Basic Relationships of Well Log Interpretation
George Asquith, Daniel Krygowski, Steven Henderson, Neil Hurley, 2004. "Basic Relationships of Well Log Interpretation", Basic well log analysis, George Asquith, Daniel Krygowski, Steven Henderson, Neil Hurley
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This chapter provides a general introduction to well logging principles and methods that will be used throughout the book. Succeeding chapters (2 through 6) introduce the reader to specific log types. The text discusses how different log types measure various properties in the wellbore and surrounding formations, what factors affect these measurements, where on a standard log display a particular curve is recorded, and how interpreted information is obtained from the logs using both charts and mathematical formulas. Unlike many other logging texts, the logging tools are grouped according to their primary interpretation target, rather than their underlying measurement physics.
Spontaneous potential (SP) and gamma ray logs are discussed first, as their primary use is correlation and their primary interpretive target is gross lithology (the distinction between reservoir and nonreservoir). The porosity logs (i.e., sonic, density, and neutron logs) are covered next, then the resistivity logs. Nuclear magnetic-resonance logs, although they provide porosity (among other quantities of interest), are presented after resistivity logs. This is due in part to their recent arrival and to their relative absence in historical data archives.
The final four chapters again deal with interpretation of the data, this time in detail with example problems and their solutions. These chapters bring the introductory material of Chapter 1 together with the specific measurement information and are intended to provide a coherent view of the interpretation process. The reader is encouraged to work the examples to gain familiarity with the interpretation techniques and to begin to
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Basic well log analysis
This publication is a general introduction to common openhole logging measurements, both wire line and MWD/LWD, and the interpretation of those measurements to determine the traditional analytical goals of porosity, fluid saturation, and lithology/mineralogy. It is arranged by the interpretation goals of the data, rather than by the underlying physics of the measurements. The appendix files contain digital versions of the data from the case studies, a summary guide to the measurements and their interpretation, and a simple spreadsheet containing some of the more common interpretation algorithms. This Second Edition of Basic Well Log Analysis delivers a great impact on training and self-training along with superior workbook exercises, newer measurements, borehole imaging, and nuclear magnetic resonance in separate chapters, all directed to provide a guide through the lengthy and sometimes ambiguous terminology of well logging and petrophysics. It provides readers with interpretation examples (and solutions) so that the techniques described here can be practiced.