PROCESSING AND INTERPRETATION OF SUBSURFACE MODEL OF THE KAMOJANG GEOTHERMAL FIELD BASED ON GRAVITY DATA
The Kamojang geothermal area in Garut Regency has geothermal indications characterized by the appearance of hot springs and fumaroles. Therefore, research was conducted to find out the subsurface model of the Kamojang geothermal field system. In this study, an analysis of the gravity method was c...
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| Format: | Final Project |
| Language: | Indonesia |
| Online Access: | https://digilib.itb.ac.id/gdl/view/65805 |
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| Institution: | Institut Teknologi Bandung |
| Language: | Indonesia |
| Summary: | The Kamojang geothermal area in Garut Regency has geothermal indications characterized
by the appearance of hot springs and fumaroles. Therefore, research was conducted to find
out the subsurface model of the Kamojang geothermal field system. In this study, an analysis
of the gravity method was carried out which started from data processing in the form of
observational gravity which was the result of measurements by the ITB Geophysical
Engineering and Environmental in 2006 until a Complete Bouguer Anomaly was obtained.
The complete Bouguer anomaly value of the Kamojang geothermal area has a range of 25.5
mGal to 40 mGal. Then anomaly separation is carried out with moving average filter,
Butterworth filter, and SVD Elkins operator filter. The obtained values of regional and
residual anomalies have the same range and predisposition. Furthermore, forward modelling
was carried out with a background density of 2.5 gr/cc that obtained from the estimation of
the average density near the surface using the Parasnis method. The results of forward
modelling for subsurface of the Kamojang geothermal area on two line have similarities in
showing the presence of layers which is corresponding to geological maps where high
anomaly values come from the intrusion of igneous rocks with a density contrast of + 0.2 gr/cc
and some location of low anomaly values cause by irregularity of layering due to the active
geological structures. Inversion modelling is carried out based on the result of forward
modelling with the iteration is carried out using the algorthms of Occam and Marquardt. The
results of the inversion modelling show the similarity of layering patterns as in the forward
modelling results. Based on the result of the study, the reservoir is located at a depth of 100
until 600 m and 700 until 900 m above sea level with an upflow zone estimated to be in the
east direction of the study area. |
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