THE APPLICATION OF GEOLOGIC LINEAMENT EXTRACTED FROM DUAL ORBIT SAR IMAGES FOR FLUID FLOW PATH DETECTION AND CHARACTERIZATION IN GEOTHERMAL SYSTEM

• Main Author: Brahmanta Aulia, Ahmad
• Format: Final Project
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/39004
• Institution: Institut Teknologi Bandung

The limited nature of subsurface imaging data in geothermal field makes surface data important to infer subsurface geologic conditions. One of the main geologic features that can be extracted from surface data is lineament which can be attributed to fractures, including joints and deep-seated faults. Fractures play a dominant role in the creation of porosity and permeability that allow the storage and flow of thermal fluid in geothermal reservoirs. Therefore, it is important to characterize rock fractures and model the flow of thermal fluid through them to better understand the geothermal reservoir. This study evaluates the application of lineaments extracted from dual-orbit Synthetic Aperture Radar (SAR) images acquired by the Phased-L Synthetic Aperture Radar (PALSAR) sensor on the Advanced Land Observing Satellite (ALOS) as input for fracture modeling to reservoir simulation in geothermal field. The SAR images were acquired from the Geureudong area in Aceh. Lineaments were extracted automatically from SAR images using modified Segment Tracing Algorithm (mSTA). Noise filtering and edge enhancement algorithms were applied to the SAR images prior to mSTA to optimize the extraction of geologically significant lineaments. The extracted lineaments were spatially analyzed to create lineament density map, lineament length density map, lineament intersection density map, and lineament direction rose diagram. Representative rock fracture model with vertical dip angle was created from the extracted lineaments and was assigned with reservoir properties, including permeability and porosity. Fluid flow was simulated through the model to detect flow path and to characterize fluid flow. Spatial analysis of the extracted lineaments showed good correlation with the trend of geological structures and thermal manifestations observed in the field. The simulated fluid flow path showed good agreement with the spatial distribution of geothermal manifestations. Simulation results showed strong correlation between fluid flow charactersitics to the geometry of the fractures represented by the extracted lineaments.