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Line 37: − The lowstand phase of the ''Glob alt'' depositional sequence is sand prone (Figure 4-29) and produces hydrocarbons from at least 23 fields within the High Island–East Breaks depocenter (Figure 4-40). The sandstone reservoirs were deposited within slope valleys by gravity-flow processes.<ref name=ch04r7>Armentrout, J., M., 1991, Paleontological constraints on depositional [[modeling]]: examples of integration of biostratigraphy and seismic stratigraphy, Pliocene–Pleistocene, Gulf of Mexico, in Weimer, P., Link, M., H., eds., Seismic Facies and Sedimentary Processes of Submarine Fans and Turbidite Systems: New York, Springer-Verlag, p. 137–170.</ref> The abundance of ''Glob alt'' sandstone is interpreted to be the consequence of a major fall in relative sea level. The falling sea level resulted in enhanced bypass of sand across the shelf and into the slope basins and deposition of a lowstand systems tract. − + + +
Superimposed sea level cycles (view source)
Revision as of 20:44, 20 February 2014
, 20:44, 20 February 2014→Effect on reservoir deposition
==Effect on reservoir deposition==
==Effect on reservoir deposition==
[[file:sedimentary-basin-analysis_fig4-40.png|thumb|{{figure number|4-40}}See text for explanation.]]
[[file:sedimentary-basin-analysis_fig4-40.png|thumb|{{figure number|3}}See text for explanation.]]
The lowstand phase of the ''Glob alt'' depositional sequence is sand prone (Figure 4-29) and produces hydrocarbons from at least 23 fields within the High Island–East Breaks depocenter ([[:file:sedimentary-basin-analysis_fig4-40.png|Figure 3]]). The sandstone reservoirs were deposited within slope valleys by gravity-flow processes.<ref name=ch04r7>Armentrout, J., M., 1991, Paleontological constraints on depositional [[modeling]]: examples of integration of biostratigraphy and seismic stratigraphy, Pliocene–Pleistocene, Gulf of Mexico, in Weimer, P., Link, M., H., eds., Seismic Facies and Sedimentary Processes of Submarine Fans and Turbidite Systems: New York, Springer-Verlag, p. 137–170.</ref> The abundance of ''Glob alt'' sandstone is interpreted to be the consequence of a major fall in relative sea level. The falling sea level resulted in enhanced bypass of sand across the shelf and into the slope basins and deposition of a lowstand systems tract.
The ''Glob alt'' sequence mapped on Figure 4-29 represents the lowstand depositional phase of the Haq et al.<ref name=ch04r43 />) third-order 3.7 cycle (Figure 4-25). Cycle 3.7 begins with the most significant relative fall in sea level of the Tejas B-3 supersequence after the second-order highstand (cycles 3.4 and 3.5). This significant fall in sea level resulted in transport of large volumes of sand from the paleo-Mississippi River system into the slope basins of the High Island and East Breaks areas of offshore Texas (Figures 4-29 and 4-33), depositing numerous potential reservoirs of gravity-flow sands during maximum amplification of falling sea level. Following lowstand deposition, relative rise in sea level cut off the sand supply and resulted in deposition of hemipelagic mudstones, forming a regional top seal to the ''Glob alt'' sandstones (Figures 4-29 and 4-33). The top seal is a condensed section that correlates laterally with the transgressive and early highstand systems tracts.
The ''Glob alt'' sequence mapped on Figure 4-29 represents the lowstand depositional phase of the Haq et al.<ref name=ch04r43 />) third-order 3.7 cycle (Figure 4-25). Cycle 3.7 begins with the most significant relative fall in sea level of the Tejas B-3 supersequence after the second-order highstand (cycles 3.4 and 3.5). This significant fall in sea level resulted in transport of large volumes of sand from the paleo-Mississippi River system into the slope basins of the High Island and East Breaks areas of offshore Texas (Figures 4-29 and 4-33), depositing numerous potential reservoirs of gravity-flow sands during maximum amplification of falling sea level. Following lowstand deposition, relative rise in sea level cut off the sand supply and resulted in deposition of hemipelagic mudstones, forming a regional top seal to the ''Glob alt'' sandstones (Figures 4-29 and 4-33). The top seal is a condensed section that correlates laterally with the transgressive and early highstand systems tracts.