Impact of different injection sites on the water and oil exchange in a fractured porous medium for different polymers: A visual study

This study aimed at investigating the impact of injection sites including i) matrix and ii) fracture when polymers of PVA, PAM, and CMC are injected at different concentrations within a fractured medium. The experimental results showed that PAM for all concentrations had a high recovery factor (RF) when its injection site is matrix and also at low concentrations. PAM has performed better due to its higher viscosity as well as its high capillary pressure in water-wet condition. In different pore sizes, the amount of shear rate that will be applied to the polymers will vary, which is why in the case of PAM injection in the fracture, the tendency of polymer to penetrate through the grains is more than fracture. CMC at low concentrations of 100 and 1000 ppm cannot wash the oil effectively. However, for a concentration of 5000 ppm, it has maximum breakthrough time as well as the maximum RF of 96% and 83% when it is injected via the matrix and fracture, respectively. These efficiencies are approximately 15% and 10% higher than that of PAM although PAM is more viscous of nearly threefold. PVA can ultimately sweep 12% of the OOIP when its 5000-ppm solution is injected from the matrix.