Study on Thermal Conductivity of Thermal Insulation Cement in Geothermal Well

Abstract

When geothermal fluid flows to the wellhead along the wellbore, there is a thermal transfer from the high-temperature geothermal fluid to the low-temperature formation. This process can directly lead to the decrease of wellhead temperature and loss of geothermal energy. Even though previous studies have confirmed that reducing the thermal conductivity of cement could validly cut down the heat loss of geothermal fluid, the influence factors of thermal conductivity are limited. In this research, we conducted detailed studies of the influence factors of thermal conductivity and compressive strength for cement. The results show that with the increase of water-cement ratio and thermal insulation materials, thermal conductivity and compressive strength decline. Furthermore, curing temperature is another important factor to improve the thermal preservation effect, but the testing temperature has the opposite influence. Based on these results, the present study concluded that porosity, Skeleton ingredients, curing temperature, and test temperature are vital factors for thermal conductivity. This research provides theoretical guidance for increasing the wellhead temperature of geothermal fluid and enhancing the efficiency of geothermal energy.