首页|川西磨西断裂湾东地热水化学特征及成因机制

川西磨西断裂湾东地热水化学特征及成因机制

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  • 国家科技期刊平台
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[目的]地热能开发是实现碳达峰、碳中和的重要途径。磨西断裂位于川西鲜水河断裂南段，拥有丰富的地热资源，是未来地热能开发的重点区域。[方法]对四川磨西断裂湾东地热区开展水文地球化学研究，通过水化学相关性分析其水-岩作用过程，利用地热温标、硅-焓混合模型等方法计算其热储温度、冷热水混合比例，采用氢氧同位素探明补给来源和补给高程。[结果和结论]结果显示:磨西断裂地热水的水化学类型包括HCO3·Cl-Na型和HCO3·SO4-Ca·Mg型。地热水的水化学组分主要受水-岩作用(泥盆系大理岩方解石矿物溶解)影响，其中HCO3·Cl-Na型地热水在磨西断裂深部受岩浆水混合和CO2 脱气作用影响。HCO3·Cl-Na型地热水热储温度较高(159。16～228。57℃)，沿磨西断裂循环深度较大;HCO3·SO4-Ca·Mg型地热水的热储温度较低(111。02～138。04℃)，沿次级构造草科断裂运移，循环深度较小。地热水的补给来源均为大气降水和深部岩浆水，补给区为湾东地热区西部贡嘎山，补给高程在 2 382～2 981 m。本次研究探明了湾东地热区存在 2种不同成因模式，其水化学特征和热储温度差异显著，可为该区地热能开发提供更具针对性的理论依据。
Hydrochemical characteristics and genetic mechanism of geothermal water in the Wandong geothermal area along the Moxi fault in western Sichuan
[Objective]Geothermal energy exploitation is identified as a vital way to achieve the goals of peak carbon di-oxide emissions and carbon neutrality.The Moxi fault,located in the southern segment of the Xianshuihe fault zone in western Sichuan,boasts abundant geothermal resources,serving as a significant area for subsequent geothermal energy exploitation.[Methods]This study investigated the hydrogeochemistry of the Wandong geothermal area along the Moxi fault,analyzed the water-rock interaction process in the area based on the hydrochemical correlation,and calculated the reservoir temperatures and the mixing ratios of cold and hot water using geothermometers and the silica-enthalpy mix-ing model.Furthermore,this study investigated the recharge sources and elevations of geothermal water based on hydro-gen and oxygen isotopes.[Results and Conclusions]Key findings are as follows:(1)Geothermal water along the Moxi fault exhibits hydrochemical types of HCO3·Cl-Na and HCO3·SO4-Ca·Mg.The hydrochemical composition of geotherm-al water is subjected principally to water-rock interactions(i.e.,the dissolution of calcite in Devonian marbles).Besides,the HCO3·Cl-Na geothermal water is further affected by the mixing of magmatic water and the CO2 degasification in the deep part of the Moxi fault.This type of geothermal water displays relatively high reservoir temperatures ranging from 159.16℃to 228.57℃and large circulation depths along the Moxi fault.In contrast,the HCO3·SO4-Ca·Mg geothermal water exhibits relatively low temperatures varying between 111.02℃and 138.04℃and small circulation depths along the Caoke fault,a secondary structure.(2)The geothermal water is recharged by meteoric water and deep magmatic wa-ter.Its recharge area resides in the Gongga Mountain in the western Wandong geothermal area,with recharge elevations ranging from 2 382 m to 2 981 m.Two genetic modes of geothermal water in the Wandong geothermal area were identi-fied,manifesting significantly different hydrochemical characteristics and reservoir temperatures.This study will provide a more specific theoretical basis for geothermal energy exploitation in the area.

geothermal waterwater-rock interactionreservoir temperaturerecharge sourcegenetic modeMoxi fault in Sichuan Province

黄珣、张云辉、李晓、吕国森、郭宏洋

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西南交通大学 地球科学与工程学院,四川 成都 611756

成都理工大学 地质灾害防治与地质环境保护国家重点实验室,四川 成都 610059

地热水 水-岩作用 热储温度 补给来源 成因模式 四川磨西断裂

国家自然科学基金国家自然科学基金四川省科技计划四川省科技计划地质灾害防治与地质环境保护国家重点实验室开放基金

42102334420723132022NSFSC04132023YFS0356SKLGP2022K017

2024

10.12363/issn.1001-1986.23.10.0710

煤田地质与勘探
中煤科工集团西安研究院

煤田地质与勘探

CSTPCD北大核心
影响因子：1.079
ISSN：1001-1986
年,卷(期)：2024.52(6)
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