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Enhancing residual trapping of supercritical CO 2 via cyclic injections
Author(s) -
Herring Anna L.,
Andersson Linnéa,
Wildenschild Dorthe
Publication year - 2016
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl070304
Subject(s) - imbibition , trapping , supercritical fluid , saturation (graph theory) , materials science , capillary pressure , residual , capillary action , multiphase flow , porous medium , mechanics , composite material , porosity , thermodynamics , ecology , botany , germination , physics , mathematics , combinatorics , algorithm , computer science , biology
We utilize synchrotron X‐ray tomographic imaging to investigate the pore‐scale characteristics and residual trapping of supercritical CO 2 (scCO 2 ) over the course of multiple drainage‐imbibition (D‐I) cycles in Bentheimer sandstone cores. Capillary pressure measurements are paired with X‐ray image‐derived saturation and connectivity metrics which describe the extent of drainage and subsequent residual (end of imbibition) scCO 2 trapping. For the first D‐I cycle, residual scCO 2 trapping is suppressed due to high imbibition capillary number (Ca ≈ 10 −6 ); however, residual scCO 2 trapping dramatically increases for subsequent D‐I cycles carried out at the same Ca value. This behavior is not predicted by conventional multiphase trapping theory. The magnitude of scCO 2 trapping increase is hysteretic and depends on the relative extent of the sequential drainage processes. The hysteretic pore‐scale behavior of the scCO 2 ‐brine‐sandstone system observed in this study suggests that cyclic multiphase flow could potentially be used to increase scCO 2 trapping for sequestration applications.