Carbonate cements in Miller field of the UK North Sea: a natural analog for mineral trapping in CO2 geological storage

• Published in: Environmental earth sciences Vol. 62; no. 3; pp. 507 - 517
• Main Authors: Lu, Jiemin, Wilkinson, Mark, Haszeldine, R. Stuart, Boyce, Adrian J.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01-02-2011; Springer; Springer Nature B.V
• Subjects: Biogeosciences; Calcite; Carbon dioxide; Carbon sequestration; Carbonates; Cement; Dissolution; Earth and Environmental Science; Earth Sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Environmental Science and Engineering; Exact sciences and technology; Geochemistry; Geology; Hydrology/Water Resources; Isotope geochemistry; Isotope geochemistry. Geochronology; Isotopes; Offshore oil wells; Original Article; Pollution, environment geology; Reservoirs; Sandstone; Terrestrial Pollution; Trapping; Great Britain; Europe; Atlantic Ocean; Scotland; United Kingdom; Northeast Atlantic; North Atlantic; North Sea; Western Europe; Mineral dissolution; Carbonate cements; Carbon dioxide capture and storage; Mineral sequestration; Stable isotopes; Miller field; reservoir rocks; O-18/O-16; pore fluid; reservoirs; calcite; sandstone; greenhouse gas; underground storage; pH; retention; clastic rocks; emplacement; carbon dioxide; stable isotopes; accumulation; C-13/C-12; dissolution; concentration; carbonates; sedimentary rocks; cement; concretions
• ISSN: 1866-6280; 1866-6299
• DOI: 10.1007/s12665-010-0543-1

Miller field of the North Sea has had high concentrations of natural CO
2
for ~70 Ma. It is an ideal analog for the long-term fate of CO
2
during engineered storage, particularly for formation of carbonate minerals that permanently lock up CO
2
in solid form. The Brae Formation reservoir sandstone contains an unusually high quantity of calcite concretions; however, C and O stable isotopic signatures suggest that these are not related to the present-day CO
2
charge. Margins of the concretions are corroded, probably because of reduced pH due to CO
2
influx. Dispersed calcite cements are also present, some of which postdate the CO
2
charge and, therefore, are the products of mineral trapping. It is calculated that only a minority of the reservoired CO
2
in Miller (6–24%) has been sequestrated in carbonates, even after 70 Ma of CO
2
emplacement. Most of the CO
2
accumulation is dissolved in pore fluids. Therefore, in a reservoir similar to the Brae Formation, engineered CO
2
storage must rely on physical retention mechanisms because mineral trapping is both incomplete and slow.