Borehole Logging from Sample Collection to Borehole Geophysics

Richard Laton
,
California State University, Fullerton
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Summary

Drilling the borehole is only the beginning. Data collection, handling and interpretation are the most important aspects to the field hydrogeologist. This session will use an exercise that combines both physical soil samples and borehole geophysical logs to build an interpretation of the subsurface.

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Context

Audience

Entry level hydrogeology course for both major and non-majors; pre-requisites include Geology 101 lecture and lab.

Skills and concepts that students must have mastered

Students should have had basic mineralogy and physics so that they can begin to understand borehole geophysics and its relationship to both grain size and mineralogy.

How the activity is situated in the course

This lab activity is one of many field/laboratory exercises that students conduct over the course of a semester.

Goals

Content/concepts goals for this activity

  1. Accurate description of logged soil samples, especially of features with which the students are unfamiliar.
  2. Recognition of grain size variation, texture, color and mineralogy as it changes with depth.
  3. The integration of sample description/classification to porosity and permeability measurements or observations.

Higher order thinking skills goals for this activity

  1. In many cases the use of samples involves descriptive analysis and, in some cases, may involve problem solving through the integration and synthesis of previously presented material—Thinking!
  2. Formulation of hypotheses, especially multiple hypotheses that might explain the features described.

Other skills goals for this activity

  1. Note taking and sketching: How to carefully make a written description with a logical organization.
  2. May include oral communication of ideas and working in groups.

Description of the activity/assignment

In January of 2003, CSUF drilled and completed a deep multiport-monitoring well on the north side of campus. This was done in order to gain a better understanding of the local subsurface geology and groundwater conditions in and around CSUF. Samples were collected from the drill hole (boring) every 5-feet. The total depth of the well is 870 feet below ground surface (grade). Borehole geophysical data (E-log) information was collected from the boring prior to the installation of the well pipe. As you describe the soil samples, compare and contrast your findings to those of the geophysical signature (gamma-ray log) found in the accompanying "E-log" for the boring.

Determining whether students have met the goals

The students construct a complete well log including descriptions of each hand sample. For each identified unit, students are to describe the geophysical response to the unit and explain its physical properties as they are related to permeability. This description is written into a short narrative.

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Teaching materials and tips

Other Materials

Supporting references/URLs

Aller, L., Bennett, T. W., Hackett, G., Petty, R. J., Lehr, J. H., Sedoris, H., Nielsen, D. M., and Denne, J. E., 1989, Handbook of Suggested Practices for the Design and Installation of Ground-Water Monitoring Wells: EPA, EPA 600/4-89/034.

Australian Drilling Industry Training Committee Ltd., 1996, Drilling: The Manual of Methods, Applications, and Management: New York, Lewis Publishers.

California Department of Water Resources, 1996, Well Standards Bulletin, 74-90.

Driscoll, F. G., 1995, Groundwater and Wells: St. Paul, MN, Johnson and Johnson, 1089 p.

Everett, L. G., 1984, Groundwater Monitoring: New York, Genuine Publishing Corp.

Lapham, W. W., Wilde, F. D., and Koterba, M. T., 1995, Ground-Water Data-Collection Protocols and Procedures for the National Water-Quality Assessment Program: Selection, Installation, and Documentation of Wells, and Collection of Related Data, USGS Open-File Report 95-398.

Lapham, W. W., Wilde, F. D., and Koterba, M. T., 1996, Guidelines and Standard Procedures for Studies of Groundwater Quality: USGS Water Resources, 96-4233.

Palmer, C. M., 1996, Principles of Contaminant Geology. Chapter 3: Groundwater Monitoring Well Installation, Principles of Contaminant Hydrogeology, p. 51-67.

Roscoe Moss Company, 1990, Handbook of Groundwater Development: New York, John Wiley and Sons, Inc.

San Diego County Department of Environmental Health, 2000, Site Assessment Mitigation Manual (SAM).

US Department of the Interior Bureau of Reclamation, 1990. Earth Manual, Part 1 and 2. 311 p. http://www.usbr.gov/pmts/writing/earth/earth.pdf

US EPA, 1995, Chapter 8, Monitoring Well Development, Technical Guidance Manual for Hydrogeologic Investigations and Ground-Water Monitoring: PB93-139-350: Washington D.C.

Williams, D. E., 1985, Modern Techniques in Well Design: AWWA, p. 68-74.