3D Seismic Visualization of Minibasins Controlled by Shale Tectonics in the Frio Formation, South Texas Gulf Coast

Osareni Ogiesoba, William Ambrose, and Rodolfo Hernandez
[email protected]

Salt tectonic and associated structures are common features in offshore and onshore Gulf of Mexico. However, there are certain areas of the Gulf Coast that exhibit shale diapiric structures instead of salt. We used 3D seismic visualization tools together with coherence and curvature attributes to examine minibasins formed by shale tectonics in the Frio Formation in the South Texas Gulf Coast. Our results show that orientation of shale diapiric structures varies within fields. In the northeast of study area, the shale diapirs and corresponding minibasins are mostly oriented NW-SE, approximately perpendicular to the coastline. In addition, we observed two main fault types- NW-SE and NE-SW trending faults. The NE-SW faults are composed of synthetic growth faults and antithetic faults parallel to the coastline. These faults constitute north and south boundaries of minibasins. The NW-SE faults are coincident with, and in some cases, form one of the flanks of the shale diapirs separating the minibasins. In the southeast part of the acreage, shale diapirs and minibasins are oriented WNW-ESE. Two fault types are also recognized. The first type is composed of growth faults and their respective antithetic faults with a NE-SW orientation parallel to the coastline. Major faults with this trend dip SE and form the north boundary of the minibasins. The second type of fault is composed of lateral faults with orientations parallel to the diapirs. These are closely related to the shale diapirs that constitute lateral boundaries of the minibasins.

AAPG Search and Discovery Article #90167©2013 GCAGS and GCSSEPM 63^rd Annual Convention, New Orleans, Louisiana, October 6-8, 2013