Song Yongchen

Magnetic Resonance Imaging Study on the Miscibility of a CO2/n-Decane System *

We provide a feasible method to estimate the minimum miscibility pressure (MMP) of a CO2/n-decane system by using high spatial resolution magnetic resonance imaging (MRI). During the measurement, the signal intensity of n-decane with CO2 dissolved is measured. The MRI images show that the signal intensity of n-decane decreases to zero and the interface disappears at the MMP. A good exponential growth relation is found between the signal intensity and the pressure of the CO2/n-decane system. The relationship between the MMP and the temperature is established quantitatively, which is in close agreement with previous studies. Moreover it could be used to predict the MMP of the CO2/n-decane system.

In-situ observation for formation and dissociation of carbon dioxide hydrate in porous media by magnetic resonance imaging

The study of formation and dissociation of CO2 hydrate in porous media was characterized by magnetic resonance imaging (MRI) system in in situ conditions. This work simulated porous media by using glass beads of uniform size. The growth and dissociation habit of CO2 hydrate was observed under different temperature and pressure conditions. The induction time and the hydrate saturation during the growth and dissociation process in different sizes of porous media were obtained by using the MRI signal intensity. The results indicate that hydrate growth rate and the induction time are affected by the size of porous media, pressure, and degree of supercooling. There are three hydrate growth stages, i.e., initial growth stage, rapid growth stage and steady stage. In this study, the CO2 hydrate forms preferentially at the surface of vessel and then gradually grows inward. The hydrate tends to cement the glass beads together and occupies the pore gradually. As the hydrate decomposes gradually, the dissociation rate increases to the maximum and then decreases to zero.

Research Progress of the Basic Physical Properties of CO2 Brine in the Sequestration of CO2

Asses the capability and security of the sequestration of CO2 in underground saline aquifer/seawater need high accurate data and models. Based on the existing data and models, this paper summarizes the progress on the density and solubility characters of CO2 brine. It found that the range of temperature, pressure and salinity is likely to encompass a very large proportion of the environments that might be considered for the sequestration of CO2, but the accuracy and the consistency of these data are not very well. And most of the models were congressed from experimental data which without fully take the solution composition or salinity factors into account, and have certain limitations in theory, do not satisfy the need of the sequestration of CO2. So a systematic experimental data and a theoretical model with wide applicable range and high prediction accuracy are the basis of the sequestration of CO2.