Publications

A depositional model has been developed to explain and predict the reservoir distribution within the ",Main", interval of the Upper Cibulakan Formation in the ARC0 Indonesia Offshore Northwest Java (ONWJ) area. All the available biostratigraphic, conventional core, cuttings and well-logs data were integrated in this study. Geological workstation applications were extensively used.Biostratigraphic, wireline log and core data were integrated to establish regional isochronous ",packages",, which served as the primary tool for understanding, mapping and predicting reservoir distribution. Two major types of sandbodies occur in the ",Main", interval. The first type is sharp-based, bioturbated, glauconite-rich sandstone. The lower contact of these sands is commonly associated with a Glossrfungites surface and siderite mudclasts. Overlying and underlying mudstones are relatively devoid of burrowing. Well log derived net-sand isopach and seismic amplitude maps depict predominantly north-south elongate features that are 1-2 km wide and 5-8 km long. Sandbodies of the same age and similar facies were observed in outcrops in onshore West Java where they pinch out over a distance of 500 m. The lower bounding contact appears to be discordant with underlying interbedded sandstone and mudstone. This type of sandbody is interpreted to have formed in response to sea-level lowstand.The second type of sandbody is a middle to lower shoreface ",cleaning upward",, burrowed sandstone with a sharp upper-contact. The lower contact consists of burrowed, interbedded siltstones and mudstones. This type of sandbody tends to be laterally extensive and is correlative over inter-field distances (10's of km).Our understanding of reservoir geometry and sedimentologic characteristics is leading to a more effective exploitation strategy for these sandbodies. The reservoir distribution prediction away from areas of well control has become possible at both reservoir and regional scale in the ARII ONWJ area.