Thermal Treatment Effects on Physico-mechanical Properties of Deep Geothermal Reservoir Rocks of Chitral Region, KPK, Pakistan

This study aims to investigate the impact of heat treatment on the physical and mechanical properties of selected rocks. Effect of heat treatment on the physico-mechanical properties of selected Garam Chashma Pluton (GCP) and Kafiristan Pluton (KP) granites was analysed by heating them from 25-600 °C. Physical properties including porosity (n), resonance frequency (Fr), and dynamic Young's modulus (Ed), along with mechanical properties such as uniaxial compressive strength (UCS) and Brazilian tensile strength (BTS), were measured at each heat-treatment temperature. At 600 °C, increase in (n) of both the GCP and KP granites was 4.38 and 3.17 times respectively, relative to the (n) values at ambient temperature. Fr and Ed decreased with increase in temperature for both the granites. At 600 °C, Fr for both the GCP and KP granites decreased by 38% and 34 % respectively relative to the ambient temperature values. Ed at 600 °C for both the GCP and KP granites decreased by 61.5 % and 57.2 % respectively relative to the ambient temperature values. Mechanical properties such a UCS and BTS also showed decreasing trends with increasing temperature. Decrease in UCS at 600 °C for both the GCP and KP granites was 50 % and 65 % respectively, while decrease in the BTS at 600 °C for both the GCP and KP granites was 70 % and 40 % respectively. The findings of this study will assist in developing geothermal resources in the selected study region.