New Techniques in Volumetric Imaging of Salt-Contaminated Aquifers

Paul D. Bauman
Komex International Ltd, Calgary, AB

Chloride and sulfate contamination, while often considered to be less "glamorous" problems to address than hydrocarbon contamination, frequently carry more severe consequences. This is due to the conservative nature of chlorides and sulfates (they do not sorb or biodegrade), the significant negative impact salts may have on groundwater quality in a part of the world where highly productive aquifers are scarce, the corrosive effects of salinized water, and the high cost of remediating salt contaminated aquifers. Costs of intrusive characterization (drilling, analytical chemistry, etc.) and remediation of salt contaminated aquifers are directly related to the volume of contaminated water and the physical properties of the aquifer.

Fortunately, a number of geophysical techniques are available for mapping, cross-sectionally slicing, and volumetrically imaging subsurface salt contamination. This paper will describe the relatively new geophyiscal techniques of two dimensional (2-D) and three dimensional (3-D) electrical resistivity tomography which can cost-effectively, and in a rapid and non-intrusive fashion, provide volumetric images of subsurface inorganic groundwater contamination associated with flare pits, drilling sumps, injection wells, pipeline breaks, tank leaks, tanker spills, and so forth. Numerous case studies will be discussed. Various techniques of minimally intrusive "truthing" of the geophysical data sets will be examined.

AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005