Seismic velocity modeling of the Southern California Coastal Basins:Methods and Applications
M. Peter Suess1, Carlos Rivero2, John H. Shaw3, and Jeroen Tromp4
1University of Tuebingen, Department of Geosciences, [email protected]
2Chevron Corp., Houston, [email protected]
3Harvard University, Department of Earth and Planetary Sciences, [email protected]
4Division of Geological and Planetary Sciences, California Institute of Technology, [email protected]
Proper velocity model building is a key to integrated reservoir
and basin modeling, and errors in the velocity models can pose severe consequences for subsequent quantitative basin evaluations. Here we will review different methods for constructing velocity models and their applications in the Southern California Coastal Basins and Borderlands. Seismic velocities are measured in various ways, ranging from direct measurements in the lab, measurement in wells, check-shots and seismic reflection or refraction experiments. When working with observational data, several steps must be taken in generating a petrophysical property model including initial quality control, upscaling, interpolation and calibration. Using modern basin modeling tools, it is then possible to generate advanced velocity models integrating analytical functions, local and regional measurements as well as results from stratigraphic forward
simulations
. Furthermore, the velocity fields of complicated structures like thrust-wedges or salt-bodies, which are generally difficult to represent in classic layered-pie type models, can be addressed by modern approaches. Velocity models are primarily used for seismic reflection processing and time/depth conversion, thereby aiding to reduce the uncertainty of
reservoir
and basin models. Moreover, velocity is an important physical property that constrains the propagation of seismic waves. Hence besides their conventional application many other fields of uses of these models have developed. Our
field
of applications ranges from the relocation of seismic events to the the simulation of strong ground motions. The latter offers a unique opportunity to independently assess the quality of the models, through comparisons of observed and sythetic waveforms. The same techniques may also be used for higher frequency 3D-seimic forward
simulations
. New wave-form tomographic inversion methods further enhance the quality of our models.




AAPG Search and Discover Article #90066©2007 AAPG Hedberg Conference, The Hague, The Netherlands