西藏罗布莎铬铁矿区高海拔巨厚覆盖层钻探技术

Drilling technology for massive overburden at high altitude in Luobusa Chromite Mine， Tibet

摘要:

西藏罗布莎铬铁矿区海拔高、覆盖层厚、地质条件复杂，岩层破碎、裂隙发育，局部岩层水溶、水蚀、水敏，存在地层漏失、缩径等钻探难题。本文总结了该区28个中深钻孔施工经验，包括：钻孔结构、钻进工艺、冲洗液、护壁堵漏技术、复杂情况采取的技术措施等，取得了较好的效果，各项指标满足设计要求，岩（矿）心采取率达到90%以上，台月效率555 m，各项质量指标均符合设计要求。

Abstract:

The Luobusa Chromite Mine in Tibet is characterized by high altitude， thick overburden， complex geological conditions， broken rock strata， developed fractures， local water dissolution， water erosion and water sensitivity， leading to some drilling problems such as formation leakage and borehole shrinkage. This paper summarizes the drilling experiences from 28 medium and deep boreholes in this area in respect of drilling structure， drilling technology， drilling fluid， wall protection and plugging technology， technical measures taken in complex situations， etc. Good results have been achieved with all index meeting the design requirements. The core recovery rate is more than 90%， the rig-month efficiency is 555m， and all quality indicators meet the design requirements.