Effect of wettability changes on evaporation rate and the permeability impairment due to salt deposition
Author(s)
Rufai, AK
Crawshaw, John
Type
Journal Article
Abstract
Pore-scale visualization was employed to investigate evaporative drying of brine and associated salt deposition at different wetting conditions, using a 2.5D etched-silicon/glass micromodel based on a thin section image of a carbonate rock. We also compared air drying with CO2 drying, with the latter having important applications in CO2 sequestration processes. The resulting permeability impairment was also measured. For deionized water in a water-wet model, we observed the three classical periods of evaporation: the constant rate period (CRP), the falling rate period (FRP), and the receding front period (RFP). The length of the deionized water CRP was much shorter for a uniformly oil-wet model, but mixed wettability made little difference to the drying process. For brine systems at all wetting conditions, the dry area became linear with the square root of time after a short CRP. This is due to the deposited salt acting as a physical barrier to hydraulic connectivity, unlike the case of deionized water, which is due to capillary disconnection from the fracture channel. For the water-wet model, we observed two regions of a linear downward trend in the matrix and fracture permeability measurements. A similar trend was observed for the mixed-wet systems. However, for the oil-wet systems, fracture permeability only changes slightly even for 360 g/L brine, a result of the absence of salt deposits in the fracture caused by the early rupture of the liquid-wetting films needed to aid hydraulic connectivity. Overall, matrix permeability for all wetting conditions decreased with increasing brine concentration and was almost total for the 360 g/L brine. Finally, using CO2 rather than air as carrier gas makes the brine phase more wetting, especially in the deionized water case, with the result that hydraulic connectivity was maintained for longer in the CO2 case compared to dry out with air.
Date Issued
2018-02-14
Date Acceptance
2018-02-14
Citation
ACS Earth and Space Chemistry, 2018, 2 (4), pp.320-329
ISSN
2472-3452
Publisher
American Chemical Society
Start Page
320
End Page
329
Journal / Book Title
ACS Earth and Space Chemistry
Volume
2
Issue
4
Copyright Statement
© 2018 American Chemical Society
Sponsor
Qatar Shell Research and Technology Center QSTP LLC
Grant Number
490000724
Subjects
Science & Technology
Physical Sciences
Chemistry, Multidisciplinary
Geochemistry & Geophysics
Chemistry
brine
drying
wettability
liquid films
micromodel
contact angle
CAPILLARY-POROUS MEDIA
SODIUM-CHLORIDE
CO2 INJECTION
PORE-NETWORK
SALINE AQUIFERS
PRECIPITATION
CRYSTALLIZATION
DYNAMICS
FLOW
TRANSPORT
Publication Status
Published
Date Publish Online
2018-02-14