浅析北京平谷地区片麻岩地热水的水化学特征

Hydrochemical Analysis on the Geothermal Water within the Gneiss in Pinggu District,Beijing

本文搜集了11个水样点的水化学数据,其中p1-p5取自北京平谷地区的5个片麻岩地热井。通过对比,片麻岩水样的水化学类型主要为SO4-Na,且地热水中氟、偏硅酸、偏硼酸普遍偏高,大部分能够达到有医疗价值的浓度。p1-p5均为半腐蚀性、不结垢的地热水,推测北京平谷地区片麻岩地热水为半腐蚀性、不结垢的地热水,地热水在开发利用过程中要有效防范腐蚀性问题。从p1-p5水化学数据分析结果来看,平谷地区片麻岩地热水中有冷水混入的可能。通过硅-焓模型分析,推测平谷地区片麻岩地热水的热储温度在98℃~207℃,水样中混入的冷水比例大部分在77%~88%之间。

Hydrochemical data of 11 water samples were collected,among which samples p1-p5 were from 5 gneiss’s geothermal wells in Pinggu District,Beijing.Through comparison,the hydrochemical types of gneiss’s water samples are mainly SO4-Na;the contents of fluorine,metasilicic acid and metaboric acid in geothermal water are generally high,most of which can reach the concentration of medical value.Samples p1-p5 are all semi-corrosive and non-scaling geothermal water.It is speculated that gneiss’s geothermal water in Pinggu District of Beijing is semi-corrosive and non-scaling geothermal water,and the geothermal water should be effectively prevented from corrosivity in the development and utilization process.According to the analysis results of p1-p5 hydrochemistry data,it is possible for cold water to mix into gneiss’s geothermal water in Pinggu District.Through the silicon-enthalpy model analysis,probably the thermal storage temperature of gneiss reaches 98 to 207,and the geothermal water may be mixed with cold water,which proportion ranges from 77%to 88%.