Well Logging and Formation Evaluation
Covering all aspects of well logging and formation evaluation, this comprehensive guide offers practical techniques that will be valuable to petrophysicists and engineers in their day-to-day jobs.
TABLE OF CONTENTS Well Logging and Formation Evaluation
Chapter 2: Quicklook Log Interpretation
OVERVIEW
Once the section TD (total depth) of the hole has been reached, the petrophysicist will be expected to make an interpretation of the openhole logs that have been acquired. Before starting the log interpretation, the petrophysicist should have:
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All the relevant daily drilling reports, including the latest deviation data from the well, last casing depth, and mud data
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All the latest mud-log information, including cuttings description, shows, gas reading, and ROP (rate of penetration)
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Logs and interpretations on hand from nearby wells and regional wells penetrating the same formations, in particular where regional or fieldwide values of m, n, R w, rho g and fluid contacts are available
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A copy of the contractor's chart book
2.1 BASIC QUALITY CONTROL
Once the log arrives, the petrophysicist needs to ensure the quality of the log data and should perform the following regimen:
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Check that the logger's TD and last casing shoe depths roughly match those from the last daily drilling report.
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Check that the derrick floor elevation and ground level (or seabed) positions are correct.
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Check that the log curves are on depth with each other. The tension curve can be used to identify possible zones where the toolstring has become temporarily stuck, which will put the curves off depth and result in "flatlining."
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Check that the caliper is reading correctly inside the casing (find out the casing ID) and that it is reading the borehole size in nonpermeable zones that are not washed out.
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Check the density borehole...
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