The ester is injected at about 50,000 ppm concentration in oil or diesel. Since the ester partition coefficient is measured in the laboratory before the test using produced water and test reservoir oil. For this example, the ester K value is 0.1. This means that the ester, iso-propyl acetate, is five times more soluble in the oil than it is in the water. As a test example we will illustrate a 1000 bbl SWCT test for connate water saturation. The first 250 bbls of injected oil will carry the iso-propyl acetate, into the reservoir. As soon as the ester enters the pore space containing connate water, the ester partitions slightly into the stationary connate water according to the partition coefficient K. The black dots represent this ester. The green represents the injected oil. The ester travels at almost the same speed as the injected oil. The ester spends most of the time in the mobile oil phase.