Tuscaloosa Marine Shale, Gulf Coast Basin, Louisiana and Mississippi
By Celeste D. Lohr, U.S. Geological Survey, Reston, VA
The Upper Cretaceous Tuscaloosa marine shale (TMS) continues to be a minor and largely undeveloped unconventional shale oil play. The potential production area spans over 20.4 million acres across central Louisiana (LA), southern Mississippi (MS), southwestern Alabama (AL), and a small southwestern portion of the Florida panhandle (Fig. 1a; Hackley et al., 2018). However, realized production from the TMS has been confined to a limited area along the east-west LA-MS State boundary (Lohr et al., 2020). The U.S. Geological Survey (USGS) estimated mean undiscovered, technically recoverable resources of 1.5 billion barrels of oil and 4.6 trillion cubic feet of gas in a 2018 assessment of the TMS (Hackley et al., 2018). This assessment is less than the 7 billion barrels of oil originally estimated by John et al. (1997).
The late Cenomanian to Turonian TMS is self-sourced and can be up to approximately 500 ft thick (Fig. 1b; Enomoto et al., 2017; Hackley et al., 2020). The TMS thins to the west onto the Sabine Uplift in LA and to the east in Alabama; it thickens north to south and is thickest south of the Lower Cretaceous shelf margin (Rouse et al., 2018; Enomoto et al., 2017). Recent biostratigraphic research suggests that the TMS is entirely Turonian in southwestern MS and southeastern MS to southwestern AL (Lowery et al., 2017; Self-Trail et al., 2019), which is equivalent to the upper Eagle Ford Shale in Texas. Workers also identified that the maximum flooding surface occurs in the middle of the TMS; the lower portion of the TMS is associated with transgression and maximum flooding whereas the upper portion represents highstand and regression (Liu, 2005; Lowery et al., 2017).
The TMS is characterized by a high resistivity zone (HRZ) near the base of the unit. The HRZ, when present, has a resistivity of 5 Ω-m or greater and peaks at 11 Ω-m in Pike County, MS (John et al., 1997; Lu et al., 2015). The HRZ ranges up to 280 ft thick and thins on the Sabine Uplift, north of Amite County, MS, and downdip of the Lower Cretaceous shelf margin (Enomoto et al., 2017; Rouse et al., 2018). Workers attributed the higher resistivity to petroleum content in the interval (Enomoto et al., 2017). Mean XRD values from regional data show little difference in mineralogical content between the HRZ and the overlying TMS (Enomoto et al., 2017), though a subsequent study by Borrok et al. (2019) generally found that calcite concentration is greater near the base of the TMS. Porosity ranges from 4.78% to 6.59% in the HRZ compared to 3.86% to 9.86% in the TMS (Lohr and Hackley, 2018).
Currently there are 75 active wells producing from the TMS, of which 58 are in Mississippi, 17 are in Louisiana, and 95% are horizontals (IHS Markit, 2021). Nearly all the active wells in MS are in Amite and Wilkinson counties (IHS Markit, 2021). Australis Oil and Gas, based in Australia, remains the dominant operator in the play followed by Goodrich Petroleum Corporation, Signal Oil LLC, and several other operators with ≤ 5 active wells each (IHS Markit, 2021). Through May of 2021, Australis raised approximately USD $5.7 million and $0.509 million through two tranche placements to resume leasing TMS Core Area mineral rights and for working capital (Australis Oil & Gas, 2021a; Australis Oil & Gas, 2021b).
Total oil production in 2020 was 769,000 barrels, a decrease from 1.22 million barrels in 2019 (Fig. 2a). From January 2020 to May 2020 production in the TMS decreased (Fig. 2b), likely due to the initial economic effects of the global COVID-19 pandemic (EIA, 2020; Saha, 2020). Production increased in June 2020 with gas production showing a greater increase in August 2020 than oil production (Fig. 2b).
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Several recent research articles have been published that use the TMS as a case study to investigate engineering questions related to maximizing well productivity. These include a study on the performance of inhibitive drilling fluid systems (Konate and Salehi, 2020); optimum fluid soaking time before the flowback of hydraulic fracture fluids (Guo et al., 2020); and the oil recovery potential of silica nanoparticles with enhanced oil recovery techniques in shale oil reservoirs (Afekare et al., 2021). Funding from the U.S. Department of Energy “Tuscaloosa Marine Shale Laboratory” grant (Project No. DE-FE0031575) supported the research articles by Konate and Salehi (2020) and Guo et al. (2020). Since the last iteration of this report for 2019-2020, the number of TMS-related papers published since the start of 2019 has not increased much. Google Scholar currently shows 147 publications that mention the TMS while SCOPUS and AAPG Datapages remain at 9 and 2 publication products, respectively, with TMS in the title.
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Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
References
Afekare, D., Garno, J., and Rao, D., 2021. Enhancing oil recovery using silica nanoparticles: Nanoscale wettability alteration effects and implications for shale oil recovery. Journal of Petroleum Science and Engineering, v. 203, 108897 https://doi.org/10.1016/j.petrol.2021.108897.
Australis Oil & Gas, 2021a, “Completion of Placement—Tranche 1 and SPP Opens,” Australis Oil & Gas, March 8, 2021, https://www.australisoil.com/irm/PDF/fac5af1e-c413-4115-a862-00ee1859e11d/CompletionTranche1PlacementandSPPOpens, accessed June 17, 2021.
Australis Oil & Gas, 2021b, “Completion of Placement—Tranche 2,” Australis Oil & Gas, May 21, 2021, https://www.australisoil.com/irm/PDF/e65e539f-0213-4cf0-829e-1d9be64f2c06/CompletionofPlacementTranche2andAppendix2A, accessed June 17, 2021.
Borrok, D.M., Yang, W., Wei, M., and Mokhtari, M., 2019. Heterogeneity of the mineralogy and organic content of the Tuscaloosa Marine Shale. Marine and Petroleum Geology, v. 109, p. 717-731, https://doi.org/10.1016/j.marpetgeo.2019.06.056.
Energy Information Administration (EIA), 2020. “EIA forecasts U.S. petroleum demand will remain below 2019 levels for several more months,” EIA, July 20, 2020, https://www.eia.gov/todayinenergy/detail.php?id=44417, accessed June 17, 2021.
Enomoto, C.B., Hackley, P.C., Valentine, B.J., Rouse, W.A., Dulong, F.T., Lohr, C.D., and Hatcherian, J.J., 2017. Geologic characterization of the hydrocarbon resource potential of the Upper Cretaceous Tuscaloosa marine shale in Mississippi and Louisiana, U.S.A. Gulf Coast Association of Geological Societies Transactions, v. 67, p. 95–109.