Page 344 - Enhanced Oil Recovery in Shale and Tight Reservoirs

Forced imbibition 317

blocks is bypassed, resulting in a very low oil recovery factor (w0.01). Oil
can hardly be produced after 0.4 days of injection. Figs. 11.8A, 11.8B
show the oil saturations at 0.4 and 9 days of injection, respectively in the
matrix, almost unchanged, especially near the producer which is in the
right-hand side. The oil saturation in the fractures is zero.
For comparison, the oil saturations at 0.4 and 9 days in the case of
surfactant injection only for the sand model are shown in Figs. 11.9A,
11.9B, respectively. It can be seen that the saturation changes significantly

Figure 11.8 Oil saturation at 0.4 days (A) and 9 days (B) in the case of surfactant injec-
tion only (shale rock).