Neil Chelsea W, Yang Yun, Nisbet Haylea, Iyare Uwaila C, Boampong Lawrence O, Li Wenfeng, Kang Qinjun, Hyman Jeffrey D, Viswanathan Hari S
Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
PNAS Nexus. 2024 Sep 18;3(9):pgae388. doi: 10.1093/pnasnexus/pgae388. eCollection 2024 Sep.
Controlling atmospheric warming requires immediate reduction of carbon dioxide (CO) emissions, as well as the active removal and sequestration of CO from current point sources. One promising proposed strategy to reduce atmospheric CO levels is geologic carbon sequestration (GCS), where CO is injected into the subsurface and reacts with the formation to precipitate carbonate minerals. Rapid mineralization has recently been reported for field tests in mafic and ultramafic rocks. However, unlike saline aquifers and depleted oil and gas reservoirs historically considered for GCS, these formations can have extremely low porosities and permeabilities, limiting storage volumes and reactive mineral surfaces to the preexisting fracture network. As a result, coupling between geochemical interactions and the fracture network evolution is a critical component of long-term, sustainable carbon storage. In this paper, we summarize recent advances in integrating experimental and modeling approaches to determine the first-order processes for carbon mineralization in a fractured mafic/ultramafic rock system. We observe the critical role of fracture aperture, flow, and surface characteristics in controlling the quantity, identity, and morphology of secondary precipitates and present where the influence of these factors can be reflected in newly developed thermo-hydro-mechanical-chemical models. Our findings provide a roadmap for future work on carbon mineralization, as we present the most important system components and key challenges that we are overcoming to enable GCS in mafic and ultramafic rocks.
控制大气变暖需要立即减少二氧化碳（CO）排放，以及从当前排放源中积极去除和封存CO。一种有前景的降低大气中CO水平的策略是地质碳封存（GCS），即将CO注入地下并与地层反应以沉淀碳酸盐矿物。最近报道了在镁铁质和超镁铁质岩石中的现场试验实现了快速矿化。然而，与历史上考虑用于GCS的盐水层和枯竭的油气藏不同，这些地层的孔隙率和渗透率可能极低，将储存量和反应性矿物表面限制在现有的裂缝网络中。因此，地球化学相互作用与裂缝网络演化之间的耦合是长期可持续碳储存的关键组成部分。在本文中，我们总结了在整合实验和建模方法以确定裂缝性镁铁质/超镁铁质岩石系统中碳矿化的一级过程方面的最新进展。我们观察到裂缝孔径、流动和表面特征在控制次生沉淀物的数量、种类和形态方面的关键作用，并指出这些因素的影响可在新开发的热-水-力学-化学模型中得到体现。我们的研究结果为未来碳矿化工作提供了路线图，因为我们展示了最重要的系统组件以及我们为在镁铁质和超镁铁质岩石中实现GCS而正在克服的关键挑战。
