STRUCTURAL EVOLUTION IN THE LATE MIOCENE AND ITS INFLUENCE ON THE TRAP FORMATION IN SOUTH SESULU AREA EAST KALIMANTAN PROVINCE

• Main Author: Andika Setiawan, Diky
• Format: Theses
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/41491
• Institution: Institut Teknologi Bandung

Effort to fulfill the needs of oil and gas are increasingly demanding company engaged in order to strive to increase oil and gas reserves through exploration and production. Exploration activity is the beginning of the cycle in oil and gas industry which is related to the concept and technology. Exploration activities include evaluation of source rock, hydrocarbon migration time, reservoir rocks, seal presences and evolution of geological structures that determine the time of trapping hydrocarbons. Location of research is taking place in the South Sesulu working area which is located at the offshore of East Kalimantan.. There are many oil and gas fields encountered surrounding the area of study. This block is operated by PT. Saka Indonesia Sesulu as a subsidiary of Perusahaan Gas Negara (PGN) which is engaged in the upstream industry. The location of research area in the southern part of the basin boundary Kutei give a different geological characteristics from the central part of the Kutei Basin. Structural geology framework in this region is characterized by the presence of the fault trend with northwest-southeast orientation direction nearly perpendicular to the trend of the geological structure in the center of the Kutei Basin. The distribution of Late Miocene sedimentary basin is controlled by the basin configuration that was formed as a result of a manifested tectonic activity that occurred at the end of the Middle Miocene. Key surfaces in stratigraphic framework is guided by biostratigraphy data that is tied to the seismic so that the distribution of sediments can be controlled properly. In the study area, there are several faults with northwest-southeast and northeastsouthwest orientation and east-west and the northeast-southwest orientation of fold structure. Structures that developed in the study area has a different movement history over geological time. In this research will be a discussion about the evolution of the structure during the Late Miocene. Northwest- southeast trending normal faults are a local manifestation of a large tectonic events that occurred during the Miocene. The structure of the northwest-southeast trending is initially a normal fault which then it was reactivated later on and it changed its status to a dextral strike-slip fault. The formation of a northwest-southeast trending normal faults is strongly associated with regional tectonic events. It was interpreted that reactivation of some faults in Adang fault zone, causing a change in status of the northwest-southeast trending fault become strike-slip. A contemporaneous folds zone was formed within Jumelai structure domain.