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NMR study comparing capillary trapping in Berea sandstone of air, carbon dioxide, and supercritical carbon dioxide after imbibition of water
Author(s) -
Prather Cody A.,
Bray Joshua M.,
Seymour Joseph D.,
Codd Sarah L.
Publication year - 2016
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1002/2015wr017547
Subject(s) - supercritical fluid , imbibition , capillary action , trapping , supercritical carbon dioxide , carbon dioxide , carbon sequestration , materials science , phase (matter) , saturation (graph theory) , mineralogy , chemistry , composite material , organic chemistry , ecology , botany , germination , biology , mathematics , combinatorics
Nuclear magnetic resonance (NMR) techniques were used to study the capillary trapping mechanisms relevant to carbon sequestration. Capillary trapping is an important mechanism in the initial trapping of supercritical CO 2 in the pore structures of deep underground rock formations during the sequestration process. Capillary trapping is considered the most promising trapping option for carbon sequestration. NMR techniques noninvasively monitor the drainage and imbibition of air, CO 2 , and supercritical CO 2 with DI H 2 O at low capillary numbers in a Berea sandstone rock core under conditions representative of a deep underground saline aquifer. Supercritical CO 2 was found to have a lower residual nonwetting (NW) phase saturation than that of air and CO 2 . Supercritical CO 2 behaves differently than gas phase air or CO 2 and leads to a reduction in capillary trapping. NMR relaxometry data suggest that the NW phase, i.e., air, CO 2 , or supercritical CO 2 , is preferentially trapped in larger pores. This is consistent with snap‐off conditions being more favorable in macroscale pores, as NW fluids minimize their contact area with the solid and hence prefer larger pores.