ANALYSIS OF SOURCE ROCK AND DISTRIBUTION OF CO2 GAS IN SUNDA BASIN

• Main Author: Sari, Andam
• Format: Theses
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/74382
• Institution: Institut Teknologi Bandung

Sunda Basin has been proven as prolific source for oil and gas in the area. Nearly forty years, oil development and production has become the main interest. However as the oilfields is getting old and mature, the focus now is shifted to the development of gas discovery. Risk analysis in the development of both oil and gas field is very essential and important cause it can give a significant impact on project economic and eventually can lead to managerial decision to whether or not develop the field. In the gas field development, one of the risks is the existence of impurities such as H2S and CO2. H2S content in gas accumulations in Sunda Basin is known to be quite low but the CO2 content is in wide range, 1 - 48%. Based on this situation, it is important to understand the source and characteristic of CO2 gas in Sunda basin and furthermore to know what factors are controlling the content and distribution of CO2 gas. Gas characterization was carried on based on the stable isotope of 13C of gas CO2, CH4 dan C2H6 to know if the gas is originnaly come from organic or inorganic material and formed under biogenic or thermogenic condition. The study shows that CO2 gas is organic and thermogenic. Correlation between CO2 concentration and factors such as depth and thickness of source rock were performed to know what factors are controlling CO2 distribution in the basin. Banuwati shale has been widely known as hydrocarbon source rock for oil and gas accumulations in Sunda basin, including CO2 gas. Meanwhile, CO2 distribution indicates an enrichment of CO2 in Gita level. Gita coal is suspected to be another source of CO2 gas. Hydrous pyrolysis of Gita coal is showing the ability of the coal to produce CO2 gas. CO2 content which is getting lower in the shallower structure within Gita Formation indicates structure is controlling the concentration and so does the coal thickness.