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Seismic
Methods
for Delineating Coal Seams
The mining and export of coal is a major
industry in Australia, and the Bowen Basin in Queensland holds a vast reserve
of this commodity. The problem in extracting the coal from the ground is
knowing the coal seam structure ahead of the mining process. If while mining
a coal seam an unknown fault, unstable roof conditions or a gas pocket
are encountered, they can lead not only to equipment damage and downtime,
but risk of life to personnel. Currently, coal seams are mapped by borehole
information, but these are expensive and lack detail. The industry needs
to take advantage of the seismic method, which offers a cheap way of continuously
imaging the subsurface.
The use of 3-D reflection surveying is ideal in
geologically complex areas since geology is three-dimensional in nature
and modern processing and interpretation methods will allow subtle features
to be mapped.
The research will involve the processing, integration
and interpretation of a past 2-D seismic survey, RVSP, and well log information
with a 3-D survey. Detailed analysis of the 3-D volume including seismic
and trace attributes will be used to help identify subtle faulting along
with possible coal bed methane gas pockets. Further processing and analysis
of the data would then be required for fracture and stress detection.
By combining RVSP, 2-D and 3-D seismic methods
and borehole data
, the merits of each method will be highlighted and a
new insight into their use for similar work conducted in the future will
be provided.
AAPG Search and Discovery Article #90925©1999 AAPG Foundation Grants-in-Aid