A large 3D seismic survey at the South West CO2 Hub Project near Harvey was acquired.
The survey is of great importance for the characterisation of the reservoir, seals and structures in the area. Often, the positioning of the seismic source pointsis not easy or convenient. These issues arise because of the nature of the land and vegetation in the area (wetlands etc.), and also because the larger size of the commercially owned vibrating trucks is likely to cause significant disturbance to the landowners. Gate removal and fence demolition are both impactful, and the trucks may leave very large footprints over soft ground. It is therefore of high importance to investigate the use of alternative sources to replace conventional seismic sources in parts of the commercial 3D survey.
This project was planned to evaluate and demonstrate the effectiveness of the UNIVIB sources acquired under the EIF granting scheme to the National Geosequestration Laboratory (NGL). The broad band signal generated by the UNIVIB trucks, in combination with tight geophone spacing, provided a technical solution for resolving shallow structures and lithological variations. The latter are features of prime importance for the long term CO2 storage program at this site. In addition, the system would be used to demonstrate to the community their low environmental impact.
A high quality, broad band, low impact seismic source produced very high resolution data in the first kilometre of depth along Riverdale Road, Cookernup. Despite the high ambient noise (traffic and farming machinery) this source, combined with unconventionally light-weight seismic equipment, produced high quality data. Shallow sediments were imaged with superior resolution. The main unconformity can now be mapped with much improved accuracy in comparison to the 2011 data, which was acquired with much stronger sources.
- With a relatively low environmental impact, the lighter weight UNIVIB proved very successful in demonstration to the general community. A vibrator truck was exhibited at the Harvey Agricultural Show in late 2013 and attracted a lot of interest and positive comments from the local community.
- The results of the new survey demonstrated that high resolution surveys were achievable for imaging the top 1000m of sediments and improving our understanding of the fault patterns.
- The new broad band source also proved to be quite a powerful source; capable of producing enough energy to record reflections from depths of over 3000m.
- It showed it was possible to utilise UNIVIB trucks in the existing large-size 3D survey, to close the gaps in survey coverage where access is otherwise not possible, due to local land conditions.