After filling the core with sand to the desired porosity, the experimental procedures involved are as follows:
1.
Vacuum sandpack for three hours, then saturate core with brine.
2.
Inject oil with desired viscosity into core holder at the rate of 0.1 ml/min until saturation.
3.
To apply the EOR techniques for oil production, either 1% NaCl brine (for waterflooding) or carbon dioxide (for CO2 flooding) is injected into the core at a rate 0.2 ml/min, until oil production is considered to be negligible. The produced oil was collected in a test tube at the end of the sandpack every 25 min. The test tubes were put into a centrifuge to separate the water from the oil for more accurate measurement. The oil production was considered to be negligible if the increment of production was less than 1% for three consecutive test tubes. At this point, maximum recovery was assumed.
4.
Clean sandpack with toluene and let it dry overnight.
5.
Repeat from step 1 for the next experiment.