Implications of natural analogue studies for CO2 storage in coal measures with enhanced coal bed methane
(0) High-CO2 coal seams in the Gunnedah and Bowen Basin, eastern Australia provide natural analogues of the processes likely to occur as a result of CO2 injection and storage in coal systems. CO2 storage in coal seams should be linked to enhanced production of CH4 because of the low permeability of coals that have not been previously drained of CH4. Our results indicate that CO2 has largely been used for carbonate precipitation (mineral trapping) in eastern Australian coal basins with a significant proportion stored in coal seams as adsorbed molecules on coal since the Mesozoic (adsorption trapping). Siderite I is the earliest carbonate phase and occurs with kaolinite in mudrocks and sandstones. It is interpreted to have formed during early diagenesis under low temperature reducing conditions where methanogenesis produced residual C-enriched CO2.Calcite-ankerite-siderite II-clay assemblages occur as veins and replacement of rock fragments in sandstones of the Bowen and Gunnedah Basins and formed as a result of meteoric hydrothermal activity in the Late Triassic and Cretaceous respectively. Interaction of these fluids with the coal seams has resulted in thermal degradation of organic matter and the formation of CO2 and CH4 with the CO2 incorporated into the Ca-Mg-Fe carbonates. Dawsonite is a late stage diagenetic phase that occurs as vein fill in the coal seams and sandstones and cement in sandstones; it is interpreted to form under close to present day formation temperatures except in the immediate vicinity of igneous intrusions. Dawsonite 13C values are remarkably consistent across the basin system and mainly fall within a narrow range from 2‰ to 3‰ that suggests a magmatic source in view of dawsonite occurrence in non-marine as well as marine strata. The bulk of the CO2 currently stored in the coal seams is of magmatic origin and variously associated with Late Triassic tectonism and major episodes of igneous activity in the Cretaceous and tertiary. Gas stable isotopes confirm generation of secondary biogenic methane in COz-rich coal seams by reduction of CO2 that suggests methanogenesis provides an additional sequestration mechanism for CO2 in coal seams.
vertical roller mill grinding simulation
S. D. Golding I.T.Uysal C.J.Boreham K.A.Baublys J.S.Esterle
Earth Sciences and CO2CRC, University of Queensland, QLD 4072, Australia Geoscience Australia and CO2CRC, GPO Box 378, Canberra, ACT 2601, Australia
国际会议
徐州
英文
712-725
2009-09-24（万方平台首次上网日期，不代表论文的发表时间）