--> Abstract: Undiscovered Exploration Leads in Shattered Gulf Coast Sediments, by A. Lowrie, F. E. Talbert, M. G. Mackenzie, J. C. Pratsch, I. Lerche, T. C. Klekamp, and R. L. Adams; #90932 (1998).

Datapages, Inc.Print this page

Abstract: Undiscovered Exploration Leads in Shattered Gulf Coast Sediments

LOWRIE, ALLEN
Picayune, MS;
F. ELIZABETH TALBERT
Pass Christian, MS;
MICHAEL G. MACKENZIE
New Orleans, LA;
JOHANN Christian PRATSCH
Houston, TX,
IAN LERCHE
University of South Carolina;
THOMAS C. KLEKAMP
Mandeville, LA;
RICHARD L. ADAMS
The Woodlands, TX

The salt-floored basin (S-FB) concept provides a dynamic view of a passive margin geosyncline evolution. This concept incorporates tectonics created by dynamics of sediment wedge, and tectonics or both salt and basement. Exploration of interaction between these different tectonic suites may reveal heretofore unknown specific hydrocarbon exploration targets and up-grade areas for further investigation.

Salt domes, ridges, and massifs move basinward at rates of one to ten cm/yr, causing fracturing, thermal anomalies, and under- and overpressure horizons. Basin-spanning shelf-edge growth faults sole out in shale layers; migrating salt can create counter-regional and local growth faults that terminated in semi-plastic salt and may create aureoles of fractures in front of the advancing salt. Counter-regional normal faults may exist in the sub-salt section shearing intra- and inter-salt providing minute, plastic deformation. Abundant earthquake activity (some 150 events in the last 50 years) provides energies for continuing tectonics.

Increasing fluid pressures eventually fracture calcite-Filled shale top seals or deep, overpressured fluid compartments. With salt absent and/or prior to salt intrusion, topography can influence sedimentation. With time, thinning and draping of deposits can focus subsequent bending, flexing, and fracturing over basement highs. Uneven basement subsidence can be caused by varying sediment loads, local geothermal anomalies, ancestral faulting patterns from pre- and post-rifting and then subsequent fault reactivation (note historic seismicity) and possible magma intrusions. Uneven Subsidence maintains basement-related tectonics. The intersection of several tectonic types, regardless of origin, may improve hydrocarbon migration in a shattered sediment wedge as through a colander, not a sieve.

AAPG Search and Discovery Article #90932©1998 GCAGS/GCS-SEPM Meeting, Corpus Christi, Texas