This chapter presents two case studies where resistivity-tool-response modeling was applied for formation evaluation. Induction logs from one field were modeled for a number of deviated wells assuming that mud-filtrate invasion was negligible (i.e., by applying 1-D modeling). In the second example, laterolog (DLL) logs from another field show clear separation between the deep and shallow curves, indicating possible invasion. Therefore, 2-D modeling was applied in this case.
These two case studies are not meant to comprise an exhaustive set of examples for the application of resistivity modeling. They are simply the examples that were available for release at the time of writing.
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Understanding resistivity-tool response and resistivity-log interpretation for formation evaluation is vital for the matching of the reconstructed deep-reading resistivity logs with the field log curves. AAPG Archie 2 introduces the fundamental concepts required. Resistivity-logging-tool physics and measurement accuracy are reviewed, and forward- and inverse-modeling resistivity-tool responses are introduced. In the case studies presented, well-deviation, shoulder-bed, bed-thickness, borehole, mud-resistivity, and invasion effects on restivity-log responses are discussed. This volume has been written for geoscientists and engineers working with and interpreting resistivity logs, petrophysicists and reservoir engineers integrating resistivity-based and capillary-pressure-based quantitative calculation of formation water saturation, and formation evaluation specialists.