Geology topics

Cortland F. Eble

Publications and source records attributed to Cortland F. Eble.

9 recordsLinked to original sources

USGS2021

Coking coal of the United States—Modern and historical coking coal mining locations and chemical, rheological, petrographic, and other data from modern samples

Coking coal, or metallurgical coal, has been produced in the United States for nearly 200 years. Coking coal is primarily used in the production of coke for use in the steel industry, and for other uses (for example, foundries, blacksmithing, heating buildings, and brewing). Currently, U.S. coking coal is produced in Alabama, Arkansas, Pennsylvania, Virginia , and West Virginia. Historically, coking coal has also been produced in 15 other states (Alaska, Colorado, Georgia, Illinois, Indiana, Kentucky, Maryland, Montana, New Mexico, Ohio, Oklahoma, Tennessee, Utah, Washington, and Wyoming), but currently is not. Coals from the Appalachian, Arkoma, and Illinois basins are Pennsylvanian in age, while coals in Alaska, Colorado, Montana, New Mexico, Utah, Washington, and Wyoming range in age from Early Cretaceous through Eocene. This Open-File Report presents the geographic locations of current and historical coking coal deposits of the United States, with additional information about recent and historical mining and exploration activities. Chemical, rheological, petrographic, and other criteria for evaluating the coking potential of coals are discussed, and historical data for coking coals in the United States are presented. In addition, new coking coal samples from Alabama, Arkansas, Kentucky, and Oklahoma were collected and analyzed for this report, and the data are presented in multiple tables, including proximate and ultimate analyses; calorific value; sulfur forms; major-, minor-, and trace-element abundances; Free-Swelling Index; Gieseler Plastometer analyses; American Society for Testing and Materials (ASTM) dilatation; coal petrography; and predicted values of Coal Stability Factor and Coal Strength after Reaction with CO 2 (pCSF and pCSR, respectively). Data from previously analyzed coking coal samples in Kentucky, Pennsylvania, Virginia, and West Virginia were supplied by three companies, including results from all the tests listed above, plus oxidation, Hardgrove Grindability Index, and ash fusion (in a reducing environment) temperatures are also presented in tables in the report. Geographic Information System (GIS) data compiled for this project are available for download for public and private utilization and may be used to create maps for a variety of energy resource studies. These GIS data are in shapefile format, and metadata files are included describing all GIS processing. Additional geographic information about coking coal areas of the United States are also presented in tabular format in the report, including the following: names of coal basins, fields, regions, districts, and areas; coal beds or zones; geographic locations including States, counties, towns, rivers, mountains, etc.; stratigraphic hierarchy and age of the coal-bearing interval; coking characteristics including sulfur content, ash yield, volatile matter, moisture, calorific value, and Free-Swelling Index; coal rank; names of coal mines and coal-mining companies; current and past mining activity; and references for reports about the coal.

Open-File Report↗

USGS2021

Organic petrology and geochemistry of the Sunbury and Ohio Shales in eastern Kentucky and southeastern Ohio

As part of a study to determine the origin of oil and gas in the Berea Sandstone in northeastern Kentucky and southeastern Ohio, 158 samples of organic-rich shale from the Upper Devonian Olentangy and Ohio Shales and the Lower Mississippian Sunbury Shale, collectively referred to as the “black shale,” were collected and analyzed from 12 cores. The samples were analyzed for total organic carbon ( TOC ) content, organic petrography, and programmed pyrolysis. Previously acquired analytical data for 11 samples from 2 additional wells in eastern Kentucky were also used. Most of the samples were organic rich (>5 wt. % TOC ), high in sulfur (>2.0 wt. %), and dominated by liptinite macerals. The vitrinite reflectance ( VR o ) and equivalent vitrinite reflectance ( VR eq ) values, calculated from bitumen reflectance ( BR o ) measurements, were found to be in close agreement. The calculated reflectance values from programmed pyrolysis temperature at which the maximum release of hydrocarbons occurs ( T max ) showed better agreement with measured VR o after T max was corrected for excessive hydrogen index values for several samples. Thermal maturation parameters were found to increase in a northwest–southeast direction, paralleling an increase in black shale thickness and depth of burial. The thermal maturity proxies indicate the northwestern part of the study area to be more thermally mature than previously indicated. Geochemical and biomarker data from Berea oils indicate migration of oil from more thermally mature to less thermally mature areas. As such, the occurrence of petroleum liquids in the Berea Sandstone cannot be predicted directly from conventional thermal maturity proxies ( T max , VR o , and BR o ) because these methods do not account for migrated petroleum.

Ohio, Kentucky↗

USGS2020

Testing reproducibility of vitrinite and solid bitumen reflectance measurements in North American unconventional source-rock reservoir petroleum systems

An interlaboratory study (ILS) was conducted to test reproducibility of vitrinite and solid bitumen reflectance measurements in six mudrock samples from United States unconventional source-rock reservoir petroleum systems. Samples selected from the Marcellus, Haynesville, Eagle Ford, Barnett, Bakken and Woodford are representative of resource plays currently under exploitation in North America. All samples are from marine depositional environments, are thermally mature (T max >445 °C) and have moderate to high organic matter content (2.9–11.6 wt% TOC). Their organic matter is dominated by solid bitumen, which contains intraparticle nano-porosity. Visual evaluation of organic nano-porosity (pore sizes < 100 nm) via SEM suggests that intraparticle organic nano-pores are most abundant in dry gas maturity samples and less abundant at lower wet gas/condensate and peak oil maturities. Samples were distributed to ILS participants in forty laboratories in the Americas, Europe, Africa and Australia; thirty-seven independent sets of results were received. Mean vitrinite reflectance (VR o ) values from all ILS participants range from 0.90 to 1.83% whereas mean solid bitumen reflectance (BR o ) values range from 0.85 to 2.04% (no outlying values excluded), confirming the thermally mature nature of all six samples. Using multiple statistical approaches to eliminate outlying values, we evaluated reproducibility limit R, the maximum difference between valid mean reflectance results obtained on the same sample by different operators in different laboratories using different instruments. Removal of outlying values where the individual signed multiple of standard deviation was >1.0 produced lowest R values, generally ≤0.5% (absolute reflectance), similar to a prior ILS for similar samples. Other traditional approaches to outlier removal (outside mean ± 1.5*interquartile range and outside F10 to F90 percentile range) also produced similar R values. Standard deviation values < 0.15*(VR o or BR o ) reduce R and should be a requirement of dispersed organic matter reflectance analysis. After outlier removal, R values were 0.1%–0.2% for peak oil thermal maturity, about 0.3% for wet gas/condensate maturity and 0.4%–0.5% for dry gas maturity. That is, these R values represent the uncertainty (in absolute reflectance) that users of vitrinite and solid bitumen reflectance data should assign to any one individual reported mean reflectance value from a similar thermal maturity mudrock sample. R values of this magnitude indicate a need for further standardization of reflectance measurement of dispersed organic matter. Furthermore, these R values quantify realistic interlaboratory measurement dispersion for a difficult but critically important analytical technique necessary for thermal maturity determination in the source-rock reservoirs of unconventional petroleum systems.

Marine and Petroleum Geology↗

USGS2019

Berea Sandstone petroleum system

Since 2011, production of sweet high gravity oil from the Upper Devonian Berea Sandstone in northeastern Kentucky has caused the region to become the leading oil producer in the state. Remarkably, Berea oil is being produced at depths of 2,200 ft or less and in an area in which the prospective source rocks—the overlying Mississippian Sunbury Shale and underlying Devonian Shale—are interpreted to be immature for oil production. Further downdip, the Berea appears to produce primarily gas in the oil window. The economic viability of Berea production is also a function of reservoir porosity and permeability.

Kentucky↗

USGS2017

Assessment of thermal maturity trends in Devonian-Mississippian source rocks using Raman spectroscopy: Limitations of peak-fitting method

The thermal maturity of shale is often measured by vitrinite reflectance (VRo). VRo measurements for the Devonian–Mississippian black shale source rocks evaluated herein predicted thermal immaturity in areas where associated reservoir rocks are oil-producing. This limitation of the VRo method led to the current evaluation of Raman spectroscopy as a suitable alternative for developing correlations between thermal maturity and Raman spectra. In this study, Raman spectra of Devonian–Mississippian black shale source rocks were regressed against measured VRo or sample-depth. Attempts were made to develop quantitative correlations of thermal maturity. Using sample-depth as a proxy for thermal maturity is not without limitations as thermal maturity as a function of depth depends on thermal gradient, which can vary through time, subsidence rate, uplift, lack of uplift, and faulting. Correlations between Raman data and vitrinite reflectance or sample-depth were quantified by peak-fitting the spectra. Various peak-fitting procedures were evaluated to determine the effects of the number of peaks and maximum peak widths on correlations between spectral metrics and thermal maturity. Correlations between D-frequency, G-band full width at half maximum (FWHM), and band separation between the G- and D-peaks and thermal maturity provided some degree of linearity throughout most peak-fitting assessments; however, these correlations and those calculated from the G-frequency, D/G FWHM ratio, and D/G peak area ratio also revealed a strong dependence on peak-fitting processes. This dependency on spectral analysis techniques raises questions about the validity of peak-fitting, particularly given the amount of subjective analyst involvement necessary to reconstruct spectra. This research shows how user interpretation and extrapolation affected the comparability of different samples, the accuracy of generated trends, and therefore, the potential of the Raman spectral method to become an industry benchmark as a thermal maturity probe. A Raman method devoid of extensive operator interaction and data manipulation is quintessential for creating a standard method.

Frontiers in Energy Research↗

USGS2014

Results of coalbed-methane drilling, Meadowfill Landfill, Harrison County, West Virginia

The U.S. Environmental Protection Agency funded drilling of a borehole (39.33889°N., 80.26542°W.) to evaluate the potential of enhanced coalbed-methane production from unminable Pennsylvanian coal beds at the Meadowfill Landfill near Bridgeport, Harrison County, W. Va. The drilling commenced on June 17, 2004, and was completed on July 1, 2004. The total depth of the borehole was 1,081 feet (ft) and contained 1,053.95 ft of Pennsylvanian coal-bearing strata, and 27.05 ft of Mississippian strata. A total of 37.02 ft of high-volatile A and B bituminous Pennsylvanian coal was cored and desorbed from the Harlem, Brush Creek, Upper Freeport, Upper Kittanning upper split, and Upper Kittanning coal beds and the Clarion coal zone. Intact coal intervals were desorbed for a maximum period of 92 days before they were crushed to approximately 10-mesh to determine residual gas amounts. Crushed coal was desorbed for a period of 36 days. Measured gas content, on a dry, ash-free basis, ranged from 79.69 standard cubic feet per ton (SCF/ton), or 2.49 cubic centimeters per gram (cc/g), for the Harlem coal bed to 223.21 SCF/ton, or 6.98 cc/g, for the Clarion coal zone. Methane contents of desorbed gas from coal samples in the Meadowfill Landfill study area ranged from 14.87 to 98.73 percent (corrected for air contamination) for the Harlem coal bed and Clarion coal zone, respectively. Proportions of methane to the sum of the higher molecular weight hydrocarbons ranged from about 40 to 340 as the desorbed gas contained only a small percentage of higher weight hydrocarbons. Coalbed methane from the Upper Kittanning upper split and the Upper Kittanning coal beds is thermogenic in origin with isotopic composition of carbon (carbon 13, 13 C) in methane (expressed as δ 13 C in units of parts per thousand (per mil) relative to the Vienna Peedee belemnite (VPDB) standard) ranging from -46.6 to -48.7 per mil. Coalbed methane from the Brush Creek and Upper Freeport coal beds and the Clarion coal zone contains some biogenic methane with δ 13 C values ranging from -51.05 to -51.56 per mil.

West Virginia↗

USGS1999

Characterization of fly ash from low-sulfur and high-sulfur coal sources: Partitioning of carbon and trace elements with particle size

Fly ash samples were collected in November and December of 1994, from generating units at a Kentucky power station using high- and low-sulfur feed coals. The samples are part of a two-year study of the coal and coal combustion byproducts from the power station. The ashes were wet screened at 100, 200, 325, and 500 mesh (150, 75, 42, and 25 mu m, respectively). The size fractions were then dried, weighed, split for petrographic and chemical analysis, and analyzed for ash yield and carbon content. The low-sulfur ''heavy side'' and ''light side'' ashes each have a similar size distribution in the November samples. In contrast, the December fly ashes showed the trend observed in later months, the light-side ash being finer (over 20 % more ash in the 500 mesh [25 mu m] fraction) than the heavy-side ash. Carbon tended to be concentrated in the coarse fractions in the December samples. The dominance of the 325 mesh (42 mum) fractions in the overall size analysis implies, though, that carbon in the fine sizes may be an important consideration in the utilization of the fly ash. Element partitioning follows several patterns. Volatile elements, such as Zn and As, are enriched in the finer sizes, particularly in fly ashes collected at cooler, light-side electrostatic precipitator (ESP) temperatures. The latter trend is a function of precipitation at the cooler-ESP temperatures and of increasing concentration with the increased surface area of the finest fraction. Mercury concentrations are higher in high-carbon fly ashes, suggesting Hg adsorption on the fly ash carbon. Ni and Cr are associated, in part, with the spinel minerals in the fly ash.

Energy Sources↗

USGS1995

Comparison of the petrography, palynology, and paleobotany of the Little Fire Creek coal bed, southwestern Virginia, U.S.A.

Two continuous cores that penetrated the Lower Pennsylvanian Little Fire Creek coal bed in the Southwestern coal field in southwestern Virginia were sampled and X-ray radiographed to determine subunit distinctions. Comparison of petrographic, palynologic, and paleobotanic data from the same sample sets from the two cores allowed for comparison of compositional data within the Little Fire Creek coal bed. The proximate, petrographic, palynologic, and plant tissue data from two sets of samples indicate a high ash, gelocollinite- and liptinite-rich coal consisting of a relatively diverse paleoflora, including lycopsid trees, small lycopsids, tree ferns, small ferns, pteridosperms (seed ferns), and rare calamites and cordaites. The relatively very high ash yields (3–80 wt%), the relatively thin subunits (1–28 cm), and the large scale vertical variations in palynomorph floras suggest that the study area was at the edge of the paleopea-forming environment. As a result, most of the compositional correspondences are among those components indicative of degradation or decomposition.

Virginia↗

USGS1993

Comparison of the petrography, palynology and paleobotany of the Stockton coal bed, West Virginia and implications for paleoenvironmental interpretations

The Stockton coal bed (Middle Pennsylvanian) is a relatively high ash coal composed primarily of moderately thin banded, sparsely thin banded, and nonbanded coal (splint and cannel coal). Comparisons of petrographic, palynologic, and paleobotanic data gathered from the same sample sets from a single column of the Stockton coal bed indicate that compositional correspondences among the sets exist regardless of coal type. Some correspondences are believed to exist because of original plant constituents and others because of the paleoenvironment of peat formation. Using some combination of these data is critical when interpreting paleoenvironmental conditions because (1) a direct correspondence is lacking between many of the data and (2) each of the three data sets provides a unique and important perspective on the paleomire. The Stockton paleomire in the area of this study supported a diverse flora that consisted of both small and arboreous lycopsids, small ferns and tree ferns, calamites, cordaites, and pteridosperms. There appear to have been two successions of Lycospora spore-dominated, vitrinite-rich, liptinite-poor peat formation, which were followed by inertinite-rich peat formation marked by a tree fern-dominant spore assemblage and abundant unidentifiable plant tissues. These are interpreted to be two water-laden or topogenous peat formational stages followed by slightly domed, better drained peat formation.

West Virginia↗