3-D Imaging of Cleat and Micro-cleat Characteristics, South Walker Creek Coals, Bowen Basin, Australia: Microfocus X-ray Computed Tomography Analysis
DOI:
https://doi.org/10.17014/ijog.7.1.1-9Keywords:
cleat characteristics, coal, X-ray Computed Tomography, Bowen Basin, AustraliaAbstract
The Permian coals of the South Walker Creek area have a moderately to highly developed cleat system. The cleat fractures are well developed in both bright and dull bands, and generally parallel, inclined or perpendicular to the bedding planes of the seam, with the spaces open or filled by mineral matter, such as clay and carbonate minerals. Microfocus X-ray computed tomography (CT) technique was performed to identify cleat characteristics in the coal seams. This technique allows visualizing of microcleat distribution and mineralization in three dimensional images. Cleat mineralization in the coal seam occurs either as single mineral (monomineralic) or intermixed mineral (polymineralic) masses. The cross cutting relationship was shown by X-ray CT scan analysis. The timing of microcleat formation in the coal seam from early to late is carbonate minerals, clay minerals (kaolinite) plus minor high density (rutile or anatase) phases. Thus, a high resolution of microfocus X-ray CT does not only provides a better visualization, but also could identify microcleat orientation, cleat mineralization, and generation of microcleat.
References
Arnold, J.R., Testa, J., Friedman, P.J., and Kambic, G.X., 1982. Computed tomographic analysis of meteorite inclusions. Science, 219, p 383-384. doi:10.1126/science.219.4583.383
Close, J. C. and Mavor, M.J., 1991. Influence of coal composition and rank on fracture development in Fruitland coal gas reservoirs of San Juan Basin. In: Schwochow, S., Murray, D.K., and Fahy, M.F. (Eds.), Coalbed Methane of Western North America. Rk.Mt. Association Geological Field Conference (1991), p.109-121.
Geet, M.V., Swennen, R., and David, P., 2001. Quantitative coal characterisation by means of microfocus X-ray computer tomography, colour image analysis and backscattered scanning electron microscopy. International Journal of Coal Geology, 46, p.11-25. doi:10.1016/S0166-5162(01)00006-4
Hainsworth, J.M. and Aylmore, L.A.G., 1983. The use of computer-assisted tomography to determine spatial distribution of soil water content. Australian Journal of Soil Research, 21, p.435-443. doi:10.1071/SR9830435
Haubitz, B., Prokop, M., Dohring, W., Ostrom, J.H., and Wellhofer, P., 1988. Computed tomography of Archeopterix. Paleobiology, 14, p.206-213.
Hounsfield, G.N., 1972. A method of and apparatus for examination of a body by radiation such as X- or gammaradiation. British Patent No 1.283.915, London.
Hounsfield, G.N., 1973. Computerized transverse axial scanning (tomography). Part 1: Description of system. British Journal of Radiology, 46 (10), p.16-22. doi:10.1259/0007-1285-46-552-1016
Karacan, C.O. and Okandan, E., 2000. Fracture cleat analysis of coals from Zonguldak Basin, northwestern Turkey/relative to the potential of coalbed methane production. International Journal of Coal Geology, 44, p.109-125. doi:10.1259/0007-1285-46-552-1016
Renter, J.A.M., 1989. Applications of computerized tomography in sedimentology. Marine Geotechnology, 8, p.201-211. doi:10.1080/10641198909379868
Laubach, S.E., Marrett, R.A., Olson, J.E., and Scott, A.R., 1998. Characteristics and origins of coal cleat: a review. International Journal of Coal Geology 35, p.175-207. doi:10.1016/S0166-5162(97)00012-8
Mazumder, S., Wolf, K.-H.A.A., Elewaut, K., and Ephraim, R., 2006. Application of X-ray computed tomography for analyzing cleat spacing and cleat aperture in coal samples. International Journal of Coal Geology, 68, p.205-222. doi:10.1016/j.coal.2006.02.005
Mees, F., Swennen, R., Van Geet, M., and Jacobs, P. (eds)., 2003. Applications of X-ray Computed Tomography in the Geosciences. Geological Society, London, Special Publications, 215, p.1-5. doi: 10.1144/GSL.SP.2003.215.01.01
Permana, A.K., Ward, C.R., Li, Z., Gurba, L.W., and Davison, S., 2010. Mineral matter in the high rank coals of the South Walker Creek area, northern Bowen Basin. In: Beeston, J.W. (Ed), Proceedings of Bowen Basin Symposium - Back in (the) Black, Geological Society of Australia Coal Geology Group and Bowen Basin Geologists Group, Mackay, Qld, 6-8 October, 2010, p.27-34.
Permana, A.K., 2011. Mineralogical variation and changes in the South Walker Creek coals, Bowen Basin, Queensland, Australia. M.Sc Thesis. University of New South Wales, Sydney, 276pp. (Unpublished).
Petrovic, P.E., Siebert, A.M., and Rieke, I.E., 1982. Soil bulk density analysis in three dimensions by computed tomographic scanning. Soil Science Society of America Journal, 46, p.445-450. doi:10.2136/sssaj1982.03615995004600030001x
Raynaud, S., Fabre, D., Mazerolle, F., Geraud, Y., and Latiere, H.J., 1989. Analysis of the internal structure of rocks and characterisation of mechanical deformation by a non-destructive method: X-ray tomodensitometry. Tectonophysics, 159, p.149-159. doi:10.1016/0040-1951(89)90176-5
Sasov, A.Y., 1987. Microtomography: I. Methods and equipment. II. Examples of applications. Journal of Microscope, 147, p.169-192. doi:10.1111/j.1365-2818.1987.tb02830.x
Simmons, F.J., Verhelst, F., and Swennen, R., 1997. Quantitative characterization of coal by means of microfocal X-ray computed microtomography (CMT) and color image analysis (CIA). International Journal of Coal Geology, 34, p.69-88. doi:10.1111/j.1365-2818.1987.tb02830.x
Vinegar, H.J., 1986. X-ray CT and NMR imaging of rocks. Journal of Petroleum Technology, 38, p.257-259. doi:10.2118/15277-PA
Vinegar, H.J. and Wellington, S.L., 1986. Tomographic imaging of three-phase flow experiments. Review of Scientific Instruments, 58, p.96-107. doi:10.1063/1.1139522
