Influence of CO2-brine-rock Interactions on the Physical Properties of Tight Sandstone Cores via Nuclear Magnetic Resonance

For sandstone reservoirs with extra-low permeability, CO2 injection is regarded as a valid method to enhance oil recovery. When CO2 injection is implemented in such reservoirs, the physical properties of the formation could be altered owing to the interactions between CO2, water, and rock. In this s...

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Bibliographic Details
Published in:IOP conference series. Earth and environmental science 2021-10, Vol.898 (1)
Main Authors: Liu, Hanbin, Li, Chengzheng, Zhao, Zhenfeng, Wang, Guangtao, Li, Changheng, Zhao, Jinsheng
Format: Article
Language:English
Subjects:
Brines
Carbon dioxide
Cores
Enhanced oil recovery
Injection
Magnetic properties
NMR
NMR technique
Nuclear magnetic resonance
Oil recovery
Permeability
Physical properties
Pore size
Pore size distribution
Porosity
Reservoirs
Rocks
Sandstone
Size distribution
Tight sandstone
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Summary:For sandstone reservoirs with extra-low permeability, CO2 injection is regarded as a valid method to enhance oil recovery. When CO2 injection is implemented in such reservoirs, the physical properties of the formation could be altered owing to the interactions between CO2, water, and rock. In this study, the influence of CO2–brine–rock interactions on the physical properties of tight sandstone cores was analyzed by comparing the obtained T 2 spectrum before and after CO2 injection. The results revealed that the T2 spectrum after CO2 injection was significantly different from the original T2 spectrum. CO2 injection changed the pore size distribution of the core samples. When the injection pressure was low, the pore volume decreased from micropores to macropores leading to a decrease in both permeability and porosity. As the injection pressure increasing, the dissolution of CO2 in the micropores was enhanced thus improving the pore-throat connectivity; which ultimately improved the reservoir physical properties.
ISSN:1755-1307
1755-1315
DOI:10.1088/1755-1315/898/1/012021