Research and application of key drilling and completion technologies for in-situ leaching wells in deep uranium deposits of the Yili Basin， Xinjiang

Abstract:

Aiming at the difficulties faced by in-situ leaching mining of uranium deposits in deep and complex formations of Honghaigou， Xinjiang， such as low drilling efficiency， high cost and strict well completion requirements， this paper conducts a study on high-quality and rapid drilling technology. By comparing the performance and drilling efficiency of three types of equipment， namely water well rigs， engineering rigs and petroleum rigs， the applicability of different equipment is clarified. Meanwhile， drill bit selection， environment-friendly low-solid anti-sloughing drilling fluid， deviation control technology， casing structure and slotting completion technology are optimized. A total of 19 boreholes were constructed on site with a total footage of 13731 m， and all construction indicators met the design requirements. Results show that crawler-type deep well rigs are suitable for deep drilling； the optimized composite casing program achieves both stability and economy； PDC bits， environment-friendly drilling fluid， PVC casings and cutting and windowing completion technology can improve drilling efficiency， protect formation permeability and extend well service life. The established high-quality and rapid drilling technology system effectively solves construction challenges caused by deep burial， complex formations and special requirements of in-situ leaching， providing technical support for efficient and green exploration and development of Honghaigou and similar sandstone-type uranium deposits.