EOR IOR DIFFERENCE

 The main difference between IOR and EOR is that EOR approach is used to recover mostly immobile oil that remains in the reservoir after application of primary and secondary methods while IOR strategies are used to recover mobile oil. But sometimes, IOR is used to recover an immobile oil as well.

Thereof, what are the differences between secondary and tertiary enhanced recovery methods?

Secondary recovery employs water and gas injection, displacing the oil and driving it to the surface. The way to further increase oil production is through the tertiary recovery method or EOR. Although more expensive to employ on a field, EOR can increase production from a well to up to 75% recovery.