U.S. Department of the Interior U.S. Geological Survey Fischer assays of oil-shale drill cores and rotary cuttings from the Piceance Creek Basin, Colorado by John R. Dyni U.S. Geological Survey Denver, Colorado Open-File Report 98-483 Prepared in cooperation with the U.S. Department of Energy This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards (or with the North American Stratigraphic Code). Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. 1998 ABSTRACT This CD-ROM includes Fischer assays of samples of drill cores and cuttings from bore holes drilled in the Eocene Green River oil-shale deposits in western Colorado. The size of this database is 22.8 megabytes and contains about 298,500 records divided into 737 sets of assays. Each data set represents analyses from one bore hole. The data are in ASCII format in column-delimited fields for use on a PC computer. Intervals that were not assayed owing to missing samples are included in the database and are identified by depth and a series of "0.0B"s that fill each field. The data include Fischer assays made by the former U.S. Bureau of Mines (USBM) oil-shale laboratory in Laramie, Wyoming, but also include many analyses made by private laboratories which were donated to the U.S. Geological Survey (USGS). These assays are part of a larger collection of subsurface information including geophysical and lithologic logs, water data, chemical and X-ray diffraction analyses on the Green River oil-shale deposits in Colorado, Wyoming, and Utah held by the USGS. Because of current interest by industry, this CD-ROM disc containing Fischer assay data for the Green River oil-shale deposits in western Colorado is being released to the public. Company-confidential assays are not included. INTRODUCTION For many years, the USGS has collected drill cores and subsurface data from bore holes drilled in the Eocene Green River oil-shale deposits in the three-state area of Colorado, Wyoming, and Utah. Some data and drill cores were also collected from the Devonian oil-shale deposits in eastern United States as well as from a few foreign deposits. The purpose of collecting these drill cores and data was to preserve them for use by researchers and for the time when Green River oil-shale deposits becomes economic as an alternate source of fossil energy. The types of data include thousands of Fischer (shale-oil) assays of drill cores and cuttings from rotary-drilled holes; geophysical and lithologic logs of drill holes; chemical, water-quality and X-ray diffraction analyses; rock mechanics data; and other types of information. Although this collection of data is far from complete, it probably represents the largest single source of subsurface information on the Green River oil-shale deposits in the three-state area. Most of the Fischer assays were obtained from the former USBM laboratory in Laramie, Wyoming. From the late 1940s to the early 1980s, this agency analyzed many cores and cuttings from holes drilled by Federal agencies and by industry in the Green River deposits in the three-state area. A large amount of data for exploratory holes drilled in the Green River Formation was also obtained from energy companies that hold private or leased oil-shale lands in the region. Many of these companies generously donated much analytical data as well as drill cores that are being preserved by the USGS. During the 1970's and 1980's, the USBM and the USGS each prepared digital databases of the Fischer assays of the Green River oil-shale deposits. The USBM database included all of the assays made at its Laramie laboratory from the 1940's to the early 1980's, plus some analyses of drill cores furnished by several private companies. These data were made available to the public through the National Technical Information Service (NTIS) (Laramie Energy Technology Center, 1984). The USGS also prepared a digital database that included the USBM assays, but also included many analyses from numerous core holes drilled by private companies that were not available to the USBM. These analyses were also made available to the public on magnetic tapes through the NTIS (Pitman, 1982, and Pitman and Van Trump, 1974, 1975). However, recent inquiries found that some of these tapes containing Fischer assays have degraded in storage and are no longer readable. In the early 1990's the U.S. Department of Energy (DOE) and the USGS initiated a project to create a digital National Oil Shale Database (NOSDB) that would combine all available Fischer assay data in the possession of the USBM and the USGS. Assay data on private lands that were not in USGS files were also obtained from private companies and these were added to the database. The DOE provided two years of funding for clerical help to digitize the Fischer assay analyses. Most of this work was accomplished at the local office of the DOE in Laramie, Wyoming, under the direction of the author. The original data sheets were scanned and saved as PCX image files. These image files are not included on this disc. The data are not complete with respect to bore hole location, especially for wells which were rotary-drilled. However, most of these wells are oil and gas tests, and their locations can be obtained from commercial service companies. FISCHER ASSAYS A total of 737 sets of Fischer assay data for Colorado--mostly for bore holes drilled in the Piceance Creek Basin--are included on this CD-ROM. The total size of the database is 22.8 megabytes containing about 298,500 records. The data are in ASCII format in column-delimited fields. Each file contains assay data for a single bore hole. Each bore hole was assigned a unique 4-digit number preceded by "C" for Colorado. In a few instances, two sets of assays from the same bore hole are indicated by an "A" or "B" following the bore hole number. Rotary- drilled holes are identified by the suffix "R" following the well number. Fischer assays on samples collected from several surface sections have an "S" appended to the file number. The first two records in each file contain information about the drill hole as follows: Record 1 Columns 1 to 46: name of the company and the drill hole name. Columns 47 to 64: well location by township, range, and section. Record 2 Columns 1-10: well location within the section measured in feet from the west or east boundaries of the section (i.e., FEL or FWL). Columns 11-20: well location measured in feet from the south or north boundaries of the section (i.e., FNL or FSL). Columns 21-32: well location in degrees latitude to six decimal places. Columns 33-45: well location in degrees longitude to six decimal places. Columns 46-50: elevation of the well in feet above sea level. Columns 51-52: elevation datum indicated by one or two characters as follows: DC = top of drill collar, G = ground elevation, RB = top of rotary bushing). The first Fischer assay begins with record 3 and continues to the last record in the file. The format is similar to that used by the USBM. Beginning with record 3, the assay data are ordered by columns as follows: Columns 1-11: Six-digit USBM Laramie laboratory number, left justified. The first two digits of the laboratory number indicate the year the analysis was made and the remaining four digits indicate the order in which the analysis was made in that year. These laboratory numbers are included in the database because the unused portions of the samples analyzed by the USBM are preserved by the USGS and are identified by these numbers. Laboratory numbers of samples analyzed by private laboratories are not included in this database because the USGS did not retain the unused portions of these samples. Columns 12-21: Depth, in feet, measured from the surface datum to the top of the sampled interval. Columns 22-29: Depth, in feet, measured from the surface datum to the base of the sampled interval. Columns 30-35: Amount of shale oil in weight percent. Columns 36-41: Amount of water in weight percent. Columns 42-47: Amount of shale residue in weight percent. Columns 48-54: Amount of "gas plus loss" in weight percent. Columns 55-60 Shale oil in U.S. gallons per short ton of rock. Columns 61-66: Water in U.S. gallons per short ton of rock. Columns 67-72: Specific gravity of the shale oil. Columns 73-76: Tendency for spent shale to coke. Missing data are indicated by "0.0B", or "0.000B" for a missing specific gravity value. Missing sequences of drill core are not distinguished as such, but are included in a sequence with a top and bottom depth followed by 0.0Bs in all of the data fields, as well as a missing laboratory number if the sample was analyzed by the USBM. Therefore, the depths recorded in each data set are continuous from the top of the assayed sequence to the bottom of the sequence and include missing sequences of drill core. Most of the 298,500 records in this database are Fischer assays but do include records of missing samples or intervals. It should be kept in mind that results of the Fischer assays made by different laboratories may not be strictly comparable because of differences in the method of analysis. Although most laboratories followed the ASTM modified Fischer assay method (American Society for Testing and Materials, 1980), there were some differences found between several laboratories. One laboratory was noted to yield consistently higher results, owing in part to using a more finely ground sample. Another laboratory gave consistently higher than expected results, but the reason is unclear. However, most Fischer assays made by the USBM should give consistent values between bore holes. Fischer assays of cuttings from rotary holes should be used with caution because the cuttings tend to mix and blend with each other on their recovery from the bore hole. They are not recommended for resource evaluations. Although useful for resource evaluation and stratigraphic studies of oil-shale deposits, the Fischer assay does not give a complete picture of the energy available in the organic fraction of the oil shale. The method does not measure the composition of the gases released, but merely subtracts the sum of the weights of oil, water, and spent shale from 100 percent, and reports this amount as "gas plus loss". Gas plus loss includes all noncondensable gases released in the Fischer assay including light hydrocarbons and carbon dioxide, plus analytical errors. In the Piceance Creek Basin, the carbonate minerals dawsonite [NaAl(OH)2CO3] nahcolite (NaHCO3) are abundant in oil shale in the central part of the basin. These sodium carbonates decompose at retorting temperatures giving anomalously high amounts of "gas plus loss" (i.e., carbon dioxide) and water for samples of oil shale containing these minerals. The high values of water and "gas plus loss" can be used to estimate the percentages of nahcolite and dawsonite in the sample (Beard, Tait, and Smith, 1974). If errors or omissions in this database are found, users of this disc are encouraged to contact the author at jdyni@crgdmail1.cr.usgs.gov. References American Society for Testing and Materials, 1980, Standard method of test for oil from oil shale: Annual Book of ASTM Standards, Part 25, Designation D 3904-80, p. 513- 515. Beard, T.N., Tait, D.B., and Smith, J.W., 1974, Nahcolite and dawsonite resources in the Piceance Creek basin, Colorado, in Guidebook to the energy resources of the Piceance Creek basin, Colorado, Rocky Mountain Association of Geologists, 25th Annual Field Conference: p. 101-109. Laramie Energy Technology Center, 1984, Fischer assay oil- shale data (June 1940-June 1983): National Technical Information Service [magnetic tape] PB-110881/XDD. Pitman, J.K., 1982, Oil-shale Fischer assay analysis from selected coreholes in the Piceance Basin, Colorado: National Technical Information Service [magnetic tape] PB82-134875/XDD. Pitman, J.K., and Van Trump, George, 1974, Oil shale Fischer assay data for coreholes in the Piceance Creek Basin, Colorado: National Technical Information Service [magnetic tape] PB-230 607/4/XDD. Pitman, J.K., and Van Trump, George, 1975, Magnetic tape containing oil-shale Fischer assay data for coreholes in the Uinta Basin, Utah: National Technical Information Service [magnetic tape] PB-238 682/9/XDD. 7