| Title | Insight into the geothermal structure in Tatun volcano group, Taiwan |
|---|---|
| Authors | C. Chen, P. Lee, C. Lin, L. Tong, T. Guo, W. Lin, M. Chen |
| Year | 2023 |
| Conference | New Zealand Geothermal Workshop |
| Keywords | Geothermal Structure, Tatun Volcanic Group, 3D Inversion, Database, Conceptual Model |
| Abstract | The Tatun Volcano Group (TVG) which is known as the highest temperature geothermal field in Taiwan. There are four geothermal potential areas named Beitou, Matsao, Shi Huang-Ping and Chinshan. The government conducted exploration activities in the late 1960s focused on these areas. The highest drilling temperature encountered, nearly 290 ℃ at the Matsao area at a depth of less than 2 km, implies there is a commercial temperature for power generation. However, the geothermal development has been suspended due to a high acid content and highly corrosive fluids. Last decade, some review and exploration activities raised the possibility of finding neutral brine and developing geothermal generation at TVG. This study integrates previous research studies and newly completed geological, geophysical and geochemical surveys to establish a geothermal conceptual model of the TVG. The deep hydrothermal fluid along the extensional fracture is one of the primary heat sources in TVG that meets the criteria of high temperature and neutral geothermal brine based on E208 drilling data. Based on the MT 3D resistivity model, a total of 5 low resistivity areas that could be the possible clay cap are proposed. The low-resistivity is located at the bottom of the volcanic rock body, and the resistivity, as low as 10 ohm-m, is consistent with the mineral character of smectite, illite, and chlorite. All the data mentioned above was transformed into digital form and combined with the TWD97 projection system. Finally, a digital 3D geothermal conceptual model based on Leapfrog geothermal was established. There are some areas with high temperature and low acid fluid in the TVG area, from the perspective of the geochemistry view. However, the new proposed potential areas need further confirmation by the drilling of an exploration well. Applying developed volcanic activity observation techniques to monitor environmental changes while conducting geothermal surveys can ensure the safety of future geothermal development efforts. |