Integrated use of Seismic, Ground and Airborne Gravity/Gravity Gradiometer, and Ground Geological Mapping Methods in the Eastern Papuan Basin, PNG

Abstract

InterOil has complemented the use of seismic data in its PNG petroleum exploration licences with both ground and airborne gravity/gravity-gradient and aeromagnetic data. Potential field methods may be used to significantly reduce exploration costs in jungle-covered areas due to the relatively high effort and helicopter support required to deploy seismic equipment. Airborne gravity gradient and aeromagnetic data are used to interpolate and extrapolate reprocessed seismic data in InterOil?s PPL 236. They confirm and extend fault correlations on widely spaced seismic lines. Seismic data acquired in PPLs 237 and 238 show that faults do not, as suspected by some, sole out at shallow depth (eg 1 to 2 km). Instead, steeply dipping faults continue to several kilometers Surface geological mapping, together with Landsat TM and digital terrain model data, greatly assist in planning, acquisition and interpretation of seismic data. Ground gravity data acquired along seismic lines shows good character which can be correlated with the seismic data interpretation. Relatively low effort (shallow holes, small charges), optimally located seismic data acquisition is shown to be effective in substantially resolving ambiguous structure and extending interpretation from surface dip and lithology data. Potential field data, once calibrated with seismic data, is demonstrated as a method capable of substantially extending the seismic interpretation.