Sensitivity Analysis and Evaluation for Carbon Dioxide Storage Coefficient in the Process of Oil Displacement

Achieving a permanent CO₂ storage in the process of CO₂ flooding in oil reservoir, which is the most realistic way to fulfill CO₂ emission reduction obligations for developing countries. It will provide reliable data for CO₂ reduction and enhanced oil recovery to evaluate correctly and research clearly the CO₂ storage and displacement efficiency. Through theoretical analysis and numerical simulation methods, the introduction of the concept of CO₂ storage coefficient, the CO₂ storage and displacement efficiency are analyzed and evaluated under CO₂ miscible and immiscible flooding. It focuses on the effects of the reservoir parameters, fluid parameters and CO₂ injection methods on CO₂ storage and flooding in the CO₂ miscible flooding with the different injection volume conditions. The results show that the CO₂ storage and displacement efficiency for miscible flooding is significantly higher than immiscible flooding. Moreover, with the increasing volume of CO₂ injected, CO₂ storage coefficient and oil recovery are increased. The vertical and horizontal permeability ratio, oil viscosity and the injection method have the important implications on the CO₂ storage coefficient. It can be drawn from the analysis and evaluation results, CO₂ miscible flooding is an effective way of storage and displacement, meanwhile, the CO₂ storage and oil recovery can be the best in a certain range of CO₂ injection volume. The conclusions and understanding achieved is technical reference for CO₂ storage in oil reservoir, and to provide a strong basis for CO₂ storage project implementation on site.