Publications

The Sebatik PSC, operated by Star Energy, is situated in the northern part of the Tarakan Basin, North Kalimantan Province close to the border with Malaysia. The PSC lies mainly in shallow water but also includes parts of Nunukan and Sebatik Islands in the north and goes beyond the shelf break in to deeper water to the east. The discovery of Badik by Anadarko in 2010 has opened up a new phase of appraisal drilling in the shallow water area of the Tarakan Basin. This discovery lies some 40 km south of, and within the same structural compartment as the nearest offshore prospects identified in Sebatik PSC. The pay sand in Badik is believed to be Late Miocene and Pliocene in age. One of the geological challenges within the area is the difficulty in correlating stratigraphic units with biostratigraphic data. This leads to problems in calibrating seismic using well data. The purpose of this study is to establish a stratigraphic correlation of well data and therefore facilitating the prediction of reservoir targets in prospects already identified from seismic interpretation. In order to achieve this, a new approach using the INPEFA Log Transform technique has been applied. The main interest of the study was the reservoir targets within the shallow water area of the PSC. The INPEFA Log Transform technique, developed by ENRES, is a method based on climate stratigra-phy creating real surfaces and depositional trends according to pattern recognition. Climate stratigra-phy is based on the principles of global cyclostratigraphy which develops the idea that climate change goes through recognizable and predictable patterns, and that lithofacies variation can be predicted from these patterns. From the identification of 16 stratigraphic packages covering the Miocene to Pleistocene section it was possible to create a high resolution stratigraphic correlation in the Sebatik area. The study shows that there is a reasonable correlation between stratigraphic and biostratigraphic data. The evaluation of res-ervoir-seal quality based on the result of this study has also been determined. The results suggest that potentially the best reservoir capacity can be expected in the Late Miocene and Pliocene sedimentary section.