oa A Thorough Investigation of Newly Improved CO2 Huff-and-Puff Injection for Storage and Enhancing Gas/Condensate Recovery

Gas production is considered as an attractive alternative energy source to coal or oil to consolidate cleaner energy transition. CO2-injection in gas condensate (GC) reservoirs can be beneficial both in terms of CO2-storage, and GC-improved recovery.

Several literatures reported conflicting findings on trends and level of CO2-GC interactions, especially when an untuned equation of state (EOS) was used. These suggests a better understanding of CO2-GC interactions.

The benefits of a newly improved CO2-Huff and Puff (HnP) injection method, compared to conventional-HnP method have recently been highlighted in our laboratory on high permeability core. This study investigates the combined multi-parameter-interactions effects between CO2-GC fluid affecting their phase and flow behaviours in porous media. Coreflood simulations were first performed to history match the core flood experimental results whilst varying Corey-fitted relative permeability (kr) parameters, then larger reservoir scale was considered.

The results indicated that using an EOS tuned to measured CO2-GC PVT data improved GC-recovery by realistically capturing the CO2/GC-interactions, and enhanced CO2-injectivity. Also, adjusting the parameters of the Corey kr-model resulted in an improved CO2/GC-match and the prediction processes. Overall, the new method ensured CO2/GC- interactions at maximum condensate saturation with lower injected-CO2, and resulted in improved GC-recovery, and higher CO2-storage.