Publications

The Abadi Field, located in the offshore Bonaparte Basin in the eastern part of the Timor Sea in eastern Indonesia, contains a significant gas column within the Middle Jurassic reservoir interval. Based on the biostratigraphy and sequence stratigraphy study of the Abadi wells, it is confirmed that the Middle Jurassic consists of three formations such as Lower Plover, the lower to middle part of the Upper Plover, and the upper part of the Upper Plover Formation equivalent to the Elang Formation in Sunrise Giant Field in the offshore NW Australia and Bayu Undan Field in the offshore Timor Leste. However, in the Abadi Field, for the purpose of reservoir characteristic evaluation, the Plover Formation is subdivided into 5 stratigraphic units (A-E) by using additional well log analysis to check each of the signatures (Shikama et al, 2018). The incised valley deposit can be observed in Zones C and D. The Ichnofabric analysis was performed for a better understanding of the paleodepositional environment. The results of the Ichnofacies analysis indicate that the Abadi Field sedimentary system is dominated by a marine to brackish delta coastal, possibly traversed by channels (Shikama et al, 2018). In general, the morphology of ichnofossil in brackish water environments is rather simple and its diversity is generally low. The Abadi cores exhibit predominantly marine ichnofossil aggregates, whereas the characteristics are small and dominated by morphologically simple structures. The characteristic sandstones in this marine-to-brackish environment range from fine to very fine grains are carboniferous-rich with lack of prominent wave or tidal sedimentary structures observed in the cores. This indicates relatively low-energy environments such as tide-dominated estuaries i.e., incised valley systems. The system suggests a protected embayment marine that may be like the modern analog of Norton Sound on the west coast of Alaska or Chesapeake Bay along the east coast of the United States. This core showcase will introduce the detailed characteristics of the incised valley deposit of the Upper Plover Formation in one of the Abadi well and its reservoir characteristics potential by using the sequence stratigraphy analysis conducted by the Abadi Field Subsurface Team which was presented in the IPA Core Workshop in 2018 (Shikama et al, 2018).