The Sequence Stratigraphy of the Woodbine and Eagle Ford Groups in the East Texas Basin (USA): A new Chronostratigraphic Framework to Properly Identify & Map their Associated Plays and Play Fairways
Abstract
The Woodbine and Eagle Ford Groups are prolific hydrocarbon-bearing reservoirs in the East Texas Basin (ETB). However, complex stratigraphic relationships between these units in the subsurface has led to the succession simply being referred to as the “Eaglebine.” Along the outcrop belt, the organic-rich mudstones at the base of the Eagle Ford Group unconformably overlie Early Cenomanian argillaceous mudstones and sandstones of the Woodbine Group. In sharp contrast, within the southern ETB, Late Cenomanian sandstones, as well as the underlying Middle Cenomanian organic-rich mudstones, are typically included within the Woodbine Group. To resolve the stratigraphic inconsistencies between the outcrop belt and the subsurface, a surface-based, sequence-stratigraphic approach was applied to a grid of well log cross sections, as well as research cores, which tie to the outcrop belt to the west and extend into the sub-subsurface to the east. This study indicates that the unconformity-bounded Woodbine and Eagle Ford Groups, as defined in the outcrops, can be successfully correlated into the subsurface. Within this sequence stratigraphic framework, the Upper Member of the Lower Eagle Ford Formation, as defined in this study, contains Late Cenomanian (Harris Delta) sandstone beds, previously mis assigned to the Early Cenomanian Woodbine Group. With this new sequence stratigraphic framework in place, detailed chrono-stratigraphically defined paleogeographic maps were constructed. These stratigraphic maps reveal for the first time the various conventional and unconventional plays, as well as the associated play fairways of the Woodbine and Eagle Ford Groups.
Citation
Gifford, Scott R (2021). The Sequence Stratigraphy of the Woodbine and Eagle Ford Groups in the East Texas Basin (USA): A new Chronostratigraphic Framework to Properly Identify & Map their Associated Plays and Play Fairways. Master's thesis, Texas A&M University. Available electronically from https : / /hdl .handle .net /1969 .1 /193195.