The Geothermal Conceptual Model and Resource Assessment of the Shamao Mountain Geothermal Potential Area in the Tatun Volcano Group (TVG), Taiwan

Renewable energy is a sustainable and clean with no (or very few) carbon dioxide emissions. Geothermal energy is a renewable energy, it uses the geo-heat from the Earth and can generate a base-load electricity. Taiwan aims to achieve zero-emission by 2050. For this target, geothermal energy plays a crucial role to help Taiwan make the goal of zero-emission electricity possible.

Taiwan, located at the Pacific Ring of Fire, has abundant geothermal resources. The estimated conventional geothermal potential in Taiwan is about 989 MW. In which, The Tatun Volcano Group (TVG) in northern Taiwan has the most conventional geothermal potential of over 500 MW. The investigation and development of geothermal resources in the Tatun Volcano Group is important for the development of Taiwan's geothermal energy.

The purpose of this study is to conduct a geothermal resource investigation in the Mt. Shamao area a located in the Tatun Volcano Group in order to apply the information for the next-step exploration well drilling. This research establishes a three-dimensional geothermal conceptual model by geothermal geological surveys and estimate the geothermal resources based on the developed conceptual model.

 

This study primarily involves initiating field geological investigations to explore the lithology of the geothermal reservoir and potential structures and fractures in the Mt. Shamao area. Based on the rock types recorded during field geological investigations and subsurface geological interpretations, we aim to establish a geothermal conceptual model for the region. Additionally, a three-dimensional geothermal geological model will be developed for heat storage assessment.

Field investigation is used in this study to explore the lithology of the targeted geothermal reservoir as well as the potential structures and fractures in the Mt. Shamao area. By combining the findings from the field investigation and the subsurface geological interpretations from the neighboring existed deep wells, the geothermal conceptual model is established. All information is integrated in a 3-D model built in the GOCAD simulator. Based on this 3-D model, the geothermal resources is estimated by a numerical simulator, CMG STARS.

 

The geological model of Mt. Shamao area is built  based on  previously and newly reconstructed geological profiles, lithological well logs, DEM data, regional fracture and structural lineament data, and lithofacies descriptions in the field. This area is characterized by numerous high-angle faults, which may serve as effective geothermal conduits. The geological model shows andesite of about 750 meters overlying sandstone-rich formations in the Mt. Shamao area. From the temperature records of nearby deep wells, the highest temperature is in the andesite reaching 174°C, and the maximum temperature is 240°C found in the sandstone formation.

Based on the constructed geological model and the temperature log of existed wells, the natural state model for the Mt. Shamao area is established from the numerical simulation method. The storage heat capacity is estimated for the area of about 12 square kilometers with the thickness of 5 km. By considering the development period of 20 years, the estimated power potential of Mt. Shamao area is over 200 MW from the volumetric method.