深部互层咸水层二氧化碳分布特征探究

Distribution of CO_2 in deep saline aquifers composed of alternating layers

通过构造砂页岩互层结构,并根据渗透率对砂岩层岩性进行分类,建立了多岩相非均质模型,利用多组分多相流数值模拟软件TOUGH2/ECO2N探究二氧化碳注入深部互层咸水层后的分布特征,结果显示二氧化碳聚集在低渗透性的页岩层底部,呈分层结构,砂岩层中优先在渗透率较高的岩相中运移并呈分散分布;超临界二氧化碳不断溶于地层水,含饱和二氧化碳的咸水密度增加并缓慢下沉,无明显分层现象。

Alternating layers of sandstone and shale were established. According to the permeability values,the lithology of the sandstone layer was classified, and a multiple lithofacies model was built to investigate the heterogeneity. The distribution of CO2 injected into deep saline aquifers composed of alternating layers was simulated using TOUGH2/ECO2N software,which was often used to simulate multi-component and multi-phase flow. The results show that CO2 accumulated in the bottom of the low-permeability shale layer and showed a layered structure. CO2 preferred to migrate in highly permeable rocks and was distributed dispersedly in the sandstone layer. The supercritical CO2 dissolved in the formation water continuously, and the density of the salt water consisting of saturated CO2 increased, leading to the gradual subsidence of the salt water. No significant stratification was found.