OVERPRESSURE CHARACTERISTIC ANALYSIS BASED ON WELL DATA IN TUNU FIELD, KUTAI BASIN, EAST KALIMANTAN

• Main Author: Fauziah Auliawati, Anis
• Format: Final Project
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/82123
• Institution: Institut Teknologi Bandung

Tunu Field, situated in the Kutai Basin, is one of Indonesia's productive hydrocarbon fields. Previous studies reported the presence of overpressure zones in this field. This research was conducted to enhance the understanding of overpressure characteristics, including the depth of the top of overpressure, pore pressure estimate, overpressure generating mechanism, and the relationship between the presence of overpressure and the stratigraphy. This study utilized data from five wells (Y-11, X-ST1, X-1, X-27, and X-38) consisting of log data, pressure tests, mud weight, and drilling reports. Pore pressure estimation in this study was performed using the Eaton Method. The findings show the deepest top of overpressure is at Well Y-11 at a depth of 3600 mSS, whereas in the other four wells, the top of overpressure is at 3100 mSS. The pore pressure gradient is between 5.47 psi/ft and 11.8 psi/ft. Overpressure in Tunu Field is generated by both loading and non loading mechanisms. The depth of the top of non loading overpressure in Well Y-11 is 3800 mSS, whereas in the other four wells, it is 3250 mSS. The difference in the top of overpressure between Well Y-11 and the other wells may likely be related to the depositional environments controlling sediment supply and the thickness of the shale in each well.