OVERPRESSURE DISTRIBUTION AND GENERATING MECHANISM IN PRB AND WCK FIELD, TARAKAN SUB-BASIN, EAST BORNEO

• Main Author: HARTANTO WICAKSONO (NIM: 22014331), PRABU
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/29951
• Institution: Institut Teknologi Bandung

The Tarakan Sub-basin is an oil and gas exploration target in Indonesia. One of the handicaps in drilling exploratory wells in this area is the presence of overpressure. In order to avoid negative impact caused by the presence of overpressure, a study comprising the presence, distribution, prediction, and estimation of overpressure is of paramount importance to perform. <br /> This study analyses overpressure characteristics as mentioned above. The data used in this study are drilling parameters, vitrinite reflectance, wireline log, and 2D seismic section. The results of the analysis show that the overpressuring in this area is controlled by its geologic condition. The rapid basin subsidence, in combination with rapid sedimentation and the presence of toe thrust fault are the geological processes responsible for overpressure generation in the study area. The temperature and vitrinite reflectance data show that clay diagenesis and hydrocarbon maturation can be ruled out as overpressure generating mechanism in stratigraphic intervals investigated in this study. The analysis also shows that the overpressure magnitude in the study are could be estimated by using the Eaton’s Method, by applying the Eaton’s exponent of 3 – 4.5 and 1.2, for sonic and resistivity logs, respectively.