Shale-filled channel system in Wilcox Group (Paleocene-Eocene), north-central south Louisiana

Conference · Mon Sep 01 00:00:00 EDT 1986 · Am. Assoc. Pet. Geol., Bull.; (United States)

OSTI ID:6982613

McCulloh, R P; Eversull, L G

Anomalously thick shale intervals of limited extent within normally sandy facies of the Wilcox are evident on published regional electric log structure sections through south Louisiana. These intervals were investigated with a series of subregional stratigraphic electric log sections and by mapping. The stratigraphic sections show that in places the shale cuts out nearly 1000 ft (300 m) of adjacent interstratified sandstone and shale section and has lenticular, channel-like, cross-sectional geometry. The sections also indicate that the uppermost parts of the thick shale intervals are stratigraphically equivalent to, or at least contiguous with, a persistent subregional shale marker bed known informally as the Big Shale, but are distinguishable from it in places by more uniform log character. A map of the anomalously thick and uniform shale indicates a south-trending, relatively straight channel with a single bifurcation in southern Avoyelles Parish. The branches probably continue downdip, although they cannot be traced with confidence south of central St. Landry Parish because of the overall shalier Wilcox section and scarcity of adequately deep control wells. The channel shale is analogous to other early Cenozoic subsurface truncational shale masses that have been mostly interpreted as submarine canyon-channel fills. Stratigraphic trapping possibilities are evident from the truncation of bounding permeable units, but the possible continuation of the branches downdip suggests the potential for deep sandy equivalents and deep gas.

• Research Organization: Louisiana Geological Survey, Baton Rouge
• OSTI ID: 6982613
• Report Number(s): CONF-8610199-
• Journal Information: Am. Assoc. Pet. Geol., Bull.; (United States), Vol. 70:9; Conference: 36. annual meeting of the Gulf Coast Association Geological Societies and the Gulf Coast Section of SEPM, Baton Rouge, LA, USA, 22 Oct 1986
• Country of Publication: United States
• Language: English

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