Imaging and Interpretation in Fold and Thrust Belts
E. D. Bowering, A. J. Fox, R. Gonzalez, A. K. Mathur, M. P. Thornton, R. W. Wiener
Imaging and interpretation in complexly structured environments is often
hampered by seismic data quality problems brought on by such factors as severe
terrain, steep dips, strong lateral velocity
contrasts and 3D effects.
Application of seismic modeling, processing and structural modeling technology by the appropriate experts in an integrated approach can help the exploration team understand the source and effects of the data quality problems and identify ways to overcome them.
Data quality problems due to large elevation changes are common in fold and
thrust belts, presenting unique problems in data processing. Wave equation
statics is a promising way to properly adjust the datum of the unstacked data,
clearing the way for better velocity
analysis by removing the raypath
distortions caused by the irregular surface topography. Good
velocity
analysis
is critical, in turn, to model building for depth
migration
. Depth
migration
is
necessary to deal with
velocity
pull-up and distortion due to non-hyperbolic
moveout. These problems are caused by large lateral
velocity
changes often found
where older, faster rock is thrust over younger formations, a common scenario in
mountain belt exploration. Seismic and structural modeling can be useful to help
progress towards more optimal solutions by testing the geophysical and
geological feasibility of the model iterations at various stages in the
processing sequence.
Examples of application of these techniques on mountain belt datasets will be shown.
AAPG Search and Discovery Article #91020©1995 AAPG Annual Convention, Houston, Texas, May 5-8, 1995