Part 4 - Berg - Hughes Center

gas with some oil, not only within the Bossier shale, but also in overlying Upper Jurassic
and Lower Cretaceous reservoirs, particularly in the Bossier and Cotton Valley.
The Bossier petroleum system includes essentially the same underburden and
overburden rocks as the Smackover petroleum system. The petroleum source rocks are
the Bossier shale beds. Generation of hydrocarbons was initiated in the late Early
Cretaceous with the generation of secondary, non-associated thermogenic gas
commencing in the Late Cretaceous (Figs. 349-351). Hydrocarbon expulsion appears
minimal suggesting the Bossier has potential as a shale gas reservoir (Fig. 352).
Sandstones within the Bossier and in the Cotton Valley Group also probably acted as
reservoirs for the hydrocarbons that were expelled from the Bossier shale beds.
Hydrocarbon Flow Pathway Modeling
Hydrocarbon flow pathway modeling indicates that Smackover hydrocarbons were first
generated and expelled in the Early Cretaceous from the southern part of the North
Louisiana Salt Basin and migrated north and updip into the areas of the Sabine Uplift,
Monroe Uplift, and northern parts of the basin (Figs. 353-355). Hydrocarbons, essentially
thermogenic gas, generated and expelled in the late Early Cretaceous from the Bossier
followed the same flow pathways as Smackover hydrocarbons (Figs. 356-367). However,
expulsion modeling (Fig. 352) indicates that much of the gas generated from the gas-
prone Type III kerogen in this source rock was retained in the Bossier and was not
expelled. The low total organic carbon content of the Bossier contributed to the
accumulation of in situ thermogenic gas. The IES PetroMod® 2D software application
was used for the hydrocarbon flow pathway modeling. No thermogenic hydrocarbon
expulsion occurred in the immediate vicinity of the Monroe Uplift, and the main source
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