Part 4 - Berg - Hughes Center

North Louisiana Salt Basin. The structure maps constructed on top of the Cotton Valley
(Fig. 14), on top of the Lower Cretaceous (Fig. 15) and on top of the Upper Cretaceous
(Fig. 16) show the configuration of the basin. The cross sections and isopach maps of the
interval from the top of the Smackover to the top of the Cotton Valley (Fig. 17) and of
the interval from the top of the Cotton Valley to the top of the Lower Cretaceous (Fig.
18) show that the area updip or along the northern margin of the basin is characterized by
a thinner stratigraphic section, and the area downdip or along the southern margin of the
basin is characterized by a thicker stratigraphic section. The formation lithology maps
illustrate lithologic changes in the various units (Figs. 21-40). Although an unconformity
is present at the base of the Upper Cretaceous section throughout the basin (Figs. 3-13),
this unconformity is particularly developed in Lower Cretaceous strata onlapping the
Monroe Uplift as illustrated by the isopach map of the interval from the top of the Lower
Cretaceous to the top of the Upper Cretaceous (Fig. 19), by the map that shows the
erosional thickness of the total Lower Cretaceous section (Fig. 20), and by the cross
sections.
Thermal Maturation History
The thermal history of a basin is critical to petroleum identification and is a crucial
element as to whether the basin has hydrocarbons in commercial quantities and as to
whether these hydrocarbons are oil, natural gas or both. Thermal maturity modeling,
which builds on burial history modeling, assists in this hydrocarbon determination. In the
North Louisiana Salt Basin, Smackover oil has not been produced below 12,000 feet.
Study of the thermal maturation history profiles (Figs. 87-128) indicates that in the
North Louisiana Salt Basin hydrocarbon generation and maturation trends are evident.
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