Publications

Tectonically, reservoirs in Indonesia cannot be separated from the influence of volcanic activity. This has occurred consecutively since subduction activity started in the Late Cretaceous. This relationship between volcanic activity and reservoir quality can be seen in the Sambipitu formation, western Pegunungan Selatan physiographic zone. The lithology of the Sambipitu formation consists of andesite breccia, pebbly sandstone, lithic arenite, siltstone, claystone, and wackestone where there is a gradual change from volcanogenic silisiclastics to carbonates. The lithology of Sambipitu Formation mineralogically is composed dominantly of plagioclase and ash. This study uses field mapping and analytical petrography methods. Field mapping is used to map the distribution of volcanogenic rock. Meanwhile, analytical petrography determines reservoir characteristics based on its mineralogy consisting of volcanic ash and clay minerals derived from plagioclase. This composition directly influences the porosity and permeability of the reservoir. This study shows how lithological composition derived from volcanic activity can influence the quality of reservoir, specifically with regard to its porosity and permeability. Keywords: Volcanic activity, reservoir characteristic, volcanic ash, clay minerals.