Synthetic Seismic Modeling of Turbidite Outcrops
Seismic forward models of turbidite outcrop sections have been created to illustrate how reservoir architecture details may be expressed within the scale of resolution of commonly available, marine seismic data. These can be instructive for refining seismic interpretations and recognizing uncertainties inherent in those interpretations. Outcrop sections having sufficient length and thickness were digitized at a bed scale to generate models (Table 1). These cover a variety of sheet, channel, and mixed architecture styles.
The outcrop sections were derived from various sources (Table 1); additional outcrops are discussed in the full-length version of this paper on the CD-ROM in the back of this book (chapter 119). The sections were digitized at the finest resolution possible. This usually approximated bed scale; however, very thin, heterolithic laminae were usually lumped together as thin-bed facies. The models are relatively simple, noise-free, normal-incidence, synthetic seismograms. Velocity and density were assigned by facies and given values typical of oil-saturated sands in Gulf of Mexico Tertiary minibasin settings (Table 2). The geometries are, therefore, geologically realistic. However, in real subsurface reservoirs there is likely to be more rock property variation within facies, and also more noise in the seismic response. Shear-wave rock properties or amplitude vs. offset are not considered in the models shown here. The workflow is illustrated in Figure 1.
Testing the seismic response of a single geometry assuming different acoustic contrast and velocity can be instructive. We looked at the seismic response of outcrop sections
Figures & Tables
Atlas of Deep-Water Outcrops
Tor H. Nilsen, a red-haired Scandinavian who stood more than six feet tall, died October 9, 2005, at his San Carlos, California, home. This was after a valiant five-year fight with melanoma cancer. He was 63. His ashes were scattered at his family plot in Norway in 2006.
He was born in New York City on November 29, 1941, to Mollie Abrahamson and Nils Marius Nilsen of Mandal, Norway, and was the first of their children to be born in the United States. After graduating from Brooklyn Tech, he earned his B.S. in geology from City College of New York in 1962. While there, his prowess on the basketball court impressed a scout from the New York Knicks, but Tor went on to graduate school and earned his M.S. and Ph.D. degrees in geology from the University of Wisconsin at Madison in 1964 and 1967, respectively. His M.S. thesis was a study of Precambrian metasedimentary deposits in the Lake Superior area, and his Ph.D. thesis was a study of Devonian alluvial-fan deposits of the Old Red Sandstone in western Norway.
Dr. Nilsen’s principal expertise was in depositional systems analysis, stratigraphic analysis, and the relationships among tectonics, eustasy, and sedimentation. He began his industry career in 1967 as a research geologist with the Shell Development Company in Houston, Texas, and Ventura, California, where he worked on the tectonics and sedimentation of Tertiary shelf systems of coastal California. He subsequently spent two years with the U.S. Army Corps of Engineers as the Military