George Asquith, Daniel Krygowski, Steven Henderson, Neil Hurley, 2004. "Log Interpretation", Basic well log analysis, George Asquith, Daniel Krygowski, Steven Henderson, Neil Hurley
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As shown in the previous chapters, determining the porosity and true resistivity of a zone is the first step in converting the raw log data into estimated quantities of oil, gas, and water in a formation. These estimated quantities are used to evaluate a zone and to determine whether a well completion attempt is warranted. This chapter covers some of the different methods from which these estimates are derived. The methods discussed are: Archie water saturations (Sw and Sxo) and the ratio method, quick-look technique, bulk volume water (BVW), and saturation crossplots (Pickett plots and Hingle plots). Determination of log-derived permeability (Ke) and shaly sand analysis are also discussed.
As important as this log-derived information is, however, it should not be applied without the inclusion of other data. This statement is, perhaps, obvious to the reader, but it can’t be overemphasized. A geologist should always consider every item of relevant data, such as drill stem tests, sample shows, mud-log analysis, nearby production, etc., before making a decision to set pipe.
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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.