The process of oil blending, reasons and prerequisites for using oil blending technology in Russia and other countries were studied. A review of compounding technological schemes used in Russia was carried out. Equivalent stresses arising in T-joints from internal pressure were investigated. A study of oil blending efficiency and local resistance coefficient for T-joints with different articulation angles was carried out. For the study, 3D models of T-joints with articulation angles from 0° to 30° were made. The strength and hydraulic calculations of the T-joints were carried out by finite element modelling in the ANSYS software. Strength simulation results were processed according to the standards for assessing the inadmissibility of plastic deformation of the structure from the applied load. The hydraulic results of the simulation were evaluated according to the theoretical formulas for calculating the local resistance coefficient, pressure distribution pattern in the cross section of the mixing unit and flowlines of the components during mixing. It was concluded that the oil mixing technology is relevant and will be developed in the future. As a result of strength calculations, maximum equivalent stresses and a pipe joint limit angle of 25° were found. As a result of hydraulic calculations of T-joint with an angle of articulation 25° an improvement of miscibility of components by 11.2 % in comparison with the standard T-joint was revealed. The modified T-joint, according to calculations in the finite element modelling software, had a local resistance coefficient that is 19.3% lower than that of the standard T-joint. According to theoretical calculation results using Gardel's formulas, this coefficient was 23% lower. Finally, a 3D model of an upgraded T-joint was developed which can act as a mixing unit and has better miscibility of components and energy efficiency in operation.