A Deterministic Evaluation of eismic Fidelity using Velocity Modeling ...

integrate stratigraphic interpretations into the geologic model to begin to piece together
events related to salt tectonics.
6.3 Interpretation
6.3.1 Seismic
I was able to identify small, compartmentalized faults in the area identified by the
operator on the well-based PSDM volume. A comparison of the well-based PSDM with
the prestack time migrated velocity model PSDM data shows the higher resolution
achieved with the well-based model (Figure 81). To determine which of the two is the
proper placement I used electronic well logs to compare well ties. The well-based PSDM
consistently placed the salt picked with well logs at the high acoustic impedance
boundary on the surface seismic data while the prestack time migrated velocity model
PSDM placed the salt pick from well logs below the high acoustic impedance boundary.
Wells tie in the inline, crossline, and depth slices with the well-based data (Figure 82).
Based on the correct placement of salt in the x, y, and z directions it is apparent that the
prestack time migrated velocity model is too slow and the fidelity of the well-based
PSDM is higher.
I was able to enhance resolution along the salt flanks with depth migration. Using
sediment layers to determine where they truncate next to the salt flank, a complex
geometry begins to emerge. Interpretations show the salt body is mainly a cylindrical
shape with various protuberances, salt wedges, and overhangs (Figure 83).
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