17:15 〜 19:15
[SVC35-P01] Thermal-Hydrological Analysis of the Lushan Geothermal Area, Taiwan, Using Coupled Numerical Simulations
キーワード：2050 Net-Zero Emission, Geothermal energy, Lushan geothermal area, Thermal-hydrological coupled simulations
In response to the growing environmental, ecological, and energy challenges posed by climate change, numerous countries have pledged to achieve net-zero emissions by 2050. Aligning with this global initiative, the Taiwanese government announced "Taiwan's Pathway to Net-Zero Emissions in 2050" in 2022, accompanied by the "Twelve Key Strategies" to facilitate the nation's low-carbon energy transition. Among the key strategic initiatives, the development of advanced energy sources is also prioritized in addition to the continued expansion of renewable energy. In this context, deep geothermal energy has been identified as a critical component of Taiwan's future energy portfolio.
Despite Taiwan’s relatively small land area of approximately 36,000 km², its location along the circum-Pacific volcanic belt provides significant geothermal potential across various geological settings, including volcanic high-temperature systems, extensional crustal zones, sedimentary basins, and uplifted hot rock formations. To date, ten geothermal potential zones have been identified, with geothermal gradients reaching up to 50 °C/km and downhole temperatures in the Lushan geothermal area recorded as high as 170 °C. While extensive geophysical and geochemical surveys have facilitated the development of geothermal geological conceptual models, these models remain largely unverified through numerical simulation.
This study investigates the Lushan geothermal area through thermal-hydrological coupled numerical simulations to better understand the region’s geothermal characteristics. The study site consists of three deep wells (CPC1–CPC3, with depths ranging from 262 to 1020.5 m) and six shallow wells (NL-1A and NL-2 to NL-6, with depths between 300 and 550 m), with the NL-2 well yielding approximately 50 tons per hour of geothermal fluid. The Miocene-aged Lushan Formation dominates the geological setting, which primarily consists of slate interbedded with metamorphosed sandstone. The area is structurally complex, intersected by high-angle faults trending N10W and N35E and strike-slip faults trending N20W and N80W. Notably, the primary geothermal production zones are located within metamorphosed sandstone units associated with dense strike-slip fault networks, which likely enhance fluid flow and permeability.
A three-dimensional geothermal geological conceptual model was constructed based on available geological and geophysical data, and thermal-hydrological coupled simulations were performed using COMSOL Multiphysics. Model calibration was conducted using temperature data from deep wells (CPC1–CPC3). The simulation results indicate that while deep circulation of geothermal fluids plays a role in the region’s thermal regime, this mechanism alone does not fully account for the observed downhole temperature distribution. Additional constraints, particularly regarding temperature boundary conditions and heat flux, are required to reproduce the subsurface thermal structure accurately.
Future research will focus on parameter sensitivity analyses to identify the key hydrogeological and thermal parameters governing the geothermal system in Lushan. Additionally, we will estimate the geothermal production potential of the region based on numerical simulation outcomes and compare these estimates with observational data to validate the credibility of the geothermal geological conceptual model. These findings will contribute to developing deep geothermal resources as part of Taiwan’s long-term energy transition strategy under the 2050 Net-Zero Emissions Pathway.
Despite Taiwan’s relatively small land area of approximately 36,000 km², its location along the circum-Pacific volcanic belt provides significant geothermal potential across various geological settings, including volcanic high-temperature systems, extensional crustal zones, sedimentary basins, and uplifted hot rock formations. To date, ten geothermal potential zones have been identified, with geothermal gradients reaching up to 50 °C/km and downhole temperatures in the Lushan geothermal area recorded as high as 170 °C. While extensive geophysical and geochemical surveys have facilitated the development of geothermal geological conceptual models, these models remain largely unverified through numerical simulation.
This study investigates the Lushan geothermal area through thermal-hydrological coupled numerical simulations to better understand the region’s geothermal characteristics. The study site consists of three deep wells (CPC1–CPC3, with depths ranging from 262 to 1020.5 m) and six shallow wells (NL-1A and NL-2 to NL-6, with depths between 300 and 550 m), with the NL-2 well yielding approximately 50 tons per hour of geothermal fluid. The Miocene-aged Lushan Formation dominates the geological setting, which primarily consists of slate interbedded with metamorphosed sandstone. The area is structurally complex, intersected by high-angle faults trending N10W and N35E and strike-slip faults trending N20W and N80W. Notably, the primary geothermal production zones are located within metamorphosed sandstone units associated with dense strike-slip fault networks, which likely enhance fluid flow and permeability.
A three-dimensional geothermal geological conceptual model was constructed based on available geological and geophysical data, and thermal-hydrological coupled simulations were performed using COMSOL Multiphysics. Model calibration was conducted using temperature data from deep wells (CPC1–CPC3). The simulation results indicate that while deep circulation of geothermal fluids plays a role in the region’s thermal regime, this mechanism alone does not fully account for the observed downhole temperature distribution. Additional constraints, particularly regarding temperature boundary conditions and heat flux, are required to reproduce the subsurface thermal structure accurately.
Future research will focus on parameter sensitivity analyses to identify the key hydrogeological and thermal parameters governing the geothermal system in Lushan. Additionally, we will estimate the geothermal production potential of the region based on numerical simulation outcomes and compare these estimates with observational data to validate the credibility of the geothermal geological conceptual model. These findings will contribute to developing deep geothermal resources as part of Taiwan’s long-term energy transition strategy under the 2050 Net-Zero Emissions Pathway.