Research and Application of Geothermal Exploration Well Drilling Technology in Dachang Area

To evaluate the thermal reservoir thickness and geothermal potential of the Wumishan Formation in the Dachang area of Huanghua Depression, two exploration wells, DRT1 and DRT2 (1 production, 1 irrigation), were deployed in this block for geothermal water extraction. During the drilling process, there were challenges such as difficulty in optimizing the wellbore structure, poor drillability in deep formations, limited drilling speed due to drill bit wear, difficulty in controlling wellbore trajectory, high risk of wellbore instability and collapse, and high geothermal temperature affecting the stability of drilling fluid performance and cementing quality. To this end, combined with the geological structure and lithology characteristics of the region, research on wellbore structure and wellbore trajectory optimization is conducted to reduce the difficulty of drilling construction and improve construction safety; Using a combination of screw and MWD drilling tools for trajectory control; Using high-temperature resistant potassium salt polymer drilling fluid to solve the problem of poor performance stability of drilling fluid in high-temperature environments; Adopting high-temperature resistant dual setting cement slurry and adopting targeted technical measures to ensure the quality of well cementing in high-temperature environments. By applying the above technical measures, DRT1 and DRT2 successfully completed the drilling construction and achieved the predicted water temperature and volume targets, providing a reference for geothermal well drilling in the Dachang area