Publications

The results from core and wireline log analysis of the West Kerendan-1 (WK-1) exploration well shows that parts of the carbonates complex consists of interlayered reservoir-quality grainstone and wacke-packstone units and depicting influence of high-to-low energy fluctuations in shallow to near-shore environment. Petrographic and SEM analysis also indicates rather persistent presence of clastic materials which suggesting a land-attached setting that allows to provide a continuous terrestrial influx into the carbonate shoal systems. Integrated re-interpretation supported with the new datasets confirms the Kerendan Platform as a complex of open platform carbonates that comprised of coral build-up clusters in deeper area and carbonate shoals developed episodically in shallow water area during high-energy as washover deposits and the terrestrial influence becoming more dominant during low-energy periods. Reservoir facies lateral trends distribution may extend extensively following the NE-SW Greater Kerendan platform structural high. Diagenesis has controlled the porosity development in the carbonate platform and introduced the development of secondary porosity by: (1) non-fabric selective microporosity through burial leaching and dolomite replacement, and (2) intercrystalline microfractures. C-O isotope analysis indicates the burial leaching and dolomite replacement were associated with increasing-temperature trend during burial settings where acidic fluid being funneled from compacting basinal shales into the platform interior. Latter diagenetic sequence associated with cooling-temperature trend introduces fracture and micro-fracture porosity during tectonic uplift and basin inversion episodes. Based on the observations seen in the Kerendan field, the new exploration and development paradigm of the Oligocene carbonate platform has been expanded from “reefal” build-up into multi-layered carbonates platform with extensive lateral extent and enhanced secondary porosity from structural overprint. Keywords: Oligocene carbonate platform, Central Kalimantan, land-attached-oligophotic, interlayered reservoir, C-O isotope analysis, burial and uplift induced secondary porosity.