Stratigraphic and Structural Interpretations by Using Diffraction Seismograms

Richard K. Snavely, A. K. M. Sarwar

A two-dimensional seismic diffraction modeling method has been applied to an east-west cross section of Bay Marchand located 1 ¼ mi north of the Bay Marchand/South Timbalier area boundary in block 2 through block 4 of T23S, R23E. A 20-layer geologic depth model has been constructed from the correlation of SP-induction and sonic well logs. Each layer has been assigned a velocity determined from the corresponding sonic logs and a density approximated from Gardner's rule. A synthetic seismogram has been generated due to the geologic depth model using diffraction modeling computer code.

A comparison of the synthetic seismogram and the seismic field trace reveals salt dome piercement, graben faulting, pinch-out reflectors, and salt truncation reflectors. The reflector shape, shadow zone from faulting, and diffraction pattern outlining the boundary of the salt dome on the synthetic seismic section are similar to those on the field seismic section.

AAPG Search and Discovery Article #91036©1988 GCAGS and SEPM Gulf Coast Section Meeting; New Orleans, Louisiana, 19-21 October 1988.