New developments for coal exploration in Australia

Abstract

© 1994 SEG Annual Meeting. All Rights Reserved. During 1993, five experimental seismic surveys, in three different coal basins of Australia, were performed for a consortium of coal companies. The initial goal was to determine if seismic methods could be applied to support mining operations in these areas. Small charges of explosive were chosen as the major energy source. Three of the mines provided sonic and density logs prior to the field experiments. A reverse vertical seismic profile (RVSP) was recorded at all sites, followed by the recording of a short (500-600 m) 2-D seismic line over each RVSP bore-hole. The RVSP investigations were initially used to test the applicability of surface seismic in the area and to design optimum acquisition parameters. For this purpose, pre-processing had to be carried out in the field. Later, RVSP data were further processed to obtain a detailed velocity field, map the coal seams at and away from the borehole, and to estimate the quality factor of seams and surrounding rocks. All seismic lines were processed using a novel surface consistent refraction static routine. To further analyse the potential of seismic methods in these areas, unconventional interpretation was performed. Pseudo 3-D map analysis in a combination with trace attributes were used in the two areas where the existence of low throw faults and fracture swarms were suspected. The major outcome of the study was that all areas had their optimum seismic parameters defined. This allowed the mining companies to interface future seismic exploration strategies into their mine planning activity with greater confidence than previously.