Publications

Four wells (ITB-URC-1, ITB-URC-2, ITB-URC-3, and ITB-URC-4) have recently been drilled into the Rajamandala Limestone outcrops at Cikamuning and Batu Nunggal, Bandung area, West Java, Indonesia. By integrating the core description results with the outcrop geometries, and comparing these results with several as subsurface carbonate reservoirs of the Cepu Block we can better understand the controls on reservoir quality in the subsurface. The aim of this study is to characterize the sedimentology, petrography, and sequence stratigraphic architecture of this intricate Oligocene exposed carbonate as an analogue for the Tertiary subsurface reservoirs of Southeast Asia. Characterizing the facies and stratigraphic framework of this formation can play an important role in better understanding the heterogeneity of carbonates in the region.Three environments of deposition (platform interior, platform margin and slope) and seventeen facies types have been identified from the 1150 feet of core based on grain composition, sedimentary texture and field geometry. For consistency, the core description was carried out with similar standards and procedures as the previously described cores from the Cepu Block (Sekti et al., this volume). The facies range from autochthonous (characterized by corals in growth position (platy, branching, and massive corals) and shallow water benthic foraminifera) to allochthonous (characterized by abundant planktonic and redeposited shallow water benthic foraminifera) representing the three EOD.The sequence stratigraphy suggest an early aggradational (early highstand) to progradational (late highstand) platform margin and interior, followed by erosion (lowstand and sequence boundary) prior to onlap of slope deposits on the previous deposited prograding platform margin. The synthetic seismic model identified the main geometries and EOD and the comparison with Cepu examples highlight challenges in subsurface interpretation. The Rajamandala outcrops studied are of seismic scale and thus provide vertical and lateral correlations that help to refine sequence stratigraphic and facies models and aid in the understanding of reservoir geometry distribution and reservoir continuity in the subsurface.