云南省泸西抽水蓄能电站900 m特深孔钻进关键技术

Discussion onKey Techniques for 900m Deep Hole Drilling at Luxi Pumped Storage Power Station in Yunnan Province

泸西抽水蓄能电站ZK611号孔设计孔深900m,地层岩性为灰岩,地下水位埋深大,岩溶发育,地层复杂,钻进难度大,选用绳索取心工艺。经过研究和摸索,根据钻孔地层结构,使用性能优良的钻井液用屏蔽暂堵剂及钻杆油,合理调配冲洗液、优化钻进参数,积极克服并创新性解决了岩体溶蚀发育强烈、孔内漏水、多段跨孔、地下水位埋深极大、地应力较高等复杂技术难题。该孔为综合勘察钻孔,钻孔结构设计还需考虑钻孔声波、钻孔全孔壁数字成像、高压压水试验、地应力测试及水位观测等。同时,介绍了钻探设备材料的选择和安装,并结合施工情况,对超深孔水位长期观测管施工、超深孔压水试验提出了建议。

The design depth of hole ZK611 in Luxi Pumped Storage Power Station is 900m,and the lithology of the formation is limestone.The groundwater level is deeply buried,karst is developed,the formation is complex,and drilling is difficult.Therefore,the rope coring process is selected.After research and exploration,based on the geological structure of the borehole,this paper uses high-performance drilling fluid,shielding temporary plugging agent,and drill rod oil to reasonably allocate flushing fluid and optimize drilling parameters.It actively overcomes and innovatively solves complex technical problems such as strong rock dissolution development,water leakage in the hole,multi stage cross hole,extremely deep groundwater level,and high ground stress.This hole is a comprehensive survey borehole,and the design of the borehole structure also needs to consider drilling sound waves,digital imaging of the entire borehole wall,high-pressure water pressure testing,in-situ stress testing,and water level observation.At the same time,this paper introduces the selection and installation of drilling equipment materials,and proposes suggestions for the construction of long-term observation pipes for ultra deep hole water levels and ultra deep hole water pressure tests based on the construction situation.