Diffusivity of gases in oil is an important consideration in several oil recovery processes and knowing the value of diffusion coefficient is necessary. Currently, for calculating the molecular diffusion coefficient, indirect methods especially pressure decay method are used. The most important point in this method is the useage of appropriate model and analyze the experimental results.
Gholami et al.[1] investigated diffusivity of CO2 into water at different boundary condition. Jafari Raad et al.[2] measured diffusivity of CO2 into different solutions, including saline aquifer taken from oil field and distilled water. Nategh et al. [3] investigated effect of surfactants and silica nanoparticles synthesized in cationic reverse micellar system on CO2 diffusion to light oil. In this study, the diffusion coefficient of CO2 in condensate is calculated using pressure decay methods. Then analytical methods for analyzing experimental data from the pressure decay method have been evaluated.