Jubb, Aaron M. Ruppert, Leslie F. Birdwell, Justin E. Stokes, M. Rebecca Croke, Mary R. 20230815 tabular digital data https://doi.org/10.5066/P96XAVEO Petroleum within unconventional source-rock reservoirs is hosted in organic matter and mineral pore space as well as in voids and microfractures. Recent work has shown that for source-rock reservoirs in the dry gas window, significant portions of methane (CH4), the main component of petroleum at elevated maturities, can be stored within fine organic matter porosity. However, within reservoirs at lower thermal maturities (e.g., peak oil or wet-gas conditions), the distribution and behavior of CH4 and the higher alkanes that comprise gas condensates across pore sizes is unclear, especially for fine pores with diameters <50 nm. Understanding CH4 within these settings provides insight for petroleum generation, movement, and recoverability, ultimately enabling increased accuracy of estimated ultimate recovery. Here wide Q-range total neutron scattering was used to evaluate perdeuterated methane (CD4) behavior at reservoir pressures and temperature in a sample at the late oil/wet gas thermal maturity stage from the Late Cretaceous Niobrara Formation, an active petroleum producing formation within the Denver-Julesburg Basin, United States. Data were collected to evaluate neutron scattering to evaluate perdeuterated methane within Niobrara source rock. The file contains data available in comma separated value (.csv) file format. The user must have software capable of opening and viewing a .csv file. 2023 publication date Complete None planned -105.2335000 -105.2334000 40.2111000 40.2110000 USGS Thesaurus Shale Contrast Matching Gas Condensate Natural Gas Neutron Scattering USGS Metadata Identifier USGS:64ac0523d34e70357a28a074 Geolex, https://ngmdb.usgs.gov/Geolex/search Denver-Julesburg Basin Common geographic areas Colorado None. Please see 'Distribution Info' for details. None. Users are advised to read the dataset's metadata thoroughly to understand appropriate use and data limitations. Aaron M Jubb U.S. Geological Survey, Northeast Region Research Chemist mailing address

Mail Stop 954, 12201 Sunrise Valley Dr

Reston VA 20192 US 703-648-6481 703-648-6419 ajubb@usgs.gov No formal attribute accuracy tests were conducted No formal logical accuracy tests were conducted Data set is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details. No formal positional accuracy tests were conducted No formal positional accuracy tests were conducted Kienzle, Paul 2014 application/service https://www.ncnr.nist.gov/resources/sldcalc.html Digital and/or Hardcopy 2014 publication date NIST SLD Calculator Scattering light density calculation formula The sample consists of an aliquot of the Late Cretaceous Niobrara Formation collected as part of a greater U.S. Geological Survey (USGS) shale geochemical reference material sample set and is roughly equivalent to the Niobrara C-marl (Birdwell and Wilson, 2019). Birdwell, J.E., Wilson, S.A., 2019. Variability in results from mineralogical and organic geochemical interlaboratory testing of U.S. Geological Survey shale reference materials, in: SEG Global Meeting Abstracts. pp. 2431–2449. https://doi.org/10.15530/urtec-2019-457 2019 The sample aliquot analyzed for N2 SCG adsorption was ground and sieved to 40 mesh and then degassed under vacuum at 200ºC for 12 h prior to measurement. The sample aliquot used for neutron scattering was ground to 0.5 - 1 mm (18 mesh) particle size for ease of loading into a null-scattering TiZr alloy high pressure (1 kbar) sample cell and to minimize scattering from interparticle pores and multiple scattering events (Ji et al., 2022). Additionally, use of a ground sample allows for orientational averaging of neutron scattering from pore shapes avoiding issues with pore anisotropy (Blach et al., 2020). Prior to neutron scattering experiments the ground sample was cleaned by washing in de-ionized water for 15 minutes, dried overnight at 50°C in atmosphere, and finally sieved at 60 mesh (250 mm) to remove any remaining fines. While dehydration of shales following heating at 200°C has been demonstrated to create mesopores (Lee et al., 2014), the lower temperature used to dry the sample here prior to the neutron scattering measurements is assumed to be insufficient for porosity creation via dehydration. Ji, Y., Radlinski, A.P., Blach, T., de Campo, L., Vu, P., Roshan, H., Regenauer-Lieb, K., 2022. How to avoid multiple scattering in strongly scattering SANS and USANS samples. Fuel 325, 124957. Blach, T., Radlinski, A.P., Edwards, D.S., Boreham, C.J., Gilbert, E.P., 2020. Pore anisotropy in unconventional hydrocarbon source rocks: A small angle neutron scattering (SANS) study on the Arthur Creek Formation, Georgina Basin, Australia. International Journal of Coal Geology 225, 103495. Lee, S., Fischer, T.B., Stokes, M.R., Klingler, R.J., Ilavsky, J., McCarty, D.K., Wigand, M.O., Derkowski, A., Winans, R.E., 2014. Dehydration effect on the pore size, porosity, and fractal parameters of shale rocks: Ultrasmall-Angle X-ray scattering study. Energy Fuels 28, 6772–6779. 2022 Neutron scattering experiments (beamtime allocation RB2010249) were performed on NIMROD at the ISIS Neutron and Muon Source, STFC Rutherford Appleton Laboratory, United Kingdom in July 2022. Raw scattering data can be accessed at https://doi.org/10.5286/ISIS.E.RB2010249 following an embargo period (ends July 2025) and all processed data are immediately available in the associated USGS data release (Jubb et al., 2023). NIMROD measures scattered neutrons from Q = 0.02 to Q = 50 Å-1 where Q is the magnitude of the momentum transfer vector of a scattered neutron defined as Q = (4p/l) sin(q) where l is the neutron wavelength and 2q is the scattering angle. A complete description of NIMROD is available in Bowron et al. (2010). Jubb, A.M., Ruppert, L.F., Birdwell, J.E., Stokes, M.R., 2023. Total neutron scattering data on methane behavior in the Niobrara Formation. U.S. Geological Survey Data Release, https://doi.org/10.5066/P96XAVEO 2022 Neutron scattering measurements were made using null-scattering Ti0.676Zr0.324 high-pressure cells at 60 degrees C. Scattered neutrons were counted as a function of neutron time-of-flight and then corrected for instrument and cell backgrounds, absorption, multiple scattering, and inelastic scattering (primarily from H) contributions in addition to normalization to an absolute scale with a VNb standard in the Gudrun software suite (Day et al., 2004; Soper, 2012). Scattering signals from the Niobrara sample were initially collected under vacuum until ~400 mAmps of signal were reached (~13 h). For CD4 measurements, CD4 (99% pure, CK Isotopes Limited) was introduced to the sample cell at a specific pressure before a scattering profile was collected. Typically each run collected ~40 mAmps of signal (~1.5 h). Following signal collection, the CD4 pressure was increased to the next specific pressure, the pressure was allowed to equilibrate, and then another scattering profile was collected. This iterative process was continued until the CD4 pressure could not be increased further (750 bar), at which point a scattering profile was collected until ~300 mAmps of signal was reached (~10 h) to ensure robust counting statistics at the highest pressure. Following data collection at 750 bar, the pressure was lowered and scattering profiles were collected at ~400 bar CD4, ~200 bar CD4, and under vacuum to evaluate potential changes induced to the Niobrara sample structure from exposure to supercritical CD4. In total, scattering profiles were collected from the Niobrara sample under vacuum and in CD4 pressures of 200 bar, 400 bar, 500 bar, 600 bar, 685 bar, and 750 bar. Additionally, ~240 mAmps (8 h) of scattering signal were collected from only CD4 (i.e., no Niobrara sample in sample cell) at 500 bar and 60°C. Day, P., Enderby, J.E., Williams, W.G., Chapon, L.C., Hannon, A.C., Radaelli, P.G., Soper, A.K., 2004. GEM: The General Materials diffractometer at ISIS - Multibank capabilities for studying crystalline and disordered materials. Neutron News 15, 19–23. Soper, A.K., 2012. GudrunN and GudrunX Programs for correcting raw neutron and x-ray total scattering data to differential cross section. https://www.isis.stfc.ac.uk. 2022 Table 2.csv Bulk sample parameters including solid bitumen reflectance (BRo), total organic content (TOC), skeletal density, kerogen isolate elemental composition, X-ray diffraction (XRD) major mineralogy, and N2 sub-critical gas (SCG) analysis. Producer Defined Parameter Bulk sample parameter Producer Defined solid bitumen reflectance (%) Reflectance measurement taken on solid bitumen in sample, in percent reflectance Producer defined Total organic carbon (wt%) Total organic carbon in sample in weight percent Producer defined Skeletal density (g cm-3) Skeletal density of sample, in grams per inverse cube centimeters as determined through He pycnometry Producer defined Kerogen carbon (wt%) Carbon in sample kerogen in weight percent Producer defined Kerogen hydrogen (wt%) Hydrogen in sample kerogen in weight percent, determined through kerogen isolate elemental composition Producer defined Kerogen nitrogen (wt%) Nitrogen in sample kerogen in weight percent, determined through kerogen isolate elemental composition Producer defined Kerogen oxygen (wt%) Oxygen in sample kerogen in weight percent, determined through kerogen isolate elemental composition Producer defined Kerogen sulfur (wt%) Sulfur in sample kerogen in weight percent, determined through kerogen isolate elemental composition Producer defined Calcite (wt%) Calcite in sample in weight percent, as determined by X-ray diffraction (XRD) Producer defined Quartz (wt%) Quartz in sample in weight percent, as determined by X-ray diffraction (XRD) Producer defined Illite (wt%) Illite in sample in weight percent, as determined by X-ray diffraction (XRD) Producer defined Smectite (wt%) Smectite in sample in weight percent, as determined by X-ray diffraction (XRD) Producer defined Plagioclase (wt%) Plagioclase in sample in weight percent, as determined by X-ray diffraction (XRD) Producer defined Dolomite (wt%) Dolomite in sample in weight percent, as determined by X-ray diffraction (XRD) Producer defined Pyrite (wt%) Pyrite in sample in weight percent, as determined by X-ray diffraction (XRD) Producer defined BET surface area (m^2/g) Brunauer–Emmett–Teller calculated surface area, in meters squared per gram, as determined by N2 sub-critical gas (SCG) analysis Producer defined Cumulative pore volume (cm^3/g) Cumulative pore volume, in centimeters cubed per gram, as determined by N2 sub-critical gas (SCG) analysis Producer defined Average pore diameter (nm) Average pore diameter in nanometers, as determined by N2 sub-critical gas (SCG) analysis Producer defined Value Measurements taken on bulk sample parameters, measurements units vary depending on parameter Producer Defined 0.0296 72.0 Percent, weight percent, grams per cm^3, square meters per gram, centimeters squared per gram, nanometers Table 3.csv Scattering length density (SLD) for the sample, two pressures of CD4 at 60ºC, isolated sample kerogen, and sample mineral components. SLDs were calculated using the NIST SLD calculator (https://www.ncnr.nist.gov/resources/sldcalc.html) Producer Defined Component Component examined Producer Defined Whole rock Scattering length density measurements taken on whole rock sample Producer defined CD4 @ 200 bar Scattering length density measurements taken on sample CD4 at 200 bar and 60 degrees Celsius Producer defined CD4 @ 750 bar Scattering length density measurements taken on sample CD4 at 750 bar and 60 degrees Celsius Producer defined Sample kerogen Scattering length density measurements taken on kerogen in sample Producer defined Calcite Scattering length density measurements taken on calcite in sample Producer defined Quartz Scattering length density measurements taken on quartz in sample Producer defined Illite Scattering length density measurements taken on illite in sample Producer defined Smectite Scattering length density measurements taken on smectite in sample Producer defined Plagioclase Scattering length density measurements taken on plagioclase in sample Producer defined Dolomite Scattering length density measurements taken on dolomite in sample Producer defined Pyrite Scattering length density measurements taken on pyrite in sample Producer defined Density (g cm-3) Measured density of sample component Producer Defined 0.16 5.01 Grams per centimeter^-3 Scattering length density (10-6 Å-2) Scattering length density, as calculated using the NIST SLD calculator (https://www.ncnr.nist.gov/resources/sldcalc.html) Producer Defined 1.62 5.4 10-^6 Å^-2 Figure 1.csv Scattering intensity versus the Q-range of the NIMROD. Producer Defined Q (Å-1) Q-range of the NIMROD Producer Defined 0.012 50.024 Reciprocal Angstrom (Å-1) Intensity vacuum (barn sr-1 atom-1) Scattering intensity measured under vacuum at 60 degrees Celsius Producer Defined 0.63 345.45 (barn sr-1 atom-1) Intensity 200 bar CD4 (barn sr-1 atom-1) Scattering intensity measured under 200 bar at 60 degrees Celsius Producer Defined 0.69 141.58 Intensity 400 bar CD4 (barn sr-1 atom-1) Scattering intensity measured under 400 bar at 60 degrees Celsius Producer Defined 0.65 84.24 Intensity 750 bar CD4 (barn sr-1 atom-1) Scattering intensity measured under 750 bar at 60 degrees Celsius Producer Defined 0.62 62.28 Figure 2.csv Scattering intensity ratios of the Niobrara sample with pressurized CD4 over the Niobrara sample in vacuum across the Q-range of the NIMROD for each CD4 pressure tested Producer Defined Q (Å-1) Q-range of the NIMROD Producer Defined 0.012 50.024 Reciprocal Angstrom Intensity_200 bar CD4 / Intensity_vacuum Sample scattering intensity measured at 200 bar CD4 Producer Defined 0.0 1.92 Unitless Intensity_400 bar CD4 / Intensity_vacuum Sample scattering intensity measured at 400 bar CD4 Producer Defined 0.0 1.97 Unitless Intensity_500 bar CD4 / Intensity_vacuum Sample scattering intensity measured at 500 bar CD4 Producer Defined 0.0 2.09 Unitless Intensity_600 bar CD4 / Intensity_vacuum Sample scattering intensity measured at 600 bar CD4 Producer Defined 0.0 2.22 Unitless Intensity_685 bar CD4 / Intensity_vacuum Sample scattering intensity measured at 685 bar CD4 Producer Defined 0.0 2.22 Unitless Intensity_750 bar CD4 / Intensity_vacuum Sample scattering intensity measured at 750 bar CD4 Producer Defined 0.0 2.28 Unitless Figure 3.csv Niobrara sample pore volume as a function of average pore diameter from N2 sub-critical gas (SCG) adsorption Producer Defined Pore diameter (Å) Average pore diameter, in angstroms Producer Defined 17.4 2972.2 Angstroms BET Pore volume (10^-2 cm^3 g/1) Pore volume contributions from subcritical gas adsorption Producer Defined 0.00373 0.02063 10^-2 cm^3 g/1 BET-NIMROD Pore volume (10^-2 cm^3 g/1) Pore volume contributions from NIMROD scattering ratios Producer Defined 0.00451 0.02063 10^-2 cm^3 g/1 Figure 4.csv Scattering intensity ratios of the Niobrara sample at two paired pressures and under vacuum pre- and post-CD4 exposure Producer Defined Q (Å-1) Q-range of the NIMROD Producer Defined 0.012 50.024 Reciprocal angstrom Vacuum ratio Scattering intensity ratio of Niobrara sample under vacuum Producer Defined 0.003 1.098 Unitless Error vacuum ratio Error of scattering intensity ratio for samples under vacuum Producer Defined 0.0 0.464 Unitless 200 bar CD4 ratio Scattering intensity ratio of Niobrara sample under 200 bar pressure Producer Defined 0.007 1.141 Unitless Error 200 bar CD4 ratio Error of scattering intensity ratio for samples under 200 bar pressure Producer Defined 0.0 0.563 Unitless 400 bar CD4 ratio Scattering intensity ratio of Niobrara sample under 400 bar pressure Producer Defined 0.941 1.06 Unitless Error 400 bar CD4 ratio Error of scattering intensity ratio for samples under 400 bar pressure Producer Defined 0.0 0.618 Unitless Figure 5a.csv Scattering intensity of only CD4 at 500 bar and 60 C. Producer Defined Q (Å-1) Q-range of the NIMROD Producer Defined 0.012 50.024 Reciprocal angstrom Intensity 500 bar CD4 (barn sr-1 atom-1) Intensity measured at 500 bar and 60 degrees celsius Producer Defined 0.852 1.682 barn sr^-1 atom^-1 Figure 5b.csv Scattering intensities of the Niobrara sample with pressurized CD4 minus the scattering intensity of the Niobrara sample in vacuum for each pressure tested Producer Defined Q (Å-1) Q-range of the NIMROD Producer Defined 0.204 50.024 Angstrom Intensity 200 bar CD4 (barn sr-1 atom-1) Intensity measurement of Niobrara sample in presence of perdeuterated methane (CD4) under 200 bar of pressure Producer Defined -0.157 0.856 barn sr-1 atom-1 Intensity 400 bar CD4 (barn sr-1 atom-1) Intensity measurement of Niobrara sample in presence of perdeuterated methane (CD4) under 400 bar of pressure Producer Defined -0.207 0.723 barn sr-1 atom-1 Intensity 500 bar CD4 (barn sr-1 atom-1) Intensity measurement of Niobrara sample in presence of perdeuterated methane (CD4) under 500 bar of pressure Producer Defined -0.221 0.842 barn sr-1 atom-1 Intensity 600 bar CD4 (barn sr-1 atom-1) Intensity measurement of Niobrara sample in presence of perdeuterated methane (CD4) under 600 bar of pressure Producer Defined -0.223 0.94 barn sr-1 atom-1 Intensity 685 bar CD4 (barn sr-1 atom-1) Intensity measurement of Niobrara sample in presence of perdeuterated methane (CD4) under 685 bar of pressure Producer Defined -0.246 0.946 barn sr-1 atom-1 Intensity 750 bar CD4 (barn sr-1 atom-1) Intensity measurement of Niobrara sample in presence of perdeuterated methane (CD4) under 750 bar of pressure Producer Defined -0.247 0.997 barn sr-1 atom-1 Figure 5c.csv The ratio of intermolecular scattering peaks from densified CD4 at Q = 1.64 Å-1 over the CD4 peak at Q ~ 1.5 Å-1 Producer Defined CD4 pressure (bar) Pressure of CD4 Producer Defined 200 750 bar Intensity ratio Intensity of intermolecular scattering peaks Producer Defined 0.696 0.965 Unitless Intensity ratio error Error of intermolecular scattering peak intensity Producer Defined 0.017 0.037 Unitless Figure S1.csv Scattering intensity versus the Q-range of the NIMROD. Producer Defined Q (Å-1) NIMROD Q-range Producer Defined 0.012 50.024 Reciprocal Angstrom Intensity vacuum (barn sr-1 atom-1) Intensity measurement of Niobrara sample under vacuum Producer Defined 0.63 345.45 barn sr-1 atom-1 Intensity 200 bar CD4 (barn sr-1 atom-1) Intensity measurement of Niobrara sample in presence of perdeuterated methane (CD4) under 200 bar of pressure Producer Defined 0.69 141.58 barn sr-1 atom-1 Intensity 400 bar CD4 (barn sr-1 atom-1) Intensity measurement of Niobrara sample in presence of perdeuterated methane (CD4) under 400 bar of pressure Producer Defined 0.65 84.24 barn sr-1 atom-1 Intensity 500 bar CD4 (barn sr-1 atom-1) Intensity measurement of Niobrara sample in presence of perdeuterated methane (CD4) under 500 bar of pressure Producer Defined 0.64 71.59 barn sr-1 atom-1 Intensity 600 bar CD4 (barn sr-1 atom-1) Intensity measurement of Niobrara sample in presence of perdeuterated methane (CD4) under 600 bar of pressure Producer Defined 0.64 64.13 barn sr-1 atom-1 Intensity 685 bar CD4 (barn sr-1 atom-1) Intensity measurement of Niobrara sample in presence of perdeuterated methane (CD4) under 685 bar of pressure Producer Defined 0.62 64.28 barn sr-1 atom-1 Intensity 750 bar CD4 (barn sr-1 atom-1) Intensity measurement of Niobrara sample in presence of perdeuterated methane (CD4) under 750 bar of pressure Producer Defined 0.62 62.28 barn sr-1 atom-1 GS ScienceBase U.S. Geological Survey mailing address

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Denver CO 80225 United States 1-888-275-8747 sciencebase@usgs.gov Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Digital Data https://doi.org/10.5066/P96XAVEO None 20230815 Mary R. Croke U.S. Geological Survey, Northeast Region Physical Science Technician mailing address

Mail Stop 954, 12201 Sunrise Valley Dr

Reston VA 20192 US 703-648-6454 mcroke@usgs.gov FGDC Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998