Prospect Identification Using AVO Inversion and Lithology Prediction

In 2008, WesternGeco acquired the 5000 sq/km Keystone multi-client survey located offshore between the giant Io/Jansz and Scarborough gas fields on Australia’s NW shelf, in order to image potential gas reservoir’s at multiple stratigraphic levels within complex geology. Searching for leads and prospects within such a large volume using seismic data alone is traditionally a time-consuming process. An efficient prospect screening tool has been produced in the form of a well log-calibrated gas sand probability cube derived from amplitude variation with offset (AVO) inversion outputs. Using advanced visualisation techniques the data can then be rapidly interrogated highlighting a number of direct hydrocarbon indicators (DHI's) and potential prospects. AVO and quantitative interpretation have played a key role in a number of discoveries in this area, particularly within the Triassic.