Abstract Neogene shelf, slope, canyon, and slope-to-basin-floor transition plays in the southern Laguna Madre–Tuxpan (LM-T) continental shelf reflect a variety of structural and stratigraphic controls, including gravity sliding and extension, compression, salt evacuation, and lowstand canyon and fan systems. The Neogene in the LM-T area was deposited along narrow shelves associated with a tectonically active coast affected by significant uplift and erosion of carbonate and volcanic terrains. This study characterizes 4 structurally defined trends and 32 Neogene plays in a more than 50,000-km 2 (19,300-mi 2 ) area linking the Veracruz and Burgos basins. Copyright © 2009 by The American Association of Petroleum Geologists. Reprinted from AAPG Bulletin, v. 89, no. 6, (June 2005), pp. 725 – 751. DOI:10.1306/13191099M903340 The Cañonero trend in the southern part of the LM-T area contains deep-seated basement faults caused by Laramide compression. Many of these faults are directly linked to the interpreted Mesozoic source rocks, providing potential pathways for vertically migrating hydrocarbons. In contrast, the Lankahuasa trend, north of the Cañonero trend, contains listric faults, which detach into a shallow horizon. This trend is associated with thick Pliocene shelf depocenters. The dominant plays in the Faja de Oro–Náyade trend in the central part of the LM-T area contain thick lower and middle Miocene successions of steeply dipping slope deposits, reflecting significant uplift and erosion of the carbonate Tuxpan platform. These slope plays consist of narrow channel-fill and levee sandstones encased in siltstones and mudstones. Plays in the north end of the LM-T area, in the southern part of the Burgos basin, contain intensely deformed strata linked to salt and shale diapirism. Outer-shelf, slope, and proximal basin-floor plays in the Lamprea trend are internally complex and contain muddy debris-flow and slump deposits. Risk factors and the relative importance of play elements vary greatly among LM-T plays. Reservoir quality is a critical limiting play element in many plays, especially those in the Cañonero trend directly downdip from the trans-Mexican volcanic belt, as well as carbonate-rich slope plays adjacent to the Tuxpan platform. In contrast, trap and source are low-risk play elements in the LM-T area because of the abundance of large three-way and four-way closures and the widespread distribution of organic-rich Upper Jurassic Tithonian-age source rock. The potential for hydrocarbon migration in LM-T plays is a function of the distribution of deep-seated faults inferred to intersect the primary Mesozoic source. Their distribution is problematic for the Lankahuasa trend, where listric faults sole out into the Paleocene. Seal is poorly documented for LM-T plays, although the presence of overpressured zones and thick bathyal shales is favorable for seal development in middle and lower Miocene basin and slope plays. Reprinted from AAPG Bulletin, v. 89, no. 6, (June 2005), pp. 725–751.

Abstract During the past two decades, petroleum exploration has moved into frontier basins both onshore and offshore. Prospects in these basins have become increasingly deeper and often consist of potential deep-water reservoirs, in addition to more conventional shallow marine clastic and carbonate reservoir facies. By definition, frontier basins lack sufficient well control to permit conventional subsurface facies analysis and mapping. Consequently, the explorationist must extract maximum subsurface information from seismic reflection profiles. Without stratigraphic interpretation of frontier basins, exploration is limited to structural anomalies drilled without benefit of reservoir source or seal discrimination. Hence, concepts and techniques of seismic stratigraphic interpretation have developed to meet this need.

Abstract Seismic-stratigraphic interpretation has become an important element of exploration in basins with limited well control. This new direction in exploration imposes new responsibilities and qualifications on both the geologist and the geophysicist. Two general approaches are developing in response to exploration requirements—a physical approach involving processing and synthetic modeling, and a seismic-stratigraphic approach involving a new application of traditional facies geology. Seismic-stratigraphic analysis of Brazilian offshore basins permits the development of approaches and concepts that can be applied to other basins. Analysis involved development of seismic-stratigraphic framework, interpretation of reflection patterns, chronostratigraphic correlation, mapping seismic-stratigraphic (depositional system) units, synthesis of depositional and facies interpretations, and, in many cases, strategic mapping of specific facies. Within Brazilian offshore basins, three principal depositional systems are recognized—delta and fan delta, carbonate platform and shelf, and slope. By integrating seismic and limited well data, it is possible to recognize on reflection seismic sections: (1) three deltaic facies—prodelta and distal delta, front or barrier; delta, front or barrier; and alluvial and delta plain; (2) two fan-delta facies—proximal and medial fan, and distal fan and prodelta; (3) three shelf and platform facies—neritic; reef, bank, shoal, and shelf edge; and submarine canyon fill; and (4) three principal arrangements of slope facies—offlap, onlap, and uplap. Integration of conventional and seismic-stratigraphic analyses permits recognition of five fundamental types of rift and pull-apart basins in Brazilian offshore areas: early rift-fault basin, post-rift clastic basin with salt tectonism, post-rift basin with stable carbonate platform, pull-apart basin with passive clastic-carbonate offlap and onlap deposition, and pull-apart basin with deltaic sedimentation. Seismic-stratigraphic analysis permits extrapolation of limited well data to predict depositional systems tracts, tectonic elements, principal depositional modes, and source area and drainage characteristics. Similarly, the geologist can predict reservoir type and spatial distribution, Stratigraphic and structural trap possibilities, and source bed and seal potential.