3.3. Osmotic pressure enhancing oil recovery experiments
Firstly, fractured rock was saturated with one high solute fluid.
Secondly, oil was injected to build irreducible water saturation.
Thirdly, one pore volume (PV) copper sulfate solution was injected
and followed by one PV potassium hexacyanoferrate solution.
Fourthly, the process was shut in for twelve hours after which we
took out the fractured rock and put it in water drainage apparatus
with low solute fluid. Fifthly, the produced oil volume was recorded. Dividing the volume of the produced oil by the volume of
the saturated oil in rock, the oil recovery could be calculated. The
core flood setup is sketched in Fig. 2