To this day, petroleum acids are still being studied by a number of researchers. Interest in the above class of organic compounds is not only attributed to practical perspective, but also to general humanitarian purposes. According to S. Nametkin, "... composition and structure of petroleum acids are closely related not only to the genesis of oil, but to the origin of life on Earth as well". Depending on their origin, oils may contain different amounts of naphthenic acids, extremely insignificant in all cases. Naphthenic acids are extracted from oils using alkali alcoholic solutions. Structure of naphthenic acids in any oil is the same and depends on the nature of oil. Among the oil produced worldwide, and particularly in the CIS region, Azerbaijan's oil features the highest content of petroleum acids. Oils of Bibi-Heybat, Romani, Binagadi, Balakhani, Sabunchi and other fields are rich in petroleum acids, which content in some crude oil grades reaches 1.5 – 2%. Due to the fact that acids extracted from naphthene-base crude of Baku oil fields have the same composition and physical-chemical properties as synthetic naphthenic acids, they are often referred to as natural naphthenic acids.