New Insight of Surface and Subsurface Sedimentology of Salodik Group, Banggai Basin

Abstract

The research area is situated in the Eastern Arm of Sulawesi, Banggai Basin. The complexity of geological components in Sulawesi greatly affects the pattern of sedimentary rocks. Certainly, these conditions have implications of the petroleum system in this basin. The characterization of carbonate rock in the Banggai Basin requires the integration of multi-disciplines in order to conduct reservoir characterization on a detailed scale. This study focuses on integrating surface to subsurface sedimentology aspects to evaluate the reservoir characterization. The two methods are used to analyzed, the surface field observation and subsurface study. These methods will then be assisted by several methods, such as petrographic analysis, XRD and SEM, biostratigraphic analysis, and routine core analysis. The outcrop sampling is carried out in the northward and subsequently integrated with subsurface in the southward (Tiaka-Tiara Field). In the surface area, Tomori Formation has two part, Lower Tomori Formation is composed of Large Foram-Red Algae facies with deposited inner-middle sublittoral. Wherein, Upper Tomori Formation is composed of planktic-large foram packstone-wackestone with deposited Middle-Outer Sublittoral and skeletal packstone-wackestone with deposited Inner-Middle Sublittoral. Minahaki Formation is overlying of Tomori Formation, there are two facies namely large foram packstone-mudstone with deposited at Middle Sublittoral-Upper bathyal and skeletal packstone-wackestone with deposited at Inner-Middle Sublittoral. The youngest formation of the Salodik Group on the surface is Mentawa Formation where this member is reefal facies. On the subsurface, the Salodik Group consists of Tomori Formation, Matindok Formation, and Minahaki Formation. The Tomori Formation was deposited at Bathyal-Inner shelf with mudstone-grainstone facies and slightly dolomite. Younger than Tomori Formation on the subsurface is calcareous sedimentary rocks, known as Matindok Formation. The Minahaki Formation was directly overlying the Matindok Formation in the transgressive phase.