ISSN 1000-3665 CN 11-2202/P
    赵丽,黄尚峥,张庆,等. 注入时间和静水压力对孔隙热储层中Cl运移影响[J]. 水文地质工程地质,2023,50(2): 189-197. DOI: 10.16030/j.cnki.issn.1000-3665.202206026
    引用本文: 赵丽,黄尚峥,张庆,等. 注入时间和静水压力对孔隙热储层中Cl运移影响[J]. 水文地质工程地质,2023,50(2): 189-197. DOI: 10.16030/j.cnki.issn.1000-3665.202206026
    ZHAO Li, HUANG Shangzheng, ZHANG Qing, et al. Effect of injection time and hydrostatic pressure on chloride migration in a porous geothermal reservoir[J]. Hydrogeology & Engineering Geology, 2023, 50(2): 189-197. DOI: 10.16030/j.cnki.issn.1000-3665.202206026
    Citation: ZHAO Li, HUANG Shangzheng, ZHANG Qing, et al. Effect of injection time and hydrostatic pressure on chloride migration in a porous geothermal reservoir[J]. Hydrogeology & Engineering Geology, 2023, 50(2): 189-197. DOI: 10.16030/j.cnki.issn.1000-3665.202206026

    注入时间和静水压力对孔隙热储层中Cl运移影响

    Effect of injection time and hydrostatic pressure on chloride migration in a porous geothermal reservoir

    • 摘要: 迄今为止,注入时间和静水压力对溶质在深层承压地热水中的运移规律影响研究少有报道。通过模拟35℃的低温地热环境,开展了注入时间1,2,3,4,5 h以及静水压力0,6,9 MPa条件下Cl的运移柱模拟试验。采用CXTFIT 2. 1软件进行数值模拟,探讨了孔隙型热储砂土中Cl的运移规律和影响因素。结果表明:在模拟的低温孔隙型热储层中,不同注入时间和静水压力下,Cl的运移曲线均呈正态对称分布,一维对流弥散(CDE)模型也可较好地表征其穿透曲线,因此溶质扩散过程符合菲克定律。注入时间的不同,会引起Cl的穿透曲线、运移参数发生变化,这与不同注入时间条件下溶质注入总量、柱内溶质浓度差以及分子扩散能力不同有关。在不同静水压力条件下,弥散系数从0 MPa的25.22 cm2/h增加到9 MPa的36.13 cm2/h,分子扩散系数、机械弥散系数以及弥散度也随之增大,因此溶质的弥散作用随静水压力的增大而增强。研究结果对于丰富地下水的溶质运移理论具有重要意义。

       

      Abstract: Few studies have focused on the effects of injection time and hydrostatic pressure on the solute transport in porous geothermal reservoirs to date. The chloride displacement experiments were individually carried out at 35 °C at the injection time of 1 h, 2 h, 3 h, 4 h and 5 h individually through the simulated columns packed with the thermal reservoir fine sand. Column experiments were performed at 35 °C at hydrostatic pressure of 0, 6 and 9 MPa individually. By using the one-dimensional CDE model in the CXTFIT 2.1 software, the migration law of Cl and its influencing factors in the studied matrix were examined. The results show that the Cl breakthrough curves under different injection time and hydrostatic pressure are symmetrically distributed, and they can all be well described by the CDE model. Thus, the solute dispersion can conform to the Fick’s law in the simulated low-temperature pore geothermal water. The breakthrough curve and transport parameters of Cl are highly correlated with the injection time due to the variations of the total amount of solute mass injected, concentration differences and molecular diffusion ability in the studied geothermal water. In addition, the value of D increases from 25.22 cm2/h at 0 MPa to 36.13 cm2/h at 9 MPa, combining with the increasing molecular diffusion coefficient, dispersion coefficient and dispersivity with hydrostatic pressure. Hence, the solute hydrodynamic dispersion in the simulated sandy column are enhanced with the increasing hydrostatic pressure. The results are of great significance to enrich the theory of solute transport in groundwater.

       

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