Systematic sensitivity analysis to investigate performance of carbonated water injection based on computational dynamic modeling

Abstract

Oil recovery is expected to increase considerably by implementation of carbonated water injection (CWI) particularly in the secondary mode, according to various experimental and modeling research works. There have been a few modelling studies and coreflooding tests reported on CWI in open sources. This inadequacy fuels the objectives of this paper. This study reports core scale experiments and computational fluid dynamic (CFD) modeling. To effectively capture the physics involved during CWI, the mass balance equations, momentum balance equations, and reaction equations are solved for the same computational domains of CO2, water, and oil phases. The modeling results are validated by the core scale experimental data of CWI in its secondary application. It is found that there is good agreement between the modeling results and real data; thus, the introduced CFD model can adequately simulate the CWI process. The developed model is also used to investigate the effects of operational parameters/conditions and rock dissolution during CWI. Based on the research results, an increase in the injection rate from 0.2 cm3/min to 0.8 cm3/min gives an additional oil recovery of 6% for a core with a length of 10.33 cm and a diameter of 3.83 cm. There is an optimum injection rate above which there is no significant change in the oil recovery. Increasing the injection pressure leads to a more dissolution of CO2 into the resident fluid, which improves the overall performance of CWI such that the oil recovery is enhanced by an additional 16% upon an increase in the injection pressure from 1500 psi to 3500 psi. There is no evidence of rock dissolution based on the results attributed to permeability changes in a property-distance plot. With the use of the developed model and experimental results, the CWI upscaling can be performed with careful technical, environmental, and economic considerations.