活塞式双模超低损岩心取样钻具的研制与应用

Development and application of a piston-type dual-mode ultra-low disturbance core sampling drilling tool

摘要:

针对ICDP湖泊钻探过程中，常钻遇流塑态湖相软泥（含水率>80%，贯入阻力<10 kPa），小口径岩心钻探常规取样方法和钻进工艺对岩心质量扰动大、采取率低的技术难题，创新研制了?122.60 mm小口径活塞式双模取样钻具，通过三管单动贯入式设计与液动控制技术应用，第二次青藏高原科考西藏纳木错湖泊钻探项目于水深101.70 m以下成功获取湖相软泥岩样共计58回次，累计长度127.40 m，扰动系数η<0.15、采取率>80%，实现低损取心的重大突破，其中CL-1G钻孔终孔深度510.20 m，刷新国内高海拔深水湖泊钻深纪录。该技术装置为重建青藏高原冰期-间冰期气候演变序列提供了关键的钻探岩心样本，对古环境重建与未来气候预测提供了宝贵资料。钻具的成功应用，显著提升湖泊沉积物尤其是超软弱塑性地层的取心质量与钻深极限，为全球深水湖泊古环境研究提供了可靠的技术装备支撑。

Abstract:

To address the technical challenges encountered during ICDP lake drilling， specifically， frequent encounters with fluid-plastic lacustrine silt （water content>80%， penetration resistance<10kPa） where conventional coring methods and drilling techniques for small-diameter cores result in high core disturbance and low recovery rates， a ?122.60 mm small-diameter piston-type dual-mode sampler was innovatively developed. Utilizing a triple-tube， non-rotating penetration design and hydrostatic control technology， this system successfully recovered lacustrine silt core samples over 58 runs totaling 127.40m in length from the depths of below 101.70m water during the Second Tibetan Plateau Scientific Expedition at Nam Co Lake， Tibet. The cores exhibited a disturbance coefficient η of less than 0.15 and a recovery rate of more than 80%， representing a major breakthrough in low-disturbance coring. The CL-1G borehole reached a final depth of 510.20m， setting a new domestic record for drilling depth in high-altitude deep-water lakes. This technology provides critical drill core samples for reconstructing the glacial-interglacial climate evolution sequence of the Tibetan Plateau， offering valuable data for paleoenvironmental reconstruction and future climate prediction. The successful application of this sampler significantly enhances core quality and achievable drilling depth limits in lake sediments， particularly in ultra-soft plastic formations， providing reliable technical equipment support for global paleoenvironmental research in deep-water lakes.