Page 62 - Enhanced Oil Recovery in Shale and Tight Reservoirs

50 Enhanced Oil Recovery in Shale and Tight Reservoirs

Figure 2.42 Oil recovery of different molecular weight alkanes under dynamic CO 2

exposure at 5000 psi and 110 C from rock samples of the round rod geometry of
1 cm diameter and 4 cm length. The numbers in the legend represent the hydrocarbon
components, e.g., 7 represents C7; “total HC” represents the total hydrocarbon mass
recovered regardless of molecular weight (Hawthorne et al., 2013).

(showninDARCY in the figure) from matrix to fractures combined grav-
ity plays an important role; inclusion of the gravity, pressure gradient, and
diffusion in the simulation model makes the experimental data matched.
They also showed the hydrocarbon recovery by solvent soaking with the
mixture of 85% C 1 and 15% C 2 , and nitrogen. Their study shows that
the synergy between diffusion and pressure gradient plays the dominant
role in solvent soaking; the dominant mechanism is diffusive-advective