西藏谷露地热田地热资源前景及勘探方向

西藏亚东-谷露裂谷带是新生代的活动构造带,具有构造活跃、地震频繁、热泉广布、大地热流高等特征,孕育了丰富的地热资源。已实现商业开发多年的羊八井地热田和羊易地热田正是位于亚东-谷露裂谷带的中部,而位于该构造带北部的谷露地热田地热资源前景和勘探方向还有待深入认识。为此,本文解析了地表地热构造,对比了羊八井地热模式,分析了谷露地热田的深部热动力学背景,并结合钻井试采资料揭示谷露地热田具有良好的地热资源前景。在此基础上,利用大地电磁和重力预测了谷露地热田的地热分布具有南北分带性,即北部和中部具有深部和浅部两个层次的地热储层,而南部地热储层则以浅部为主。为深入研究亚东-谷露裂谷带的地热系统模式及指导地热勘探开发提供了重要的地球物理依据。     

咸阳地区地热水化学特征分析

在研究咸阳地区地质和地热背景条件基础上,探讨了地热水的主要化学成分特征和形成机制。分析结果表明:热水属深循环高温高氟高矿化热水;水化学类型以Cl-Na、Cl·HCO3-Na、HCO3-Na、HCO3·SO4-Na、SO4·HCO3-Na、HCO3·Cl·SO4-Na等类型为主,地热水与渭河北岸断裂及其次级断裂关系密切。     

西藏羊八井地热田水热蚀变的时空演化特征

西藏亚东—谷露裂谷中—北段的羊八井地热田是我国著名的高温地热田,研究其水热蚀变的时空演化有助于更好地认识藏南地热的发育特征。通过对羊八井地热田及其水热蚀变岩开展地表调查、显微特征与X衍射分析等工作,总结了其主要蚀变类型特征,划分出黄褐色蚀变中心带、灰白色中强蚀变带、灰白色中等蚀变带和浅灰白色弱蚀变带4个不同的水热蚀变带,并区分出红褐色—黄褐色蚀变期、灰白色蚀变期和淡黄色—灰色蚀变期共3期蚀变。研究结果揭示,羊八井地热田高温地热活动中心一直在北区硫磺沟区域,其水热蚀变活动主要受亚东—谷露裂谷内部的活动断裂构造控制,并与断裂构造活动具同步性;地热水的排泄方式早期为沿北东向断裂构造直接排泄,晚期为经浅层第四系径流后再排泄,由直接排泄向间接排泄转变;中高温地热水的排泄区由北区硫磺沟地区向南区藏布曲迁移。根据研究结果推断,硫磺沟区域的北东向断裂与北西向断裂交汇区可作为羊八井热田北区深部地热勘查的主要方向。     

Hydrogeochemistry of high-temperature geothermal systems in China: A review

As an important part of the Mediterranean-Himalayas geothermal belt, southern Tibet and western Yunnan are the regions of China where high-temperature hydrothermal systems are intensively distributed, of which Rehai, Yangbajing and Yangyi have been investigated systematically during the past several decades. Although much work has been undertaken at Rehai, Yangbajing and Yangyi to study the regional geology, hydrogeology, geothermal geology and geophysics, the emphasis of this review is on hydrogeochemical studies carried out in these geothermal fields. Understanding the geochemistry of geothermal fluids and their environmental impact is critical for sustainable exploitation of high-temperature hydrothermal resources in China. For comparison, the hydrogeochemistry of several similar high-temperature hydrothermal systems in other parts of the world are also included in this review.     

Natural attenuation of geothermal arsenic from Yangbajain power plant discharge in the Zangbo River,Tibet, China

The Yangbajain geothermal field located in central Tibet is characterized by the highest measured reservoir temperature among all hydrothermal systems in China. The high-temperature geothermal fluid extracted from Yangbajain has been used for electricity generation for over 30 years. The geothermal wastewater generated by the Yangbajain power plants, with arsenic (As) concentrations up to 3.18 mg/L, drains directly into the Zangbo River, the major surface water at Yangbajain, which has elevated arsenic concentrations in the segments downstream of wastewater discharges. However, along the flow direction of the river, the arsenic concentration decreases sharply. Further inspection reveals that the concentrations of weakly bound arsenic, strongly adsorbed arsenic and total arsenic in riverbed sediment were affected by the drainage of geothermal wastewater, indicating that the sediment serves as a sink for geothermal arsenic. A logarithmic relationship between the integrated attenuation coefficients (IAC) for three river segments and the corresponding adsorption distribution coefficients of riverbed sediment samples also suggests that besides the dilution of geothermal arsenic in the Zangbo River, natural attenuation of arsenic may be caused by sorption to riverbed sediment, thereby reducing its health threat to local residents using the Zangbo River as a drinking water source.     

四川巴塘地热田水文地球化学特征及成因

地下热水的地球化学特征能够揭示深部地热过程。川西巴塘地区域地热资源丰富,但当前研究程度较低。为进一步查明川西地区地热资源赋存状态及热源来源,揭示热循环机理,定量评估研究区热储温度、冷水混入比例、热循环深度等,利用巴塘热坑和巴塘热水塘两处地热田共20组温泉水样进行水化学分析和氢氧同位素分析,进行定量计算,并分析巴塘地区地下热水的演化过程。结果表明:巴塘地区地下热水主要为HCO3—Na型;水中Sr2+、Li+和F-与Cl-的相关性不佳;主要受大气降雨补给;冷水混入比例为64%~68%,未混入冷水时深部热储温度为218~229 ℃,热储循环深度4 546.32~4 777.89 m;Na+、HCO-3、SiO2浓度在热水循环过程中变化相对较大。说明Sr2+、Li+和F-只来自于水岩作用的矿物溶解,且该地区地下水补给主要来自于大气降水,川西地区地热水于围岩发生水岩作用,进行离子交换,在完成一系列水化学作用及水岩作用后,升至地表,最终形成温泉水。研究成果可为川西巴塘地区地热研究提供数据支撑及理论支持,同时也为川西整体区域地热研究提供方法借鉴,为研究区地下水开发利用研究提供参考。     

The Experimental Investigations on Motion Features of Groundwater Flow near the Pumping Well

Hot springs are natural exposed points of the hydrothermal system. The hydro-geochemistry of hot springs can be used to interpret the formation of the hydrothermal system; and the 14C dating can be used to evaluate the renewability of the hydrothermal system. The hot springs exposed from fault zones in western Guangdong are classified as granite fissure water and clastic rock fissure water, which are sampled and tested. The results of water chemistry analysis show that hot spring water is mainly HCO3-Na type in the beginning, while the mixing of seawater leads to the increase of Cl-. Hydrogen and oxygen isotopes indicate that these hot springs mainly come from atmospheric precipitation, and water-rock interactions produce oxygen isotope exchange reactions, where a significant “oxygen drift” phenomenon can be observed. The relationship between δ13C and HCO3- indicates that there is a deep source of CO2 “dead carbon” in hot spring water. This systematic error is not considered in the existing 14C dating correction models. The 14C age of the deep source “dead carbon” correction proposed in this paper is close to the 14C age of the reverse chemical simulation correction, the Gonfiantinie model, and the Mook model. The deep source “dead carbon” correction method can improve the systematic error. Therefore, the 14C age corrected by the deep source “dead carbon” may be more representative in terms of the actual age of geothermal water.     

张掖盆地地热资源赋存特征及成因分析

张掖盆地地处甘肃省河西走廊黑河流域中游地区,地势南东高北西低。已有勘探资料显示,张掖盆地赋存丰富的水热型地热资源。通过研究该区域地球物理勘探、钻探、地温测量及水文地球化学等成果资料,分析了张掖盆地地热资源赋存特征,探讨了其成因模式。张掖盆地地热田属沉积盆地型中低温地热田,热储为呈层状分布的新近系白杨河组砂岩、砂砾岩,选择钾镁地球化学温标计算热储温度为47～82°C,盖层为新近系上新统疏勒河组泥岩及第四系松散地层;地热水类型主要为碎屑岩类孔隙水,根据氢氧同位素特征推断其主要补给来源为南部祁连山区大气降水;祁连山北缘深大断裂和盆地内NNW向基底断裂是地热流体深循环良好的导水通道,地下水接受补给后沿导水断裂带或岩层孔隙裂隙运移,在深部热传导的增温作用下,赋存于碎屑岩类孔隙之中形成了本区的地热资源。水质分析结果表明：本区地热水属于溶滤型的陆相沉积水,水化学类型为Cl·SO₄—Na型,F-、SiO₂、溶解性总固体、总硬度含量随水温的升高而增大;区内地热水3H值普遍小于2.0 TU,说明形成年代较早;¹⁴C分析结果进一步证实,区域地...     

Geochemical genesis of geothermal waters from the Longling hydrothermal area,Yunnan, Southwestern China

Longling is characterized by a wide distribution of hydrothermal areas, among which the Banglazhang hydrothermal system is the most geothermally active. Banglazhang is marked by intensive hydrothermal activities including hot springs, geysers, fumaroles and hydrothermal explosions. The geothermal waters from the Longling region are mainly HCO_3-Na type with low but comparable SO_4 and Cl concentrations. Calculations based on a variety of chemical geothermometers and a K-Ca geobarometer indicate that the Banglazhang hydrothermal system has much higher subsurface temperature and CO_2 pressure compared to the other systems such as Daheba, Dazhulin and Huangcaoba. However, geothermal water samples collected from all these alternative hydrothermal areas are either partially equilibrated with reservoir minerals or are immature. The silica-enthalpy relationships of Banglazhang geothermal waters indicate the presence of a deep geothermal fluid with an enthalpy value and silica concentration of 945 J/g(up to around 220 °C) and 339 mg/L. Our work indicates the Banglazhang area is a promising source in terms of long-term utilization of hydrothermal resources.     

龙岩地区地下热水资源地质特征及开发利用探讨

龙岩地区有温泉及地热点共31处,总流量为260.9L/s,已探明有7处,可采热水量112.59L/s。预测全区可采热水量380L/s以上,可采热量58 963kW,年可利用热能量3.05×109（MJ/a）,相当于10.4万t/a标准煤中型煤矿的年采煤量。水质类型为HCO3—Na或HCO3—Ca型,部分达理疗热矿水命名标准。均属低温地热资源,热源主要为深部岩浆余热和花岗岩体中放射性元素衰变。可分为带状和层状2种热储类型：带状热储主要沿北西构造贮存于侵入岩和火山岩的构造破碎带中;层状热储主要贮存于沉积岩中。     

Hydrogeochemical characteristics of hot springs exposed from fault zones in western Guangdong and their ~(14)C age correction

Hot springs are natural exposed points of the hydrothermal system. The hydrogeochemistry of hot springs can be used to interpret the formation of the hydrothermal system; and the ~(14)C dating can be used to evaluate the renewability of the hydrothermal system. The hot springs exposed from fault zones in western Guangdong are classified as granite fissure water and clastic rock fissure water, which are sampled and tested. The results of water chemistry analysis show that hot spring water is mainly HCO_3-Na type in the beginning, while the mixing of seawater leads to the increase of Cl~-. Hydrogen and oxygen isotopes indicate that these hot springs mainly come from atmospheric precipitation, and water-rock interactions produce oxygen isotope exchange reactions, where a significant "oxygen drift" phenomenon can be observed. The relationship between δ~(13)C and HCO_3~- indicates that there is a deep source of CO_2 "dead carbon" in hot spring water. This systematic error is not considered in the existing ~(14)C dating correction models. The ~(14)C age of the deep source "dead carbon" correction proposed in this paper is close to the ~(14)C age of the reverse chemical simulation correction, the Gonfiantinie model, and the Mook model. The deep source "dead carbon" correction method can improve the systematic error. Therefore, the ~(14)C age corrected by the deep source "dead carbon" may be more representative in terms of the actual age of geothermal water.     

福建漳浦东山地热田基本特征及成因分析

漳浦东山地热田属于中低温地热田Π-2类型,热储呈带状分布,受地形、地层岩性、地质构造等因素影响。地下热水贮存于北东向与北西向断裂的复合部位,控制的可开采量338m3/d,推断的可开采量485m3/d,水温78℃,水质类型为HCO3-·SO42-1—Na＋型,pH值7.40～7.56,偏硅酸含量112.52～117.3mg/L,F离子含量10.99～12.85mg/L,可命名为氟水、硅水,达到理疗热矿水水质标准。     

南阳城区地下热水同位素特征及其水文地质意义

南阳城区地下热水的氢氧稳定同位素研究表明,本区地热水起源于降水补给。氚同位素揭示了地热水的形成年龄,采用同位素方法对本区地下热水与浅层冷水的混合作用对地下热水温度的影响进行了讨论,探讨了南阳城区地下热水的了解补给运移条件。     

四川西部中高温地热流体地球化学特征及其地质意义

四川西部是我国主要的高温地热资源分布区之一,水热活动的时空分布、物质来源与深部水热岩作用密切相关,地热流体化学特征可反映流体上升至近地表过程中发生的深部地球化学过程信息。通过分析鲜水河地热带、甘孜-理塘地热带和金沙江地热带典型地热田的地热流体化学组分特征,认为研究区地下水类型基本为HCO₃-Na型水。其中甘孜-理塘地热带地下热水中的K ⁺、Na ⁺、HCO₃ ^-和Mg ²⁺与Cl ^-有相似物质来源,除了来自矿物溶解外,还来源于地球深部物质。研究区地热流体径流较长,深度为2 189.93~5 620.52 m,地热流体在上升过程中冷水混入比例为 56%~78%,水岩作用仍未达到平衡状态。在循环过程中,受到含钙、镁的硅酸盐矿物溶解的影响。厘清区域内地热流体汇聚的路径及其控制因素,提高对四川西部地区地热资源分布规律和成因的认识,可为区域内工程建设施工提供参考依据。     

基于水化学组分和环境同位素信息探讨山东德州深层承压地下水起源

本文针对海河流域平原长期过量开采深层水导致地下水位不断下降,引发地面沉降等环境地质问题,选择德州深层水分布区作为重点研究区,以深层地下水化学组分及同位素信息作为主要研究对象,探讨深层地下水起源与更新性。研究结果表明,德州深层水主要形成于末次冰期盛期较寒冷的大气降水淋滤,在形成及径流过程中,遭遇较强烈的蒸发作用和阳离子交换作用,形成以HCO3-Na型水为主要成因类型,具有高氟、高钠、低钙、偏碱性的水化学特征,和氢氧稳定同位素低,氚含量低的同位素特点;深层地下水循环缓慢,更新能力较弱。     

Reconstruction of deep fluid chemical constituents for estimation of geothermal reservoir temperature using chemical geothermometers

This paper elaborates the chemical constituent change principles of deep geothermal fluid during the process of upward movement. It summarizes research methods of hydrochemistry, isotope and numerical modelling technique for the physiochemical processes such as decreasing temperature, shallow groundwater infusion, and degassing. The multi-component chemical geothermometry methods including gas geochemical method are discussed. High-temperature geothermal fields in China are mostly located in the southwest with frequent new tectonic movements, especially in Tibet high-temperature geothermal areas. Therefore the paper also focuses the status of high-temperature geothermal fluid research. At last, it’s pointed out in the paper that in the future we can start from typical high-temperature geothermal zones and geothermal fields to explore optimization of the multi-component geothermometry method and use it in the reconstruction and analogue of the formation mechanism and internal relevancy of regional geothermal systems.     

青藏高原地热资源与地壳热结构

青藏高原具有独特的地壳结构和高热背景。南部的喜马拉雅地块属于"热壳冷幔"型,拉萨-冈底斯地体属于"热壳热幔"型地块,该区域内中地壳范围内存在一低速高导层,可能为部分熔融岩浆囊,形成了规模宏伟的地热带。高原水热活动带主要出露在喜马拉雅-冈底斯-念青唐古拉之间,>25℃的水热区有283处,>80℃的沸、热泉有近40处。著名的羊八井高温热储地热田,已经建成装机容量达25.18 MW的地热电站,为拉萨输送了大量电力,地热资源在高原能源结构中占有重要的地位,具有巨大的开发前景和价值。      

贵德盆地地下热水水文地球化学特征

研究工作对完善区内高温地热系统成因机理和后期勘探及钻探工作提供一定的参考意义.为进一步研究贵德盆地地热资源赋存状态及热源来源,在充分了解贵德盆地地热地质条件的基础上,采集区内地热流体样品,进行水化学全分析和氢氧同位素分析,得到该区地热流体化学特征和氢氧同位素特征,估算了区内高温热田-扎仓寺热田的热储温度.分析结果表明:该区高温地下热水的水化学类型主要为SO₄·Cl-Na型,低温水水化学类型较为复杂,主要为SO₄-Na、SO₄·HCO₃-Na型;扎仓寺热田地下热水中Li+、F-、Sr2+、As3+与Cl-存在很好的正相关性,显示了相同的物质来源,SiO₂2-与Cl-极高的正相关性进一步验证了扎仓寺地热为深部热源;氢氧同位素数据都集中在当地大气降水线附近,说明地下热水主要为大气降水补给.选用合理的水文地球化学温标计算了扎仓寺热田的热储温度,并利用硅-焓模型分析了该热田地热流体中冷水混入比例及冷水混入前的热储温度,分析认为扎仓寺热田4 000 m以内存在两个热储层,第一热储层热储温度约为133 °C,热循环深度为1 800 m;第二热储层热储温度约为222 °C,热循环深度约为3 200 m.      

西藏搭格架地热区天然水的水化学组成与稳定碳同位素特征

为探究青藏高原搭格架地热区地热水、湖水、河水、冰雪融水等天然水体的水化学组成及物质来源控制因子,于2014年8月对该地区进行了考察和取样。利用紫外-可见光分光光度计和ICP-OES测定了水样中各阴、阳离子含量,利用Gas Bench连接同位素质谱仪测定了水样中溶解无机碳（DIC）同位素比值。结果表明,地热水中总溶解固体（TDS）含量为977.13~1 279.50 mg/L,阳离子以K+和Na+为主,阴离子以HCO3-和Cl-为主,湖水的TDS含量为77.81~810.94 mg/L,阳离子以Na+和Ca2+为主,阴离子以HCO3-(CO32-)和SO42-为主,地热水和湖水的水化学类型为HCO3-Na型;河水和冰雪融水的各离子含量较低,水化学类型为HCO3-Ca型;地热水的DIC浓度范围为9.2~15.4 mmol/L,δ13CDIC值为-9.09‰~-0.95‰;湖水的DIC浓度为1.1~9.7 mmol/L,δ13CDIC值为-8.84‰~-0.27‰。根据水化学Gibbs分布模式图判断出区域水化学特征主要受硅酸盐岩风化控制,以钠长石和钾长石风化为主,但是地热水的水化学组分受到硅酸盐岩和蒸发盐岩共同控制。通过碳同位素比值分析对区域主要风化过程中CO2的来源示踪表明,湖区周围的硅酸盐风化其碳源主要为土壤CO2,热泉区硅酸盐水解其碳源为地球深部CO2输入。      

天津市蓟县系雾迷山组地热流体地球化学特征

蓟县系雾迷山组是天津地区最重要的基岩裂隙型热储层。通过对天津市平原区不同构造单元的70组蓟县系雾迷山组地热流体样品的水化学测试,从其化学类型、特殊组分、热储温度及地热水成因等方面进行分析研究。结果表明,流体化学类型北部以HCO_3·SO_4-Na、HCO_3·SO_4·Cl-Na为主,往南变为Cl·HCO_3-Na、Cl·HCO_3·SO_4-Na、Cl·SO_4·HCO_3-Na为主,南部为Cl·SO_4-Na为主;地热流体中的氟、偏硅酸、偏硼酸、温度均达到了"有医疗价值浓度"或"命名矿水浓度"标准;由于雾迷山组地热流体水-岩之间未达到离子平衡状态,K-Mg温标不适用于本地区热储温度的计算,采用玉髓温标来预测热储温度的方法比较适用于本地区的热储。通过成因分析可知该热储属于贫溴的含岩盐地层溶滤水,具有陆相沉积水的特征。