Multi-scale x-ray computed tomography analysis of coal microstructure and permeability changes as a function of effective stress
MetadataShow full item record
Gas permeability (k) and porosity (f) are the most important parameters in CBM/ECBM and CCS in deep unmineable coal seams. k and f depend on the coal microstructure, and k and f significantly change with varying effective stress. However, how the coal microstructure is related to such permeability and porosity changes is only poorly understood. We thus imaged sub-bituminous coal samples at two resolutions (medium - 33.7 µm and high - 3.43 µm voxel size) in 3D with an x-ray micro-computed tomography as a function of applied effective stress; and investigated how cleat morphology, k and f are influenced by the changes in effective stress and how these parameters are interrelated. In the images, three phases were identified: microcleats (void), a mineral phase (carbonate) and the coal matrix. When effective stress increased, the cleats became narrow and closed or disconnected. This resulted in a dramatic permeability drop with increasing effective stress, while porosity decreased only linearly.
Showing items related by title, author, creator and subject.
Experimental study on physical structure properties and anisotropic cleat permeability estimation on coal cores from ChinaXu, X.; Sarmadivaleh, Mohammad; Li, C.; Xie, B.; Iglauer, Stefan (2016)Knowledge of the natural structure properties of coal seams is essential for the coal bed methane (CBM) production because of their great influence on the inner flow characteristics and permeability features of hydrocarbons ...
Nazaralizadeh, S.; Rasouli, Vamegh (2011)Gas production from coal seams has attracted a great deal of attention around the world and in particular in Australia with its rich resources of coal. In general the coal bed methane (CBM) resources are located at lower ...
Torbatynia, M.; Rasouli, Vamegh (2011)Production of methane gas from coal seams is becoming very popular in the USA and also in Australia, as a natural source for clean gas. Coalbed methane (CBM) is classified as an unconventional reservoir, for which hydraulic ...