液氮应用于干热岩钻探的可行性探讨

Application Prospects of Liquid Nitrogen in Hot Dry Rock Drilling

摘要:

干热岩是一种清洁、可再生的地热资源，其开发需通过钻井实现。分析了目前干热岩常规钻探技术面临机械钻速慢、井下工具和钻井液性能不稳定、易发生复杂井下事故等挑战，讨论了液氮在干热岩钻探中的应用前景。认为液氮在干热岩钻探过程中具有破岩效率高、有效提高干热岩热能提取效果、解决钻井液不耐高温和井漏问题等优势，并提出了液氮在干热岩钻探过程中的工具耐低温性能、液氮携岩规律和效果、井筒压力控制、钻进参数优化、井壁稳定性等关键技术问题。

Abstract:

Hot dry rock can be obtained by drilling, which is a kind of clean and reproducible geothermal resources. By analyzing the difficult challenges faced by current conventional hot dry rock drilling technology such as slow rate of penetration, unstable performances of downhole tools and drilling fluid and freqent complicated downhole accidents, the discussion is carried out on the application prospects of liquid nitrogen in hot dry rock drilling. It is concluded that liquid nitrogen has advantages of high efficiency in rock breaking, effective improvement of the hot energy extraction, solving high temperature tolerance and well leakage for hot dry rock drilling. The paper puts forward some key technologies of low temperature performance of drilling tools with liquid nitrogen, regulation and effects of carrying cuttings by liquid nitrogen, wellbore pressure control, drilling parameters optimization and well wall stability in hot dry rock drilling.