四川巴塘地热田水文地球化学特征及成因
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摘要
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HCO_3—Na型;水中Sr~(2+)、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~-、SiO_2浓度在热水循环过程中变化相对较大。说明Sr~(2+)、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。
Geochemical characteristics of geothermal water can reveal deep geothermal processes. The Batang area in western Sichuan is taken as an example,where geothermal resources are relatively abundant,but few studies were carried out previously. Based on the existing researches,this paper aims to further identify the occurrence and source of geothermal resources in western Sichuan,reveal the mechanism of thermal cycle,and quantitatively evaluate the temperature of the geothermal reservoirs,the mixing ratio of cold water and depth of thermal cycle in the study area. Hydrochemical analyses and hydrogen and oxygen isotopes of 20 hot spring water samples from two geothermal fields in Batang are used to calculate quantitatively and analyze the evolution process of thermal groundwater in the Batang area. The results show that the thermal groundwater is mainly of HCO_3~-Na type in the Batang area. F~-,Li~(2+),As~+and Cl~-in the hot water have poor correlation,indicating that F~-,Li~(2+),As~+only come from the dissolution of minerals in the rocks. The hot water is mainly recharged by atmospheric rainfall. The temperature and depths of geothermal reservoirs before mixture with cold water are obtained by the Si-enthalpy model as 218-229 ℃ and 4 546. 32-4 777. 89 m and the mixing ratio of cold water ranges from 64% to 68%. The changes in concentrations of Na~+,HCO_3~-and Si O_2 in the Batang area are relatively large,indicating that the geothermal water only comes from the dissolution of minerals in rocks,including dissolution of calcium feldspar and silicate precipitation. Water-rock interactions and ion exchange occur between the geothermal water and surrounding rocks in western Sichuan. After completing a series of hydrochemical action and water-rock interaction,the hot water rises to the land surface and eventually emerges in the form of hot springs. The above analyses of the characteristics of the geothermal reservoirs can provide data support and theoretical support for the future geothermal research in the Batang area in western Sichuan,and can also provide methodological references for the overall regional geothermal research in western Sichuan,which is of important reference significance for the study of groundwater development and utilization in the study area.
Geochemical characteristics of geothermal water can reveal deep geothermal processes. The Batang area in western Sichuan is taken as an example,where geothermal resources are relatively abundant,but few studies were carried out previously. Based on the existing researches,this paper aims to further identify the occurrence and source of geothermal resources in western Sichuan,reveal the mechanism of thermal cycle,and quantitatively evaluate the temperature of the geothermal reservoirs,the mixing ratio of cold water and depth of thermal cycle in the study area. Hydrochemical analyses and hydrogen and oxygen isotopes of 20 hot spring water samples from two geothermal fields in Batang are used to calculate quantitatively and analyze the evolution process of thermal groundwater in the Batang area. The results show that the thermal groundwater is mainly of HCO_3~-Na type in the Batang area. F~-,Li~(2+),As~+and Cl~-in the hot water have poor correlation,indicating that F~-,Li~(2+),As~+only come from the dissolution of minerals in the rocks. The hot water is mainly recharged by atmospheric rainfall. The temperature and depths of geothermal reservoirs before mixture with cold water are obtained by the Si-enthalpy model as 218-229 ℃ and 4 546. 32-4 777. 89 m and the mixing ratio of cold water ranges from 64% to 68%. The changes in concentrations of Na~+,HCO_3~-and Si O_2 in the Batang area are relatively large,indicating that the geothermal water only comes from the dissolution of minerals in rocks,including dissolution of calcium feldspar and silicate precipitation. Water-rock interactions and ion exchange occur between the geothermal water and surrounding rocks in western Sichuan. After completing a series of hydrochemical action and water-rock interaction,the hot water rises to the land surface and eventually emerges in the form of hot springs. The above analyses of the characteristics of the geothermal reservoirs can provide data support and theoretical support for the future geothermal research in the Batang area in western Sichuan,and can also provide methodological references for the overall regional geothermal research in western Sichuan,which is of important reference significance for the study of groundwater development and utilization in the study area.
引文
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[6]焦杏春.地下水水质评价与水资源管理:水文地球化学与同位素方法的应用研究进展[J].地质学报,2016,90(9):2476-2489.[JIAO X C.Groundwater quality assessment and groundwater resource management:a review on hydrogeochemical and stable isotope approaches[J]. Acta Geologica Sinica,2016,90(9):2476-2489.(in Chinese)]
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[13]张健.川西高温水热活动区的地热学分析[J].中国科学:地球科学,2017,47(8):899-915.[ZHANG J. Geothermal data analysis at the hightemperature hydrothermal area in Western Sichuan[J]. Science China:Sciences,2017,47(8):899-915.(in Chinese)]
[14]张未.吉林省长岭县浅层地下水水文地球化学演化规律分析[J].水资源与水工程学报,2016,27(5):59-63.[ZHANG W. Analysis of evolution law of hydrology and geochemistry of shallow groundwater in Changling county of Jilin Province[J]. Journal of Water Resources and Water Engineering,2016,27(5):59-63.(in Chinese)]
[15]袁建飞.西藏羊八井高温地热田水环境中硼的迁移和转化研究[D].武汉:中国地质大学,2010.[YUAN J F. Transport of boron in the aquatic environment of the Yangbajing Geothermal field,Tibet[D]. Wuhan:China University of Geosciences,2010.(in Chinese)]
[16]张锡根.同位素地球化学在地热勘探中的应用[J].水文地质工程地质,1988(1):28-31.[ZHANG X G. Application of isotopic geochemistry in geothermal exploration[J]. Hydrogeology&Engineering Geology, 1988(1):28-31.(in Chinese)]
[17] Dansgaard. Sable isotopes in precipitation[M].Tellus,1964:436-438.
[18]苏艳,马致远,刘方.西安咸阳地下热水氘过量参数研究[J].煤田地质与勘探,2007,35(3):39-41.[SU Y,MA Z Y,LIU F. Deuterium excess parameter features study on thermal groundwater of Xi'an and Xian yang[J]. Coalgeology&Exploration,2007,35(3):39-41.(in Chinese)]
[19]张洪平,刘恩凯,王东升,等.中国大气降水稳定同位素组成及影响因素[J].中国地质科学院水文地质环境地质研究所所刊,1991(7):101-109.[ZHANG H P, LIU E K, WANG D S, et al.Composition of stable isotopes of precipitation and controlling factors in china. bull[J]. Institute of Hydrogeology and Engineering Geology CAGS,1991(7):101-109.(in Chinese)]
[20]孙占学,李学礼,史维浚.江西中低温地热水的同位素水文地球化学[J].华东地质学院学报,1992,15(3):243-248.[SUN Z X,LI X L,SHI W J.Isotopic hydrogeochemistry of mid-low temperature geothermal water in Jiangxi province[J]. Journal of East China Geological Institute,1992,15(3):243-248.(in Chinese)]
[21]王皓,柴蕊.地热温标在地热系统中的应用研究[J].河北工程大学学报(自然科学版),2009,26(3):54-58.[WANG H,CHAI R. Application of geothermometers in the geothermal system[J].Journal of Hebei University of Engineering(Natural Science Edition),2009,26(3):54-58.(in Chinese)]
[22]佟伟,章铭陶.西藏地热[M].北京:科学出版社,1981.[TONG W,ZHANG T M. Geothermals beneath Xizang(Debit)plateau[M]. Beijing:Science Press,1981:74-100.(in Chinese)]
[23]曹烈.致密砂岩天然气成藏动力学研究—以川西坳陷上三叠统须家河组为例[D].成都:成都理工大学,2010:41-43.[CAO L. Gas accumulation dynamics of tight sandstone reservoir——Example from the upper Xujiahe formation in Western Sichuan depression[D]. Chengdu:Chengdu University of Technology,2010:41-43.(in Chinese)]
[2]沈照理.水文地质学[M].北京:科学出版社,1985.[SHEN Z L. Hydrogeology[M]. Beijing:Science Press,1985.(in Chinese)]
[3]钱会,马致远.水文地球化学[M].北京:地质出版社,2005.[QIAN H,MA Z Y. Hydrogeochemistry[M]. Beijing:Geological Publishing House,2005.(in Chinese)]
[4]魏亚妮,李培月.水文地球化学模拟研究与应用[J].水资源与水工程学报,2010,21(1):58-61.[WEI Y N,LI P Y. Research and application of hydro-geochemical simulation[J]. Journal of Water Resources&Water Engineering,2010,21(1):58-61.(in Chinese)]
[5]张萌,王贵玲.西藏谷露高温地热系统水文地球化学特征及成因模式[J].成都理工大学学报(自然科学版),2014,41(3):382-392.[ZHANG M,WANG G L. Hydrogeochemical characteristics and genetic model of Gulu high-temperature geothermal system in Tibet, China[J]. Journal of Chengdu University of Technology(Science&Technology Edition),2014,41(3):382-392.(in Chinese)]
[6]焦杏春.地下水水质评价与水资源管理:水文地球化学与同位素方法的应用研究进展[J].地质学报,2016,90(9):2476-2489.[JIAO X C.Groundwater quality assessment and groundwater resource management:a review on hydrogeochemical and stable isotope approaches[J]. Acta Geologica Sinica,2016,90(9):2476-2489.(in Chinese)]
[7]郎旭娟,蔺文静,刘志明,等.贵德盆地地下热水水文地球化学特征[J].地球科学,2016,41(10):1723-1734.[LANG X J,LIN W J,LIU Z M,et al. Hydrochemical characteristics of geothermal water in Guide Basin[J]. Earth Science,2016,41(10):1723-1734.(in Chinese)]
[8]袁建飞,邓国仕,徐芬,等.毕节市北部岩溶地下水水文地球化学特征[J].水文地质工程地质,2016,43(1):12-21.[YUAN J F,DENG G S,XU F,et al. Hydrogeochemical characteristics of karst groundwaterin the northern part of the city of Bijie[J]. Hydrogeology&Engineering Geology,2016,43(1):12-21.(in Chinese)]
[9]史杰,乃尉华,李明,等.新疆曲曼高温地热田水文地球化学特征研究[J].水文地质工程地质,2018,45(3):165-172.[SHI J,NAI W H,LI M,et al. Hydrogeochemical characteristics of high temperature geothermalfield of the Quman geothermal field in Xinjiang[J]. Hydrogeology&Engineering Geology,2018,45(3):165-172.(in Chinese)]
[10]武斌,曹俊兴.音频大地电磁测深法在川西地热勘查研究中的应用[J].工程勘察,2011(9):91-94.[WU B,CAO J X. The application of AMT to the study of geothermal exploration in the western Sichuan[J]. Geotechnical Investigation&Surveying,2011(9):91-94.(in Chinese)]
[11]倪高倩,张恒,韦玉婷,等.四川地热流体水文地球化学及同位素特征简析[J].新能源进展,2016,4(3):184-194.[NI G Q,ZHANG H,WEI Y T,et al. Hydrogeochemical and isotope characteristics of geothermal fluid in Sichuan[J]. Advances in New and Renewable Energy,2016,4(3):184-194.(in Chinese)]
[12]罗敏,任蕊.四川地热资源类型、分布及成因模式[J].四川地质学报,2016,36(1):47-50.[LUO M, REN R. Type, distribution and genesis of geothermal resource in Sichuan[J]. Acta Geologica Sichuan,2016,36(1):47-50.(in Chinese)]
[13]张健.川西高温水热活动区的地热学分析[J].中国科学:地球科学,2017,47(8):899-915.[ZHANG J. Geothermal data analysis at the hightemperature hydrothermal area in Western Sichuan[J]. Science China:Sciences,2017,47(8):899-915.(in Chinese)]
[14]张未.吉林省长岭县浅层地下水水文地球化学演化规律分析[J].水资源与水工程学报,2016,27(5):59-63.[ZHANG W. Analysis of evolution law of hydrology and geochemistry of shallow groundwater in Changling county of Jilin Province[J]. Journal of Water Resources and Water Engineering,2016,27(5):59-63.(in Chinese)]
[15]袁建飞.西藏羊八井高温地热田水环境中硼的迁移和转化研究[D].武汉:中国地质大学,2010.[YUAN J F. Transport of boron in the aquatic environment of the Yangbajing Geothermal field,Tibet[D]. Wuhan:China University of Geosciences,2010.(in Chinese)]
[16]张锡根.同位素地球化学在地热勘探中的应用[J].水文地质工程地质,1988(1):28-31.[ZHANG X G. Application of isotopic geochemistry in geothermal exploration[J]. Hydrogeology&Engineering Geology, 1988(1):28-31.(in Chinese)]
[17] Dansgaard. Sable isotopes in precipitation[M].Tellus,1964:436-438.
[18]苏艳,马致远,刘方.西安咸阳地下热水氘过量参数研究[J].煤田地质与勘探,2007,35(3):39-41.[SU Y,MA Z Y,LIU F. Deuterium excess parameter features study on thermal groundwater of Xi'an and Xian yang[J]. Coalgeology&Exploration,2007,35(3):39-41.(in Chinese)]
[19]张洪平,刘恩凯,王东升,等.中国大气降水稳定同位素组成及影响因素[J].中国地质科学院水文地质环境地质研究所所刊,1991(7):101-109.[ZHANG H P, LIU E K, WANG D S, et al.Composition of stable isotopes of precipitation and controlling factors in china. bull[J]. Institute of Hydrogeology and Engineering Geology CAGS,1991(7):101-109.(in Chinese)]
[20]孙占学,李学礼,史维浚.江西中低温地热水的同位素水文地球化学[J].华东地质学院学报,1992,15(3):243-248.[SUN Z X,LI X L,SHI W J.Isotopic hydrogeochemistry of mid-low temperature geothermal water in Jiangxi province[J]. Journal of East China Geological Institute,1992,15(3):243-248.(in Chinese)]
[21]王皓,柴蕊.地热温标在地热系统中的应用研究[J].河北工程大学学报(自然科学版),2009,26(3):54-58.[WANG H,CHAI R. Application of geothermometers in the geothermal system[J].Journal of Hebei University of Engineering(Natural Science Edition),2009,26(3):54-58.(in Chinese)]
[22]佟伟,章铭陶.西藏地热[M].北京:科学出版社,1981.[TONG W,ZHANG T M. Geothermals beneath Xizang(Debit)plateau[M]. Beijing:Science Press,1981:74-100.(in Chinese)]
[23]曹烈.致密砂岩天然气成藏动力学研究—以川西坳陷上三叠统须家河组为例[D].成都:成都理工大学,2010:41-43.[CAO L. Gas accumulation dynamics of tight sandstone reservoir——Example from the upper Xujiahe formation in Western Sichuan depression[D]. Chengdu:Chengdu University of Technology,2010:41-43.(in Chinese)]