Exploratory Progress Towards Proving the Billion Barrel Potential of the Tuscaloosa Marine Shale

Chacko J. John, Bobby L. Jones, Brian J. Harder, and Reed J. Bourgeois
Louisiana Geological Survey, 3079 Energy, Coast and Environment Building, Baton Rouge, Louisiana 70803

It has long been known by operators and drillers that the Tuscaloosa Marine Shale lying between the sands of the upper and lower Tuscaloosa sections (upper Cretaceous) contained hydrocarbons. This section varies in thickness from approximately 500 feet in southwestern Mississippi to more than 800 feet in the southern part of southeastern Louisiana. The primary zone of interest is a highly resistive zone at the base of the shale section which ranges in thickness from 0-325 feet. Our preliminary evaluation indicated that the Tuscaloosa Marine Shale may contain potential reserves of about seven billion barrels of oil covering an area of approximately 750,000 acres. Recently as a result of the prevailing high oil prices there has been an upsurge of interest in the exploratory drilling and exploitation of this resource.

The Bakken Shale in the Williston Basin, the Antrim Shale in the Michigan Basin and the Barnett Shale in the Fort Worth Basin are examples of economically successful production from shale sections. The recent tremendous success in the Barnett Shale has resulted in continuous improvement of the drilling, completion, fracturing and production techniques resulting in drastic cost reductions. While all these shales produce gas, the Tuscaloosa Marine Shale is oil productive but has attracted comparatively little attention resulting in minimum drilling and geologic evaluation. Since 1998 limited oil production from the Tuscaloosa Marine Shale has been established in Southwest Mississippi in the Orca and Gillsburg Fields in Amite County and the South Magnolia Field and the Tangipahoa River Field in Pike County. Reports indicate that plans for new and continued development from the Tuscaloosa Marine Shale from both vertical and horizontal wells are in progress. With continuing technological improvements in the various aspects of drilling and production, especially horizontal drilling, and also evaluating the use of the technology adapted for the Barnett Shale, the Tuscaloosa Marine Shale still remains a potentially very attractive large oil resource which could be commercially exploited.

AAPG Search and Discovery Article #90080©2005 GCAGS 55th Annual Convention, New Orleans, Louisiana