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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1.2.1 Geology<br />
Vinton Dome is a piercement salt dome located in the upper continental margin <strong>of</strong> the<br />
Gulf <strong>of</strong> Mexico. Sediments surrounding the dome range in age from Oligocene to<br />
Miocene. Salt tectonics and deposition have influenced the structural characteristics<br />
surrounding the dome. Issues <strong>of</strong> interest are the depositional environments, salt tectonics<br />
and structure associated with the dome. Even though this is a mature basin with over one<br />
hundred years <strong>of</strong> geologic investigation, there are a number <strong>of</strong> geologic issues to be<br />
resolved.<br />
1.2.2 Processing<br />
An examination <strong>of</strong> shot gathers from the field data revealed the need for pre-migration<br />
processing. The most pr<strong>of</strong>ound problem was high amplitude low frequency noise. To<br />
focus the study on velocity modeling and depth migration I used a simplistic approach to<br />
pre-migration processing. My main objective in processing was to maintain as high a<br />
bandwidth as possible and eliminate the noise. Testing and filtering data provided a data<br />
set to apply deconvolution and to calculate a residual static. Data were common midpoint<br />
(CMP) sorted and I used stacking velocities calculated <strong>using</strong> the velocity field from<br />
the PSTM. I gained CMP sorted data <strong>using</strong> a spherical divergence gain control and had<br />
both the datum static and residual static applied. Static corrected data were amplitude<br />
balanced <strong>using</strong> automatic gain control (AGC). These data then had a shot deconvolution<br />
applied and were filtered <strong>using</strong> a 5-6-70-80 filter. Filtered data had the first breaks muted<br />
and amplitude balanced again <strong>using</strong> AGC. These data were the input for the PSDM.<br />
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