Abstract: The dry hot rock(HDR) geothermal resources are abundant and have great development potential, which is of great strategic significance to the transformation of China’s energy structure and the realization of the "double carbon" goal. However, HDR drilling faces extreme geological challenges such as high temperature, high rock hardness, high in-situ stress, and low permeability, leading to low rock-breaking efficiency, high risks of wellbore instability, and accelerated failure of drilling tools and working fluids, which severely hinders its cost-efficient development. This paper analyzes the drilling engineering practice of enhanced geothermal system (EGS) at home and abroad, sorts out the core technical challenges of hot dry rock drilling, and focuses on the technical development status of hot dry rock wellbore stability, hot dry rock drilling rate-of-penetration (ROP) enhancement techniques and wellbore working fluid system. The analysis indicates that significant progress has been achieved in the research of major technical fields such as wellbore stability control, efficient rock breaking and ROP enhancement, and high-temperature-resistant drilling fluids, while challenges persist in the long-term thermal stability of tools, the process system integration, and intelligentization level. Therefore, from the perspective of national strategy and engineering needs, recommendations are proposed for the systematic development, including the breakthroughs in full-system high-temperature-resistant drilling system, advance in the integration of customized processes with intelligent systems, development of "intelligent regulation and functional synergy" type drilling fluid systems, establishment of a Chinese technical standard mode, and design of next-generation rock-breaking methods. These recommendations aim to provide decision-making references for breakthroughs in HDR drilling technology and the large-scale development of deep geothermal resources in China.

Key words: hot dry rock, drilling technology status, ROP enhancement, enhanced geothermal system, geothermal energy

摘要： 干热岩型地热资源储量丰富,开发潜力巨大,对中国能源结构转型及"双碳"目标的实现具有重要战略意义。但干热岩钻井面临高温度、高硬度、高应力和高致密的极端地质挑战,导致破岩效率低、井壁失稳风险高、钻井工具与工作流体失效快,严重制约了其经济高效开发。通过剖析国内外增强型地热系统(EGS)钻井工程实践,梳理了干热岩钻井核心技术挑战,重点阐述了干热岩井壁稳定性、干热岩钻井提速技术以及井筒工作流体体系等方面的技术发展现状。分析表明,围绕"井壁稳定控制、高效破岩提速、耐高温工作流体"三大技术方向的研究已取得阶段性进展,但在工具长效耐温、工艺系统集成与智能化水平方面仍存在不足。为此,从国家战略与工程需求出发,提出了攻关全链条耐高温钻井装备、推动个性化工艺与智能化系统融合、研发"智能调控+功能协同"型工作流体体系、构建中国技术标准模式以及布局前瞻性破岩方法等系统性发展建议,以期为中国干热岩钻井技术突破与深层地热资源规模化开发提供决策参考。

关键词: 干热岩, 钻井技术现状, 钻井提速, 增强型地热系统, 地热能