Bulletin of the Geological Society of Malaysia, Volume 33, Nov. 1993, pp. 289-301
1Australian Geological Survey Organisation, Canberra, ACT, Australia
2Office of Energy Affairs, Makati, Metro Manila, Philippines
Abstract: During March-May 1992, the Australian Geological Survey Organisation and the Philippine Office of Energy Affairs conducted a cooperative marine seismic, gravity, magnetic, bathymetry and geochemical “sniffer” survey in four offshore Philippine basins: NE Palawan, Cuyo Platform, Tayabas Bay and Ragay Gulf. The project was funded by the Australian International Development Assistance Bureau. The survey work was conducted using the Australian Government‘s geoscientific vessel, Rig Seismic.
The cruise achieved all its objectives and was a major success. Of the four survey areas, the Ragay Gulf is of particular interest, with complex structures, multi-phase tectonism and massive sediment infill. It was in this region that many geochemical “sniffer” seeps were located.
The geochemical “sniffer” data and its C-13 and C-14 isotope analyses have indicated the presence of significant source rocks. These seeps are thermogenic in origin and have reached sufficient maturity to generate significant quantities of hydrocarbons. In the near future, the geochemical data will be integrated with the seismic data to provide clues for hydrocarbon migration.
The preliminary seismic interpretation have revealed the existence of five sedimentary sub-basins with 2.5 – 5 seconds of Eocene to Recent sediments. Several types of potential traps were documented.
No well has been drilled in the offshore Ragay Gulf. Onshore well log information and stratigraphy have assisted in the correlation and interpretation of offshore seismic data. In addition, the importance of the carbonate and clastic reservoirs was recognised.
Overall, the oil and gas potential in the Ragay Gulf area looks most encouraging.