1. n. [Formation Evaluation]

A technique for estimating the cation-exchange capacity of a sample by measuring the conductivity of the sample during titration. The technique includes crushing a core sample and mixing it for some time in a solution like barium acetate, during which all the cation-exchange sites are replaced by barium (Ba⁺⁺) ions. The solution is then titrated with another solution, such as MgSO₄, while observing the change in conductivity as the magnesium (Mg⁺⁺) ions replace the Ba⁺⁺ ions. For several reasons, but mainly because the sample must be crushed, the measured cation-exchange capacity may differ from that which affects the in situ electrical properties of the rock.

See related terms: multiple salinity