Abstract: Synthetic Seismic Reflection Profiles of Experimental Salt Structures

Bruno C. Vendeville, M. P. A. Jackson, A. Sattar

We used sections cut through experimental models of salt structures and normal growth faults to produce synthetic seismic-reflection profiles and to compare these profiles with published seismic data from nature. We investigated a wide range of salt structures and tectonic settings, including listric-normal growth faults above salt rollers, non-emergent reactive diapirs below symmetric or asymmetric grabens, extrusive diapirs with wide overhangs, extensionally subsiding diapirs bounded by diapir relics and turtle structures, diapirs formed above actively faulting or inherited basement topography, and diapirs deformed in a late episode of regional shortening.

We digitized cross sections of actual models and produced synthetic unmigrated (normal incidence ray tracing) or migrated (image ray tracing) profiles using the SIERRA-Halliburton MIMIC+^R, QUIK+^R, and SLIPR^R software.

Comparison between true-depth sections and synthetic seismic profiles in time exemplifies some of the potential pitfalls encountered in interpreting seismic reflection profiles of natural salt structures. Our seismograms show (1) how large diapiric overhangs obscure normal faults and folds near diapir stems at depth, (2) that salt diapirs can distort significantly the apparent geometry of basement basins at the base of salt, and (3) how younger normal faults and sedimentary wedges can mask the occurrence of older folds at depth. Finally, synthetic profiles of models with turtle structures help in picking the location and geometry of subtle normal faults in crestal grabens. Such faults can compartmentalize reservoirs.

AAPG Search and Discovery Article #90986©1994 AAPG Annual Convention, Denver, Colorado, June 12-15, 1994