Publications

The Central Sumatra Basin (CSB) is one of the most hydrocarbon prolific basins in Indonesia. Most of hydrocarbons are produced from the structural trapping of tertiary reservoirs. As these become more and more limited, basement reservoirs are possible alternatives to sustain the hydrocarbons production in the CSB. These reservoirs have become regionally one of the most important exploration targets, with several successful developments in western Indonesia. At a regional scale, the CSB has an estimated hydrocarbon capacity generative potential much larger than its identified hydrocarbon resources. While, the basement play is proven to exist in CSB, with the Beruk NE Field, which produced to date over 1.23 MMBO from its basement, and several other wells showing evidence of hydrocarbon occurrences in this reservoir, it is still considered underexplored.. The CSB basement play could reveal to be an important exploration target that could add significant amounts of easily accessible onshore hydrocarbon resources. The study consisted in an extensive review of worldwide basement reservoirs in order to define their key characteristics, with the final objective to define areas of interest to explore the Rokan Area basement. Basement reservoirs are found commonly in platform regions of elevated fault blocks, occurring beneath unconformities that record extensive periods of weathering and erosion. They are interpreted to be sourced by, overlying or flanking, younger source rock formations. The presence of a top seal is critical for trapping hydrocarbons, and understanding the seal distribution and capacity can reduce the risk of this play. Reservoir flow is dominated by fracture porosity and permeability of various origins, typically enhanced by leaching/weathering. Several diagnostic tectonic and lithologic subdivisions of the pre-tertiary basement underlying the CSB were recognized. The CSB basement is organied into four informal terranes: the Malacca, Mergui, Kluet, and Mutus terranes. These lithologies have different characteristic. Having complete drilling and testing data could help to better understand reservoir characterization of this reservoir. Accordingly, the objective of this study is to give a better understanding of basement reservoir characterization and its potential in CSB.