Sequence and Seismic Stratigraphy of the Bossier Formation (Tithonian; Uppermost Jurassic), Western East Texas Basin
George D. Klein, Kenneth R. Chaivre, 2002. "Sequence and Seismic Stratigraphy of the Bossier Formation (Tithonian; Uppermost Jurassic), Western East Texas Basin", Sequence Stratigraphic Models for Exploration and Production: Evolving Methodology, Emerging Models and Application Histories, John M. Armentrout, Norman C. Rosen
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Sequence and seismic stratigraphic analysis of well logs and 2-D seismic lines from Freestone, Anderson, Leon, Houston, Madison, Robertson and Limestone Counties, Texas, demonstrates that the Bossier Formation of the western East Texas basin can be subdivided into two recognizable sequences separated by a major sequence boundary (SB-2). Similarly, the Bossier Formation is also bracketed by a basal (SB-1) and upper (SB-3) sequence boundary separating it from the Gilmer (Cotton Valley) Lime of the Haynesville Formation below, and the Cotton Valley Sand above, respectively.
In seismic sections, the SB-2 boundary in the middle of the Bossier Formation was identified by tracing mounded basal reflectors and sigmoid basal reflectors representing basin floor and slope fans. This boundary was correlated onto the shelf below deltaic sands. In well log sections, basin floor fan log shapes were traced laterally into slope fan and stacked delta log patterns to identify SB-2. These basin floor and slope fans immediately above the SB-2 boundary represent a lowstand systems tract, whereas the lower Bossier (below the SB-2 Sequence Boundary) represents a transgressive systems tract and the upper Bossier (above the SB-2 boundary) represents a prograding complex.
Burial history analysis suggests that the lower Bossier accumulated during a time of rapid mechanical subsidence when the East Texas basin was underfilled. A drop in sea level associated with the SB-2 boundary represents a major climate shift from tropical to cooler conditions, favoring rapid influx of sands from the ancestral Mississippi, Ouachita, and Red River systems. These sands developed inner shelf prograding deltaic packages, outer shelf and incised valley fill stacked deltas, and basin submarine fan systems. The stacked deltas and basin fan sand systems all represent prospective gas plays.