ISSN 1000-3665 CN 11-2202/P

    太原西山地区变质岩热储回灌示踪试验

    Reinjection tracer test on thermal reservoir of metamorphic rock in Xishan area of Taiyuan City

    • 摘要: 太原市西山河口镇一带的变质岩地热资源属山地型中低温地热田,热储为条带状分布,地热水温度为40~42 °C,水化学类型为Cl·SO4—Na型。区内目前有2眼地热井,但连通情况尚不清楚,若长期开采且不进行回灌,将造成区内地下水资源的巨大浪费。为延长地热田使用寿命,需对变质岩热储开展回灌示踪试验,以掌握研究区地热流体运移特征及回灌能力,探讨热突破产生的原因,从而提出合理的采灌方案。文章将GJDR-1地热井作为回灌井,进行KI示踪剂的投放,监测井内水位及回灌水温;将GJ-WEMC地热井作为开采井和示踪剂观测井,监测示踪剂成分及水温。根据已有地热地质资料,结合本次示踪试验成果,计算地热井的保护半径。结果表明:采灌井之间存在水力联系,地热流体运移速度在0.009~0.030 m/s之间,示踪剂的回收率为0.008%;自然条件下本区变质岩热储层回灌能力为9.2 m3/h,以488 m的井间距会产生热突破现象,建议采灌井间距保持在1140 m以上;研究表明采灌井间距、回灌水温度、回灌量均会影响热突破。

       

      Abstract: The metamorphic rock geothermal resources in Hekou Town, Xishan area, Taiyuan City belong to the medium-low temperature geothermal field of mountain type, the geothermal water temperature is 40−42 °C, and the hydrochemical type is Cl·SO4—Na type. At present, the connectivity of the two geothermal wells is not clear. In order to extend the service life of the geothermal field, a reasonable mining and reinjection scheme needs to be proposed. Master the migration characteristics and recharge capacity of geothermal fluid in the study area, so as to explore the causes of thermal breakthrough. In this study, the GJDR-1 geothermal well was used as a recharge well and a KI tracer delivery well to monitor the water level and recharge water temperature. It is necessary to carry out reinjection tracer test on metamorphic rock thermal reservoir. The GJ-WEMC geothermal well is used as a mining well and a tracer observation well to monitor the tracer composition and water temperature. According to the existing geothermal geological data combined with the results of this tracer test, the protection radius of the geothermal well is calculated. The results show that there is a hydraulic connection between the production and reinjection wells. Under natural conditions, the recharge capacity of metamorphic rock thermal reservoir in this area is 9.2 m3/h, and the thermal breakthrough phenomenon will occur with the well spacing of 488 m, and the well spacing should be more than 1140m. The well spacing, recharge temperature and recharge amount will affect the thermal breakthrough.

       

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