工程力学 ›› 2019, Vol. 36 ›› Issue (7): 238-247.doi: 10.6052/j.issn.1000-4750.2018.06.0340

• 土木工程学科 • 上一篇    下一篇

地热对井系统裂隙岩体三维渗流传热耦合的等效模拟方法

李馨馨1, 李典庆1, 徐轶2   

  1. 1. 武汉大学水资源与水电工程科学国家重点实验室, 湖北, 武汉 430072;
    2. 长江勘测规划设计研究院, 湖北, 武汉 430010
  • 收稿日期:2018-06-16 修回日期:2018-09-26 出版日期:2019-07-06 发布日期:2019-07-06
  • 通讯作者: 李馨馨(1990-),女,安徽马鞍山人,博士后,主要从事水工结构工程及岩土工程数值仿真研究(E-mail:lixinxin@whu.edu.cn). E-mail:lixinxin@whu.edu.cn
  • 作者简介:李典庆(1975-),男,湖北竹溪人,教授,博士,主要从事岩土工程可靠度分析与风险控制研究(E-mail:dianqing@whu.edu.cn);徐轶(1989-),男,湖北黄冈人,工程师,博士,主要从事水利工程和岩土工程多场耦合与稳定性研究(E-mail:xuyi@cjwsjy.com.cn).
  • 基金资助:
    中央高校基本科研业务费专项资金项目(2042018gf0015)

Equivalent simulation method of three-dimensional seepage and heat transfer coupling in fractured rock mass of geothermal-borehole system

LI Xin-xin1, LI Dian-qing1, XU Yi2   

  1. 1. State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan, Hubei 430072, China;
    2. Changjiang Institute of Survey, Planning, Design and Research, Wuhan, Hubei 430010, China
  • Received:2018-06-16 Revised:2018-09-26 Online:2019-07-06 Published:2019-07-06

摘要: 研究地热对井系统中的裂隙岩体渗流传热问题对于开采深层地热能和发展可再生清洁能源利用技术具有重要价值。基于渗流传热耦合理论和离散裂隙网络模型,提出了裂隙岩体三维热流耦合的等效模拟方法:考虑由岩块基质及复杂离散裂隙网络组成的双重介质,采用无厚度单元模拟裂隙、线单元模拟对井,通过裂隙、对井和岩块三者之间的流量和热量交换实现渗流和传热过程耦合分析。通过与解析方法和精细模拟方法相比较,验证了等效模拟方法的有效性;并将其应用于含大规模裂隙岩体地热对井系统热采过程的数值模拟,获取了储层内温度场的分布规律,评价了裂隙开度对储层平均温度和整体开采率的影响。结果表明:该文方法能够对裂隙及井筒中的渗流传热行为进行细致模拟,在保证精度的前提下,可大幅减小计算量和计算时长;裂隙网络的非均匀及各向异性分布导致岩体温度场分布呈现高度不均匀性,反映了热流耦合的早期热突破和长尾效应等特点;裂隙内水的对流传热作用明显,冷锋面沿储层内的主要贯通裂隙网络移动,裂隙开度是影响岩体温度场分布的重要因素。

关键词: 地热对井系统, 裂隙岩体, 渗流传热耦合, 等效模拟方法, 离散裂隙网络

Abstract: The study on the seepage and heat transfer coupling in fractured rock mass of a geothermal doublet system is of great importance to the exploitation of deep geothermal energy and clean energy utilization technology. Based on the coupling theory of fluid flow and heat transfer as well as a discrete fracture network model, the 3D equivalent numerical method is proposed to model a geothermal doublet system. Presumed that the natural fractured reservoir consists of a block matrix and discrete fracture network, the numerical simulation for thermal extraction is implemented where the zero-thickness elements and line elements are used to model complex fracture networks and inlet/outlet wells, respectively. Seepage flow and heat transfer in fractures, wells and matrix are calculated, along with their flux and heat exchange. The proposed method is validated against results from the analytical models and refined modeling approach, and further employed for modeling the thermal recovery process in fractured rock mass containing large-scale fracture network and for assessing the effects of fracture apertures on average temperature and heat extraction ratio. It shows that the proposed method is capable to precisely simulate the hydraulic-thermal behaviors in discrete fractures and wells, which would bring down the computational cost on the premise of ensuring calculation accuracy. The temperature field in fractured rock mass is nonuniformly distributed due to the spatial inhomogeneity and anisotropy of fracture network. And the characteristics of flow and heat transfer could also be captured. The cold front moves along the percolated fracture network, and the convective heat transfer of fluid is obviously observed. Fracture aperture is an essential factor affecting the heat transfer.

Key words: geothermal doublet system, large-scale fractured rock mass, hydraulic and thermal coupling analysis, equivalent numerical method, discrete fracture network

中图分类号: 

  • TV139.1
[1] Olsthoorn D, Haghighat F, Mirzaei P A. Integration of storage and renewable energy into district heating systems:A review of modelling and optimization[J]. Solar Energy, 2016, 136:49-64.
[2] Wei G, Meng J, Du X, et al. Performance analysis on a hot dry rock geothermal resource power generation system based on kalina cycle[J]. Energy Procedia, 2015, 75:937-945.
[3] Tester J W, Anderson B, Batchelor A, et al. The future of geothermal energy:Impact of enhanced geothermal systems (EGS) on the United States in the 21st century[R]. Cambridge, MA, USA:Massachusetts Institute of Technology, 2006.
[4] Samardzioska T, Popov V. Numerical comparison of the equivalent continuum, non-homogeneous and dual porosity models for flow and transport in fractured porous media[J]. Advances in Water Resources, 2005, 28(3):235-255.
[5] 胡剑, 苏正, 吴能友, 等. 增强型地热系统热流耦合水岩温度场分析[J]. 地球物理学进展, 2014, 29(3):1391-1398. Hu Jian, Su Zheng, Wu Nengyou, et al. Analysis on temperature fields of thermal-hydraulic coupled fluid and rock in enhanced geothermal system[J]. Progress in Geophysics, 2014, 29(3):1391-1398. (in Chinese)
[6] Jiang F M, Chen J L, Huang W B, et al. A three-dimensional transient model for EGS subsurface thermo-hydraulic process[J]. Energy, 2014, 72:300-310.
[7] Zeng Y C, Su Z, Wu N Y. Numerical simulation of heat production potential from hot dry rock by water circulating through two horizontal wells at Desert Peak geothermal field[J]. Energy, 2013, 56(63):92-107.
[8] 张树光, 李志建, 徐义洪, 等. 裂隙岩体流-热耦合传热的三维数值模拟分析[J]. 岩土力学, 2011, 32(8):2507-2511. Zhang Shuguang, Li Zhijian, Xu Yihong, et al. Three-dimensional numerical simulation and analysis of fluid-heat coupling heat-transfer in fractured rock mass[J]. Rock and Soil Mechanics, 2011, 32(8):2507-2511. (in Chinese)
[9] 陈必光, 宋二祥, 程晓辉. 二维裂隙岩体渗流传热的离散裂隙网络模型数值计算方法[J]. 岩石力学与工程学报, 2014, 33(1):43-51. Chen Biguang, Song Erxiang, Cheng Xiaohui. A numerical method for discrete fracture network model for flow and heat transfer in two-dimensional fractured rocks[J]. Chinese Journal of Rock Mechanics and Engineering, 2014, 33(1):43-51. (in Chinese)
[10] Xu C S, Dowd P A, Tian Z F. A simplified coupled hydro-thermal model for enhanced geothermal systems[J]. Applied Energy, 2015, 140:135-145.
[11] 薛娈鸾. 裂隙岩体渗流-传热耦合的复合单元模型[J]. 岩土力学, 2016, 37(1):263-268. Xue Luanluan. A composite element model for coupled seepage-heat transfer of fractured rock mass[J]. Rock and Soil Mechanics, 2016, 37(1):263-268. (in Chinese)
[12] 黄诗冰, 刘泉声, 程爱平, 等. 低温裂隙岩体水-热耦合模型研究及数值分析[J]. 岩土力学, 2018, 39(2):735-744. Huang Shibing, Liu Quansheng, Cheng Aiping, et al. A coupled hydro-thermal model of fractured rock mass under low temperature and its numerical analysis[J]. Rock and Soil Mechanics, 2018, 39(2):735-744. (in Chinese)
[13] Xu C, Dowd P A, Zhao F T. A simplified coupled hydro-thermal model for enhanced geothermal systems[J]. Applied Energy, 2015, 140:135-145.
[14] 李鹏飞, 朱其志, 顾水涛, 等. 岩石类材料裂隙形成和扩展的相场方法模拟[J]. 工程力学, 2018, 35(3):41-48. Li Pengfei, Zhu Qizhi, Gu Shuitao, et al. A phase field method to simulate crack nucleation and crack propagation in rock-like materials[J]. Engineering Mechanics, 2018, 35(3):41-48. (in Chinese)
[15] Thovert J F, Mourzenko V V, Adler P M. Percolation in three-dimensional fracture networks for arbitrary size and shape distributions[J]. Physical Review E, 2017, 95(4):042112.
[16] Li X X, Chen S H, Xu Q, et al. Modeling capillary water absorption in concrete with discrete crack network[J]. Journal of Materials in Civil Engineering, 2017, 30(1):04017263.
[17] Li X X, Xu Y, Chen S H. Computational homogenization of effective permeability in three-phase mesoscale concrete[J]. Construction and Building Materials, 2016, 121:100-111.
[18] Berrone S, Pieraccini S, Scialo S. On simulations of discrete fracture network flows with an optimization-based extended finite element method[J]. SIAM Journal on Scientific Computing, 2013, 35(2):A908-A935.
[19] 钱鹏, 徐千军. 基于单元嵌入技术和弹性比拟的含裂纹混凝土三维渗流模拟方法[J]. 工程力学, 2017,34(4):125-133. Qian Peng, Xu Qianjun. Three-dimensional seepage analysis for cracked concretes based on embedded elements and elastic analogy[J]. Engineering Mechanics, 2017, 34(4):125-133. (in Chinese)
[20] 钱鹏, 徐千军. 不同裂纹分布的孔隙材料渗透系数[J]. 工程力学, 2017, 34(12):39-47. Qian Peng, Xu Qianjun. Permeability of porous material with different crack distributions[J]. Engineering Mechanics, 2017, 34(12):39-47. (in Chinese)
[21] 张超, 段寅, 刘杏红, 等. 基于并层单元的大体积混凝土水管冷却温度场热-流耦合精细计算[J]. 工程力学, 2014, 31(12):147-154. Zhang Chao, Duan Yin, Liu Xinghong, et al. The precise heat-fluid coupling method of mass concrete with cooling pipes based on layer-merged element[J]. Engineering Mechanics, 2014, 31(12):147-154. (in Chinese)
[22] Sarkar S, Toksöz M N, Burns D R. Fluid flow modeling in fractures[R]. Cambridge:Massachusetts Institute of Technology, Earth Resources Laboratory, 2004.
[23] Sanyal S K, Butler S J. An analysis of power generation prospects from enhanced geothermal systems[C]. Geothermal Resources Council Transactions 2005, Antalya, Turkey, April 24-29, 2005.
[24] Jiang F M, Chen J L, Huang W B, et al. A three-dimensional transient model for EGS subsurface thermo-hydraulic process[J]. Energy, 2014, 72:300-310.
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