BANYUMENENG CALCICLASTIC SUBMARINE FAN (CSF) AS A LATE NEOGENE RECORD IN THE CURVATURE BORDER OF WESTERN KENDENG, JAVA: NEW SIGHT FOR EXPLORATION TARGET

摘要

This study aims to present an unusual depositional system reservoir target, called Calciclastic Submarine Fan (CSF) deposits. In the past, these deposits were thought to have poor porosity due to the poorly sorted grain size. Although these deposits have a diverse grain size, the potential thickness of these deposits cannot be underestimated, which indicates good reasons for CSF to be an exploration target, especially if the sand bodies have interconnected with each other and have been affected by their burial diagenesis. This study is located on Dolok River, Banyumeneng, Demak, Central Java. As a part of the Western Kendeng Zone, this location has a direct relation to the Sunda Shelf which may act as the largest sediment supply for the Kendeng Zone. The methods used in this study are measuring stratigraphy, petrography analysis, microfossil, weighted method for the porosity and also through the permeameter gas for the permeability analysis. From the 467m corrected measured stratigraphic section, there are 4 lithologies and there were grouped into several lithofacieses that consist of Graded Calciturbidite, Thin-bedded Calciturbidite, Conglomeratic Calciturbidite, Clast-supported Calciturbidite, Laminated Calciturbidite, Cross-bedded Carbonate Clastic, Hemipelagic Mudstone and Muddy Debrites. Based on lithofacies association, it showed that the depositional facies are Outer Fan to Outer Shelf. The results showed the Conglomeratic Calciturbidite can act as the best reservoir target based on its physical properties (5.61% porosity and 79.06 mD permeability) and the thickness (up to 4 m in a single layer). Thus, these CSF deposits could be the next play to be explored in Kendeng Zone.