重庆市统景温泉水化学特征及混合作用

Hydrochemical characteristics and mixing effect in Tongjing hot springs of Chongqing

为了探讨温泉水的热储温度、深部热水与冷水的混合作用,以期为勘探、评价和合理开发利用温泉资源提供科学依据,文章对重庆统景温泉、岩溶地下水和地表水物理化学指标进行监测和分析。结果表明:(1)温泉水化学类型为SO_4-Ca·Mg型,浅层岩溶水为HCO_3-Ca·Mg型,温塘河为HCO_3-Ca型;温泉水TDS、Ca^(2+)、Mg^(2+)、SO_4^(2-)、Si、B、Sr高于岩溶地下水和地表水,主要与温泉水流经碳酸盐岩热储层并发生强烈的水岩作用有关。(2)不同地热温标法的对比应用发现,阳离子和玉髓地热温标法不适用,而无蒸汽损失石英和修正后的SiO_2地热温标法更适于计算统景温泉热储的温度,利用这两种方法算出来的热储平均温度为86℃。(3)通过Na-K-Mg三角图判断出岩溶地下水在深部含水层与地下热水发生混合。利用混合模型和硅-焓图解法估算出鸳鸯泉中冷水的混入比例分别为89%、86%;2号井中冷水的混入比例分别为80%、79%。2号井冷水混入比例比鸳鸯泉低,可能受2号井周围水泥护壁的影响。

The thermal reservoir temperature and the mixture of deep and shallow grounwater are discussed in this study, with the intention of providing a scientific basis for reasonable exploration, scientific evaluation and sustainable development and utilization of thermal water resources. Physical and chemical parameters of hot springs, karst groundwater and surface water in Tongjing, Chongqing were monitored and comparatively studied. Results show that the water chemistry of hot springs, the shallow karst water, and Wentang River belongs to type water of SO4 --Ca ·Mg, HCO3-Ca · Mg,and HCO3 - Ca, respectively. Compared with the shallow karst groundwater and surface water, the higher values of TDS, Ca^2＋ , Mg^2＋ , SO4^2- , Si, B, and Sr are probably attributed to the runoff through the thermal reservoir formation and intense water-rock interaction. It was found that the methods of quartz without steam loss and modified SiO2 geothermometers rather than cationic and chalcedony geothermometers are more suitable for geothermometric calculation in Tongjing. An average reservoir temperature of 86 ℃ was estimated by the quartz without steam loss and modified SiO2 geothermometers. Based on the Na--K--Mg plot, the mixture of shallow karst water and thermal water occurred at deep aquifer. The mixture modeI and silicon-enthalpy diagram show that the ratios of mixture of cold water for the Yuanyang hot spring are 89~ and 86~, respectively, and 80% and 79% for No. 2 geothermal well water, respectively. The ratio of mixed cold water of No. 2 geothermal well water is lower than that of the Yuanyang hot spring, probably because the No. 2 geothermal well water is affected by the application of cement in the borehole wall protection.