Experiments on spontaneous imbibition processes in Hele-Shaw cells were car
ried out in squared cells (20 cm x 20 cm) with separations of 0.005, 0.015
and 0. 075 cm using twice-distilled water and Soltrol 170 as the displacing
and displaced fluids, respectively. The experiments indicated that it was
possible to repeat the main features of the spontaneous imbibition process
using a procedure for wettability restoration of the glass sheets. The best
sweep efficiency was achieved for the 0. 015 cm cell gnp. Two or three con
secutive stages occurred depended on the cell gap, as evidenced by a charac
teristic speed and a characteristic advancing front structure. The initial
stage speed/development stage speed ratio and the oil total area/water-oil
total interfacial length ratio as functions of time were gap-dependent. The
capillary number and interfacial power density estimations indicated that
at about 0.033 cm gap there was a flow pattern transition from slightly uni
form displacement to fingering flow.