Mid-Continent Section

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Sequence stratigraphy of the Woodford Shale present on the southern Cherokee Platform of central Oklahoma: Implications for regional play definitions limited to localized studies


The Woodford Shale on the southern Cherokee Platform of central Oklahoma was deposited mainly within two linear trends (Trend 1 and Trend 2) that correspond to eroded and missing sections in the underlying Hunton Group. These trends have been interpreted as incised valleys that were carved out of the underlying Hunton Group by erosional processes that occurred prior to the deposition of the Woodford Shale. The Woodford Shale preferentially filled the incised valleys as they represent the maximum accommodation that was available in the study area at the time of deposition. Identification, correlation and mapping of 12 well-log facies (RGRPs) from 137 wells reveals that Trend 2 began to backfill during regional transgression prior to the onset of backfilling of Trend 1. This indicates that the relief on the subaerially exposed Trend 2 surface was greater than that on the Trend 1 surface. In addition to transgressive backfilling to the north-northwest, an overlying highstand interval appears to have been derived from the northeast and prograded to the southwest. As a result, the well-log facies are not necessarily correlative between the two trends in either time or space. Total organic carbon content (TOC) models, estimated from Δ Log R log calculations, suggest that the linear trends contain separate organic rich RGRPs. This observation implies that the hydrocarbons present in the terminal extents of each trend were sourced by separate organic-rich strata.