3. Material and methods
3.1. Material
NaCl, CaCl2, copper sulfate, potassium hexacyanoferrate trihydrate are all analytical reagent grade. The dynamic viscosity and
density of the model crude oil sample at 22 Celsius were 1.2 mPa s
and 0.91 g/mL, respectively.
A copper hexacyanoferrate membrane could be formed either
by sequential injection of solutions, or by the injection of copper
sulfate solution followed by the diffusion of potassium hexacyanoferrate solution. The mole ratio between copper sulfate and
potassium hexacyanoferrate trihydrate was 2.
Fractured rocks were prepared with different permeability
carbonate rocks using splitting technique (Paraszczak and Hadjigeorgiou, 1994). Gas permeability and porosity values of carbonate
rocks were listed in Table 1. The fractured rocks, 25.4 mm*100 mm
(diameter*length), were used