Collaborative Reserach: CO2 Leakages as Cold-Geysers and Diffusive CO2 Transport: Continuous Monitoring of in-situ P,T, Chemistry and CO2 Flux with Numerical Verificaiton

由于大气中人为二氧化碳浓度的上升而导致的全球气候变化，以及由此产生的减少二氧化碳排放的必要性，是普遍的科学共识。缓解大气中二氧化碳浓度的一种方法是从其来源捕获二氧化碳，并将其封存到地下。然而，如果储存的二氧化碳到达断层和裂缝等高渗透性管道，二氧化碳可能会有增无减地泄漏到其他地层或地表。所述的喷发机制类似于天然的二氧化碳喷发机制，这种机制在世界各地由二氧化碳驱动的冷水间歇泉中都能找到。在这个项目中，将通过收集犹他州Little Grand和Salt Wash断层系统附近的现场P、T、水化学(pH、EC、溶解氧和总溶解气体)的连续数据集来研究冷水间歇泉、泉水和二氧化碳扩散输送的现象学二氧化碳泄漏。具体项目目标包括：(1)确定原始二氧化碳来源；(2)在冷水间歇泉观察到的循环模式和扩散的土壤二氧化碳通量的原因。此外，还将研究断层系统对这些冷水间歇泉和土壤CO2通量模式的影响。该项目的第一部分特别侧重于了解二氧化碳驱动的冷水间歇泉(水晶间歇泉和特米尔间歇泉)的喷发特征。第二部分重点描述了断层系统中扩散土壤CO2通量的短期(日)和长期(月)变化。第三部分将进行数值模拟，验证间歇泉CO2喷发的动态背景和土壤中CO2的扩散通量。该项目涉及二氧化碳通量重要性的社会问题，二氧化碳通量被认为是全球气候变化和碳循环的最关键组成部分。了解二氧化碳驱动的冷水间歇泉喷发在未来十年对于测试安全储存被隔离的二氧化碳的可行性将是重要的。具体地说，对冷水间歇泉喷发中热物理变化的深入了解将有助于设计操作和存储条件，防止潜在的灾难性二氧化碳从储存层泄漏，并开发现场最佳传感器来跟踪工程地质二氧化碳储存点的地下二氧化碳羽流迁移。最后，研究热水间歇泉喷发、油田井喷过程和火山喷发的科学界将有兴趣找到喷发模式/时期和二氧化碳作用的相似之处。

Global climate change due to the rise in anthropogenic CO2 concentrations in the atmosphere and resulting necessity for the reduction of CO2 emissions is the general scientific consensus. One method for mitigating CO2 concentrations in the atmosphere is to capture CO2 from its sources and sequester it into the subsurface. However, if the stored CO2 reaches highly permeable conduits such as faults and fractures, CO2 could leak unabated to other formations or to the surface. The addressed eruptive mechanisms are analogues to natural CO2 eruption mechanisms, which are found in CO2-driven cold-water geysers around the world. In this project, phenomenological CO2 leakages from cold-water geysers, springs, and diffusive CO2 transport will be investigated by collecting continuous datasets of in-situ P, T, water chemistry (pH, EC, dissolved oxygen, and total dissolved gas) adjacent to the Little Grand and Salt Wash fault systems in Utah. Specific project goals include (1) identification of the original CO2 sourcing and (2) the causes of cyclic patterns observed at cold-water geysers and diffusive soil CO2 flux. In addition, (3) the role of fault systems on these cold-water geysers and soil CO2 flux patterns will be investigated. Part I of the project specifically focuses on understanding the eruption characteristics of CO2-driven cold-water geysers (Crystal and Tenmile geysers). Part II focuses on characterizing the short (daily)- and long-term (month) variations of diffusive soil CO2 flux on the fault systems. In Part III, the numerical simulations will be conducted to validate the dynamic setting of CO2 eruption at the geysers and diffusive CO2 flux from soils. The project involves societal issues of the importance of CO2 flux, which is considered to be the most critical component for global climate change and the carbon cycle. Understanding CO2-driven cold-water geyser eruptions will be important in the next decade for testing the feasibility of safe storage of the sequestered CO2. Specifically, the advanced understanding of thermophysical changes in cold-water geyser eruptions will help design the operational and reservoir conditions preventing the potential catastrophic CO2 leakage from the storage formation and develop the in-situ optimum sensors to track the subsurface CO2 plume migration at the engineered geologic CO2 storage site. Finally, scientific communities who study hot-water geyser eruption, the well blow-out processes in the petroleum field, and volcanology eruptions will be interested in finding similarities of eruption patterns/periods and the role of CO2.