This paper presents an initial evaluation and concept description of an approach to CO₂ storage where the reservoir rocks are volcanic terrains that have been built up from the seafloor and consist of several kilometers of stacked lava, pyroclastic, and volcano-sedimentary rocks, and where CO₂ could be injected in large quantities in the supercritical or liquid state. These coastal “Saline Volcanic Basins” (SVB) have massive volume, heterogeneous internal structure, and relatively low temperatures. SVB's occur in island arcs and so-called hot spots such as Hawaii and Iceland. In both settings, the volcanic formations are exceedingly thick, border the ocean, are below sea level, and are saturated with seawater at storage depths. Many SVB reservoirs are accessible with onshore wells within which intercalated high and low-permeability layers and low temperatures can keep supercritical CO₂ in a relatively high-density state and promote solution and capillary trapping, in addition to mineralization. Some regions of the subsurface may be at low enough temperature to allow for CO₂ hydrate formation as an additional trapping mechanism. Our initial assessment of storage potential focuses on the northeast portion of the island of Hawaii, where there is direct information about the subsurface volcanic stratigraphy and hydrology based on observations made during two scientific drilling projects that penetrated to 3.5 km with continuous coring. Initial analysis, including simulations of a 50 Megaton injection of supercritical CO₂, suggests that this region could be effective for permanent storage, and potentially for gigatons of CO₂.

本文介绍了一种 CO ₂封存方法的初步评估和概念描述，其中储层岩石是从海底建造的火山地形，由数公里堆积的熔岩、火山碎屑和火山沉积岩组成，其中CO ₂可以在超临界或液态下大量注入。这些沿海“咸水火山盆地”（SVB）体积庞大，内部结构不均匀，温度相对较低。SVB 发生在岛弧和所谓的热点地区，例如夏威夷和冰岛。在这两种情况下，火山地层都非常厚，靠近海洋，低于海平面，并且在储存深度被海水饱和。许多 SVB 储层可通过陆上井进入，其中插入的高渗透层和低渗透层以及低温可以将超临界 CO ₂保持在相对高密度的状态，并促进溶液和毛细管捕集以及矿化。地下的某些区域可能处于足够低的温度以允许 CO ₂水合物的形成作为一种额外的捕集机制。我们对存储潜力的初步评估集中在夏威夷岛的东北部，根据两个科学钻探项目中的观察结果，那里有关于地下火山地层和水文的直接信息，这些项目通过连续取芯深入 3.5 公里。初步分析，包括对 50 兆吨超临界 CO ₂注入的模拟，表明该区域可有效用于永久储存，并有可能储存数十亿吨的 CO ₂。