A Deterministic Evaluation of eismic Fidelity using Velocity Modeling ...
A Deterministic Evaluation of eismic Fidelity using Velocity Modeling ...
A Deterministic Evaluation of eismic Fidelity using Velocity Modeling ...
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5.1 Introduction<br />
Chapter 5<br />
Impact <strong>of</strong> Prestack Depth Migration on S<strong>eismic</strong> Attribute Analysis<br />
Improving the s<strong>eismic</strong> fidelity <strong>of</strong> the Vinton Dome survey was the primary goal <strong>of</strong> this<br />
study. One <strong>of</strong> the techniques I used to achieve this was to use coherence for both<br />
interpretation and to QC data. Poor fidelity <strong>of</strong> the PSTM data volume presented a<br />
problem. Poor fidelity was manifested in low s<strong>eismic</strong> resolution that reduced and<br />
eliminated interpretation <strong>of</strong> structures and stratigraphic features to include imaging <strong>of</strong> the<br />
salt flanks. Imaging these features was necessary to gain a better understanding <strong>of</strong> the<br />
geology <strong>of</strong> the area. Data were migrated <strong>using</strong> the robustness <strong>of</strong> the PSDM to image the<br />
features obscured by low fidelity. To take advantage <strong>of</strong> the power <strong>of</strong> the PSDM I used<br />
two different approaches to velocity modeling and tested the results <strong>using</strong> attributes as a<br />
QC tool.<br />
Using attributes as a means to compare migration is a recognized technique (Rietveld, et<br />
al., 1999). Coherence was the attribute used to compare two different velocity models<br />
used to PSDM and to compare the PSTM to the PSDM volumes. Coherence I applied to<br />
the data was enhanced <strong>using</strong> edge-preserving filtering. Edge-preserving filtering<br />
improves attributes (Duncan and Marfurt, 2003). I used improved attributes to interpret<br />
details that were not imaged in the s<strong>eismic</strong> data volume.<br />
Attributes provided both a means to qualitatively demonstrate the enhancements PSDM<br />
provided over PSTM and serve as a QC for the velocity models. Improved s<strong>eismic</strong><br />
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