A three-dimensional seismic interpretation of a complexly faulted area of the Green River basin of southwestern Wyoming has identified two major thrust faults and three seismically defined areas. The La Barge fault is a sigmoid-shaped, east verging thrust fault.To the east of and beneath the La Barge fault the Calpet fault is a west verging backthrust which terminates into the La Barge fault. The area between the faults forms a triangle zone from which significant gas production occurs.
On seismic, the two faults disappear into a no-data zone at approximately the same location to the north. Reflections from beneath the no-data zone appear to pull up, suggesting a shallow, high velocity zone. The no-data zone is interpreted to be an area where the La Barge and Calpet faults break up into a series of shallow faults that dissipate the seismic signal.
To the east of the triangle and no-data zones, a series of six near-vertical faults have been identified. The faults are interpreted to be tear faults caused by a strike-slip component to the major compression (transpression).
Four stratigraphic horizons were interpreted throughout the extent of the survey. The horizons were chosen for their potential for hydrocarbon production. The four horizons from oldest to youngest are (1) the Nugget Formation, (2) the Dakota Formation, (3) the Frontier Formation, and (4) the Baxter Formation.
This research was conducted in the J. Richard Hunt 3-D seismic laboratory using Landmark Graphics software on Silicon Graphics Octane workstations. This thesis represents the first interpretation on the workstations and a significant part of the project involved installation of the software, hardware, and data. Although difficulties were encountered in all aspects of installation, the final visualization capabilities of the system are remarkable. Seiscube, in particular, where time slices can be viewed anywhere within the data are spectacular. The enhanced graphical capabilities of the system allows the interpreter to easily visualize complex structures --Abstract, page iii