Seismic Attribute Analysis for the Characterisation of Fault and Fracture Networks: South West Hub, Harvey, Australia

Abstract

As part of the South West Hub Project to characterise the sedimentary sequences around the Harvey 3 well, a combination of 3D surface and borehole seismic data was acquired in 2017. The geological data from the same area previously revealed that although a conventional seal is absent, residual trapping mechanisms in the form of paleosols are present. To analyse the structural linkages and associated geo-mechanics at Harvey, faults and fracture networks were analysed at various scales and with various techniques. To better delineate the stratigraphic distribution of sandy/shaly units and eventually characterise paleosol rich strata, which would deter the upward migration of CO2, the lithology needed to be tied to the seismic data. To this end, various seismic attributes are tested on the transmitted wavefield of the Zero Offset VSP and are correlated to lithology by comparing to well logs. Additionally, seismic sequence attributes are found to provide good results. Therefore, we apply these attributes to the 3D surface seismic data to facilitate a qualitative interpretation. In conclusion, it was found that the combination of these attributes provides valuable insights regarding the paleosol content.