| 红河流域元古界大红山群变质岩系的热储结构及热流特征 |
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| 引用本文： | 李传伟,王宇,曾威,王家兴,庄海俊.红河流域元古界大红山群变质岩系的热储结构及热流特征[J].中国岩溶,2022,41(3):384-394. |
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| 作者姓名： | 李传伟 王宇 曾威 王家兴 庄海俊 |
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| 作者单位： | 1.西南有色昆明勘测设计(院)股份有限公司, 云南 昆明 650051 |
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| 基金项目： | 云南省有色地质局产业发展专项资金（2022）；戛洒外滩酒店建设项目地热勘探与开发工程 |
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| 摘 要： | 经过地热地质调查、物探验证和分析论证，在红河流域中段的戛洒盆地古元古界大红山群变质岩系中钻探获得了可供开发利用的热矿水。勘探孔深2 200.71 m，大红山群第4至第5段（Pt1dhs4-5）热储层富水性强，钻孔涌水量1 089 m3·d?1，孔底测温84.3 ℃，地热水矿化度9 777 mg·L?1，水化学类型为Cl-Na型，水化学成分复杂。此次成功的勘探研究，揭示了大红山变质岩系的热储特征及地热资源潜力，拓展了地热水勘探开发的新领域。综合研究认为，大红山群变质岩系中的硬脆性大理岩、石英片岩、火成岩等热储层（带）、导热导水的深大断裂及上覆隔水隔热的三叠系红层等盖层，构成了较为典型的带状热储。热储层赋存承压地热水，主要由地下水在重力和热力作用下，沿区域深大断裂带的主干和次级导热导水断裂作深循环逐渐增温和对流运动所形成，实测地热增温率为3.0 ℃·(100 m)?1。
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| 关 键 词： | 地热地质 地下热水 热储结构 热流特征 热水循环 红河流域 |
| 收稿时间： | 2022-01-01 |
Geothermal reservoir structure and heat flow characteristics of proterozoic metamorphic rock series of Dahongshan group in Honghe river basin |
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| Institution: | 1.Southwest Nonferrous Kunming Survey and Design (Institute) Co., LTD., Kunming,Yunnan 650051, China2.Yunnan Geological Survey, Kunming,Yunnan 650051, China |
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| Abstract: | Hot mineral water for development and utilization has been drilled from the metamorphic rock series of Dahongshan group of paleoproterozoic in the Gasa basin in the middle part of the Honghe river basin through geothermal geological survey, geophysical exploration and analysis. The exploration hole depth is 2,200.71 m, and the water intake target layer of 4th to 5th section of Dahongshan group (Pt1dhs4-5) thermal reservoir is rich in water with 1,089 m3·d?1 of borehole water inflow, 84.3 ℃ of borehole bottom temperature and 9,777 mg·L?1 of degree of mineralization of geothermal water.The hydrochemistry type is Cl-Na type, and the hydrochemistry composition is complex. The successful exploration revealed the thermal reservoir characteristics and geothermal resource potential of Dahongshan metamorphic rock series, and expanded a new field of geothermal water exploration and development. The terrestrial heat flow value of the study region is 73.3 mW·m?2. Hot springs are sparsely distributed along the Honghe fault zone,and the water temperature is generally 25 ℃ to 40 ℃. The current fault activity is relatively weak. Due to the continuous activity of the fault, the brittle dolomite marble and schist in the metamorphic rock series of the Dahongshan group distributed in the Jiasa area have formed a water-bearing fissure zone, forming a deep permeable rock zone. The overlying Quaternary loose layers and Triassic clastic rock layers are soft and flexible rock layers in the Jiasa valley basin, with good structural plane closure and poor permeability, and the thermal conductivity of rocks is as low as 2.4 W·(m·k)?1 to 2.6 W·(m·k)?1, making the layer a good thermal reservoir caprock. The high-density cold water formed by Ailao mountain and the deep structural fissure water are exchanged in the layer, forming the geothermal water of the target mining layer. The content of cation Na+ in geothermal water is significantly higher than that of K+、Ca2+、Mg2+, the milliequivalent content is 88.3%, the anion content is mainly Cl? which accounts for 81.47% of the components;the pH value is 8.14, the content of SiO2 is 75.65 mg·L?1, and the content of ion F? is 7.46 mg·L?1. The degree of mineralizationand the content of ionic components of waterare high, indicating that the metamorphic rock series with salt-bearing minerals and metamorphic minerals in the geothermal water circulation route has dissolved a large amount of minerals through deep circulation. The Cl? and Na+ ions in the thermal fluid are mainly derived from chlorapayite and sodalite in the first to third volcanic lava section of Dahongshan group(Pt1dhs4-5). The heat source in the study area mainly comes from the rising heat flow along the fault zone and regional geothermal heating. Near the Honghe fault, which penetrates deep into the mantle,the groundwater communicates smoothly with the deep heat source, absorbing the energy released by the deep magma, radioactive decay and tectonic movement, forming underground hot water. Under the action of water pressure difference and density difference, geothermal water migrates to the shallow part along the Ailao mountain piedmont fault, Shuitang-Yuanjiang fault, fault of heat conduction and water conduction such as F1, and structual fracture zone. When geothermal water migrates through the soluble rocks and the rock strata with hard brittle fracture in the metamorphic rock series of the Dahongshan group, it forms a thermal reservoir, and the water-bearing voids are mainly joint fractures. |
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