Harold J. Gluskoter | Geology Reports

USGS2001

Coal bed sequestration of carbon dioxide

Geologic sequestration of CO 2 generated from fossil fuel combustion may be an environmentally attractive method to reduce the amount of greenhouse gas emissions. Of the geologic options, sequestering CO 2 in coal beds has several advantages. For example, CO 2 injection can enhance methane production from coal beds; coal can trap CO 2 for long periods of time; and potential major coal basins that contain ideal beds for sequestration are near many emitting sources of CO 2 . One mission of the Energy Resources Program of the U.S. Geological Survey is to maintain assessment information of the Nation’s resources of coal, oil, and gas. The National Coal Resources Assessment Project is currently completing a periodic assessment of 5 major coal-producing regions of the US. These regions include the Powder River and Williston and other Northern Rocky Mountain basins (Fort Union Coal Assessment Team, 1999), Colorado Plateau area (Kirschbaum and others, 2000), Gulf Coast Region, Appalachian Basin, and Illinois Basin. The major objective of this assessment is to estimate available coal resources and quality for the major producing coal beds of the next 25 years and produce digital databases and maps. Although the focus of this work has been on coal beds with the greatest potential for mining, it serves as a basis for future assessments of the coal beds for other uses such as coal bed methane resources, in situ gasification, and sites for sequestration of CO 2 . Coal bed methane production combined with CO 2 injection and storage expands the use of a coal resource and can provide multiple benefits including increased methane recovery, methane drainage of a resource area, and the long-term storage of CO 2 .

Conference Paper↗

USGS1996

Assessing the coal resources of the United States

In 1994, coal production in the United States reached the highest level in history (slightly more than 909 million metric tons or one billion short tons), continuing the upward trend of coal production and utilization that began 34 years ago. Previous assessments of the coal resources of the United States, which were completed as early as 1909, clearly indicated that the total coal resources of the Nation are large and that utilization at the current rate will not soon deplete them.

Fact Sheet↗

USGS1991

Petrography of Permian “Gondwana” coals from boreholes in northwestern Bangladesh, based on semiautomated reflectance scanning

Drilling through Quaternary alluvium and Tertiary cover at low-gravity anomalies in northwestern Bangladesh showed the presence of Permian sedimentary rocks in depressions that may be as much as a thousand meters deep in the crystalline basement. These Permian strata include low-sulfur, high-volatile bituminous coals in beds as thick as 15 m. The maceral group composition of these coals was determined by semiautomated reflectance scanning with a motorized microscope stage, rather than by point counting. This method was chosen to give objectively recorded raw analytical data and to provide a graphical picture of each sample. The coals are mostly “Gondwana” type (poorly layered “plum pudding” with abundant minerals and inertinite in a vitrinite groundmass) that would be classed as semi-dull (inerto-gelitite) coals. However, six samples have more than 70% vitrinite. None of the samples would be classed as sapropelic (liptinitic). The upper, middle, and lower main seams in borehole GDH-45 were sampled in 10 benches (0.1–3 m thick) each. Inertinite ranges from 7 to 100 vol% (mineral free basis) in individual benches, but composite seam averages are 41, 54 and 67%. Inertinite increases toward the top of two main seams so the bottom would yield the most valuable first mine slices. Some benches with extremely high inertinite content, such as the top 7 m of the lower thick seam, might be mined specially for blending with foreign low-inert coals to increase coke strength. The free swelling index reaches 7.5 in several vitrinite-rich benches, which can indicate good coking coal. Much of the vitrinite is fluorescent, which indicates secondary bituminization characteristic of vitrinite in good coking coals. Ash yields range from 8 to 52%, with composite seam averages of 15, 14 and 24%. Rare visible pyrite is in veinlets or small nodules; framboids and dispersed pyrite are absent. In borehole GDH-40 near Barapukuria (200–500 m depth), the mean random reflectance of vitrinite “A” ranges from 0.60 to 0.80% R o and vitrinite “B” ranges from 0.55 to 0.65%. In borehole GDH-45 near Khalaspir (287–442 m), the reflectance of vitrinite ranges from 0.79 to 0.94%. In individual cases, the vitrinite is difficult to define because of semivitrinite at higher reflectance (forming a separate peak on several reflectograms) and because of surface bitumen films or resinous (?) inclusions at lower reflectance. On the basis of vitrinite reflectance, the coals can be considered to have entered the “main phase of bitumen generation” of organic thermal maturation as understood in petroleum geochemistry.

Organic Geochemistry↗