Kepulauan Seribu, West Java Sea, Indonesia: a modern reef analog for Miocene oil and gas fields in Southeast Asia

Abstract

Abstract This paper summarizes the contents of a forthcoming book (to be published by the IPA) on the marine geology of Kepulauan Seribu, a Holocene patch reef complex located 6° south of the equator in the Java Sea about 50 kilometers northwest of Jakarta, Indonesia Figure 1. These reefs and islands provide an excellent field laboratory for making comparisons between living Holocene reef systems and Tertiary reef facies which contain much of Indonesia's hydrocarbon reserves. It is hoped that a better understanding of this reef system will aid in the exploration and exploitation of hydrocarbon reserves from similar geologic deposits. Almost 200 individual reef platforms rise up from the Java Sea to form the north-to-south trend of the Kepulauan Seribu reef complex (Figure 2). Individual reefs, however, stretch out at right angles to this and display an east-west linearity in their trends, which corresponds to the bidirectional monsoon weather pattern in this region: 1) the West Monsoon blowing from northwest to southeast from December through February and accounting for the rainy season in these months, during which wind-driven surface currents in the Java Sea flow southeastward across Kepulauan Seribu; and 2) the East Monsoon blowing from east to west from March through November, a relatively drier season, with wind-driven surface currents in the Java Sea flowing westward during this period.