Novel idea of the theory and application of 3D volume fracturing for stimulation of shale gas reservoirs
Novel idea of the theory and application of 3D volume fracturing for stimulation of shale gas reservoirs
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DOI：
10.1360/n972015-00262
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发表时间：
2016
影响因子：
--
通讯作者：
Heping Xie;F. Gao;Jingdong Yang;Lingzhi Xie;Yongming Yang;Jun Wang
中科院分区：
文献类型：
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作者：
Heping Xie;F. Gao;Jingdong Yang;Lingzhi Xie;Yongming Yang;Jun Wang
页岩气以其储量潜力巨大、绿色环保、分布广泛等显着优势，已成为许多国家优先选择的替代能源和国家战略目标。页岩气的成功开发利用深刻影响着全球经济、地区政治乃至军事战略。中国拥有世界上最大的页岩气可采储量。中国页岩气可采储量居世界第一。但我国页岩气地层大多为低渗透矿床，且地质条件复杂、构造活跃、缺水，现有方法开采页岩气难度较大。创新页岩气增产方法和技术，建立我国页岩气高效开采利用的理论和技术。本文简要回顾了油藏压裂所采用的方法、原理、难点和挑战。提出了一种有前景的储层改造理念，即三维体积压裂及其原理和技术。页岩体积压裂从力学角度定义为考虑储层岩石在复杂地应力作用下的相互作用、生长、分叉、固有节理或裂缝以及人工裂缝的三维压裂过程。页岩体积破裂是一种规模大、裂隙多、强度高、能量释放密集的破坏过程。文章从三维裂缝模式、扩展机制、人工裂缝与结构裂缝的相互作用、裂缝网络与发育、加载类型、实现大规模体积压裂的方式和介质、三维压裂过程和计算程序可视化、增产实施等方面初步构建了三维体积压裂理论。基于早期的实验室和现场测试，我们讨论了实现这一有前景的页岩气藏增产技术的关键科学问题和技术挑战。
Shale gas has become a preferably alternative energy resource and national strategic goal for many countries for its noticeable advantages, including huge reserves and potentials, green, and broad distribution. Successful exploitation and utilization of shale gas has profoundly impacted global economy, regional politics, and even military strategies around the world. China holds the largest amount of recoverable shale gas reserves in the world. The shale gas recoverable reserves of China rank firstly in the world. However, most of the shale gas formations in China are low-permeability deposit and in conditions of geological complex, tectonic active, and lack of water, which makes the exploitation of shale gas difficult using the current methods. It is imperative to renovate the methods and techniques for stimulation of shale gas formations and to establish theory and technology for achieving high-efficiency exploitation and utilization of shale gas in China. This paper briefly reviews the adopted methods, principles, intractable issues and challenges in reservoir fracturing. A promising reservoir stimulation idea, i.e., 3D volume fracturing, and its principles and technology, are proposed. The volume fracturing of shale rock is defined as a three-dimensional fracturing process from the mechanics point of view, taking into account the interaction, growth, bifurcation between internal pores, inherent joints or cracks, and artificial fractures of reservoir rock under complex geostresses. The volume fracturing of shale rock is a failure process featured by large scale, multi cracking, high strength, and intensive energy release. The paper preliminarily frames the 3D volume fracturing theory from the aspects of 3D fracture modes, growth mechanism, interaction between artificial fractures and structural cracks, crack networks and development, loading type, modes and media for realizing large-scale volume fracturing, visualization of 3D fracturing process and computing programs, and stimulation implementation. Based on the early laboratory and field tests, we discussed the key scientific issues and technical challenges in realizing this promising stimulation technology for shale gas reservoirs.