Geochemical analysis of shale gas reservoir based on well log and 3D seismic data in Pematang formation, Central Sumatera Basin

In terms of the log response, in particular zones, shale will have very high gamma ray response and high resistivity. In order to become a good reservoir, there are several criteria that must be met, such as Total Organic Carbon (TOC), the level of maturity (Ro), the thickness, permeability, mineralogy, fracture rate, and pore pressure. The intention of the paper is the evaluation of the content of TOC of Pematang Formation, Central Sumatera Basin, which was performed by using wire line logs data. In this evaluation, the data was calibrated to laboratory analysis. The study was conducted at three wells covering Pematang Formation, and calculations were performed on Pematang Brown Shale. The TOC calculation is determined by multivariate regression method in which the results show more representative prediction when validated to the well that has TOC data. From the three wells, the available geochemical data from PM-I is used as a reference for correction of the log data. Our calculation shows that TOC content of Brown Shale Formation is ranging from 0.26 wt% to 4.74 wt%, which is classified as poor to very good quality.