四川地热流体水文地球化学及同位素特征简析

Hydrogeochemical and Isotope Characteristics of Geothermal Fluid in Sichuan

四川省范围内有沉积盆地型和隆起山地型两类地热资源,共划分五个地热区。从五个区采取的205组水样的水文地球化学特征及184组~2H、^(18)O和61组^(14)C特征分析显示,四川省各地热区地热流体基本来自于大气降水补给,地热流体的水文地球化学和同位素特征与其所属的热储类型和热储开放性有关。盆地型热储主要为岩溶层状热储,山地型热储主要是变质岩为主的裂隙带状热储和层状带状复合型热储。盆地型热储开放性较山地型弱,地热流体矿化度和理疗元素含量均比山地型高,易形成深埋藏的卤水,地下水平均径流时间较山地型长。本研究可为四川省地热资源未来的开发利用规划提供参考。

There are two types of geothermal resources (conductive geothermal resource and convective geothermal resource) and five geothermal areas in Sichuan. Hydrogeochemical and isotope characteristics of samples from these five areas indicate that most of the geothermal fluids in Sichuan are supplied by atmospheric precipitation and the hydrogeochemical and isotope characteristics are related to the types and openness of the geothermal reservoir. The conductive geothermal resources are mainly stratified reservoir with carbonatite, while the convective geothermal resources are mainly fissure zoned reservoir and zoned and stratified combining reservoir on metamorphic rocks. The reservoir of conductive geothermal resource is more closed than the reservoir of convective geothermal resource, and the total dissolved solids as well as the therapeutic elements contents are higher than those in geothermal fluid of convective geothermal resource. For the geothermal fluid of conductive geothermal resource, it’s also more easily to form brine and has longer runoff time than the geothermal fluid of convective geothermal. This work may provide some references to the development and utilization of geothermal resources in Sichuan.