Interpretation of airborne geophysical data covering the Gulf St Vincent region has utilised predominantly 1964 vintage gravity and aeromagnetics that have been digitised off original Beach Petroleum contour maps, plus limited well log and seismic depth information on three target sedimentary horizons; this has also lately been augmented by the recently to hand results of a high resolution aeromagnetic survey flown by Canyon in April 1994. The project objective was to delineate basement structures and faults and to confirm the suspected presence of subtle cross faults, in support of seismic interpretation of possible reef build-ups associated with fracturing and tectonic controls on porosity development.