Sea Level Highstand Shales and Thin Stacked Deltas: Paleocene Middle Wilcox of Central Louisiana and Southwest Mississippi

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ABSTRACT The Wilcox Group is subdivided into the Lower, Middle and Upper Wilcox. The newly created Middle Wilcox subdivision has produced most of the nearly one billion barrels of oil from the Wilcox of east-central Louisiana and southwest Mississippi. The E-2/C5/Turner parasequence set is bounded by the Big Shale transgressive systems tract above and the Baker Shale transgressive systems tract below. A stratigraphic model is developed for the E-2/C5/Turner parasequence set. The set is a thin (300ft=91m), highstand systems tract, aggradational parasequence set. An apparent sea-level rise during Baker Shale deposition resulted in a transgression of older delta deposits, forming oil productive transgressive barriers, shoals and related sands. These sands are analogues of Holocene stratigraphic models of the coastal areas and near-shore locations of Louisiana and Mississippi. The E-2/C5/Turner parasequence set provides no analogues to modern stratigraphic models. The model established in this paper for the E-2/C5/Turner parasequence set describes cyclic deposition of a constructive interval bay fill shale overlain by bay fill sand overlain by a thin lignite. In part, the model seeks to develop predictive procedures for mapping and locating optimal drilling locations for potential reservoirs of the aggradational parasequence set which is an important oil producing set in east-central Louisiana and southwest Mississippi.