Abstract

During Paleogene to Neogene times the North-West Java basinal area was being filled progressively by continental, paralic and marine sediments. Locally, Paleogene continental volcanoclastics were deposited in pretertiary graben-like deeps and depressions. During the Neogene, deposition of the Cibulakan Formation took place as the first transgressive-regressive sequence, which was followed by the deposition of the Parigi and Cisubuh Formations as the second transgressive-regressive sequence. Apart from the proven hydrocarbon bearing volcanic Jatibarang Formation, the Cibulakan Formation is now the main target in the search for hydrocarbons in the North-West Java basinal area.

This Cibulakan Formation was formed simultaneously in a paralic to shallow marine environment on and around basement highs, and in an outer neritic to bathyal environment in basement deeps. These conditions explain the close relationship between source and reservoir rocks, where all the factors governing the generation, migration and accumulation of hydrocarbons could be expected.

Detailed subsurface mapping of this formation will enable us to locate prospective areas of hydrocarbon accumulation.