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Recent Workshop

OGW BG provides formal and informal geophysical training to USGS offices and cooperators. This page provides an overview of a recent workshop conducted by OGW BG. Because training is customized to address specific interests and needs, each training event is unique.

In Fall 2005 the USGS Office of Ground Water, Branch of Geophysics (OGW BG) conducted a geophysical methods workshop for the Central Region. The workshop focused on

1. borehole and surface geophysical methods useful for characterizing aquifer frameworks and delineating fresh/saline water interfaces; and
2. an integrated suite of borehole geophysical methods useful for planning, executing, and assessing water-quality sampling programs in wells that are open to multiple aquifer zones.

Borehole geophysical methods discussed included

• borehole-wall imaging;
• electromagnetic induction;
• magnetic susceptibility;
• full wave-form sonic;
• flowmeter; and
• fluid property logging and sampling.

Surface geophysical methods included

• transient electromagnetic and
• audio-magnetotelluric soundings.

The workshop included hands-on field work in the methods discussed, as well as hands-on computer processing, analysis, and interpretation of the field data collected. Geophysical case studies and field demonstrations focused on boreholes completed in the carbonate Edwards Aquifer and across the associated fresh/saline water interface. Students also had the opportunity to bring their own project case studies for discussion. Workshop participants included USGS ground-water hydrologists as well as cooperator and University scientists.

The subject workshop was sponsored by the Central Region and the Office of Ground Water and was one of a series of workshops that presents principles and techniques for the collection and analysis of geophysical data through lectures, classroom exercises, and field demonstrations in selected aquifer settings across the United States.

Figure 1. Course participants.

Figure 2. Composite image of borehole-geophysical logs collected in a monitoring well in the Edwards carbonate-rock aquifer, Texas. From left to right: Depth below ground surface, in feet; Bulk electrical conductivity of formation surrounding the borehole, in milliSiemens per meter, collected with electromagnetic induction tool; Borehole diameter in inches, collected with caliper tool; Optical televiewer image; Acoustic televiewer data image; Vertical fluid flow, in gallons per minute, collected with electromagnetic flowmeter under ambient conditions; and Borehole fluid specific conductivity, in microSiemens per centimeter, collected under ambient and stressed (pumping) conditions.

You can also read about and see photos from other past OGW BG courses and USGS project support.