Research on Rock Temperature Field at the Bottom of High Temperature Geothermal Wells During Drilling

ABSTRACT: This study aims to explore in depth the heat transfer forms in the well-bore and bottom of high-temperature geothermal wells under the action of drilling fluid circulation. Based on the principles of energy conservation and heat transfer, combined with the heat exchange mode of high-temperature geothermal well control micro units, a high-temperature geothermal well well-bore heat transfer model and a bottom rock temperature model were established during the drilling fluid circulation process. Through a systematic study of the working temperature of the drill string, annulus, and well-bore formation, the distribution patterns of well-bore temperature and rock temperature at the bottom of high-temperature geothermal wells were revealed, and a method for predicting the rock temperature at the bottom of high-temperature geothermal wells while drilling was established. The research results indicate that the temperature distribution in the well-bore is comprehensively influenced by factors such as drilling fluid circulation flow rate, drilling fluid heat capacity, and formation thermal conductivity. The rock temperature at the bottom of the well-bore increases with drilling depth and shows different trends in different formation sections. At 3000m, the highest temperature at the bottom of the well-bore is about 308.6 °C, which is consistent with field data. This study provides a theoretical basis for temperature control and optimization in high-temperature geothermal drilling, which helps to improve drilling efficiency and safety.