Organic petrology, geochemistry, gas content and gas composition of Middle Pennsylvanian age coal beds in the Eastern Interior (Illinois) Basin: Implications for CBM development and carbon sequestration

Partial pressures of the gases in the middle ears of 14 guinea pigs were measured continuously on-line with a specially designed mass spectrometer. The average values were carbon dioxide 67.55 mm Hg, oxygen 48.91 mm Hg, and nitrogen 596.54 mm Hg. These values confirm earlier measurements and show that the gas composition of the middle ear differs basically from that of air and resembles that of venous blood. These findings are indicative of bilateral diffusion between the middle ear cavity and the blood. We propose that under physiologic as well as under pathologic (ie, atelectatic) conditions, the gas content of the middle ear is also controlled by diffusion. This mechanism fits well with the fluctuating character of atelectatic ears. Thus, a negative middle ear pressure could be secondary to excessive loss of gases through increased and excessive diffusion, although additional mechanisms are probably also involved. A likely contributing factor is poor pneumatization of the mastoid, with consequent absence of a physiologic pressure regulation mechanism by its pneumatic system.

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Geochemical investigation of hydrocarbon generation potential of coal from Raniganj Basin, India

Journal of Petroleum Exploration and Production Technology ◽

10.1007/s13202-021-01281-4 ◽

2021 ◽

Vol 11 (10) ◽

pp. 3627-3636

Author(s):

D. S. Panwar ◽

Ram Chandra Chaurasia ◽

V. K. Saxena ◽

A. K. Singh ◽

Akanksha

Keyword(s):

Gas Content ◽

Coal Bed ◽

Hydrocarbon Generation ◽

Type Iii ◽

Coal Beds ◽

Petrographic Examination ◽

Raniganj Coalfield ◽

Geochemical Investigation ◽

A Minor ◽

Van Krevelen Diagram

AbstractMethane content in a coal seam is a necessary parameter for evaluating coal bed gas, and it poses an environmental risk to underground coal mining activities. Keeping in pace with comprehensive studies of coal bed gas, 12 coal samples were selected from the Sitarampur block of Raniganj Coalfield for analysis. The Petrographic examination illustrated that significant values of reactive macerals present in samples demonstrate that organic matter is dominated by the prominent source of aromatic hydrocarbons with a minor proportion of aliphatic hydrocarbon, which falls in the region of (Type III) kerogen, confirms the suitability for the potential of hydrocarbon generation. “A” factor (aliphatic/aromatic bands) and “C” factor (carbonyl/carboxyl bands) value concluded that the sample has the lowest aromaticity and the highest hydrocarbon-generating potential, which was also validated by the Van Krevelen diagram. The Van Krevelen diagram plots between the H/C and O/C ratio indicate that coal samples lie in the type III kerogen, and bituminous coal (gas prone zone) is present in the block, which is confirmed by the cross-plot between desorbed and total gas (cc/g). The in situ gas content values are high enough to produce methane from coal beds. The overall study concludes that the Sitarampur block from Raniganj Coalfield is suitable for hydrocarbon generation and extraction.

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Palynological Correlation of Atokan and Lower Desmoinesian (Pennsylvanian) Strata Between the Illinois Basin and the Forest City Basin in Eastern Kansas

Current Research in Earth Sciences ◽

10.17161/cres.v0i253.11834 ◽

2007 ◽

pp. 1-21

Author(s):

Russel A. Peppers ◽

Lawrence L. Brady

Keyword(s):

Coal Bed ◽

Illinois Basin ◽

Carbonaceous Shale ◽

Eastern Kentucky ◽

Coal Beds ◽

Tree Ferns

Palynological correlation is made between Atokan and lower Desmoinesian strata in the Illinois basin and the Forest City basin in eastern Kansas. Spore data from previous studies of coals in the Illinois basin and other coal basins are compared with data from spore assemblages in coal and carbonaceous shale bands in a core drilled in Leavenworth County, Kansas. Correlations are based on first and/or last occurrences of 31 species common to the Illinois basin and eastern Kansas and on significant increases or decreases in abundance of several of those taxa. The oldest coal, which is 26 ft (8 m) above the top of the Mississippian, is early Atokan (early Westphalian B) in age and is approximately equivalent to the Bell coal bed in the Illinois basin. The Riverton coal bed at the top of the studied interval in Kansas is early Desmoinesian (early Westphalian D) and correlates with about the Lewisport coal bed in the Illinois basin. Three coal beds near the base of the Pennsylvanian in three cores drilled in Cherokee County, Kansas, which were also studied, range in age from late Atokan to early Desmoinesian. As in other coal basins, Lycospora, borne by lycopod trees, greatly dominates the lower and middle Atokan spore assemblages in coals and shale, but spores from ferns, especially tree ferns, significantly increase in abundance in the upper Atokan and lower Desmoinesian. The pattern of change of dominance among Lycospora pellucida, L. granulata, and L. micropapillata in middle Atokan (Westphalian B-C transition) that has been demonstrated earlier in the Illinois basin and eastern Kentucky and Tennessee, also occurs in eastern Kansas. At least 10 species of spores, which appeared in the middle Atokan in other parts of the equatorial coal belt, also appeared at this time in eastern Kansas. Most of these species have their affinities with the ferns, which were adapted to drier habitats than lycopods. Thus, the climate may have become a little drier in the equatorial coal belt during middle Atokan.

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