Shelf-margin sedimentation in Wilcox group, south-central Louisiana

Conference · Mon Sep 01 04:00:00 EDT 1986 · Am. Assoc. Pet. Geol., Bull.; (United States)

OSTI ID:6987858

Lowry, P; Lemoine, R C; Moslow, T F

Two well-defined trends of Wilcox oil and gas production occur in Louisiana: an updip dip-oriented trend and a downdip strike-oriented trend. The downdip trend delineates an uppermost Wilcox shelf margin and includes recent discoveries at Lockhart Crossing field and the long-established Fordoche field. This Wilcox shelf margin is adjacent to carbonate reef trends that formed a stable shelf margin throughout central Louisiana during the early Cretaceous. Shelf-margin locations remained essentially unchanged at least through the late Paleocene, by which time Wilcox clastics began to prograde out to and beyond the established margin. The depositional features of this progradational episode reflect the unstable nature of the shelf margin and a high wave-energy environment. Shelf-margin processes were responsible for the formation of a regional syndepositional normal fault system, the incision and subsequent infilling of a major submarine canyon system, and the development of stacked paralic sequences. The submarine canyon system is manifest as a mudstone-filled channel in St. Landry Parish where it reaches a maximum thickness of 1000 ft and is up to 12 mi wide. Lower to middle shoreface facies of the stacked paralic sequences constitute the primary reservoir sandstones for both Lockhart Crossing and Fordoche fields. The major producing intervals of both fields belong to two discrete sandstone bodies that are at least 30-40 mi long, 6-7 mi wide, and 30-40 ft thick, and are analogous to late Quaternary Gulf Coast shelf-margin deltas. The co-occurrence of these laterally continuous thick sandstones, favorable structural trapping mechanisms, and previous performance suggest a high potential for future exploration along this and other Gulf Coast Tertiary shelf-margin trends.

• Research Organization: Louisiana State Univ., Baton Rouge
• OSTI ID: 6987858
• Report Number(s): CONF-8610199-
• Conference Information: Journal Name: Am. Assoc. Pet. Geol., Bull.; (United States) Journal Volume: 70:9
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
03 NATURAL GAS
030200 -- Natural Gas-- Reserves
Geology
& Exploration
CARBONATE ROCKS
CENOZOIC ERA
FEDERAL REGION VI
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC FORMATIONS
LOUISIANA
MINERAL RESOURCES
NATURAL GAS DEPOSITS
NORTH AMERICA
PETROLEUM DEPOSITS
RESERVOIR ROCK
RESOURCES
ROCKS
SEDIMENTARY ROCKS
SEDIMENTATION
TERTIARY PERIOD
USA