摘要
地球化学温度计是估算深部热储温度的常用方法,在没有钻孔或钻孔深度未达到地热储层时被广泛使用.但是过去地球化学温度计的计算结果主要用于与井口温度进行对比,而与钻孔实测温度之间的对比研究工作相对较少,这不利于温度计计算结果的可靠性评估.为此,本文选择勘探相对成熟的华北平原冀中坳陷雄安新区的12口地热井开展工作,通过现场水温测定、钻孔地温测量、地热水采集与测试的手段,在水岩相互作用程度判定和矿物化学热力学平衡模拟基础上,利用地球化学温度计估算地热水的热储温度,对比钻孔实测温度和温度计计算结果的误差,进而给出研究区不同热储的最适温度计方法.研究结果表明:(1)研究区内井口温度<70℃时,井口温度落在热储层顶底板钻孔实际温度的区间范围内.但井口温度超过100℃时,受降温、减压、相分离、CO_(2)脱气、SiO_(2)沉淀等因素影响,井口温度明显低于热储层顶板温度,更低于热储层底板温度,在地球化学温度计可靠性评估时需格外注意.(2)蓟县系岩溶热储地热水未达到水岩平衡,阳离子温度计不适用,新近系砂岩热储馆陶组地热水达到部分平衡,阳离子、SiO_(2)温度计均具可行性;针对不同储层,通过与实测温度对比发现玉髓溶解度温度计最适合岩溶热储,平均误差6.2℃;Na-K温度计和玉髓温度计最适合砂岩热储,平均误差分别为6.0℃和3.4℃.(3)在使用地球化学温度计时建议结合地层信息或岩石特征及井口温度进行筛选;在无实测温度情况下,对于同一地质构造单元,可根据不同采样深度的地球化学温度计计算结果了解地下深部温度情况,指导地热资源勘探工作.研究成果对于流体温度计应用及地热资源可持续开发利用具有重要意义.
The geochemical geothermometer is a common method for estimating the temperature of deep thermal reservoirs,which is widely used where no boreholes are drilled or the borehole depths do not reach the geothermal reservoir.However,the calculation results of the geochemical geothermometer were generally compared to the wellhead temperature in the previous studies.Comparison studies with the measured temperature of the borehole are few,which results in uncertainty of the geothermometers.In this study,12 geothermal wells in the geothermal field with detailed research basis and abundant data in Xiong'an New Area,Jizhong depression,North China Plain,were selected to evaluate the reliability of the geothermometer in conjunction with water temperature measurement,borehole logging,and geothermal water collection and analysis.Nineteen geochemical geothermometers were used to estimate the thermal storage temperature of geothermal water after the evolution of water-rock interaction and multimineral thermodynamic equilibrium simulation.And then the results were compared with the measured borehole temperature and wellhead temperature.Results show that when the wellhead temperature in the study area is less than 70℃,the wellhead temperature falls within the range of the actual borehole temperature from the thermal reservoir roof to the floor.However,when the wellhead temperature exceeds 100℃,the wellhead temperature is lower than the thermal reservoir roof temperature and much lower to the bottom plate temperature.They are affected by several factors such as cooling,decompression,phase separation,CO_(2)degassing,and SiO_(2)precipitation during the transport process,which should be paid great attention in the future.Secondly,the geothermal water in Jixian karst-fissured reservoir belongs to immature water,and the cation geothermometer is not applicable,while the geothermal water in the porous Neogene sandstone reservoir is mainly located in a partial equilibrium area which implies the feasibility of both cation and SiO_(2)geothermometer.The borehole temperatures were used to verify the suitable geothermometers.It is found that the chalcedony solubility geothermometer is suitable for Jixian karst-fissured reservoir with a deviation of 6.2℃,while the Na-K geothermometer and chalcedony geothermometer are suitable for the porous Neogene sandstone reservoir with a deviation of 6.0℃and 3.4℃,respectively.Finally,a variety of geothermometers are recommended to be selected with constraints of stratigraphic information,rock characteristics,wellhead temperature,and so on.And if the borehole logging is not available,underground temperature can be roughly understood with geochemical geothermometers at different sampling depths under the same geological structural unit.Our results have significant implications for the application of geochemical geothermometers and sustainable management of geothermal resources.
作者
姜颖
李捷
邢一飞
刘玉莲
王慧群
滕彦国
王贵玲
Jiang Ying;Li Jie;Xing Yifei;Liu Yulian;Wang Huiqun;Teng Yanguo;Wang Guiling(College of Water Sciences,Beijing Normal University,Beijing 100875,China;Engineering Research Center of Groundwater Pollution Control and Remediation,Ministry of Education,Beijing 100875,China;Chinese Academy of Geological Sciences,Beijing 100037,China;Deep Earth Science and Exploration Technology Laboratory,Ministry of Natural Resources,Beijing 100037,China;Geothermal and Hot Dry Rock Exploration and Development Technology Innovation Center,Ministry of Natural Resources,Beijing 100037,China)
出处
《地球科学》
EI
CAS
CSCD
北大核心
2023年第3期958-972,共15页
Earth Science
基金
国家重点研发计划项目(No.2018YFC0604302)
中国地质调查局项目(Nos.DD20189114,DD20221677)。
关键词
流体温度计
地热水
热储温度
钻孔测温
雄安新区
地球化学
geothermometer
geothermal water
temperature of deep thermal reservoirs
borehole temperature measurements
Xiong’an New Area
geochemistry
