| CPC E21B 43/20 (2013.01) [G01N 13/02 (2013.01); G01N 2013/0241 (2013.01); G01N 2013/0275 (2013.01)] | 6 Claims | 

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               1. A method for determining interfacial tension of a hydrocarbon in a brine fluid, comprising: 
            injecting a first brine fluid into a test cell, the first brine fluid having an initial ionic composition; 
                injecting a hydrocarbon fluid into the test cell; 
                contacting the hydrocarbon fluid with the first brine fluid, forming a droplet; 
                measuring the interfacial tension of the hydrocarbon fluid in contact with the first brine fluid; 
                at least partially displacing the first brine fluid with an inert gas; 
                measuring a ionic composition of the displaced first brine fluid in an ionic chromatograph; and 
                comparing the measured ionic composition to the initial ionic composition. 
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