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In-situ analysis of solid bitumen in coal: Examples from the Bowen Basin and the Illinois Basin

Solid bitumen and associated vitrinite from selected coals from the Bowen Basin and the Illinois Basin were studied using electron microprobe and micro-FTIR techniques. The coal studied covers a range of vitrinite reflectance from 0.59% to 1.33%. Carbon content in the bitumen is generally lower than in vitrinite in coals with vitrinite reflectance below 0.67%. In coals with reflectance above 0.67%, carbon content of bitumen is higher than in vitrinite, reflecting higher aromaticity due to hydrocarbon generation. Sulfur and iron content are comparable between vitrinite and bitumen. Functional group distribution suggests the presence of two types of bitumen in the Illinois Basin coals. The more aliphatic variety occurring in veins and cleats is interpreted as pre-gas generation bitumen, and the more aromatic variety filling cells and voids in inertinite as post-gas generation bitumen. (C) 2000 Elsevier Science B.V. All rights reserved.Solid bitumen and associated vitrinite from selected coals from the Bowen Basin and the Illinois Basin were studied using electron microprobe and micro-FTIR techniques. The coal studied covers a range of vitrinite reflectance from 0.59% to 1.33%. Carbon content in the bitumen is generally lower than in vitrinite in coals with vitrinite reflectance below 0.67%. In coals with reflectance above 0.67%, carbon content of bitumen is higher than in vitrinite, reflecting higher aromaticity due to hydrocarbon generation. Sulfur and iron content are comparable between vitrinite and bitumen. Functional group distribution suggests the presence of two types of bitumen in the Illinois Basin coals. The more aliphatic variety occurring in veins and cleats is interpreted as pre-gas generation bitumen, and the more aromatic variety filling cells and voids in inertinite as post-gas generation bitumen.

International Journal of Coal Geology

CO2 storage capacity estimation: Methodology and gaps

Implementation of CO2 capture and geological storage (CCGS) technology at the scale needed to achieve a significant and meaningful reduction in CO2 emissions requires knowledge of the available CO2 storage capacity. CO2 storage capacity assessments may be conducted at various scales-in decreasing order of size and increasing order of resolution: country, basin, regional, local and site-specific. Estimation of the CO2 storage capacity in depleted oil and gas reservoirs is straightforward and is based on recoverable reserves, reservoir properties and in situ CO2 characteristics. In the case of CO2-EOR, the CO2 storage capacity can be roughly evaluated on the basis of worldwide field experience or more accurately through numerical simulations. Determination of the theoretical CO2 storage capacity in coal beds is based on coal thickness and CO2 adsorption isotherms, and recovery and completion factors. Evaluation of the CO2 storage capacity in deep saline aquifers is very complex because four trapping mechanisms that act at different rates are involved and, at times, all mechanisms may be operating simultaneously. The level of detail and resolution required in the data make reliable and accurate estimation of CO2 storage capacity in deep saline aquifers practical only at the local and site-specific scales. This paper follows a previous one on issues and development of standards for CO2 storage capacity estimation, and provides a clear set of definitions and methodologies for the assessment of CO2 storage capacity in geological media. Notwithstanding the defined methodologies suggested for estimating CO2 storage capacity, major challenges lie ahead because of lack of data, particularly for coal beds and deep saline aquifers, lack of knowledge about the coefficients that reduce storage capacity from theoretical to effective and to practical, and lack of knowledge about the interplay between various trapping mechanisms at work in deep saline aquifers. ?? 2007 Elsevier Ltd. All rights reserved.

International Journal of Greenhouse Gas Control