BONJOL GEOTHERMAL TENTATIVE MODEL BY USING 3G (GEOLOGY, GEOCHEMISTRY AND GEOPHYSICS) ANALYSIS
| Main Authors: | Helen, Aghi Savero, Joni, Wiwid, Wibowo, Paulus Febrianto Pandu, Pratama, Arisa Wahyu |
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| Format: | Proceeding PeerReviewed application/pdf |
| Bahasa: | eng |
| Terbitan: |
, 2019
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| Subjects: | |
| Online Access: |
https://repository.ugm.ac.id/275734/1/C037UNO.pdf https://repository.ugm.ac.id/275734/ |
Daftar Isi:
- Geothermal exploration is rapidly done in Indonesia. One of Indonesia prospect is Bonjol Geothermal area, West Sumatera. In order to develop geothermal indirect use (power plant energy source) in this area, we need to understand its geothermal system by built a tentative model from integrated 3G data. Geological analysis use Landsat 8 band thermal, alteration map and geological map. Landsat 8 band thermal used to determine vegetation density (normalized difference vegetation index transformation) and also surface temperature structure. Geological map used to locate major structure and lithology distribution as boundary of geothermal system. Fault and fracture density (FFD) map from DEM SRTM analysed using lineament pattern related with fault and fracture. Alteration map using spectral value of mineral used to understand geothermal system indication. Geochemical analysis use hot spring manifestation (neutral pH hot springs with temperature ranging from 49.7 ̊C to 87.9 ̊C.) to characterize geothermal system type and determine reservoir temperature. Chloride type of hot spring manifestation indicate a hot water dominated system. Geophysics analysis use 13 sites of magnetotelluric (MT) time series data. Processed by Fourier transform, robust processing, and crosspower selection. The MT data is not rotated referring to its geoelectrical strike (0 ̊). Then the data inversed to become 2D MT resistivity model. Subsurface condition imaged by magnetotelluric 2D resistivity model, it shows Bonjol’s cap rock and reservoir distribution and geometry also indication of structure. The subsurface alteration and structure distribution generated using surface structure and alteration map. Subsurface isothermal model generated by using geochemistry model. We integrate geology, geochemistry and geophysics data to build Bonjol tentative model.