ICDP西藏纳木错湖泊钻探前期施工关键技术研究与应用

Research and application of key technologies for pre-construction of ICDP Nam Co Drilling Project， Tibet

摘要:

西藏纳木错湖泊钻探是中国科学院青藏高原研究所联合国际大陆科学钻探计划（ICDP）实施的一项科学钻探工程，主要目的是获取纳木错湖泊湖相沉积岩心，研究和监测气候变化和全球环境。该项目钻孔施工水深约100 m，最深的1个钻孔的湖底沉积物钻进深度为700 m。本文对纳木错湖泊钻探的主要技术难点进行研究，开展湖泊钻探水上工作平台及施工程序设计：水上工作平台设计、搭建拼装，锚固定位，钻探设备选型，聚合物防塌冲洗液，P口径绳索取心钻具，深水套管及气囊式套管扶正系统设计等。围绕最大钻深能力800 m（含水深100 m）的湖泊钻探需求，以孔深250 m（含水深100 m）为例，开展了相关钻探技术和钻探设备研究，为中国科学院青藏高原研究所开展全球气候变化、生物进化、构造演化、古地磁变化以及水文循环等研究提供了技术支撑。

Abstract:

The Nam Co Drilling Project in Tibet is a scientific drilling program implemented by the Institute of Tibetan Plateau Research， Chinese Academy of Sciences， in collaboration with the International Continental Scientific Drilling Program （ICDP）， which is a scientific drilling initiative aimed at retrieving lacustrine sediment cores from Nam Co to study and monitor climate change and global environmental dynamics. During this project， drilling operations were conducted at a water depth of approximately 100 meters， with the deepest borehole penetrating lakebed sediments to a depth of 700 meters. This paper investigates the primary technical challenges of lake drilling in Nam Co by examining the design and operational procedures for lake drilling platforms， including： platform design and modular assembly； anchor positioning； drilling equipment selection； polymer anti-collapse drilling fluids； P-diameter wireline coring tools； deepwater casing systems； and airbag-type casing centralizer designs. Centered on the demand for lake drilling capabilities with a maximum depth of 800 meters （including water depth of 100 meters）， this study develops relevant drilling technologies and equipment using a case example of a 250 meters borehole （including water depth of 100 meters）. The research provides critical technical support for the Institute of Tibetan Plateau Research， CAS in advancing studies on global climate change， biological evolution， tectonic evolution， paleomagnetic variations， and hydrological cycles.