The purpose of the study is to identify the hydraulic resistance coefficient of the main oil pipeline. Oil transportation through pipelines is the most efficient way to deliver oil from suppliers to consumers. The volume of transported oil depends on the pipeline hydraulic resistance. In practice, the hydraulic resistance coefficient is determined by the value of the Reynolds number and the pipeline internal surface roughness. The Reynolds number depends on the oil viscosity, which changes in a non-isothermal pipeline due to the heat exchange of the oil flow with the environment. The pipeline internal surface roughness changes during main oil pipeline operation. The identification of the pipeline hydraulic resistance coefficient is necessary for accurate calculations of the technological modes of the main oil pipeline. The SCADA (supervisory control and data acquisition) system determines the actual oil data (pressure, temperature, flow rate) along the main oil pipeline length in real time. Based on the results of the thermal-hydraulic calculations and the SCADA system, the hydraulic resistance coefficient identification method was built. The methodology was tested in the OPS-3—Koschagil, Severnye Buzachi—Karazhanbas, Prorva—Kultumiyev, Kassymov—Bolshoi Chagan main pipeline sections. The approbation results have shown sufficient accuracy in identifying the hydraulic resistance coefficient of oil pipelines. The obtained hydraulic resistance coefficient dependences were used to determine the oil transportation technological modes in industrial pipelines.

The paper is devoted to the simulating of non-stationary processes of shutdown and restart on the example of a section of the Zhetybai-Uzen “hot” oil pipeline. A mathematical model of thermal-hydraulic calculation is given taking into account the rheological properties of the pumping oil. The special module of the SmartTran software developed by the work’s authors carried out the calculations. In the calculations, the decrease in time of oil temperature in the pipeline during cooling and the increase in oil pressure, temperature, velocity after the restart are determined. In addition, the calculations determine the power of pumping units, heating furnaces and the power consumption, which are necessary for restart of the pipeline after the shutdown. Simulation the processes of the pipeline cooling and restart after a shutdown makes it possible choosing the optimum parameters of pumping units at pumping stations and the time of safe shutdown of the oil pipeline.

This article presents a digital twin of hot pumping waxy oil through a main pipeline. Digital copies of the original object data were identified through sensor measurements from SCADA and ECMAS, forming the basis of the SmartTranPro 1.7.1 Software. The mathematical model of the software describes the process of hot pumping waxy oil regarding heat exchange with the environment. The intelligent algorithms of the SmartTranPro 1.7.1 Software were used to determine the actual dependencies of the digital twins of the objects, hydraulic parameters, and heat transfer for the Kassymov–Bolshoi Chagan hot main pipeline, which has a length of 450 km. The results of the thermal–hydraulic calculations for the hot pumping of waxy oil are in good agreement with the actual sensor data from SCADA and ECASM. The optimization calculations of the heating temperature for waxy oil show an economic efficiency of 38.9% for the hot pumping method.

This article is devoted to the study of heat exchange of a heated flow of waxy oil in a pipe. Heat exchange between the waxy oil flow and the surrounding environment decreases the oil temperature and sharply increases the rheological properties. The appearance of a solid-like region within the yield-stress fluid flow is a non-trivial problem. This flow property greatly complicates the numerical solution of the system of equations governing the flow and heat transfer of viscoplastic fluids. The Bingham–Papanastasiou model allows one to solve the problem by regularizing the formula for effective molecular viscosity. The novelty of this work lies in establishing the dependence of the Nusselt number on the Reynolds and Bingham numbers for the flow of viscoplastic fluid in a pipe. Via calculations, velocity, temperature, and pressure distributions in the flow were obtained for Bingham numbers ranging from 1.7 to 118.29 and Reynolds numbers ranging from 104 to 2615. The Nusselt number dependence increases with the increase in the Reynolds number and decreases with the decrease in the Bingham number along the pipe length.