Carbonate Seismic Stratigraphy of Cretaceous Paso Caballos Basin, Guatemala: New Structures in a "Structureless" Basin

J.D. Pigott, R. Mazariegos, J.M. Forgotson, Jr.

Previous exploration in the carbonate and evaporite sequences of the Paso Caballos basin focused primarily upon structural plays. Early data acquisition and processing purposely excluded the resolution advantages of broad frequency ranges and ignored the problems of statics. Interpretations based on these data were predictably unsuccessful in this large, presently karsted, Cretaceous shallow marine platform.

Seismic stratigraphic analysis of 735.5 km of statics-corrected, broad-band, zero-phase dynamic and Vibroseis data acquired in 1981 and 1982 delineates four seismic sequences within the Cretaceous (in increasing age): the Lacandon-Barton Creek limestone sequence, the upper Coban salt sequence, the middle Coban dolomitic salt sequence, and the Lower Cretaceous dolomitic sequence. The sequences overlying the faulted and folded Lower Cretaceous dolomitic sequence are relatively smooth and dip at a low angle toward a depocenter to the northwest. Within the carbonate section of the upper Coban salt sequence are several large (45 km²), mounded structures with substantial lateral and vertical variations in both reflection group configurations and wavelet characteristics. Detailed odeling and attribute analysis offer additional insight into the interpretation of these structures. For example, analysis of one such feature, the Santa Amelia structure, shows notched frequency attenuation off structure, which suggests permeable hydrocarbon-filled porosities on the flank isolated and sealed from a wet structural center.

AAPG Search and Discovery Article #91022©1989 AAPG Annual Convention, April 23-26, 1989, San Antonio, Texas.