Title : Influence of surfacants on the Rheological Pecularities of High-viscosity Oils from a Number of Fields in Azerbaijan
A decrease in the reserves of traditional light oils and an increase in the proportion of heavy oils with increased content of paraffin, resins, and asphaltenes, characterized by high density, viscosity, and pour point, significantly complicate technological processes at all stages of production, transportation through technological transport systems and main oil pipelines and processing of such oils [1, 2]. For the correct selection of technological modes that ensure efficient transportation of such multi-component hydrocarbon media, it is necessary to take into account, the physicochemical properties of the studied oils and their rheological properties . The report presents the results of experimental studies of the effect of various widely used surfactants on the rheology of high-viscosity oils from Azerbaijan's fields - Muradkhanly, Jafarly, Tarsdallar, Bulla-Deniz, and Sangachal-Deniz to assess the possibility of their use in the in-field pipeline transport of these oils. The influence of ionic (sulfonol and alkaline wastes of oil refining - sodium salts of naphthenic acids) and nonionic (Alkan-202 and Disolvan-4795) reagents has been investigated. The influences of these surfactants have been studied both individually and in various combinations. The rheological features of the indicated oils, the dependence of the dynamic viscosity and shear rate on temperature are investigated, the values of the energy and enthalpy of activation of viscous flow for these oils are determined. The analysis of the rheological characteristics of oil-water emulsions at different degrees of water cut of the studied oils, structural transformations occurring in these dispersed media at different temperatures is presented. It is shown that with an increase in temperature, the structure of the studied oils becomes more ordered, which follows from the behavior of the entropy of activation of a viscous flow when studying its dependence on temperature. It is pointed out that it is important to study the temperature dependence of the viscosity of these dispersed systems for understanding the mechanism of their flow process and elucidating the relationship between the structure of an oil dispersed system and its effect on deformation. The questions of the influence of surfactants on the main physicochemical parameters of the studied oils, on their quality and technological mode of transportation, are discussed. Along with measuring the viscosity, the spectra of dynamic light scattering (DLS), the effect of surfactants on the particle size distribution, on the average particle size, and the dependence of the DLS parameters on the measurement temperature were also investigated. The results of studies of the comparative effect of the above oil- and water-soluble reagents and their compositions on the specified characteristics of these oils with varying degrees of water cut are presented.