Fundamental investigation of reactive-convective transport: Implications for long-term carbon dioxide (CO2) sequestration
Fundamental investigation of reactive-convective transport: Implications for long-term carbon dioxide (CO2) sequestration
复制标题
反应-对流输运的基础研究：对长期二氧化碳 (CO2) 封存的影响
DOI：
10.1016/j.ijggc.2023.103916
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发表时间：
2023
影响因子：
3.9
通讯作者：
Khanal, Aaditya
中科院分区：
文献类型：
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作者：
Shahriar, Md Fahim;Khanal, Aaditya
密度驱动的对流与化学反应相结合是在盐水层中永久储存CO2的首选机制。本研究使用二维可视化Hele-Shaw单元来评估和可视化由于重力不稳定性而形成的密度驱动对流。实验的主要目的是了解不同初始离子浓度和流动渗透率的卤水中气态CO2的传质的各种机制。此外，还研究了CO2注入位置、储层倾角、渗透率非均质性等因素的影响。我们观察到，盐的存在下，导致在更早的对流和更大的对流指波长的情况下，没有溶解的盐。此外，当涉及浸渍时，观察到CO2指状物之间的更高的横向混合。CO2溶解，由pH值降低区域的面积表示，取决于盐水中存在的离子的类型和浓度，并且观察到与不存在盐时相比为0.38-0.77倍。虽然对流在盐的存在下减慢，扩散通量增强，从定性和定量结果观察。此外，通过使用流动屏障引入的地层渗透率降低导致许多区域未被溶解的CO2扫过，表明溶解效率低。我们还研究了流动屏障内离散高导流裂缝的影响，其显示出不均匀的垂直波及和增强的流动沟道。最后，对储存过程中CO2泄漏风险的参数进行了识别和讨论。
The density-driven convection coupled with chemical reaction is the preferred mechanism for permanently storing CO2in saline aquifers. This study uses a 2D visual Hele-Shaw cell to evaluate and visualize the density-driven convection formed due to gravitational instabilities. The primary goal of the experiments is to understand the various mechanisms for the mass transfer of gaseous CO2into brine with different initial ionic concentrations and flow permeability. Moreover, the impact of CO2injection locations, reservoir dipping angle, and permeability heterogeneity is also investigated. We observed that the presence of salts resulted in earlier onset of convection and a larger convective finger wavelength than the case with no dissolved salts. Additionally, a higher lateral mixing between CO2fingers is observed when dipping is involved. The CO2dissolution, indicated by the area of the pH-depressed region, depends on the type and concentration of the ions present in the brine and is observed to be 0.38–0.77 times compared to when no salt is present. Although convective flow is slowed in the presence of salts, the diffusive flux is enhanced, as observed from both qualitative and quantitative results. Moreover, the reduced formation permeability, introduced by using a flow barrier, resulted in numerous regions not being swept by the dissolved CO2, indicating an inefficient dissolution. We also investigated the effect of discrete high-conductivity fractures within the flow barriers, which showed an uneven vertical sweep and enhanced flow channeling. Lastly, the parameters regarding CO2leakage risk during storage are identified and discussed.