TY  - EJOU
AU  - Qin, Nan 
AU  - Ning, Shaofeng 
AU  - Zhao, Zihan 
AU  - Luo, Yu 
AU  - Chen, Bo 
AU  - Liu, Xiaoxu 
AU  - He, Yongming 

TI  - Numerical Investigation of Carbon Capture, Utilization, and Storage–Enhanced Gas Recovery
T2  - Fluid Dynamics \& Materials Processing

PY  - 2025
VL  - 21
IS  - 12
SN  - 1555-2578

AB  - Balancing CO<sub>2</sub> emission reduction with enhanced gas recovery in carbonate reservoirs remains a key challenge in subsurface energy engineering. This study focuses on the Maokou Formation gas reservoir in the Wolonghe Gas Field, Sichuan Basin, and employs a mechanistic model integrated with numerical simulations that couple CO<sub>2</sub>–water–rock geochemical interactions to systematically explore the principal engineering and chemical factors governing Carbon Capture, Utilization, and Storage–Enhanced Gas Recovery (CCUS–EGR). The analysis reveals that both the injection–production ratio and gas injection rate exhibit optimal ranges. Maximum gas output under single-parameter variation occurs at an injection–production ratio of 0.7 and an injection rate of 130,000 m<sup>3</sup>/d, while coordinated optimization of both parameters is essential to achieve the highest production enhancement. Excessively high injection–production ratios, however, may induce gas channeling and reduce the ultimate recovery factor. Chemical composition of the injected gas also strongly influences recovery. In the heterogeneous carbonate reservoir considered, a CO<sub>2</sub>–N<sub>2</sub> mixed gas mitigates gravity segregation due to its lower density, expanding sweep efficiency and improving overall gas recovery compared to pure CO<sub>2</sub> injection. CO<sub>2</sub>–water–rock reactions further modify reservoir properties. Near the injection well, acidic dissolution enhances porosity, whereas near the production well, a dynamic interplay of ion migration, pressure–temperature variations, and secondary mineral precipitation produces complex porosity evolution. Initial precipitation reduces porosity, while subsequent acidic dissolution partially restores it, creating a heterogeneous and time-dependent porosity profile.
KW  - CCUS-EGR; carbonate gas reservoir; numerical simulation; geochemical reaction

DO  - 10.32604/fdmp.2025.074456