Mini-SOSIE - Successful shallow 3D seismic data acquisition in an environmentally sensitive area

Abstract

Environmental and cultural restrictions are increasingly impacting exploration efforts for mineral and energy resources. It is almost impossible to gather seismic data without being constrained by these factors. 3D land seismic data acquisition requires intense source and receiver sampling particularly for high resolution work where shot and receiver line intervals can be as little as 45 metres. Consequently, the acquisition method chosen is extremely important, as it will govern the degree of environmental impact imposed by the survey. In the case of the Onley 3D survey, traditional sources such as dynamite and vibrator were deemed to be unacceptable, on environmental grounds. Mini-SOSIE, which utilises a light, portable surface compactor (Rammer) as a source was an acceptable alternative. After comparing the results from the `Rammer' source with dynamite and vibrator sources, the Mini-SOSIE system proved to have the penetration and resolution needed to acquire useful 3D data. However, as could be expected, the signal bandwidth of the Mini-SOSIE (and vibrator) data was not as high as that of the dynamite data. After extensive software and hardware development aimed primarily at increasing recording channels and receiver line numbers, a pilot 3D seismic survey was recorded. The aim of this survey was to delineate small faults and other geological features, to assist in mine planning. The Mini-SOSIE 3D data were of high quality. From the interpreted data volume it was possible to resolve a seam split as well as a likely small fault - critical information for mine planning. The environmental impact imposed by the survey was minimal, with no negative feedback from relevant landholders.