Numerical investigations and evaluation of a puga geothermal reservoir with horizontal wells using a fully coupled thermo-hydro-geomechanical model (THM) and EDAS associated with AHP

Puga geothermal reservoir in India gives promising results for the extraction of geothermal energy. On the other hand, no systematic studies were conducted to analyze the Puga geothermal reservoir's thermo-hydrogeomechanical behavior while heat extraction. Most of the researchers concentrated more on the geological and geophysical aspects of the Puga hot spring and provided basic geological data. This information is now being examined as input towards the construction of geothermal reservoirs. In this study, the THM model is enhanced by including additional dynamic fluid, rock, and fracture features, and an integrated assessment approach is anticipated to improve the heat extraction possibilities of the Puga geothermal reservoir. The variation in rock temperature in the vicinity of the production well is influenced less compared to the vicinity of the injection well. The low-temperature region is initially befalling in the vicinity of hydraulic fractures with high conductivity, flow rate, and strong heat convection further it extends to the rock matrix. Twelve injection-production scenarios were proposed for the Puga geothermal reservoir to extract heat energy with single and dual production wells and single injection well. Scenario-2 and scenario-8 are significantly showing high production temperatures when compared to other proposed scenarios. A multi-index-based evaluation system that consists of geothermal reservoir life, thermal breakthrough time, reservoir impedance, heat power, and heat recovery is employed to examine the geothermal extraction from the Puga geothermal reservoir. An integrated evaluation technique was projected for geothermal extraction which is created by coupling the analytical hierarchy process (AHP) and evaluation based on distance from average solution (EDAS) techniques. The performance of twelve injection production scenarios of the Puga geothermal reservoir are evaluated using the integrated evaluation technique. The results show that scenario-11 and scenario-9 were found to be the top two scenarios for the extraction of heat from the Puga geothermal reservoir. The results demonstrate that the proposed integrated evaluation system and improved THM model can be used for the evaluation of geothermal reservoirs effectively.