SOURCE ROCK CHARACTERIZATION AND CORRELATION WITH GAS BASED ON GEOCHEMICAL DATA IN PS FIELD, SOUTH SUMATRA BASIN

• Main Author: Septadenova Dwi Ananta, Pravito
• Format: Final Project
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/79736
• Institution: Institut Teknologi Bandung

The PS field is located in Musi Banyuasin Regency, South Sumatra Province. Geologically, the study area is included in the South Sumatra Basin. PS Field is one of the largest gas fields in Indonesia. The study aims to determine the organic geochemical characteristics of host rocks, determine the geochemical character of hydrocarbon gas, and interpret the correlation between host rock and hydrocarbon gas in the PS Field. Organic geochemical analysis was carried out on 61 samples which were selected based on TOC>1% values into 38 samples to determine the quantity/richness, type, and maturity of organic materials. Gas geochemical analysis used 4 gas samples consisting of compositional data carbon isotopes, and hydrogen isotopes to be correlated with source rocks based on their Formation type and depositional environment. Core samples studied came from the Lower Palembang, Telisa, Baturaja, and Lower Talangakar Formations. Geochemical analysis results show that Lower Talangakar Formation is an effective source rock, Lower Palembang Formation and Telisa Formation are potential source rocks, and Baturaja Formation is not potential to be source rock. Lower Palembang Formation has TOC content of 1.03-55.29%; S2 0.93-138.12 mg HC/g rock; kerogen type II-III; and immature. Telisa Formation has TOC content of 1.02-1.28%; S2 0.37-2.59 mg HC/g rock; kerogen type II/III-III; and immature. Baturaja Formation has TOC content of TOC 1.02 - 1.36%; S2 0.05-0.35 mg HC/g rock; type IV; and immature. Lower Talangakar Formation has TOC content of 1.23-1.66%; S2 0.2-0.66 mg HC/g rock; kerogen type III; and early mature. Based on gas geochemical analysis, hydrocarbon gas in the study area belongs to the same gas family, thermogenic gas type, non-associated gas, and condensate gas type. The maturity of the gas reaches the late mature level (1.0-1.35% Ro). The gas is produced from mixed organic materials, namely type II (marine sourced) and type III (coal sourced) originating from the Lower Talangakar Formation with a transitional-marine depositional environment.