Abstract

A generalized empirical relationship was found which corrects spontaneous potential (SP) readings from well logs run in freshwater wells. The function was found by correlating measured and calculated spontaneous potentials. The calculated values are based on actual measured ionic content of groundwaters and are fully corrected for environmental effects and ion species. Without the empirical relationship the electrically equivalent to an NaCl solution resistivity, Rwe, is generally too low for fresh waters when computed with existing commercially available functions. The low Rwe makes the water appear saltier than it really is. One hundred sixty-two (162) individual formations from one hundred four (104) different shallow well logs from widely separated regions of the United States and different types of aquifers were examined. Each formation used in the study had to have a spontaneous potential, mud resistivity data, a chemical analysis of water from the zone, and not be in communication with other zones. Every SP had the existing commercially available geometric corrections applied. A computer program was developed which computes a simulated SP from the chemical analysis and mud data. This simulated SP was plotted against the measured SP. The resulting relationship is given by: MEASURED SP=0.3782 x SIMULATED SP + 6.9172. for 0 mv < SIMULATED SP < + 50 mv. This type of relationship is consistent with earlier work by the author in a localized area. The function can only be applied in fresh waters with simulated SPs in the indicated domain since simulated and measured SPs converge in brine formations. © 1988.

Department(s)

Civil, Architectural and Environmental Engineering

International Standard Serial Number (ISSN)

0022-1694

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2023 Elsevier, All rights reserved.

Publication Date

30 Jun 1988

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