MATERIALS AND METHODSIt's known from oilfield practice that, transportation process of not mono-componential, homogeneous but multi-componential, multiphase heterogeneous systems occurs in mining technological pipelines from exploitation wells to oil producing terminals. However, depending on the time, well product constantly changes its commodity quality in addition to its physical-chemical and rheological properties. Namely for this reason, the number of technical-technological problems and complications occuring in technological pipeline system is more but their solution is hard.Currently, the number and scope of the scientific researches, being carried out connected with the dependence of qualitative indicators on oils for oil mixtures and their mixing and specific problems occurring in this case, is being expanded. The problems created by "undesirableness" of some mixtures, during extraction, production and transportation of oils, inadmissibility of applying the additivity rule to them indicates the urgency of the problem and importance of solving the problem.In addition to a number of difficulties occuring during pipeline transportation of different types, rheological oils by being mixed with one another or light oils, as well as solvents, disbalance cases are observed in their storage as well as delivery and reception processes. In this regard, a number of oil and oil products can even be considered "undesirable" couple.The analysis related with oil losses during the transportation shows that, volume loss can occur in the mixing of the components sharply differing from each other due to their properties. The first normative document on the volume loss occuring in their mixing during the transportation of oils and oil products was published in 1996 by American Oil Institute. Such cases are possible to occur while heavy oils (oil products) are being mixed with light oil products. For instance, the volume obtained by mixing bitumen with light oil can be less than the total volume of the components. It should be noted that, such volume loss is not related to the physical loss of the substance and the total mass of the load remains unchanged during the mixing.