ORGANIC GEOCHEMISTRICAL STUDY ON SOURCE ROCK AND HYDROCARBON OF MOCCA AREA, SOUTH SUMATERA BASIN, INDONESIA

• Main Author: Argananta, Paksindra
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/40261
• Institution: Institut Teknologi Bandung

Mocca Area is located in the southern part of the South Sumatera Basin, Indonesia. Exploration drilling of the Baturaja carbonate reservoir objective in the Musi Platform continues, although the success rate appears to be declining in line with decreased opportunities to drill simple large traps. Since Baturaja and Talangakar reservoir production is declining, further exploration is needed to find new potential plays that may lead to new discoveries in this area. This study used 118 samples, consisting of the source rock samples of the Talangakar Formation,oil-gas samples from the Baturaja Formation and Telisa Formation. Crude oil characterization is based on GC, GC-MS, and carbon isotop. The type of natural gas and the origin of CO2 content are determined by carbon isotopes and detailed gas content. Migration paths can be indicated by seismic and depth map structures. Source rock from Talangakar Formation s rich of organic content and having kerogen type II-III/II. Based on the vitrinite reflectance of organic materials in wells SR-1, SR-2, and SR-3 are mature. There are two source rock facies, which are fluviodeltaic facies and shallow lacustrine facies. There are three crude oil families, they are crude oil family 1 that is dominated by higher plant organic content with few algae existency, crude oil family 2 has characteristics similar to family 1 but has a higher maturity level, crude oil family 3 that is dominated by mixed of terrestrial and algae organic contents, and family 4 has characteristics similar to family 3 but has a greater carbon isotope value. Methane content ?13CCH4 for hydrocarbon generation indicates that the gas is in the Mocca Field type thermogenic gas. The relationship between solving ethane and propane shows that the samples are mature thermogenic gases with equivalent maturity levels above 1.3% Ro. Carbon dioxide formed in the research area is formed from: organic carbon dioxide originating from the organic decomposition process, a mixture of organic and inorganic carbon. Correlations of crude oil and gas to the source rock is in positive and negtive correlation. Migration pathway of hydrocarbons leads vertically through the fault boundaries.