Predicting Potential Unconventional Production in the Tuscaloosa Marine Shale Play Using Thermal Modeling and log Overlay Anaysis
Hunter Berch and Jeffrey Nunn
The Tuscaloosa Marine Shale formation (TMS) of Central Louisiana and South Mississippi was suggested as a potential hydrocarbon play with up to seven billion barrels of reserves in a 1997 study by Louisiana State University's Basin Research Institute. The TMS is considered an unconventional resource because it is a source, reservoir, and seal. Since 1997, horizontal drilling and hydraulic fracturing have enabled exploration and documentation of oil reserves in this play. Prior to this study, high resistivity log curves were used to predict areas of economic interest. However, after drilling in several such areas, it is now known that high resistivity does not necessarily correlate with high production. In this study, information from sonic logs and resistivity logs from 92 wells were used in Schlumberger's PetroMod® software to estimate thermal maturation. Model results indicate that the TMS is in the oil window (0.55 to 1.1 %Ro) throughout the study area and %Ro roughly correlates with depth of burial. Total Organic Carbon (TOC) was estimated using a log overlay technique. Estimated TOC in the study area ranges from 0% to 2.2% and has a complex spatial distribution. Highest TOC values are predicted along the northern boundary between East Baton Rouge and Livingston Parishes; along the northern boundary of Pointe Coupee and St. Landry Parishes, and eastern Rapids Parish. Results calibrated using geochemical data provided by operators active in the TMS. This research has provided a technique to predict areas with high concentrations of TOC that are thermally mature, which are commonly associated with areas of unconventional production potential.
AAPG Search and Discovery Article #90167©2013 GCAGS and GCSSEPM 63rd Annual Convention, New Orleans, Louisiana, October 6-8, 2013