ABSTRACT: Direct imaging of structural traps with satellite gravity data

Hoffman, Nick , La Trobe 3D-GEO, Bundoora, Australia

Although many examples exist where known large hydrocarbon traps can be detected within the regional datasets derived from satellite gravity observations, it is commonly thought that there is little predictive power to the technique. In essence, most large traps are thought to have already been found, and the wavelength of the data precludes identifying the smaller remaining traps.

That conventional view is challenged with an example from a recent exploration campaign in Indonesia where a new sub-basin was identified on the basis of satellite gravity alone. A seismic program was planned over the area in consultation between oil exploration companies, a seismic contractor, and the Indonesian government agency LEMIGAS.

Interpretation of the seismic data showed that features within the satellite gravity data corresponded with a large undrilled structural feature in an area near to other gas discoveries. The acreage was gazetted and bid for by a number of international companies.

The use of the satellite technique requires recognition of an area of "new geography" where seismic exploration has previously been neglected due to boundary disputes or to adverse geological preconceptions, and within which large structures are developed. Although few such areas exist, satellite gravity provides an extremely cost-effective tool for reconnaissance in these circumstances and for high-grading the more prospective opportunities.

AAPG Search and Discovery Article #90913©2000 AAPG International Conference and Exhibition, Bali, Indonesia