地学前缘 ›› 2020, Vol. 27 ›› Issue (1): 134-151.DOI: 10.13745/j.esf.2020.1.15

• 地热开发利用模拟和实践 • 上一篇    下一篇

中国深层地热能开采的地质条件评价

庞忠和1,2,3(), 罗霁1,2,3, 程远志1,2,3, 段忠丰4, 天娇1,2,3, 孔彦龙1,2,3, 李义曼1,2,3, 胡圣标1,2,3, 汪集旸1,2,3   

  1. 1.中国科学院 地质与地球物理研究所; 中国科学院页岩气与地质工程重点实验室, 北京 100029
    2.中国科学院 地球科学研究院, 北京 100029
    3.中国科学院大学, 北京 100049
    4.中国石油大学(华东) 地球科学与技术学院, 山东 青岛 266580
  • 收稿日期:2019-03-29 修回日期:2019-10-09 出版日期:2020-01-20 发布日期:2020-01-20
  • 作者简介:庞忠和(1961—),男,研究员,博士生导师,主要从事地热地质与热储工程学研究。E-mail: z.pang@mail.iggcas.ac.cn
  • 基金资助:
    中国科学院战略性先导科技专项资助项目(XDA21050500);国家自然科学基金项目(41430319);国家自然科学基金项目(41877209)

Evaluation of geological conditions for the development of deep geothermal energy in China

PANG Zhonghe1,2,3(), LUO Ji1,2,3, CHENG Yuanzhi1,2,3, DUAN Zhongfeng4, TIAN Jiao1,2,3, KONG Yanlong1,2,3, LI Yiman1,2,3, HU Shengbiao1,2,3, WANG Jiyang1,2,3   

  1. 1. Institute of Geology and Geophysics, Chinese Academy of Sciences; Key Laboratory of Shale Gas and Geoengineering, Chinese Academy of Science, Beijing 100029, China
    2. Institutions of Earth Science, Chinese Academy of Sciences, Beijing 100029, China
    3. University of Chinese Academy of Sciences, Beijing 100049, China
    4. School of Geosciences, China University of Petroleum (East China), Qingdao 266580, China
  • Received:2019-03-29 Revised:2019-10-09 Online:2020-01-20 Published:2020-01-20

摘要:

深层地热能是指深度大于3 000 m的地热能。我国深层地热能资源丰富,但是开采条件怎么样呢?本文基于地热地质学原理,结合岩石力学等相关学科的理论,提出一种对深层地热能开采条件进行评价的指标体系,对各单一指标采用专家打分的方法赋值,继而采用模糊数学定量计算和评估深层地热能资源开发的难易程度。该方法考虑了深层地热能开发利用中的增强地热系统(EGS)的环境安全问题,即传统的“刚性造储”可能带来的诱发地震等不利于地热能行业健康发展的因素,倡导“柔性造储”和广义EGS理念,强调储层属性和地物理场的整合,针对我国地热能分布与构造活动关系密切、地壳总体上活动性强、地应力高、地震频发等构造型地热特点,是对以往评价方法的补充和拓展。该方法充分利用了专家知识,发挥了模糊数学综合评估作用,给出的量化结果易于对比和使用,可以更好地支持决策。本文基于新的评估方法,利用现有的深部地热研究及勘探成果,评估了中国大陆地区九个区域深层地热能开发的难易程度,评价区包括西藏南北地堑系、云南西部火山型地热区、青海东部共和盆地以及东北、华北等。从本文的结果可以看出,我国深层地热能开采的地质条件复杂,开采难度较大。

关键词: 干热岩, 深层地热能, 开采条件, 评价方法, 模糊数学, 中国大陆

Abstract:

Deep geothermal energy refers to geothermal energy that lies deeper than 3000 meters below Earth’s surface. China is rich in deep geothermal energy, but how favorable are the exploitation conditions? Based on the principle of geothermal geology, in association with rock mechanics, we put forward an indicator system for evaluating the conditions of deep geothermal energy exploitation. We first assign values to each indicator using the expert scoring method; then we apply the principle of fuzzy mathematics to obtain a single value so as to assess the exploitation feasibility. This method considers the safety aspect of enhanced geothermal system (EGS) technology in the development of deep geothermal energy. It advocates adopting the concept of “soft stimulation”, different from the “rigid stimulation” which may induce earthquakes and other key factors not conducive to the healthy development of geothermal energy industry. It also emphasizes the reservoir properties and geophysical fields, expanding and supplementing the previous evaluation results. The established new method is more suitable for the actual geothermal geological conditions, i.e., tectonics dominant geothermal distribution in China. In other words, geothermal energy distribution is closely related to tectonic activities, the stress is relatively high, the crust is generally active with frequent earthquake events. This method makes full use of expert knowledge, adds the role of fuzzy mathematical comprehensive evaluation, and makes the quantitative results easy to compare and use. Therefore, this method is expected to better support decision-making. Based on the new assessment method and existing deep geothermal research and geothermal exploration results, we attempted to make a preliminary assessment of the geological conditions of deep geothermal energy development in nine regions of mainland China, including the north-south geothermal zones in Tibet, the volcanic geothermal regions in western Yunnan Province, the central and eastern regions of Qinghai Province, Northeast and North China, and other regions. We revealed quantitative differences of regional geological conditions for geothermal exploitation, showing that continental China has complex geological conditions, often unfavorable to deep geothermal energy development.

Key words: hot dry rock, deep geothermal energy, geological conditions, evaluation indicator system, fuzzy mathematics, continental China

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