深海硬岩连续取心钻头的研制

Development of the continuous coring bit for hard rock formation in deep-sea

摘要:

气举反循环技术是一种可用于深井硬岩地层的高效钻进技术，不受地层裂隙、溶洞影响，排渣彻底。通过研究专用的连续取心钻头，可实现深海硬岩的连续取心作业，提高深海硬岩钻井效率及取心率，为深海钻探提供一种全新的取心方案。本文从牙掌选型、卡断器结构、岩渣及岩心通道优化设计等方面进行研究，提出了连续取心钻头的设计方案，并试制加工钻头。在地热井中进行了验证性应用，灰岩地层、砂岩地层取心率可达80%以上，高于大洋钻探统计取心率。陆地验证性应用为该技术方法在海洋取心钻探中的应用奠定了技术基础。

Abstract:

Air-lift reverse circulation drilling is an efficient drilling technique which can be used in deep well drilling in hard rock formation since it is not affected by rock fractures and karst caves with thorough removal of the cuttings. A special continuous coring bit has been developed to carry out continuous coring operations in deep-sea hard rock to improve drilling efficiency and core recovery in deep-sea hard rock； thus， providing a novel coring approach for deep-sea drilling. With studies on the selection of the cone profile， the structure of the core lifter， the optimum design of the passage for the cores and cuttings， etc.， the design of the continuous coring bit was put forward， and the test drill bit was made. The bit has been applied in a geothermal well， with core recovery in limestone and sandstone over 80%， higher than that measured in ocean drilling. The verifying test on land has laid a technical foundation for the further application of this technique in deep-sea core drilling.