Dissolution and Deformation Characteristics of Limestones Containing Different Calcite and Dolomite Content Induced by CO2‐Water‐Rock Interaction

• Published in: Acta geologica Sinica (Beijing) Vol. 97; no. 3; pp. 956 - 971
• Main Authors: CHEN, Bowen, LI, Qi, TAN, Yongsheng, ALVI, Ishrat Hameed
• Format: Journal Article
• Language: English
• Published: Richmond Wiley Subscription Services, Inc 01.06.2023; State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan 430071,China; University of Chinese Academy of Sciences,Beijing 100049,China
• Edition: English ed.
• Subjects: Acid dissolution; Bragg gratings; Calcite; Calcite dissolution; Carbon dioxide; Carbonate rocks; Carbonates; CO2 geological storage; CO2‐water‐rock interaction; Coefficients; Confining; Deformation; deformation response; Dissolution; Dissolving; Dolomite; Dolostone; Fiber Bragg gratings sensors; Flow channels; Fruits; Limestone; Mechanical properties; Mineral composition; NMR; Nuclear magnetic resonance; Physical properties; Strain; Strain sensitivity coefficient; Fiber Bragg gratings sensors; CO2-water-rock interaction; deformation response; carbonate rocks; CO2 geological storage
• ISSN: 1000-9515; 1755-6724
• DOI: 10.1111/1755-6724.15051

To investigate the impacts of mineral composition on physical and mechanical properties of carbonate rocks, limestone specimens containing different contents in calcite and dolomite are selected to perform CO2‐water‐rock reaction experiments. The X‐ray Diffraction (XRD) and Nuclear Magnetic Resonance (NMR) are carried out to examine the change characteristics of mineral dissolution and pore structure after reaction. The core flooding experiments with Fiber Bragg gratings are implemented to examine the stress sensitivity of carbonate rocks. The results show that the limestones containing pure calcite are more susceptible to acid dissolution compared to limestone containing impure dolomite. The calcite content in pure limestone decreases as the reaction undergoes. The dissolution of dolomite leads to the formation of calcite in impure limestone. Calcite dissolution leads to the formation of macropore and flow channels in pure limestone, while the effects of impure dolomite in impure limestone results in mesopore formation. When confining pressure is lower than 12 MPa, pure limestones demonstrate higher strain sensitivity coefficients compared to impure limestone containing dolomite after reaction. When confining pressure exceeds 12 MPa, the strain sensitivity coefficients of both pure and impure limestones become almost equal.