The objective of this project is to demonstrate the value of elastic-wavefield seismic stratigraphy, a new seismic interpretation science based on the principles that:
Bureau of Economic Geology
University of Texas at Austin
Fasken Oil and Ranch
Seismic stratigraphy was introduced by Exxon as a formal seismic interpretation science in 1975-77. For decades, the science was limited to single-component P-wave seismic data. This project is expanding the science to multicomponent seismic data and showing how these expanded concepts improve the detection of stratigraphic traps.
Examples have been documented in which shear (S)-wave data provide geologic information that cannot be extracted from the companion compressional (P)-wave data. Examples also have been documented in which P-wave data provide information that is not present in the companion S-wave data.
The principal benefit of this research is that it introduces a new seismic technology that will aid in the search for subtle stratigraphic trap oil reservoirs. If a subsurface structural description of major Earth layers is the only information that is needed to exploit a prospect, that information can be provided by P-wave seismic data alone. In contrast, significantly more stratigraphic information can be extracted from multicomponent (elastic wavefield) seismic data than from single-component P-wave data.
In Year 1, the study focused on West Texas 3-component, 3-D seismic data and demonstrated how this new science improves detection of carbonate stratigraphic traps. In Year 2, the research moved to a 3,000 square-mile area of 4-component (4-C), 2-D seismic data coverage across the northern shelf of the Gulf of Mexico and showed that new elastic-wavefield concepts allowed critical new insights into the distribution of stratigraphic traps in sand/shale sequences . In Year 3, the study concentrates on applying elastic-wavefield interpretation concepts to 9-component, 3-D seismic data across the Williston Basin. In each study area, the principal problem that is addressed is to improve the detection of stratigraphic traps.
Among the project highlights:
The project is on schedule and midway through its third and final year. The research team is now beginning to prepare the final project report, documenting key principles and research findings, and thinking about publications and public work-shops. Improved S-wave volumes (fast-S and slow-S) across the 9-C, 3-D Williston Basin survey will be delivered to the research team in late January. If there are significant improvements or image variations in this second processing effort compared with the volumes that have already been studied, a second interpretation will be done to develop additional comparisons of P and S seismic sequences and facies.
$189,000 (20.3% of total)
Six quarterly reports and one continuation report have been delivered to DOE.
Hardage et al., Defining P-wave and S-wave stratal surfaces with 9-C VSPs, The Leading Edge, V. 22, 2003, pp. 720-729.
Fomel et al., Multicomponent seismic data registration for subsurface characterization in the shallow Gulf of Mexico, Offshore Technology Conference, 2003, Houston, TX.
Murray et al., Interpreting multicomponent seismic data in the Gulf of Mexico, Offshore Technology Conference, 2003, Houston, TX.
DeAngelo et al., Depth registration of P and C seismic data for shallow marine sediment characterization, The Leading Edge, V. 22, pp. 96-105.
Hardage and Aluka, Elastic-wavefield seismic stratigraphy, scheduled for the January 2006 issue of AAPG Explorer.
Hardage and Aluka, Depth registration of P and S data, scheduled for the February 2006 of the AAPG Explorer.