GEOTHERMAL SYSTEM MODELLING BASED ON GRAVITY DATA OF NAGE GEOTHERMAL FIELD, EAST NUSA TENGGARA, INDONESIA

• Main Author: Akbar Widianto, Fikri
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/67997
• Institution: Institut Teknologi Bandung

Energy plays an important role in the utilization of various human activities today. Energy needs in Indonesia and the world are increasing over time. To fulfill energy needs, potential resources are targeted by considerating environmental impacts as an effort to reduce carbon emissions. Currently, the government is targeting the achievement of the energy mix of 23% of new and renewable energy in 2025 and 31% in 2050. To achieve this target, the use of geothermal energy as a potential resource, exploration and exploitation of geothermal areas must be improved. The Nage Geothermal Area in East Nusa Tenggara is one of the areas with geothermal potential with a pattern of spreading volcanic activity on the island of Flores. This study aims to determine the conceptual model of the geothermal system that develops in the Nage geothermal field. This research was conducted based on gravity observation data conducted by the Tim Survei Terpadu Panas Bumi Nage in 2017 obtained from Pusat Sumber Daya Mineral Batubara dan Panas Bumi (PSDMBP). The research was conducted to obtain the Complete Bouguer Anomaly (CBA) value of the Nage geothermal field. The results obtained from CBA data processing in the form of a Complete Bouguer Anomaly map with anomaly ranges using the density obtained from laboratory research results the average density of rocks is 2.51 gr/cm3. Then the regional and residual anomalies are separated using the Moving average and Second Degree Polynomial methods, which the window width is determined by performing a 1-D spectral analysis. The anomaly results using the Moving average method shows that the high anomaly distribution is in the middle, the low anomaly is in the north and south, and the low anomaly is in the west and a small part of the north of the research map. Furthermore, 2.5D modeling that passes through geothermal manifestations and zones of interest shows that high anomaly values can be indicated as intrusive rock which may act as a heat source.