Overview of NMR for Groundwater Geophysics

Client: Groundwater Markets
Location: International
Overview: A collection of slides provides an short overview of NMR geophysics, including example applications of GMR and Javelin technologies for groundwater investigations. Full Case Study [pdf]

Identification of Facies Controlling Contaminant Migration

Client: US Geological Survey (USGS)
Location: Cape Cod, MA, USA
Overview: The migration of contaminant plumes can be strongly influenced by the presence and geometry low permeability facies.  Javelin NMR logging measurements were collected in existing PVC cased wells at a contaminant research site.  NMR Logging results showed that the aquifer was primarily comprised of sandy sediments with high-permeability, but also identified and delineated several low-permeability silt layers.  These silt layers were confirmed by other methods and are likely to influence the transport of contaminants at the site. Full Case Study [pdf]

Characterization of Aquifer Properties and Near Surface Conditions

Client: Kansas Geological Survey (KGS)
Location: Lawrence Kansas, USA
Overview: The primary goal of this project was to delineate sediment facies and to determine their hydrogeologic properties.  Javelin log results closely match expected lithology as well as direct measurements of hydraulic conductivity from slug tests.  Javelin NMR logging measurements also revealed unexpectedly long NMR decay signals in a silt zone that are likely associated with water filling voids from tree roots or cracks in well grouting. Full Case Study [pdf]

Combination of Logging and Surface NMR with Short Dead Time

Client: Kansas Geological Survey and Stanford University
Location: Lawrence, Kansas
Overview: Logging and surface-based NMR measurements each carry distinct advantages for characterizing the near surface.  Both surface-based GMR and down-hole Javelin logging measurements were collected at the well-characterized Geohydrologic Experimental and Monitoring Site.  The two data sets not only accurately reflect the known subsurface structure, but are also remarkably consistent with one another.  The short dead time of the GMR instrument enables detection of water in the unsaturated zone which is corroborated by results from the Javelin NMR log. Full Case Study [pdf]