USGS

Borehole Geophysics Applied to Ground-Water Investigations

U.S. Geological Survey, Techniques of Water-Resources Investigations, Book 2, Chapter E-2

By W. Scott Keys


Table of Contents

Abstract

Introduction

Purpose and scope

Background

How to use this manual

why log?

Limitations of logging

Analysis of logs

Qualitative log analysis

Quantitative log analysis

Synergistic log analysis

Computer analysis of logs

Digitizing logs

Correcting and calibrating logs

Plotting data from logs

Petrophysics and log response

Mineral composition

Porosity

Particle size, shape, and cementation

Formation-resistivity factor

Rock structure

Ground-water flow and log response

Well hydraulics

Hydraulic conductivity and intrinsic permeability

Specific yield and moisture content

Interstitial fluids and log response

Electrical conductivity

Temperature

Chemical composition

Borehole effects

Drilling fluids

Borehole diameter

Well construction

Geometric effects

Volume of investigation

Bed thickness

Logging equipment

Probes

Cable and winch

Control modules

Recorders

Planning a logging program

Buying a logger

In-house service logging

Contract logging

Selecting a suite of logs

Quality control of logs

Prelogging contacts

Quality control at the well

Log headings

Calibration and standardization of logs

Calibration

Standardization

Test 1.—Principles, equipment, and log-analysis techniques.

Electric logging

Spontaneous-potential logging

Principles and instrumentation

Calibration and standardization

Volume of investigation

Extraneous effects

Interpretation and applications

Single-point-resistance logging

Principles and instrumentation

Calibration and standardization

Volume of investigation

Extraneous effects

Interpretation and applications

Normal-resistivity logging

Principles and instrumentation

Calibration and standardization

Volume of investigation

Extraneous effects

Interpretation and applications

Focused-resistivity logging

Principles and instrumentation

Calibration and standardization

Volume of investigation

Extraneous effects

Interpretation and applications

Lateral-resistivity logging

Induction logging

Microresistivity logging

Dipmeter logging

Test 2.—Electric logging

Nuclear logging

Fundamentals of nuclear geophysics

Detection of radiation

Instrumentation

Counting statistics and logging speed

Use of radioactive sources in well logging

Gamma logging

Principles

Calibration and standardization

Volume of investigation

Extraneous effects

Interpretation and applications

Gamma-spectrometry logging

Principles

Calibration and standardization

Volume of investigation and extraneous effects

Interpretation and applications

Gamma-gamma logging

Principles

Calibration and standardization

Volume of investigation

Extraneous effects

Interpretation and applications

Neutron logging

Principles

Calibration and standardization

Volume of investigation

Extraneous effects

Interpretation and applications

Other nuclear-logging techniques

Neutron-activation logging

Neutron-lifetime logging

Nuclear-magnetic-resonance logging

Test 3.—Nuclear logging

Acoustic logging

Acoustic-velocity logging

Principles and instrumentation

Calibration and standardization

Volume of investigation

Extraneous effects

Interpretation and applications

Acoustic-wave-form logging

Acoustic-televiewer logging

Principles and instrumentation

Calibration and standardization

Volume of investigation

Extraneous effects

Interpretation and applications

Caliper logging

Principles and instrumentation

Calibration and standardization

Volume of investigation

Extraneous effects

Interpretation and applications

Test 4.—Acoustic and caliper logging

Fluid logging

Temperature

Principles and instrumentation

Calibration and standardization

Volume of investigation

Extraneous effects

Interpretation and applications

Conductivity

Principles and instrumentation

Calibration and standardization

Extraneous effects

Interpretation and applications

Flow

Principles and instrumentation

Calibration and standardization

Extraneous effects

Interpretation and applications

Well-construction logging

Casing logging

Cement and gravel-pack logging

Borehole-deviation logging

Test 5.—Fluid and well-construction logging

Summary-A case history

Acknowledgments

Selected references

Answers to test questions


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