Exploration history of the offshore Southeast Sumatra PSC, Java Sea, Indonesia

Abstract

Abstract The Offshore Southeast Sumatra Production Sharing Contract (PSC) is situated in the Java Sea, just north of Indonesia’s capital, Jakarta. It was the first to produce offshore oil in Indonesia and has so far produced over 0.8 × 10 9 BOE. The crude is low sulphur, waxy and sourced by Oligocene lacustrine shales. Over 200 exploration wells have been drilled from 1970 to the present, with 21 commercial accumulations discovered. Reservoirs are Oligocene to early Miocene in age with around 25% of the reserves in carbonates and 75% in fluvial-alluvial clastics. The main basins, Sunda and Asri, are retro-arc, N-S-oriented, asymmetric half-grabens situated between the stable Sunda Shield and the active volcanic arc on Java island. This paper describes the acquisition of the area and traces its history from the initial discovery at Cinta-1 in 1970, through the oil price rise and fall of the 1980s, to the discovery of a new productive basin in 1987. Exploration is not only reliant on technological advances and available budgets, so other factors relevant to the history of exploration are also included.