Deviation prevention and control for deep holes in sandstone-type uranium mines in Yili Basin

Abstract:

In recent years， drilling depth in the sandstone-type uranium mine in Xinjiang Yili Basin is mostly between 600m and 1000m with measured average bottom hole deviation about 28m， and borehole deviation control is the main technical problem affecting the quality of drilling holes in the Yili mining area. Exploration drilling is mostly done by conventional core drilling in Yili Basin， where borehole expansion caused by complex formations is common. Low rigidity of the drill pipes and the large swinging bending range of the drill pipe due to its rotation in the hole are the main factors that cause the difficulty in controlling deep hole deviation in the sandstone-type uranium mine in Yili Basin. Large deviation in medium and deep holes affects the quality of geological results and drilling economic benefits. With proper design of the centralizer suitable for the complex formation in Yili Basin， and optimization of the drilling string combination， the average deviation in the deep holes drilled in sandstone-type uranium mines in the Yili Basin test area has been greatly reduced. The deviation prevention and control measures can provide some reference for similar drilling works.