ABSTRACT: Seismic Imaging of Steeply Dipping Salt Ridges in the Mississippi Interior Salt Basin
KAUFMANN, KARL J., Valioso Petroleum Company, Inc., Jackson, MS, and RICHARD IANNIELLO and OLIVER CARROLL, Geosignal, Inc., Houston, TX
The majority of oil and gas exploration and production in the Mississippi Interior Salt basin is confined around medium-to-high relief salt anticlines and their associated grabens. Proper imaging of the salt flanks is necessary to the understanding and drilling of these features. A high quality seismic line across one such salt ridge is presented. By manipulating various acquisition parameters on this example line and leaving the processing flow the same, one can readily see the effects that line length, group interval, and far-offset distance have on the ability to image the steep dips of the salt structure.
Four comparative cases will be presented.
(1) Migrated vs. unmigrated-shows the necessity of more than 5 mi of data to include the long diffractions from the salt flanks.
(2) Far-offset distances-are long offsets necessary to record the diffractions ?
(3) Group intervals-because of spatial aliasing, the group interval, or more properly the CDP interval, limits the degree of steep dip that can be migrated.
(4) Line length-answers the question of why a new, high-fold, small group interval line that was shot too short doesn't image the salt as well as the older, lower fold, coarse group interval regional line.
By taking the same data set, manipulating certain parameters while leaving everything else the same, it becomes apparent how critical the lengths of the line, group interval and far-offset are to properly image the steep dips along the flanks of the salt ridges in the Mississippi Interior Salt basin.
AAPG Search and Discovery Article #91014©1992 AAPG GCAGS and GC-SEPM Meeting, Jackson, Mississippi, October 21-23, 1992 (2009)