1. Scope

1.1 This guide is focused on the general procedures necessary to conduct electromagnetic-induction, induction, electromagnetic-conductivity, or electromagnetic-resistivity logging (hereafter referred as induction logging) of boreholes, wells, access tubes, caissons, or shafts (hereafter referred as boreholes) as commonly applied to geologic, engineering, ground-water and environmental (hereafter referred as geotechnical) investigations. Induction logging for minerals or petroleum applications is excluded.

1.2 This guide defines an induction log as a record of formation electrical conductivity or resistivity with depth as measured by the induction method in a borehole.

1.2.1 Induction logs are treated quantitatively and should be interpreted with other logs and data whenever possible.

1.2.2 Induction logs are commonly used to: ( 1 ) delineate lithology; ( 2 ) evaluate formation water quality and effective porosity, and ( 3 ) correlate stratigraphy between boreholes.

1.3 This guide is restricted to induction measurements that are at a frequency of less than 50 KHz; are non-directional; and average formation properties around the circumference of the borehole; which are the most common induction measurement devices used in geotechnical applications.

1.4 This guide provides an overview of induction logging including ( 1 ) general procedures; ( 2 ) specific documentation; ( 3 ) calibration and standardization; and ( 4 ) log quality and interpretation.

1.5 To obtain additional information on induction logs see References section in this guide.

1.6 This guide is to be used in conjunction with Standard Guide D 5753.

1.7 This guide offers an organized collection of information or a series of options and does not recommend a specific course of action. This guide should not be used as a sole criterion for induction logging and does not replace education, experience, and professional judgement. Induction logging procedures should be adapted to meet the needs of a range of applications and stated in general terms so that flexibility or innovation are not suppressed. Not all aspects of this guide may be applicable in all circumstances. This ASTM standard is not intended to represent or replace the standard of care by which the adequacy of a given professional service must be judged without consideration of a project's many unique aspects. The word standard in the title of this document means that the document has been approved through the ASTM consensus process.

1.8 The geotechnical industry uses English or SI units. The induction log is typically recorded in millisiemens per meter (mS/m) or millimhos per meter (mmhos/m).

1.9 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory requirements prior to use.

2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

ASTM Standards

D420 Guide to Site Characterization for Engineering Design and Construction Purposes

D653 Terminology Relating to Soil, Rock, and Contained Fluids

D5088 Practice for Decontamination of Field Equipment Used at Waste Sites

D5608 Practices for Decontamination of Field Equipment Used at Low Level Radioactive Waste Sites

D5730 Guide for Site Characterization for Environmental Purposes With Emphasis on Soil, Rock, the Vadose Zone and Ground Water

D5753 Guide for Planning and Conducting Borehole Geophysical Logging

D6167 Guide for Conducting Borehole Geophysical Logging: Mechanical Caliper

D6235 Practice for Expedited Site Characterization of Vadose Zone and Groundwater Contamination at Hazardous Waste Contaminated Sites

D6274 Guide for Conducting Borehole Geophysical Logging - Gamma

D6429 Guide for Selecting Surface Geophysical Methods

D6431 Guide for Using the Direct Current Resistivity Method for Subsurface Investigation

Keywords

borehole geophysics; electrical conductivity; electromagnetic-induction log; groundwater; induction; resistivity; water quality; well logging: Access tubes; Borehole geophysical logging; Caissons; Electric logging; Engineering criteria/design--soil/rock/related materials; Fluid conductivity/resistivity logging; Geological investigations; Geophysical investigations/geophysics; Geotechnical engineering materials/processes; Ground water; Hydrogeologic models/investigations; Induction logging; Lithology; Logging; Resistivity logging; Stratigraphic correlation/description; Water quality monitoring; Well logging;

ICS Code

ICS Number Code 07.060 (Geology. Meteorology. Hydrology); 33.100.01 (Electromagnetic compatibility (EMC) in general)

DOI: 10.1520/D6726-01

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