SUBSURFACE GEOLOGICAL STUDY AND IMPLICATIONS ON THE CONCEPTUAL MODEL OF TOMPASO GEOTHERMAL FIELD
Tompaso Geothermal Field has two upflow zone. The upflow zones are located in Sempu Block and Umeh Block. Upflow zone in Umeh Block indicate high temperature, however this block has not been used for production area. Umeh Block will be drilled in 2023 to generate electricity 1 x 20 MW, nevertheless...
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| Format: | Theses |
| Language: | Indonesia |
| Online Access: | https://digilib.itb.ac.id/gdl/view/64059 |
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| Institution: | Institut Teknologi Bandung |
| Language: | Indonesia |
| Summary: | Tompaso Geothermal Field has two upflow zone. The upflow zones are located in Sempu Block and Umeh Block. Upflow zone in Umeh Block indicate high temperature, however this block has not been used for production area. Umeh Block will be drilled in 2023 to generate electricity 1 x 20 MW, nevertheless subsurface lithology characteristics and high permeability zone as drilling target in Umeh Block has not been determined clearly. Therefore, this research is expected to determine lithological characteristics, caprock thickness, reservoir depth and permeability control in Umeh Block. The result of this research will be used to make drilling program in Umeh Block. Geological evaluation results are combined with geochemistry, geophysical and reservoir data to update conceptual model of Tompaso Geothermal Field. Subsurface geological data evaluation using binocular, petrographic, X-Ray Diffraction (XRD) and Methylene Blue Test methods show argillic and propylitic zones at wells A and B in Sempu Block were found to be deeper than wells C and D in Umeh Block. Meanwhile, borehole images data evaluation shows productive fracture zone at well E in Sempu Block is controlled by matrix permeability and dominantly fractures with NE-SW and W-E directions, while at well D in Umeh Block is controlled by dominantly fractures with NE-SW direction. An integrated geoscience data evaluation show that Sempu Block and the Umeh Block have different components of geothermal system, with NW-SE geological structure as a boundary between them. Bottom of argillic zone or caprock in Umeh Block correlates with a resistivity value of 6 ohm-m, so the prospect area is estimated around 20 km² including medium-high temperatures. The maximum reservoir temperature in Umeh Block is around 300-325°, with NE-SW Totolan-Toraget as high permeability zone in Umeh Block. |
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