ARN‐Type Naphthenic Acids in Crudes: Analytical Detection and Physical Properties

Calcium naphthenates deposits recovered on site contain massive proportions of high molecular weight tetra acids, so‐called ARN. The detection of ARN acids in crudes is of paramount importance, especially for designing future installations and allowing for mitigation means. The proposed ARN detection strategy involves a concentration step and a high‐pressure liquid chromatography/mass spectrometry analysis. Using this methodology, ARN has been detected in a large number of crude oils, most of which do not show any operational difficulties. A physicochemical model is then proposed for interpreting these results. It incorporates the formation, in specific conditions, of a polymer like structure through ARN association.