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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7.2.3 Attributes<br />
I used attributes to assess improvements in velocity modeling. Using attributes as a QC<br />
tool is significant because it is a nontraditional application <strong>of</strong> attributes, specifically<br />
coherence, to qualitatively evaluate velocity modeling. The standard method has been to<br />
use CIGs to update velocity models and serve as a QC <strong>of</strong> the velocity model. Completion<br />
<strong>of</strong> updating the velocity model is determined by evaluating the gathers. By <strong>using</strong><br />
coherence as a QC tool I was able to compare different models and evaluate them based<br />
on the noise content revealed in the coherence. A coherence cube provides an evaluation<br />
<strong>of</strong> the entire survey, enables the interpreter to quickly assess the quality <strong>of</strong> the data, and<br />
isolate problem areas.<br />
Using coherence for QC provides an efficient tool. Throughout the PSDM process the<br />
velocity model is updated and data are re-migrated. Errors incorporated into the initial<br />
sediment velocity model propagate throughout the entire process. Generating and<br />
assessing coherence quickly is a factor that makes it an attribute that is appropriate as a<br />
QC tool. A tool that is quick and efficient as coherence means that different models can<br />
be tested and evaluated. I demonstrated that attributes, specifically coherence, were used<br />
as an effective QC tool.<br />
7.2.4 Geology<br />
I based much <strong>of</strong> the body <strong>of</strong> research regarding the subsurface geology <strong>of</strong> the Upper Gulf<br />
<strong>of</strong> Mexico Basin on well log analysis and 2-D s<strong>eismic</strong> lines. Another way to view this is<br />
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