3D Quantification of Pore Networks and Anthropogenic Carbon Mineralization in Stacked Basalt Reservoirs

Abstract

Basalt formations are promising candidates for the geologic storage of anthropogenic CO 2 due to their storage capacity, porosity, permeability, and reactive geochemical trapping ability. The Wallula Basalt Carbon Storage Pilot Project demonstrated that supercritical CO 2 injected into >800 m deep Columbia River Basalt Group stacked reservoir flow tops mineralizes to ankerite-siderite-aragonite on month-year time scales, with 60% of the 977 metric tons of CO 2 converted within 2 years. The potential impacts of mineral precipitation and consequent changes in the rock porosity, pore structure, pore size, and pore size distributions have likely been underestimated hitherto. Herein, we address these knowledge gaps using X-ray microcomputed tomography (XMT) to evaluate the pore network architecture of sidewall cores recovered 2 years after CO 2 injection. In this study, we performed a detailed quantitative analysis of the CO 2 -reacted basalt cores by XMT imaging. Reconstructed 3D images were analyzed to determine the distribution and volumetric details of porosity and anthropogenic carbonate nodules in the cores. Additional mineralogic quantification provided insight into the overall paragenesis and carbonate growth mechanisms, including mineralogic/chemical zonation. These findings are being used to parametrize multiphase reactive transport models to predict the fate and transport of subsurface CO 2 , enabling scale-up to commercial-scale geologic carbon storage in basalts and other reactive mafic-ultramafic formations.

Carbon Mineralization and Critical Mineral Resource Evaluation Pathways for Mafic–Ultramafic Assets

“…The picrite core was analyzed using a North Star Imaging X-View Digital X-ray Imaging and Microfocus Computed Tomography system using the methods of Battu et al Major components of the instrument system include a flat-panel rectangular detector, a 360° rotating stage, and an X-ray tube capable of high resolution and high magnification. As the object is continuously rotated in the X-ray beam, a designated number of images are collected for each degree of rotation.…”

Parts-Per-Million Carbonate Mineral Quantification with Thermogravimetric Analysis–Mass Spectrometry

“…Carbon mineralization storage in basaltic rocks ,− has been demonstrated in laboratory experiments ,,− and pilot field-scale studies, ,− including commercialization of the technology in Iceland by Carbfix. The Wallula Basalt Pilot Project located in the Columbia River Basalt Group (CRBG) is the world’s first supercritical CO 2 injection pilot in flood basalts.…”