| Abstract:The 3000m scientific deep drilling in southern Hunan is the first 3000m geological core drilling special deep hole in Hunan province.During the drilling process, various complex strata, such as clay shrinkage, total hole leakage, water-sensitive collapse shrinkage, vertical joint development and collapse, were drilled,many accidents occurred in the hole, which seriously affected the construction progress.This paper introduces the main in-hole accidents such as stuck drilling and hole collapse in the construction process of 3000m scientific deep drilling in southern Hunan and analyzes the causes of the accidents,Through the use of side drilling, sand fishing, deep hole cement grouting and other treatment measures, and in view of the complex situation of the formation, the optimization of drilling structure, optimization of mud system, optimization of drilling tool structure and other preventive measures,The construction technology problem of deep hole complex stratum is solved effectively.The final hole depth is 3008.93m, creating the small-caliber solid ore exploration hole depth record in southern Hunan, providing detailed physical data for the research of deep-hole mineral metallogenic theory and resource exploration in this area. |