Characterization of the unconventional Tuscaloosa marine shale reservoir in southwestern Mississippi, USA: Insights from optical and SEM petrography

摘要: Abstract This study presents new optical petrography and electron microscopy data, interpreted in the context of previously published petrophysical, geochemical, mineralogical to further characterize Tuscaloosa marine shale (TMS) as an unconventional reservoir southwestern Mississippi. The basal high resistivity zone has a higher proportion Type II sedimentary organic matter than overlying TMS, indicating it is more prone oil generation. Optical reveal heterogeneous clay matrix with ubiquitous pyrite grains, quartz, feldspar, glaucony, foraminifera, shell fragments, rarer occurrences apatite crinoid fragments well liptinite, alginite, inertinite, vitrinite. Our petrographic observations suggest that abundances detrital quartz grains coupled minimal authigenic cements result porosity permeability. However, TMS also clay-rich other gas plays, which can impair effectiveness hydraulic fracture stimulation. Thin section alternating calcium carbonate laminae are reflect changes sediment flux. Planktonic foraminifera indicate oxygenated water column while benthic inoceramid pervasive anoxic or dysoxic bottom conditions. Apatite thin mixing events influx nutrient-rich sediments. Overall, these variety paleodepositional environments occurred lithofacies diversity resulting from small-scale depositional cycles makes difficult determinatively identify areas conducive enhanced economic hydrocarbon recovery.