Abstract
The interaction between CO2 and rock during the process of CO2 capture and storage was investigated via reactions of CO2, formation water, and synthetic sandstone cores in a stainless-steel reactor under high pressure and temperature. Numerical modelling was also undertaken, with results consistent with experimental outcomes. Both methods indicate that carbonates such as calcite and dolomite readily dissolve, whereas silicates such as quartz, K-feldspar, and albite do not. Core porosity did not change significantly after CO2 injection. No new minerals associated with CO2 injection were observed experimentally, although some quartz and kaolinite precipitated in the numerical modelling. Mineral dissolution is the dominant reaction at the beginning of CO2 injection. Results of experiments have verified the numerical outcomes, with experimentally derived kinetic parameters making the numerical modelling more reliable. The combination of experimental simulations and numerical modelling provides new insights into CO2 dissolution mechanisms in high-pressure/temperature reservoirs and improves understanding of geochemical reactions in CO2-brine-rock systems, with particular relevance to CO2 entry of the reservoir.
Highlights
Carbon dioxide emissions from fossil-fuel combustion are projected to increase from 13 Gt yr−1 in 2010 to 20–24 Gt yr−1 in 2050 [1]
Based on the equation of sate (EOS ) for gas, PV = ZnRT, where Z is the compressibility, n is the mole number of CO2 in the injection solution, R is gas constant, and T is temperature, we can obtain the volume of CO2 (VCO2 soluble ) dissolved in the injection solutions under the experimental condition (P = 48.45 MPa and T = 150 ◦ C)
Scanning electron microscope (SEM) analyses of core samples before and after physical simulations showed that minerals such as quartz, K-feldspar, albite, and dolomite dissolved after CO2 injection, with feldspar and dolomite showing pronounced dissolution and quartz weak dissolution
Summary
Carbon dioxide emissions from fossil-fuel combustion are projected to increase from 13 Gt yr−1 in 2010 to 20–24 Gt yr−1 in 2050 [1]. After CO2 injection, the initial physico-chemical equilibrium between saline formation fluid and reservoir rocks can be disturbed by the triggering of reactions between CO2 , fluid (brine), and reservoir rock [2] Such interactions could lead to the dissolution of carbonates, feldspars, and clay cement in the aquifers [7,8]. Simulations are less reliable without the availability of parameters derived from laboratory studies, so a combination of physical experiments and numerical simulation is the optimal choice for investigating the geochemical effects following. The numerical simulation involved the same conditions of sample compositions, temperature, pressure, and fluid composition, with the two simulation types being mutually authenticating Both numerical and physical simulations were used to document the process of short-term geochemical interactions after CO2 injection. A consistency of results would indicate the reliability of the simulations, with outcomes expected to be similar to those pertaining to actual geological conditions
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
