Why carbon storage in Alberta?
• High greenhouse gas emission level
• Carbon dioxide ranks No.1
• High storage potential
Figure 1 Alberta annual greenhouse emission and gas type
Rock/brine/CO2 interactions
Methodology
Chemical CompositionX-ray Photoelectron Spectroscopy (XPS) was
introduced to investigate the element
change in the surface introduced by exposing
to CO2 – rich brine.
Sample image using Scanning Electron
Microscope (SEM) coupled with Energy-
dispersive X-ray Spectroscopy (EDS).
Mechanical PropertyMeasurements of capillary entry pressures to
study the impact of rock/brine/CO2 interaction.
Surface chemistry analysis results
Figure 2 Conceptual diagram of a CO2 injection scheme and identified cluster of CO2/rock interactions (Gaus, 2009)
CO2 injectivity
Mechanical property change
Caprock/brine/CO2 interaction
Change in Caprock
chemistry
Sampling and Test ConditionIn order to prevent collapse of shale sample,
special holder was used to protect the sample.
Figure 3 Dimensions and photo of holder – rock system
Table 1 Average atom concentrations from XPS (Unit : %)
• Slight decrease in potassium and moderate
decrease in aluminum indicate
rock/brine/CO2 interactions have indeed
resulted in caprock mineralogy change.
• Significantly increase in carbon within the
shale specimens providing some evidence for
the potential of CO2 sorption in this shale that
could increase the capacity of storage site.
• Further investigations were need for longer
reaction time.
SEM imaging results
Intact
> 1 Month3 Weeks
1 Week2 Day
2 Weeks
Figure 4 Overall SEM images of all the testing samples
• Rock/brine/CO2 interactions result in growth
of clusters that disappear over time
• There are three kinds of clusters : spherical,
chain and mixture of two
• Spherical cluster appear to be hollow
(CO2trapping)
1 and 3 Weeks (sphere)
2 Weeks (a)(sphere and
chain)
2 Weeks (b)(mixture of two)
Figure 5 High resolution images of three types of clusters
Chemistry analysis conclusions
SEM imaging conclusions
CO2 injection induced chemical composition and mechanical property change of shaly caprock
Ming Liu([email protected]), R. J. ChalaturnykDepartment of Civil & Environmental Engineering, University of Alberta, Canada
The test conditions are:• P = 2 MPa • T = 50⁰C• The brine composition is 3g/L NaCl
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