Changes

In Figure 4-40, producing fields are along the 200-ft (60-m) net sand contour or beyond rather than in the axial thick. This is because of gravity-flow sands accumulating within the [[Syncline|synclinal]] valley axes, which continue to subside through time.

In Figure 4-40, producing fields are along the 200-ft (60-m) net sand contour or beyond rather than in the axial thick. This is because of gravity-flow sands accumulating within the [[Syncline|synclinal]] valley axes, which continue to subside through time.

The following figure shows a depositional strike seismic reflection profile across one of these valleys. The high-amplitude, more continuous reflections correlate with condensed-section claystones and often bracket [[pressure compartments]] due to their very low [[permeability]]. Between the condensed sections are the sand-prone early lowstand systems tract, sometimes with hummocky-mounded facies suggesting channel complexes, overlain by silt-prone late lowstand deposits. The differential loading of salt by sediment accumulation along the synclinal valley axis results in differential rotation of each depositional sequence. This rotation along the synclinal flanks results in the early lowstand gravity-flow sands pinching-out structurally upward, providing potential hydrocarbon traps along the valley margins (;<ref name=ch04r9>Armentrout, J., M., 1996, High-resolution sequence biostratigraphy: examples from the Gulf of Mexico Plio–Pleistocene, in Howell, J., Aiken, J., eds., High Resolution Sequence stratigraphy: Innovations and Applications: The Geological Society of London Special Publication 104, p. 65–86.</ref><ref name=ch04r20>Bilinski, P., W., McGee, D., T., Pfeiffer, D., S., Shew, R., S., 1995, Reservoir characterization of the “S” sand, Auger field, Garden Banks 426, 427, 470, and 471, in Winn, R., D. Jr., Armentrout, J., M., eds., Turbidites and Associated Deep-water Facies: SEPM (Society for Sedimentary Geology) Core Workshop No. 20, p. 75–93.</ref><ref name=ch04r65>McGee, D., T., Bilinski, P., W., Gary, P., S., Pfeiffer, D., S., Sheiman, J., L., 1994, Geologic models and reservoir geometries of Auger field, deepwater Gulf of Mexico: Proceedings, Gulf Coast Section SEPM 15th Annual Research conference, p. 245–256.</ref> ''see also'' Weimer and Bouma, 1995).

The following figure shows a depositional strike seismic reflection profile across one of these valleys. The high-amplitude, more continuous reflections correlate with condensed-section claystones and often bracket [[pressure compartments]] due to their very low [[permeability]]. Between the condensed sections are the sand-prone early lowstand systems tract, sometimes with hummocky-mounded facies suggesting channel complexes, overlain by silt-prone late lowstand deposits. The differential loading of salt by sediment accumulation along the synclinal valley axis results in differential rotation of each depositional sequence. This rotation along the synclinal flanks results in the early lowstand gravity-flow sands pinching-out structurally upward, providing potential hydrocarbon traps along the valley margins (;<ref name=ch04r9>Armentrout, J. M., 1996, High-resolution sequence biostratigraphy: examples from the Gulf of Mexico Plio–Pleistocene, in Howell, J., Aiken, J., eds., High Resolution Sequence stratigraphy: Innovations and Applications: The Geological Society of London Special Publication 104, p. 65–86.</ref><ref name=ch04r20>Bilinski, P. W., McGee, D. T., Pfeiffer, D. S., Shew, R. S., 1995, Reservoir characterization of the “S” sand, Auger field, Garden Banks 426, 427, 470, and 471, in Winn, R. D. Jr., Armentrout, J. M., eds., Turbidites and Associated Deep-water Facies: SEPM (Society for Sedimentary Geology) Core Workshop No. 20, p. 75–93.</ref><ref name=ch04r65>McGee, D. T., Bilinski, P. W., Gary, P. S., Pfeiffer, D. S., Sheiman, J. L., 1994, Geologic models and reservoir geometries of Auger field, deepwater Gulf of Mexico: Proceedings, Gulf Coast Section SEPM 15th Annual Research conference, p. 245–256.</ref><ref>Weimer, P., A. H. Bouma, and B. F. Perkins, eds., 1994, Submarine Fans and Turbidite Systems: Sequence Stratigraphy, Reservoir Architecture and Production Characteristics, Gulf of Mexico and International: Gulf Coast Section SEPM Foundation Fif- teenth Annual Resesarch Conference Proceedings, 440 p.</ref>).

The [[isochron]] thick of the ''Glob alt'' sands in the figure represents the sand-prone slope/valley fill of the ''Glob alt'' sequence. Understanding the interplay of depositional processes and tectonic [[deformation]] is essential to hydrocarbon exploration in GOM minibasins.

The [[isochron]] thick of the ''Glob alt'' sands in the figure represents the sand-prone slope/valley fill of the ''Glob alt'' sequence. Understanding the interplay of depositional processes and tectonic [[deformation]] is essential to hydrocarbon exploration in GOM minibasins.