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Total organic carbon and pyrolysis analysis data for the U.S. Geological Survey Alcova AR-1-13 core hole, Natrona County, Wyoming

November 2, 2021

In 2013 the U.S. Geological Survey (USGS) drilled a continuous core in the southeastern part of the Wind River Basin, Wyoming to evaluate the source rock potential of the Lower and lowermost Upper Cretaceous marine shales . The well, named the Alcova Reservoir AR-1-13, located on the northeast flank of the Alcova anticline was spud in the lower part of the Frontier Formation and ended in the upper part of the Cloverly Formation recovered core between 40.5 feet (ft) and 623 ft. Thirty-nine samples were selected to evaluate the source rock potential of the marine shales in the cored interval as determined by total organic carbon (TOC) and programmed pyrolysis analysis. Five samples are from the lower part of the Frontier Formation, 24 from the upper siliceous part of the Mowry Shale, 4 from the lower Mowry Shale (Shell Creek Shale of Eicher, 1962), and 6 from the Thermopolis Shale. TOC content was determined using the Leco combustion method after carbonate removal (see Jarvie, 1991 for details), and the programmed pyrolysis analysis was done using a Hydrocarbon Analyzer with Kinetics (HAWK, Wildcat Technologies) instrument (see Espitalie and others, 1977; Tissot and Welte, 1978; Peters, 1986; and Hunt, 1996 for detailed discussions of the pyrolysis method). The results of the analyses are presented in the data table. Relevant Citations: Eicher, D.L., 1962, Biostratigraphy of the Thermopolis, Muddy, and Shell Creek Formations, in Enyert, R.L., and Curry, W.H., eds., Symposium on Early Cretaceous rocks of Wyoming and adjacent areas: Wyoming Geological Association 17th Annual Field Conference Guidebook, p. 72-93. Espitalie, J., Madec, J.M., Tissot, B., Mennig, J.J., and Leplat, P., 1977, Source rock characterization method for petroleum exploration: Offshore Technology Conference, v. 3, no. 9, p. 439-444. Hunt, J.M., 1996, Petroleum geochemistry and geology: New York, W.H. Freeman and company, 743 p. Jarvie, D.M., 1991, Total organic carbon (TOC) analysis, in Merrill, R.K., ed., Source and migration processes and evaluation techniques: American Association of Petroleum Geologists Handbook of Petroleum Geology, p. 113-118. Peters, K.E., 1986, Guidelines for evaluating petroleum source rock using programmed pyrolysis: American Association of Petroleum Geologists Bulletin, v. 70, no. 3, p. 318-329. Tissot, B.P., and Welte, D.H., 1978, Petroleum formation and occurrence: New York, Springer-Verlag, 538 p.