Water Drainage from Berea: Swr in Berea Was Higher after Gel Placement than before.

Overall residual water saturation was higher at Swr after gel placement (28.7%) than before gel placement (16.0%). (See Table 2 and Figure 16.) From Figure 16, 86.1% of the pores had higher Swr values after gel placement than before gel. Presumably, gel accounted for this increase—the gel is immobile but dehydrateable. In the previous section, we estimated that oil injection reduced gel volume by 55%. Figure 16 suggests that the remaining gel was widely distributed, although it was most likely to be found in medium to small pores. Figure 16 also shows that a few pores had lower Swr values after gel placement than before gel.

Figure 16 Changes in Berea: Swr before gel to Swr after gel.