Abstract: After more than 10 years of theoretical innovation and engineering practice in shale gas fracturing, supporting the scale cost-effective development of marine shale gas, China has established a theoretical and technical system for marine shale gas fracturing in the middle and shallow layers (< 3 500 m). The technically recoverable resources of deep (3 500-4 500 m) and ultra deep (> 4 500 m) shale gas in China account for 56.63% of the total recoverable shale gas reserve. To achieve efficient gas exploitation is essential for the development of the shale gas industry and guarantee of oil and gas security. The recoverable resources of deep (3 500-4 500 m) and ultra deep (> 4 500 m) shale gas in Sichuan Basin and its periphery account for 65.8% of the total reserve, making the most important contribution to the efficient development of shale gas and the construction of "Daqing Gas Base". Based on the preliminary exploration and practical understanding of deep and ultra deep shale gas fracturing in China and according to the 10 characteristics of deep and ultra deep shale gas fracturing, this paper analyzes six basic problems or challenges that are derived from above situation and urgently need to be solved. Further, the paper proposes five key theories and methods that urgently need to be innovated, points out 10 development directions for deep and ultra deep shale gas fracturing, and emphasizes that China's shale gas development should focus on both deep and shallow layers and continue to improve large-scale production and EOR in the middle and shallow layers. There are both opportunities and challenges in advancing into the new fields of exploration in deep and ultra deep layers to achieve efficient development. It is still necessary to continuously enhance the research, and accelerate the establishment of China's fracturing theory and technology system for deep and ultra deep shale gas.

Key words: deep and ultra deep layer, shale gas, fracture, problem and challenge, development direction

摘要： 中国历经10余年的页岩气压裂理论创新与工程实践，已形成中浅层（<3 500 m）海相页岩气压裂理论与技术体系，支撑了海相页岩气规模效益开发。中国深层（3 500~4 500 m）—超深层（>4 500 m）页岩气技术可采资源量占页岩气总可采资源量的56.63%，实现高效开发是页岩气产业发展和保障油气安全的主战场；四川盆地及其周缘深层—超深层页岩气可采资源量占其总可采资源量的65.8%，是高效开发页岩气和建设"气大庆"的主阵地。基于中国深层—超深层页岩气压裂的前期探索与实践认识，根据深层—超深层页岩气压裂的10大特征，分析了由此衍生并亟待解决的6个基础问题或面临的挑战，提出了亟需创新的5个关键理论和方法，指出了深层—超深层页岩气压裂的10个发展方向，并强调：中国页岩气开发要"深浅并重"，中浅层要继续规模建产和提高采收率；深层—超深层要实现高效开发，进军深层—超深层机遇和挑战并存，尚需不断"砺剑"，加快建立中国深层—超深层页岩气压裂理论与技术体系。

关键词: 深层—超深层, 页岩气, 压裂, 问题和挑战, 发展方向