FAULT ARCHITECTURE ANALYSIS IN CARBONATE ROCK RESERVOIR, RAJAMANDALA FORMATION, CIPATAT - PADALARANG AREA, WEST JAVA

• Main Author: Nixon Jimawan, Owen
• Format: Final Project
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/42045
• Institution: Institut Teknologi Bandung

Limestone of the Rajamandala Formation is one of the units of rock that describes the process of developing Tertiary and Quaternary basins on Java, especially the Bogor Basin. The research area is located in Batununggal and Cikamuning which are geographically located at coordinates 06°50'47.5"S 107°24'38.1"E and 06°48'54.3"S 107°28'09"E. The aim of the study was to analyze the fault damage zone and fault core affected by the geological structure of normal faults in the study area. The methods used include description of rocks and observation of fault damage zone in Batununggal outcrop. Additional data in the form of clay content (CCR) in Batununggal outcrop and a number of other data for Cikamuning outcrop were obtained from the Geodynamic Research Group ITB. Data from the observations were analyzed to provide information about the fault architecture in carbonate rock complex. In observing the fault damage zone, fracture data showed that there were nine fracture sets in the fault damage zone in the outcrop with a normal fault, oriented NE-SW, in the Batununggal area. Fractures in the fault damage zone tend to be formed by local stress rather than regional stress. In addition, there is a significant similarity in fracture orientation in each facies along all fault damage zone. The fracture characteristic is influenced by facies type which is indicated by a significant difference in the density and spacing of fractures between its facies. Fracture density decreases with increasing fracture space when the fracture is away from the fault core. The highest density value of fractures (55.19%) is at the first 3 meters distance from the fault core. In the analysis of fault core, it can be seen that the permeability will be lower if the distance is closer to the core of the fault, unless the fault rock has undergone brecciation so that its permeability increases. Horizontal distance and sample position (foot wall or hanging wall) also have an influence on permeability values so that both of these factors need to be included in the approach to estimate rock permeability. The calculation of the transmissibility multiplier on Batununggal outcrop indicates that the fault will potentially leak the flow of fluid.