Amanda S. Herzberg Jenna L. Shelton Aaron M. Jubb Jessica M. Chenault Bonnie McDevitt Kaela Amundson Michael Wilkins Elliott Barnhart Christina A. Devera Madalyn S. Blondes Glenn D. Jolly 20241021 tabular digital data Reston, Virginia U.S. Geological Survey https://doi.org/10.5066/P14CRSQQ This data release includes field parameters (pH and specific conductance), major ion geochemistry (B, Ba, Br, Cl, Ca, Fe, K, Li, Mg, Mn, Na, Si, SO4, Sr), total dissolved solids, specific gravity, water isotopes (delta-2H and delta-18O), and radium isotopes (226Ra and 228Ra) from produced water samples taken from petroleum wells producing from the Niobrara Formation in the Denver-Julesburg Basin, Weld County, Colorado. Additionally, gas composition and stable isotopes (delta-13C-CO2, delta-13C-C1, and delta-D-C1) from these wells are included. Major ion geochemistry, total dissolved solids, specific gravity, water isotopes, and radium isotopes were analyzed at the U.S. Geological Survey laboratories in Reston, Virginia, USA. Gas compositions were analyzed by a commercial laboratory. The data release includes four files, including one metadata file and 3 comma-separated (CSV) files. These data were collected to characterize the produced water chemistry, gas composition, and gas stable isotopes of the Niobrara Formation in the Denver-Julesburg Basin. One or more files contain data available in comma separated value (.csv) file format. The user must have software capable of opening and viewing a .csv file. 20181006 20201123 ground condition Complete None planned -105.0500 -103.5700 41.0000 39.9900 ISO 19115 Topic Category geoscientificInformation USGS field methods time series field sampling water sampling geochemistry water chemistry produced water energy resources hydraulic fracturing oil resources radium isotopic analysis USGS Metadata Identifier USGS:6634dfdcd34ee921b712b410 None Denver-Julesburg Basin Weld County, Colorado Please see 'Distribution Info' for details. Users are advised to read the dataset's metadata thoroughly to understand appropriate use and data limitations. Amanda Herzberg U.S. Geological Survey physical

12201 Sunrise Valley Drive

Reston Virginia 20190 703-648-6462 Michael Wilkins, Associate Professor, College of Agricultural Sciences, Colorado State University and Kaela Amundson, Postdoctoral Fellow, College of Agricultural Sciences, Colorado State University collected samples. Attributes associated with USGS Laboratories in Reston, Virginia are subject to Energy and Minerals Mission Area (EMMA) Quality Management System (QMS) and adhere to Quality Assurance Requirements including but not limited to using internal and external quality control samples such as blanks, replicates, and standard reference samples. 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. Sample Collection: Samples of produced water were collected into HDPE containers and passed through silicone tubing and a 0.45 micron filter into various HDPE bottles using a peristaltic pump. For major cation analysis, samples were collected in acid-washed HDPE bottles and acidified with trace metal grade nitric acid to below a pH of 2. For anion, specific gravity, total dissolved solids (TDS), and Ra isotope analysis, water was collected in HDPE bottles without acidification. For water isotopes analysis, samples were collected into glass amber bottles without head space. pH and Specific Conductance were measured in the field using calibrated field meters for early samples, and back in the laboratory for later time series samples. 20201123 Sample Collection: Gas samples were collected directly from the separator into 0.3 L evacuated gas bags, "IsoBags" following the protocol outlined by ISOTECH Laboratories (https://www.isotechlabs.com/customersupport/samplingprocedures/ProbesSM.pdf). Gas flowed into the bag until two-thirds full. Bags were capped, stored in a five gallon shipping bucket, and sent to Champaign, Illinois for composition and stable isotope analysis. 20190529 Sample Analysis: Major ion geochemistry, total dissolved solids, specific gravity, water isotopes, and radium isotopes were analyzed at the U.S. Geological Survey laboratories in Reston, Virginia, USA. Gas compositions and stable isotope ratios were analyzed by a commercial laboratory. Major cations (B, Ba, Ca, Fe, K, Li, Mg, Mn, Na, Si, and Sr) concentrations were determined using inductively coupled plasma-optical emission spectrometry (ICP-OES) with a Horiba Ultima Expert following minimal dilution (dilution factor of 25)(Blondes et al., 2020; Engle et al., 2020). Anions (Br, Cl, and SO4) were determined using ion chromatography via EPA Method 9056A (U.S. Environmental Protection Agency, 2007). Specific gravity was determined by ASTM Method D-1429B (ASTM, 2013). TDS was determined by EPA Method 160.1 (U.S. Environmental Protection Agency, 1999). Ra isotopes were measured using radiobarite, (Ba,Ra)SO4, precipitation, and γ-ray spectrometry, following Kraemer (2005). Stable water isotopes δ18O and δ2H activities values were measured by dual-inlet isotope-ratio mass spectrometry following well-established protocols (Kendall and Coplen, 2001; Landwehr et al., 2014), and are presented relative to the Vienna Standard Mean Ocean Water (VSMOW) standard. References Blondes, M.S., Shelton, J.L., Engle, M.A., Trembly, J.P., Doolan, C.A., Jubb, A.M., Chenault, J.C., Rowan, E.L., Haefner, R.J., Mailot, B.E., 2020. Utica Shale Play oil and gas brines: Geochemistry and factors influencing wastewater managment. Environmental Science & Technology 54, 13917–13925. Engle, M.A., Doolan, C.A., Pitman, J.A., Varonka, M.S., Chenault, J., Orem, W.H., McMahon, P.B., Jubb, A.M., 2020. Origin and geochemistry of formation waters from the lower Eagle Ford Group, Gulf Coast Basin, south Central Texas. Chemical Geology 550, 119754. U.S. Environmental Protection Agency, 2007. SW-846 Test Method 9056A: Determination of Inorganic Anions by Ion Chromatography. ASTM, 2013. D1429-13: Standard Test Methods for Specific Gravity of Water and Brine. U.S. Environmental Protection Agency, 1999. Method 160.1: Total Dissolved Solids (TDS) Gravimetric, Dried at 180 Degrees C. Kraemer, T.F., 2005. Radium isotopes in Cayuga Lake, New York: Indicators of inflow and mixing processes. Limnology and Oceanography 50, 158–168. Kendall, C., Coplen, T.B., 2001. Distribution of oxygen-18 and deuterium in river waters across the United States. Hydrological Processes 15, 1363–1393. Landwehr, J.M., Coplen, T.B., Stewart, D.W., 2014. Spatial, seasonal, and source variability in the stable oxygen and hydrogen isotopic composition of tap waters throughout the USA. Hydrological Processes 28, 5382–5422. 20230906 Produced_Water_Data.csv Comma Separated Value (CSV) file containing data. Producer Defined Well ID Unique well identifier. Producer Defined Unique well identifier generated based on whether sampled well was a new well ("NW") or an existing well ("EW"), and whether well sampled was a single sample or part of a time-series ("TS"), followed by a numeric identifier; e.g. a new well as part of a time series would be "NWTS-" followed by a number, and an existing well sampled only once would be "EW-" followed by a number. If an additional sample was collected from a well, the Well ID is appended with " replicate". If more than one additional sample was collected, then " replicate" is followed by a number, e.g. "NWTS-3 replicate 1", "NWTS-3 replicate 2". For samples that were not collected from a well, the 'Sample ID' serves as the 'Well ID'. Sample ID Unique sample identifier. Producer Defined Unique sample identifier. Producing Bench Producing bench of the sampled well. Producer Defined -1111 No Data Producer defined B Producing Bench B of the Late Cretaceous Niobrara Formation in the Denver-Julesburg Basin Producer defined C Producing Bench C of the Late Cretaceous Niobrara Formation in the Denver-Julesburg Basin Producer defined Days Number of days well has been in operation. The value "-1111" indicates sample was not analyzed. Producer Defined -1111 No Data Producer defined 0 2256 days pH pH. The value "-1111" indicates sample was not analyzed. Producer Defined -1111 No Data Producer defined 5.73 9.50 n/a Specific Conductance (mS/cm) Specific conductance in milliSiemens/centimeter. The value "-1111" indicates sample was not analyzed. Producer Defined -1111 No Data Producer defined 0.85 61.3 milliSiemens per centimeter d2H-H2O (‰) delta 2H of H2O, per mill, Vienna Standard Mean Ocean Water reference. The value "-1111" indicates sample was not analyzed. Producer Defined -1111 No Data Producer defined -100.24 -43.52 per mill d18O-H2O (‰) delta 18O of H2O, per mill, Vienna Standard Mean Ocean Water reference. The value "-1111" indicates sample was not analyzed. Producer Defined -1111 No Data Producer defined -12.57 -3.71 per mill Specific Gravity at 15.6 degrees C Specific Gravity of sample at 15.6 degrees Celsius. Producer Defined 0.9988 1.0231 n/a Total Dissolved Solids (mg L-1) Total Dissolved Solids in milligrams per liter. Producer Defined 300 33000 milligrams per liter [Br] (mg L-1) Concentration of bromide in milligrams per liter. The value "-1111" indicates sample was not analyzed. The value "-9999" indicates the sample was analyzed, but analyte was undetected. Producer Defined -1111 No Data Producer defined 0.000 349 milligrams per liter [Br] ± 2s Uncertainty of the concentration of bromide at 95% confidence in milligrams per liter. The value "-1111" indicates sample was not analyzed. The value "-9999" indicates the sample was analyzed, but analyte was undetected. Producer Defined -1111 No Data Producer defined 0.000 59 milligrams per liter [Br] Flags Quality Assurance/Quality Control flags for bromide. Producer Defined Quality Assurance/Quality Control flags for bromide where "none" indicates no flags, ">stnds" indicates concentration was greater than the highest calibration standard multiplied by the dilution factor of the sample, "<pql" indicates concentration was less than the practical quantitation limit multiplied by the dilution factor of the sample, “non-detect” indicates analyte was not detected, and “not analyzed” indicates the sample was not analyzed. [Cl] (mg L-1) Concentration of chloride in milligrams per liter. The value "-1111" indicates sample was not analyzed. The value "-9999" indicates the sample was analyzed, but analyte was undetected. Producer Defined 0.482 18600 milligrams per liter [Cl] ± 2s Uncertainty of the concentration of chloride at 95% confidence in milligrams per liter. The value "-1111" indicates sample was not analyzed. The value "-9999" indicates the sample was analyzed, but analyte was undetected. Producer Defined -1111 No Data Producer defined 0.390 4800 milligrams per liter [Cl] Flags Quality Assurance/Quality Control flags for chloride. Producer Defined Quality Assurance/Quality Control flags for chloride where "none" indicates no flags, ">stnds" indicates concentration was greater than the highest calibration standard multiplied by the dilution factor of the sample, "<pql" indicates concentration was less than the practical quantitation limit multiplied by the dilution factor of the sample, “non-detect” indicates analyte was not detected, and “not analyzed” indicates the sample was not analyzed. [SO4] (mg L-1) Concentration of sulfate in milligrams per liter. The value "-1111" indicates sample was not analyzed. The value "-9999" indicates the sample was analyzed, but analyte was undetected. Producer Defined 0.000 295 milligrams per liter [SO4] ± 2s Uncertainty of the concentration of sulfate at 95% confidence in milligrams per liter. The value "-1111" indicates sample was not analyzed. The value "-9999" indicates the sample was analyzed, but analyte was undetected. Producer Defined -1111 No Data Producer defined 0.000 55 milligrams per liter [SO4] Flags Quality Assurance/Quality Control flags for sulfate. Producer Defined Quality Assurance/Quality Control flags for sulfate where "none" indicates no flags, ">stnds" indicates concentration was greater than the highest calibration standard multiplied by the dilution factor of the sample, "<pql" indicates concentration was less than the practical quantitation limit multiplied by the dilution factor of the sample, “non-detect” indicates analyte was not detected, and “not analyzed” indicates the sample was not analyzed. [B] (mg L-1) Concentration of boron in milligrams per liter. The value "-1111" indicates sample was not analyzed. The value "-9999" indicates the sample was analyzed, but analyte was undetected. Producer Defined -1111 No Data Producer defined 0.170 34.0 milligrams per liter [B] ± 2s Uncertainty of the concentration of boron at 95% confidence in milligrams per liter. The value "-1111" indicates sample was not analyzed. The value "-9999" indicates the sample was analyzed, but analyte was undetected. Producer Defined -1111 No Data Producer defined 0.001 6.5 milligrams per liter [B] Flags Quality Assurance/Quality Control flags for boron. Producer Defined Quality Assurance/Quality Control flags for boron where "none" indicates no flags, ">stnds" indicates concentration was greater than the highest calibration standard multiplied by the dilution factor of the sample, "<pql" indicates concentration was less than the practical quantitation limit multiplied by the dilution factor of the sample, “non-detect” indicates analyte was not detected, and “not analyzed” indicates the sample was not analyzed. [Ba] (mg L-1) Concentration of barium in milligrams per liter. The value "-1111" indicates sample was not analyzed. The value "-9999" indicates the sample was analyzed, but analyte was undetected. Producer Defined -1111 No Data Producer defined 0.036 50.7 milligrams per liter [Ba] ± 2s Uncertainty of the concentration of barium at 95% confidence in milligrams per liter. The value "-1111" indicates sample was not analyzed. The value "-9999" indicates the sample was analyzed, but analyte was undetected. Producer Defined -1111 No Data Producer defined 0.000 2.3 miligrams per liter [Ba] Flags Quality Assurance/Quality Control flags for barium. Producer Defined Quality Assurance/Quality Control flags for barium where "none" indicates no flags, ">stnds" indicates concentration was greater than the highest calibration standard multiplied by the dilution factor of the sample, "<pql" indicates concentration was less than the practical quantitation limit multiplied by the dilution factor of the sample, “non-detect” indicates analyte was not detected, and “not analyzed” indicates the sample was not analyzed. [Ca] (mg L-1) Concentration of calcium in milligrams per liter. The value "-1111" indicates sample was not analyzed. The value "-9999" indicates the sample was analyzed, but analyte was undetected. Producer Defined -1111 No Data Producer defined 48.0 514 milligrams per liter [Ca] ± 2s Uncertainty of the concentration of calcium at 95% confidence in milligrams per liter. The value "-1111" indicates sample was not analyzed. The value "-9999" indicates the sample was analyzed, but analyte was undetected. Producer Defined -1111 No Data Producer defined 0.8 45 mililgrams per liter [Ca] Flags Quality Assurance/Quality Control flags for calcium. Producer Defined Quality Assurance/Quality Control flags for calcium where "none" indicates no flags, ">stnds" indicates concentration was greater than the highest calibration standard multiplied by the dilution factor of the sample, "<pql" indicates concentration was less than the practical quantitation limit multiplied by the dilution factor of the sample, “non-detect” indicates analyte was not detected, and “not analyzed” indicates the sample was not analyzed. [Fe] (mg L-1) Concentration of iron in milligrams per liter. The value "-1111" indicates sample was not analyzed. The value "-9999" indicates the sample was analyzed, but analyte was undetected. Producer Defined -1111 No Data Producer defined 0.002 146 milligrams per liter [Fe] ± 2s Uncertainty of the concentration of iron at 95% confidence in milligrams per liter. The value "-1111" indicates sample was not analyzed. The value "-9999" indicates the sample was analyzed, but analyte was undetected. Producer Defined -1111 No Data Producer defined 0.000 3.3 milligrams per liter [Fe] Flags Quality Assurance/Quality Control flags for iron. Producer Defined Quality Assurance/Quality Control flags for iron where "none" indicates no flags, ">stnds" indicates concentration was greater than the highest calibration standard multiplied by the dilution factor of the sample, "<pql" indicates concentration was less than the practical quantitation limit multiplied by the dilution factor of the sample, “non-detect” indicates analyte was not detected, and “not analyzed” indicates the sample was not analyzed. [K] (mg L-1) Concentration of potassium in milligrams per liter. The value "-1111" indicates sample was not analyzed. The value "-9999" indicates the sample was analyzed, but analyte was undetected. Producer Defined -1111 No Data Producer defined 6.74 52.8 milligrams per liter [K] ± 2s Uncertainty of the concentration of potassium at 95% confidence in milligrams per liter. The value "-1111" indicates sample was not analyzed. The value "-9999" indicates the sample was analyzed, but analyte was undetected. Producer Defined -1111 No Data Producer defined 0.10 3.0 milligrams per liter [K] Flags Quality Assurance/Quality Control flags for potassium. Producer Defined Quality Assurance/Quality Control flags for potassium where "none" indicates no flags, ">stnds" indicates concentration was greater than the highest calibration standard multiplied by the dilution factor of the sample, "<pql" indicates concentration was less than the practical quantitation limit multiplied by the dilution factor of the sample, “non-detect” indicates analyte was not detected, and “not analyzed” indicates the sample was not analyzed. [Li] (mg L-1) Concentration of lithium in milligrams per liter. The value "-1111" indicates sample was not analyzed. The value "-9999" indicates the sample was analyzed, but analyte was undetected. Producer Defined -1111 No Data Producer defined 0.009 6.36 milligrams per liter [Li] ± 2s Uncertainty of the concentration of lithium at 95% confidence in milligrams per liter. The value "-1111" indicates sample was not analyzed. The value "-9999" indicates the sample was analyzed, but analyte was undetected. Producer Defined -1111 No Data Producer defined 0.000 0.32 milligrams per liter [Li] Flags Quality Assurance/Quality Control flags for lithium. Producer Defined Quality Assurance/Quality Control flags for lithium where "none" indicates no flags, ">stnds" indicates concentration was greater than the highest calibration standard multiplied by the dilution factor of the sample, "<pql" indicates concentration was less than the practical quantitation limit multiplied by the dilution factor of the sample, “non-detect” indicates analyte was not detected, and “not analyzed” indicates the sample was not analyzed. [Mg] (mg L-1) Concentration of magnesium in milligrams per liter. The value "-1111" indicates sample was not analyzed. The value "-9999" indicates the sample was analyzed, but analyte was undetected. Producer Defined -1111 No Data Producer defined 5.91 67.5 milligrams per liter [Mg] ± 2s Uncertainty of the concentration of magnesium at 95% confidence in milligrams per liter. The value "-1111" indicates sample was not analyzed. The value "-9999" indicates the sample was analyzed, but analyte was undetected. Producer Defined -1111 No Data Producer defined 0.07 5.6 milligrams per liter [Mg] Flags Quality Assurance/Quality Control flags for magnesium. Producer Defined Quality Assurance/Quality Control flags for magnesium where "none" indicates no flags, ">stnds" indicates concentration was greater than the highest calibration standard multiplied by the dilution factor of the sample, "<pql" indicates concentration was less than the practical quantitation limit multiplied by the dilution factor of the sample, “non-detect” indicates analyte was not detected, and “not analyzed” indicates the sample was not analyzed. [Mn] (mg L-1) Concentration of manganese in milligrams per liter. The value "-1111" indicates sample was not analyzed. The value "-9999" indicates the sample was analyzed, but analyte was undetected. Producer Defined -1111 No Data Producer defined 0.000 1.946948775 milligrams per liter [Mn] ± 2s Uncertainty of the concentration of manganese at 95% confidence in milligrams per liter. The value "-1111" indicates sample was not analyzed. The value "-9999" indicates the sample was analyzed, but analyte was undetected. Producer Defined -1111 No Data Producer defined 0.000 0.09 milligrams per liter [Mn] Flags Quality Assurance/Quality Control flags for manganese. Producer Defined Quality Assurance/Quality Control flags for manganese where "none" indicates no flags, ">stnds" indicates concentration was greater than the highest calibration standard multiplied by the dilution factor of the sample, "<pql" indicates concentration was less than the practical quantitation limit multiplied by the dilution factor of the sample, “non-detect” indicates analyte was not detected, and “not analyzed” indicates the sample was not analyzed. [Na] (mg L-1) Concentration of sodium in milligrams per liter. The value "-1111" indicates sample was not analyzed. The value "-9999" indicates the sample was analyzed, but analyte was undetected. Producer Defined -1111 No Data Producer defined 98.9 11100 milligrams per liter [Na] ± 2s Uncertainty of the concentration of sodium at 95% confidence in milligrams per liter. The value "-1111" indicates sample was not analyzed. The value "-9999" indicates the sample was analyzed, but analyte was undetected. Producer Defined -1111 No Data Producer defined 2.7 1000 milligrams per liter [Na] Flags Quality Assurance/Quality Control flags for sodium. Producer Defined Quality Assurance/Quality Control flags for sodium where "none" indicates no flags, ">stnds" indicates concentration was greater than the highest calibration standard multiplied by the dilution factor of the sample, "<pql" indicates concentration was less than the practical quantitation limit multiplied by the dilution factor of the sample, “non-detect” indicates analyte was not detected, and “not analyzed” indicates the sample was not analyzed. [Si] (mg L-1) Concentration of silicon in milligrams per liter. The value "-1111" indicates sample was not analyzed. The value "-9999" indicates the sample was analyzed, but analyte was undetected. Producer Defined -1111 No Data Producer defined 2.42 61.4 milligrams per liter [Si] ± 2s Uncertainty of the concentration of silicon at 95% confidence in milligrams per liter. The value "-1111" indicates sample was not analyzed. The value "-9999" indicates the sample was analyzed, but analyte was undetected. Producer Defined -1111 No Data Producer defined 0.03 3.4 milligrams per liter [Si] Flags Quality Assurance/Quality Control flags for silicon. Producer Defined Quality Assurance/Quality Control flags for silicon where "none" indicates no flags, ">stnds" indicates concentration was greater than the highest calibration standard multiplied by the dilution factor of the sample, "<pql" indicates concentration was less than the practical quantitation limit multiplied by the dilution factor of the sample, “non-detect” indicates analyte was not detected, and “not analyzed” indicates the sample was not analyzed. [Sr] (mg L-1) Concentration of strontium in milligrams per liter. The value "-1111" indicates sample was not analyzed. The value "-9999" indicates the sample was analyzed, but analyte was undetected. Producer Defined -1111 No Data Producer defined 0.77 70.9 milligrams per liter [Sr] ± 2s Uncertainty of the concentration of strontium at 95% confidence in milligrams per liter. The value "-1111" indicates sample was not analyzed. The value "-9999" indicates the sample was analyzed, but analyte was undetected. Producer Defined -1111 No Data Producer defined 0.01 5.9 milligrams per liter [Sr] Flags Quality Assurance/Quality Control flags for strontium. Producer Defined Quality Assurance/Quality Control flags for strontium where "none" indicates no flags, ">stnds" indicates concentration was greater than the highest calibration standard multiplied by the dilution factor of the sample, "<pql" indicates concentration was less than the practical quantitation limit multiplied by the dilution factor of the sample, “non-detect” indicates analyte was not detected, and “not analyzed” indicates the sample was not analyzed. Ra-226 (Bq/L) Radioactivity measurement of radium-226 in becquerels per liter. The value "-1111" indicates sample was not analyzed. The value "-9999" indicates the sample was analyzed, but analyte was undetected. Producer Defined -1111 No Data Producer defined 0.89 6.85 becquerels per liter Ra-226 error ± 1s Standard deviation of radioactivity measurement of radium-226 in becquerels per liter. The value "-1111" indicates sample was not analyzed. The value "-9999" indicates the sample was analyzed, but analyte was undetected. Producer Defined -1111 No Data Producer defined 0.04 0.33 becquerels per liter Ra-228 (Bq/L) Radioactivity measurement of Radium-228 in becquerels per liter. The value "-1111" indicates sample was not analyzed. The value "-9999" indicates the sample was analyzed, but analyte was undetected. Producer Defined -1111 No Data Producer defined non-detect non-detect becquerels per liter Ra-228 error ± 1s Standard deviation of radioactivity measurement of radium-228 in becquerels per liter. The value "-1111" indicates sample was not analyzed. The value "-9999" indicates the sample was analyzed, but analyte was undetected. Producer Defined -1111 No Data Producer defined non-detect non-detect becquerels per liter Charge Balance The relative charge balance error of the ions in percent, where a negative value indicates a greater anion molar equivalence sum, and a positive value indicates a greater cation molar equivalence sum Producer Defined -1111 No Data Producer defined -6.8 17.5 relative % Gas_Data.csv Comma Separated Value (CSV) file containing data. Producer Defined Well ID Unique well identifier. Producer Defined Unique well identifier generated based on whether sampled well was a new well ("NW") or an existing well ("EW"), and whether well sampled was a single sample or part of a time-series ("TS"), followed by a numeric identifier; e.g. a new well as part of a time series would be "NWTS-" followed by a number, and an existing well sampled only once would be "EW-" followed by a number. If an additional sample was collected from a well, the Well ID is appended with " replicate". If more than one additional sample was collected, then " replicate" is followed by a number, e.g. "NWTS-3 replicate 1", "NWTS-3 replicate 2". For samples that were not collected from a well, the 'Sample ID' serves as the 'Well ID'. Producing Bench Producing bench of the sampled well. Producer Defined B Producing Bench B Producer defined C Producing Bench C Producer defined He % Concentration of helium gas, in mol percent. The value "-9999" indicates the sample was analyzed, but analyte was undetected. Producer Defined 0.0051 0.0102 mol percent H2 % Concentration of hydrogen gas, in mol percent. The value "-9999" indicates the sample was analyzed, but analyte was undetected. Producer Defined 0.0102 0.0127 mol percent Ar % Concentration of argon gas, in mol percent Producer Defined 0.0152 0.461 mol percent O2 % Concentration of oxygen gas, in mol percent Producer Defined 0.33 10.64 mol percent CO2 % Concentration of carbon dioxide gas, in mol percent Producer Defined 1.18 2.21 mol percent N2 % Concentration of nitrogen gas, in mol percent Producer Defined 1.23 38.98 mol percent CO % Concentration of carbon monoxide gas, in mol percent. The value "-9999" indicates the sample was analyzed, but analyte was undetected. Producer Defined non-detect non-detect mol percent C1 % Concentration of methane gas, in mol percent Producer Defined 35.43 72.02 mol percent C2 % Concentration of ethane gas, in mol percent Producer Defined 6.63 16.50 mol percent C2H4 % Concentration of ethylene gas, in mol percent. The value "-9999" indicates the sample was analyzed, but analyte was undetected. Producer Defined non-detect non-detect mol percent C3 % Concentration of propane gas, in mol percent Producer Defined 4.22 9.82 mol percent C3H6 % Concentration of propylene gas, in mol percent. The value "-9999" indicates the sample was analyzed, but analyte was undetected. Producer Defined non-detect non-detect mol percent iC4 % Concentration of iso-butane gas, in mol percent Producer Defined 0.449 1.02 mol percent nC4 % Concentration of n-butane gas, in mol percent Producer Defined 1.38 2.80 mol percent iC5 % Concentration of iso-pentane gas, in mol percent Producer Defined 0.247 0.579 mol percent nC5 % Concentration of n-pentane gas, in mol percent Producer Defined 0.282 0.717 mol percent C6+ % Concentration of hexane and gases with more than six carbons, in mol percent Producer Defined 0.0974 0.411 mol percent d13C-CO2 (‰) delta 13C of carbon dioxide, per mill, Vienna Peedee Belimnite reference Producer Defined -1.01 0.96 per mill d13C-C1 (‰) delta 13C of methane, per mill, Vienna Peedee Belimnite reference Producer Defined -52.62 -50.37 per mill dD-C1 (‰) delta 2H of methane, per mill, Vienna Standard Mean Ocean Water reference Producer Defined -283 -265.4 per mill Specific Gravity Specific gravity Producer Defined 0.773 0.901 n/a BTU British Thermal Units Producer Defined 669 1386 British Thermal Units This data release includes producing bench, field parameters (pH and specific conductance), major ion geochemistry (B, Ba, Br, Cl, Ca, Fe, K, Li, Mg, Mn, Na, Si, SO4, Sr), total dissolved solids (TDS), specific gravity, water isotopes (delta-2H and delta-18O), and radium isotopes (226Ra and 228Ra) from produced water samples taken from petroleum wells producing from the Niobrara Formation in the Denver-Julesburg Basin, Weld County, Colorado. Additionally, gas composition and stable isotopes (delta-13C-CO2, delta-13C-C1, and delta-D-C1) from these wells are included. Sample collection dates, well API numbers, well depth, and lat long location data are proprietary and not provided. The data release includes four files, including one metadata file and 3 comma-separated (CSV) files. The CSV files include the following: Produced_Water_Data, Gas_Data, and Data_Dictionary. Produced_Water_Data.csv includes producing bench, field parameters, major ion geochemistry, total dissolved solids, specific gravity, water isotopes and radium isotopes for produced water samples. Gas_Data.csv includes producing bench, gas compositions, and stable isotopes for collected gas samples. Data_Dictionary.csv provides attribute definitions, minimum and maximum values, and units for the two data spreadsheets. Produced water major ion chemistry data are rounded to three significant figures and to the thousandths decimal place, such that a rounded value less than 0.001 will appear as 0.000. A value flagged as "<pql" indicates that the value is less than the analyte concentration of the lowest standard multiplied by the dilution factor of the sample. The dilution factor varies sample to sample based on TDS as each sample is diluted to approximately 1,000 mg/L TDS prior to analysis. Therefore, the practical quantitation limit (pql) varies per each sample and analyte. Similarly, if a value is flagged as ">stnds", that indicates that the value is greater than the analyte concentration of the highest standard multiplied by the dilution factor of the sample and will vary between samples and analytes. A "non-detect" flag indicates that the analyte was not detected and is represented as "-9999" in the dataset. A "not analyzed" flag indicates the sample was not analyzed and is represented by "-1111" in the dataset. Herzberg, A.S., Shelton, J.L., Jubb, A.M., Chenault, J.M., McDevitt, B., Amundson, K., Wilkins, M., Barnhard, E., Devera, C.D., Blondes, M.S., Jolly, G.D., 2024, Produced water major ion geochemistry, water isotopes, radium content, and field parameters and gas compositions from Niobrara Formation petroleum wells in the Denver-Julesburg Basin: U.S. Geological Survey data release, at https://doi.org/10.5066/P14CRSQQ U.S. Geological Survey GS ScienceBase mailing address

Denver Federal Center, Building 810, Mail Stop 302

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/P14CRSQQ None 20241021 Eric A. Morrissey U.S. Geological Survey Info Tech Spec (Internet) mailing

12201 Sunrise Valley Dr Mail Stop 954

Reston Virginia 20192 USA 703-648-6409 emorriss@usgs.gov FGDC Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998