing magnetic resonance geophysical instruments for groundwater and environmental investigations. Dave received his B.S. degree in electrical engineering from Iowa State University, and M.S. and Ph.D. degrees in electrical engineering from the University of Arizona. Dave has been President of Vista Clara Inc. since 1997. His contributions to the field include the development and commercialization of the world’s first multi-channel surface NMR instrument, and the development and commercialization of the world’s first small diameter NMR borehole logging tools.
Негізгі бет SAGA Talk - Dave Walsh - Magnetic Resonance for Groundwater Investigations
Пікірлер: 1