PORE PRESSURE PREDICTION AND OVERPRESSURE GENERATING MECHANISM IN SANGA SANGA AREA, LOWER KUTAI BASIN

• Main Author: ALFA TETELEPTA , STEFENSON
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/31078
• Institution: Institut Teknologi Bandung

This research is located at Sanga Sanga Area, Kutai Basin, East Kalimantan. This research aims at estimating overpressure zone and its generating mechanism in the study area. The data used in this research come from 7 wells in the Sanga Sanga Field, consist of drilling report containing pore pressure information and well log data. <br /> <br /> Result of the analysis shows that there are two overpressure zones in the study area, i.e. overpressure transition zona and high overpressure zone. The depth distribution of the overpressure zones is controlled by distribution of lithology in the overpressure zone and its position relative to structural geology. The sandier the environment, the deeper the top of overpressure; and the closer to the anticlinal crest, the shallower the top of overpressure. <br /> <br /> The burial history analysis shows that the presence of overpressure transition zone is caused by rapid burial in that zone. The clay mineralogy and source rock maturation analysis show that smectite to illite transformation and kerogen transformation into hydrocarbon contribute to the overpressure generation in high overpressure zone. <br /> <br /> The transition zone can be identified by constant sonic log value in that zone, while the high overpressure zone is characterized by deflection of sonic log into high sonic value. The sonic log could be inferred from seismic data. As a consequence, mapping of both overpressure zones in the future could be performed by using seismic data for the area where the well data are unavailable.