A Preliminary Sedimentological Approach of Analog Reservoir with Darcy’s Methods and Thin Section Analysis: Case Study of Walat Formation, Sukabumi, West Java

Sedimentology study provides a detailed insight about rock properties and depositional history. The study is particularly applied to find the potential rock properties, such as porosity and permeability, which plays a significant role in determining a good reservoir form where the commercial flows of hydrocarbon can be produced. The study is located on Walat Formation, Sukabumi, West Java and the evolution of the fluvial basin has been occurred since Oligocene epoch. The objective of this study is to examine the analysis of sedimentology based on the measured section in Walat Formation where the analysis is expected to explain the depositional system as well as the rock properties from the sample. Data are collected from field geological mapping, measured section, and direct sampling. Facies association based on the lithofacies analysis shows that the environment is controlled by fluvial depositional system which supports the occurrence of the continuity reservoir, and it has a similar characteristic in Talang Akar Formation as the analogue. The depositional history is investigated from the early research that shows that Walat Fm. was controlled by relatively low sea level along Paleogen and the global climate changes conditions at the Eocene-Oligocene. Proportion of coarser materials facies relatively increase in each succession in channel system. Darcy method and thin section analysis’ result demonstrates that both of the properties confirm the capability of the rock to contain hydrocarbon. Therefore, Walat Fm. can be considered as a good potential reservoir and further study is recommended to conclude the prospect of the field.