A Case Study of Semi-Automatic True Volume Interpretation in CASI of Both Structure and Stratigraphy from a 3-D Survey in the Gulf of Mexico
Geoffrey A. Dorn, Francis A. Coady, Jonathan Marbach, William S. Hammon, James A. Carlson, Benjamin J. Kadlec, and Gwen Pech
TerraSpark Geosciences, L.P., Boulder, CO
Interpretation of a seismic volume for structure and depositional systems is can be a very time-consuming process when conducted using traditional interpretation techniques. Traditional systems rely on the interpretation of horizons, faults and depositional features on in-lines, crosslines, and time-slices in the seismic volume, and may include some automation in the form of horizon autotracking.
A new workflow (CASI) and new interpretation techniques are used to interpret entire horizons, fault systems and depositional features as complete surfaces in the seismic volume, where an entire surface is interpreted at one time. The workflow steps include:
1) Semi-automatic extraction of surfaces for horizons, faults, and salt bodies
2) Creation of a stratal volume using the extracted structural surfaces and intervals as control for a 3-D stratal slice transformation.
3) Semi-automatic extraction of channel systems in the stratal volume
4) Inverse transformation of the extracted channel boundaries back to the domain of the input seismic volume
Interpreting complete surfaces in the volume significantly reduces the time and effort involved in structural interpretation. The domain transformation of the volume to create a structure free stratal-slice volume provides an ideal view of the data for extraction of depositional features as complete 3-D surfaces. Many depositional systems and features that would be completely missed in the input seismic volume become visible and interpretable in the stratal-slice volume. The inverse transformation of these surfaces into the original seismic volume, allows all aspects of the interpreted geological structure and stratigraphy to be integrated into one view leading to much more rapid and complete identification of prospects within the seismic volume.
AAPG Search and Discover Article #90078©2008 AAPG Annual Convention, San Antonio, Texas