In:
Energy Exploration & Exploitation, SAGE Publications, Vol. 39, No. 1 ( 2021-01), p. 243-255
Kurzfassung:
The interaction between shale and CO 2 is of great significance to CO 2 storage and shale gas production; however, there are few reports on chemical changes after CO 2 injection into shale reservoirs. We used Fourier transform infrared spectroscopy to study the chemical structure changes of shale samples before and after CO 2 injection. In this paper, self-developed high-temperature and high-pressure vessels were used to examine CO 2 treatment of shale to simulate the stratigraphic environment and infrared was used to study the influence of changes in pressure and temperature on the chemical interaction between shale and CO 2 . These results showed that: (1) after shale CO 2 treatment, the number of functional groups remained unchanged, though the content and structure of the shale did change; (2) pressure increases reduced hydroxyl and aliphatic group levels in the shale; the branched-chain and aromaticity indexes of the shale were reduced by 81.5% and 53.8%, respectively, relative to untreated samples; (3) below 60°C, free water in the shale increased with temperature increases and dissolution of the shale increased; however, above 60°C, dissolution was inhibited which resulted in precipitation; (4) the dissolution degree of shale carbonate minerals positively correlated with CO 2 pressure and temperature, while silicate minerals were unchanged CO 2 pressure and temperature. Finally, the change of CO 2 pressure had a more significant influence on the chemical structure of shale. These results provide a basis for the continuing study of the influence of chemical structure change of shale caused by CO 2 on shale wettability and enhance the theoretical level of CO 2 shale mining.
Materialart:
Online-Ressource
ISSN:
0144-5987
,
2048-4054
DOI:
10.1177/0144598720941171
Sprache:
Englisch
Verlag:
SAGE Publications
Publikationsdatum:
2021
ZDB Id:
2026571-2
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