【摘要】 针对地下浅层储能咸水介质复杂的水文地质条件与矿物构成的特殊性,开展可控三维物理模拟试验,基于表面化学与胶体稳定性理论,从介观尺度分析回灌溶液宏观参数变化与含水介质中微纳米颗粒重新分布过程的内在关联;探索复杂时空条件下咸水层孔隙结构变化规律;确定不同储能模式下低渗透帷幕带的形成区域。研究结果表明,回灌溶液温度、盐度变化是打破颗粒间受力平衡,造成含水介质渗透性能下降的诱导机制。在抽-注井固定与调换模式下,经历完整储能周期,含水层整体相对渗透率k/k0分别下降至63%、57%,表明由微纳米颗粒物质重组,导致含水介质空间结构变化具有不可逆性。两组储能试验中,由于形成机制不同,低渗透帷幕带分别形成于700~900 mm与500~700 mm的渗流单元。更多还原

【Abstract】 Considering the complex hydrogeology condition and the particularity of mineral composition of shallow brackish aquifers for energy storage, a controllable three-dimension infiltration experiment is conducted. Based on the theories of surface chemistry and colloid stability, the intrinsic connection between the variation of macro parameters of recharged solutions and the redistribution of micro-nano particles are analyzed from the mesoscopic standpoint. The spatial and temporal variations of the pore structure of brackish aquifer are analyzed; and the regions of low permeability curtain formed in different modes are determined. The results show that it is the variation of temperature and salinity of recharge solution that breaks equilibrium condition of forces between particles and induces the decrease of aquifer medium permeability. By fixing and switching the locations of pumping and injection well, the relative permeability of the whole aquifer medium k/k0 decrease to 63% and 57%, respectively, after one complete energy storage period, showing that the aquifer medium space structure variations are irreversible as result of micro-nano particles redistribution. Under the two working modes, low permeability curtain occurs in the 700-900 mm and the 500-700 mm seepage elements, respectively, due to their different formation mechanism.更多还原