2019 AAPG Annual Convention and Exhibition:

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Forward Stratigraphic and Organic Matter modeling applied to the Appalachian Basin


Organic-rich marine black shales were widely deposited on the North American Craton from the Devonian to Carboniferous age. Several sedimentary basins, such as the Appalachian Basin, were formed on this craton, and were separated from one to the other, and to the ocean by a series of sills. Deepwater mixing capacity in each sedimentary basin were limited by these sills. Sea-level changes controlled the partial to total isolation of these sedimentary basins.Reconstruction of paleohydrographic conditions is thus a key step to assess organic-richness of sedimentary formations. Algao et al. (2007) proposed a first approach based on the correlation between the Molybdenum (Mo) concentration in black shales, and their total organic carbon content (TOC). Over the last decades, a lot of sedimentological and geochemical data has been acquired in the Appalachian Basin, increasing progressively the understanding of the basin physiography, gross depositional environments, and organic matter deposition. In this study, we used a numerical forward stratigraphic and organic matter modeling workflow to test these geological concepts. The numerical simulation were calibrated on well log data, with a special focus on facies, depositional environments, and global physiography restriction. The main added-value of this numerical modeling workflow is a quantification of TOC and HI regional distribution for the main black-shale formations. This study demonstrates the efficiency of such process-based numerical modeling in exploration workflows to assess the probability of presence of organic-rich sediments, but also to estimate the potential distribution, quality and geochemical property of these sediments.