淮南矿区地热地质特征与地热资源评价

Geothermal geological characteristics and geothermal resources evaluation of Huainan mining area

  • 摘要: 为了探索淮南矿区地热地质特征和矿井深部热害防治对策,系统收集和分析了淮南矿区钻孔井温测井资料,基于近似稳态测温数据,拟合了测温孔孔底温度校正曲线,对简易井温测井钻孔孔底温度进行了校正;采用浅钻孔测温法,对井下巷道围岩温度进行了测定;计算了各井田的地温梯度,并结合110块煤系地层煤岩样品的热导率测试结果,计算得出淮南矿区的大地热流值,编制了淮南矿区现今地温场、地温梯度和大地热流分布图,在此基础上,系统论述了该区现今地温场、地温梯度和大地热流的展布趋势以及煤系岩石的热物理性质,探讨了地温场分布的构造控制作用,并对矿区地热资源进行了评价。研究结果表明:① 淮南矿区测温井底温度恢复与静井时间符合指数函数关系,并据此建立了简易井温测井钻孔孔底温度变化的校正公式;② 淮南矿区地热参数表现为地温梯度为1.00~4.00 ℃/hm,平均值为2.8 ℃/hm;大地热流值变化在31.87~92.68 mW/m2,平均值为65.50 mW/m2;-500 m水平平均地温为29.96 ℃,-1 000 m水平为41.84 ℃,-2 000 m水平为69.62 ℃;岩石热导率在0.37~5.22 W/(m·K),平均值为2.93 W/(m·K);③ 平面上地温梯度、地温场、大地热流总体呈现为西低东高、南低北高的分布趋势;④ 矿区现今地温场和大地热流分布主要受控于地质构造,表现为褶皱型、逆掩断层阻热型和导水断层传热型3种构造控温模式;⑤ 基于地热资源评估,该区热储层地热资源量为2.32×1016 kJ,可采热能储量为2.64×1015 kJ,矿井水和矿井回风余热资源量为0.97×1013~1.26×1013kJ/a,是一个可再生的低温热源,潜在效益显著。研究成果为淮南矿区深部煤炭开发热害防治和地热资源综合开发利用提供了地质依据。加强煤矿区深部地热资源和矿井余热资源的评价、利用研究,应是煤矿区可持续发展的方向之一。

     

    Abstract: In order to explore the geothermal geological characteristics of Huainan mining area and the prevention and control measures of deep mine heat hazard,the temperature logging data of the exploration holes of Huainan mining ar- ea were systematically collected and analyzed. Based on the approximate steady-state temperature data,the temperature calibration curve in the thermometry hole bottom was fitted,and the temperature in the hole bottom of the simple ther- mometry well was corrected. The surrounding rock temperature of the underground roadway was measured by shallow hole temperature-measuring method. The geothermal gradient of each well field was calculated,and the terrestrial heat flow value of Huainan mining area was calculated by the thermal conductivity test results of 110 coal and rock samples of coal measure strata. The current geothermal field,the geothermal gradient and the terrestrial heat flow distribution map of Huainan mining area were compiled,and the distribution characteristics of the current geothermal field,the ge-othermal gradient and the terrestrial heat flow in this area and the thermophysical properties of coal measures rocks were comprehensively expounded. The geological structure control of the geothermal field distribution was discussed and the geothermal resources in this mining area were calculated. The results show that:① The temperature recovery in the bottom of the well and the static time of well-liquid of the Huainan mining area is in accordance with the expo-nential function relationship,and the correction formula for the temperature change in the bottom of the simple ther-mometry well is established accordingly. ② The geothermal parameters in the Huainan mining area are as follows:the geothermal gradient is from 1. 00 to 4. 00 ℃ / hm with an average value 2. 8 ℃ / hm;the terrestrial heat flow value va-ries from 31. 87 to 92. 68 mW / m2 with an average value 65. 50 mW / m2 ;the average temperature of the -500 m level is 29. 96 ℃ ,and the value of -1 000 m and -2 000 m level are 41. 84 ℃ and 69. 62 ℃ ,respectively;the thermal conductivity of rock is from 0. 37 to 5. 22 W / (m·K) with an average value 2. 93 W / (m·K). ③ The distribution of the geothermal gradient,the geothermal field and the terrestrial heat flow on the plane are generally higher in the east and north than that in the west and south. ④ The current geothermal field and the terrestrial heat flow distribution in the mining area are mainly controlled by the geological structure,which show three modes of controlling temperature by the geological structure including the fold type,the overthrust fault heat-resistance type and the water-conducting fault heat transfer type. ⑤ According to the results of geothermal resources evaluation,the resources of the geothermal reser-voir in this area are 2. 32 ×1016 kJ,the recoverable heat energy reserves are 2. 64 ×1015 kJ,and the mine water and mine return air waste heat recovery resources are from 0. 97×1013 to 1. 26×1013 kJ / a,and the geothermal reservoir be-longs to a renewable low-temperature heat source with significant potential benefits. The research results can provide a geological basis for the treatment of thermal hazard and the comprehensive development and utilization of geothermal resources in deep mining in Huainan mining area. Evaluation and utilization of geothermal resources and mine waste heat resources in the deep mine should be one of the development directions for the sustainable development of coal mining areas

     

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