PROCEEDINGS, INDONESIAN PETROLEUM ASSOCIATION Thirty-First Annual Convention and Exhibition, May 2007 TEMPORAL CONTROLS AND RESULTING VARIATIONS IN OLIGO-MIOCENE CARBONATES FROM THE EAST JAVA BASIN, INDONESIA: EXAMPLES FROM THE CEPU AREA

Carbonates of the Oligo-Miocene system of the East Java Basin exist in a variety of styles resulting from multiple influences at varying scales. Global, regional, and local influences were investigated through the study of well and seismic data from the Cepu area of eastern Java. To date, five high-relief platformal carbonate buildups have been drilled: Sukowati, Banyu Urip, Jambaran, Cendana, and Kedung Tuban. All were imaged by a large 3D seismic survey and show gross differences despite having all grown from a common, broad, probable Early Oligocene carbonate platform. Timing of deposition of the buildups and the overlying sediments was established through a robust strontium isotope dating program in the carbonates coupled with a high-resolution biostratigraphic study of the clastics. Additional temporal control was gained through examination of seismic stratigraphic relationships which was critical for resolving the timing of clastic deposition due to the high degree of reworking of sediments and complicated biostratigraphic data. Carbonate deposition on the buildups was progressively terminated through time from west to east. Kedung Tuban, the westernmost of the buildups, failed to resume shallow-water deposition following the midOligocene unconformity. Cendana and Jambaran resumed growth after the Middle Oligocene unconformity, but were unable to keep up with the rapid transgression of the Late Oligocene/Early Miocene.