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Delta log R total organic carbon estimates for the Tuscaloosa marine shale, U.S.A.

January 25, 2024

This dataset contains estimated total organic carbon (TOC) calculated using the delta log R (dlogR) method, developed by Passey and others (1990), within BasinMod modeling software for the Tuscaloosa marine shale (TMS) in southwestern Mississippi, U.S.A. BasinMod is a modeling software developed by Platte River Associates, Inc. Using version 2021-03-03 of the software, sonic and resistivity logs and a background TOC of 0.8 weight percent were used to calculate dlogR TOC in the TMS high resistivity zone (HRZ) after baselining these two log curves in a non-source rock interval within the TMS. Due to variable mineralogy between the upper and lower sections of the TMS, two baselines were selected to determine whether the position of the baseline affects dlogR TOC results: 1) an upper baseline interval that extends from the top of the TMS and is characterized by relatively low resistivity and limited resistivity variability; and 2) a lower baseline interval that begins at the base of the upper baseline interval and extends to the top of the HRZ and exhibits increasing resistivity, relative to the upper interval, that transitions to the higher values in the HRZ. The dlogR calculated TOC values from these two baselining methods show that using the lower baseline interval results in an improved comparison of measured TOC to calculated TOC.

Publication Year 2024
Title Delta log R total organic carbon estimates for the Tuscaloosa marine shale, U.S.A.
DOI 10.5066/P91KVUN1
Authors Celeste D Lohr, Matthew Merrill
Product Type Data Release
Record Source USGS Digital Object Identifier Catalog
USGS Organization Geology, Energy & Minerals Science Center