Abstract The Technology of Horizontal Silicate Barriers (TFHB) is an injection technology in which a solution of sodium silicate is introduced into the aquifer, close to the water table, while below CO2 is injected and catalyzes silicate gelation. Silicate gel decreases the aquifer permeability and forms a horizontal barrier. In this work, by means of geochemical modeling, we indicate potential interactions between silicate solution injected, and the rock-water system of an exemplary aquifer. Divalent ions may unfavorably accelerate silicate gelation. For this reason, to increase the gelation time, the alkalinity of the injected solution should be increased, or spacer fluids should be used. Under the analyzed conditions, a two-fold increase in the spacer fluid injection time causes a nearly six-fold increase in the gelation time. Changes in the pH induced by the injection of silicate to the aquifer disappear at a distance of 10 m from the wells in case of the use of the pre-treatment fluid, and 7 m without the spacer fluid. CO2 injected to accelerate the gelling, causes a pH drop in the aquifer to about 5.2. Changes in the mineralogical composition of the aquifer's primary rock matrix under the influence of TFHB are small, and alone, have no effect on the porosity.

中文翻译：

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用于保护浅层地下水的注入硅酸盐水平屏障 - 技术和地球化学问题

摘要 水平硅酸盐屏障技术（TFHB）是一种注入技术，将硅酸钠溶液注入含水层，靠近地下水位，同时注入低于CO2，催化硅酸盐凝胶化。硅酸盐凝胶会降低含水层的渗透性并形成水平屏障。在这项工作中，通过地球化学建模，我们指出了注入的硅酸盐溶液与示例含水层的岩水系统之间的潜在相互作用。二价离子可能不利地加速硅酸盐凝胶化。为此，要增加胶凝时间，应增加注入溶液的碱度，或应使用隔离液。在分析条件下，隔离液注入时间增加两倍会导致胶凝时间增加近六倍。在使用预处理液的情况下，在距井 10 m 处和在不使用隔离液的情况下距井 7 m 处，由向含水层注入硅酸盐引起的 pH 值变化消失。注入 CO2 以加速胶凝，导致含水层的 pH 值下降至约 5.2。TFHB 影响下含水层原生岩石基质的矿物组成变化很小，单独对孔隙度没有影响。