Open AccessThe change in contact angle at unsaturated CO 2 ‐water conditions: Implication on geological carbon dioxide sequestration
Author(s) -
Jafari Mohammad,
Jung Jongwon
Publication year - 2016
Publication title -
geochemistry, geophysics, geosystems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.928
H-Index - 136
ISSN - 1525-2027
DOI - 10.1002/2016gc006510
Subject(s) - contact angle , wetting , mica , dissolution , carbon sequestration , materials science , capillary action , mineralogy , geology , capillary pressure , carbon dioxide , slip (aerodynamics) , substrate (aquarium) , composite material , chemistry , thermodynamics , physics , oceanography , organic chemistry , porous medium , porosity
The performance of a geologic carbon storage site strongly depends on the capillary pressure of sealing rock and formations. While wettability of minerals is a key factor in capillary pressure, published contact angles are inconsistent. This study explores the discrepancy of published contact angles in order to reduce the uncertainty of measured laboratory contact angles, and understand the variation of contact angles at unsaturated CO 2 ‐water conditions. A ratio of droplet dimension and triple line (or contact line) are used to explain the observed wide range of contact angles and the variation of contact angle at unsaturated conditions. Results show that the shape factor has a good agreement with contact angle change during CO 2 dissolution in water. Silica substrate has clear two pinned and slip stages of triple line during CO 2 droplet dissolution, which cause contact angle on silica substrate to increase from 34.5° to 42.1°. However, mica substrate has the repeated pinned and slip stages due to the heterogeneity of mica surface, which cause contact angle to increase dramatically from 25.4° to 68.1°. Thus, both the impact of the unsaturated CO 2 ‐water conditions on the wide range of contact angle and the heterogeneity of mineral surface should be considered when one estimates capillary pressure based on contact angle in geological CO 2 sequestration.