摘要
天津市区附近奥陶系地热流体TDS变化较大,存在东、西差异,且在西南部形成TDS与F-浓度高异常区,TDS最大值为4.8mg/L。通过δD--δ18O及流体动力场分析,认为奥陶系流体均为大气降水,来自北部燕山地区,并向西向南排泄。高TDS异常区与蓟县系雾迷山组储层流体液面位势异常区重合,且雾迷山组储层流体液面位势高于奥陶系流体液面位势23.21～26.96m,存在雾迷山组流体向奥陶系顶托补给的动力条件。李七庄断裂通过本异常区,是雾迷山组热流体向奥陶系补给通道;奥陶系地层中存在有1%的硫铁矿,该类矿物在氧化分解作用下,使SO42-离子提高,从而在西区形成TDS与F-浓度异常。
TDS of Ordovician geothermal fluid around Tianjin changes greatly with differences between east and west, and there is a high anomaly of TDS and F- in southwest with a maximum of TDS is 4.8 mg/L. Through the analysis of δD-δ^18O and fluid dynamic field, the authors consider that the Ordovician geothermal fluid precipitation came from northern Yanshan area, and drained to south and west. The high abnormal areas of TDS are coincident with the geopotential abnormal areas of reservoir fluid level in Wumishan Formation of Jixian System, and the geopotential of Wumishan reservoir fluid level is 23.21 - 26. 96 m higher than Ordovician＇s, which indicates recharging dynamical conditions from Wumishan geothermal to Ordovician top. The Liqizhuang fracture which traverses anomaly area is the recharging passage from Wumishan to Ordovician. The pyrites with 1% concentration at Ordovician strata can enhance the concentration of SO4^2- under oxidative decomposition action, which led to,the TDS and F^- anomalies in the western area.
出处
《世界地质》
CAS
CSCD
2009年第4期539-545,共7页
World Geology
基金
<天津市地热资源可持续开发潜力评价>:国土房热任[2006]01-06
关键词
TDS异常
流体液面位势
补排
成因分析
天津
TDS abnormly
geopotential of fluid level
recharge and discharge
cause analysis
Tianjin
