Publications

The East Java Basin is a fairly productive Tertiary Basin that has been producing oil and gas with a total of 2P reserves approaching 4 BBOE. The basin has undergone a complex tectonic history resulting in complex structural and stratigraphic patterns. The framework of this Study will lead to a better understanding of play types and fairways. Five pairs of N-S oriented mega-regional basin scale well and seismic correlations were constructed to provide the structural and stratigraphic framework. Surface geology and biostratigraphy were integrated to provide more accuracy. Infill well and seismic correlations were subsequently made which were tied to these regional cross-sections. The integrated approach has enabled construction of the mega-regional well-seismic cross sections across different structural provinces, albeit with various seismic quality, to a high degree of confidence. These led into identification of nine sedimentary cycles. More detail seismic and biostratigraphy data reveal the Ngimbang cycle can be further divided into 4 sub-cycles, the oldest cycles being present in the eastern part of the basin. It has also been clear that the basin has undergone episodic tensional rifting in Eo-Oligocene times, followed by regional differential subsidence in Oligo-Miocene and basin inversion and wrenching in late Neogene. NE-SW trending Paleogene grabens and intervening highs have been mapped associated with the rifting episodes. A regional E-W trending shelf-edge was formed during deposition of carbonate dominated CD-Kujung cycles, associated with the Oligo-Miocene differential subsidence. The pre-existing structural elements were super-imposed by east-west trending structural elements that resulted from Late Neogene subduction of the Indian oceanic crust beneath Java. The late Neogene structural elements include the relatively stable Northern Platform, the inverted and wrenched Central Uplift (RMKS), the deep Southern Basin, the Kendeng Foldbelt and the volcanic Arc.