In the pipeline transport of high-viscosity and congealing oil the issue of determining the safe shutdown time, as well as calculating the starting pressure required to resume pumping and bring the main oil pipeline into operation, is of particular relevance. In the process of shutting down the underground laying of an oil pipeline, paraffinic oil cools and crystallizes. At the same time, its rheological properties change, with a temperature decrease viscosity and shear stress increase. The oil temperature and the pressure required to bring the oil pipeline into operation depend on the duration of pumping stop. The pressure value required for start-up may turn out to be higher than the allowable one in a given section of the pipeline. In this regard, it is necessary to monitor the temperature of the oil during the shutdown process. The cooling of oil occurs unevenly both along the cross section and along the length of the pipeline. And the value of the start-up pressure depends on the position of the shear surface, which may be less than the radius of the pipeline. To take into account the temperature non-uniformity over the cross section, this paper solves the problem of conjugate heat transfer between the oil pipeline and the soil surrounding it. The article considers the case of using seasonally operating cooling devices for underground oil pipeline in permafrost soils and these devices influence on the distribution of oil temperature depending on shutdown duration. The results of a numerical study of the change in oil temperature over time under the conditions of installation of seasonally operating cooling devices and in their absence are presented. Using the results of the study, we can set the required pressure to resume pumping.
References
1. Dyagterev V.N., Voprosy puska nefteprovoda s parafinistoy neft’yu posle ego dlitel’noy ostanovki. Obzornaya informatsiya (Issues of starting an oil pipeline with paraffin oil after a long stop. Overview Information), Seriya Transport i khranenie nefti i nefteproduktov (Series Transport and storage of oil and oil products), Moscow: Publ. of VNIIOENG, 1982, 61 p.
2. Chernikin V.I., Perekachka vyazkikh i zastyvayushchikh neftey (Pumping of viscous and hardening oils), Moscow: Gostoptekhizdat Publ., 1958, 164 p.
3. Mukuk K.V., Elementy gidravliki relaksiruyushchikh anomal’nykh sistem (Elements of hydraulics of relaxing anomalous systems): edited by Mirzadzhanzade A.Kh., Tashkent: Fan Publ., 1980, 115 p.
4. RD 39-3-80-78. Vremennoe metodicheskoe rukovodstvo po gidravlicheskomu raschetu transporta nen’yutonovskikh neftey (Interim methodological guidelines for the hydraulic calculation of the transport of Non-Newtonian oils), Ufa: VNIISPTneft’, 1978, 103 p.
5. Cherentsov D.A., Yakupov A.U., Voronin K.S. et al., Application of machine learning models for intelligent management of oil transportation efficiency (In Russ.) Neftyanoe khozyaystvo. – 2021, no. 12, pp. 136-139, DOI: https://doi.org/10.24887/0028-2448-2019-12-136-139
6. Yakupov A.U., Cherentsov D.A., Toropov S.Yu. et al., Predictive control of the starting pressure of the main oil pipeline (In Russ.), Izvestiya vysshikh uchebnykh zavedeniy. Neft’ i gaz, 2021, no. 6, pp. 125-133, DOI: https://doi.org/10.31660/0445-0108-2021-6-125-133
7. Shabarov A.B., Mikhaylov P.Yu., Vilkov M.N. et al., Eksperimental’noe issledovanie poley temperatury vblizi zaglublennykh truboprovodov (Experimental study of temperature fields near buried pipelines), Collected papers “Neft’ i gaz Zapadnoy Sibiri” (Oil and gas of Western Siberia), Proceedings of International scientific and technical conference dedicated to the 55th anniversary of the Tyumen State Oil and Gas University, Tyumen’: Publ. of TyumGNGU, 2011, V. II, pp. 108–111.
8. Lykov A.V., Teoriya sushki (Drying theory), Moscow: Energiya Publ., 1968, 472 p.
9. Gorelik Ya.B., Seleznev A.A., About efficiency of the condenser finning of the short vertical thermostabilizer for building on permafrost (In Russ.), Kriosfera Zemli, 2016, V. 20, no. 2, pp. 78-89.
10. Roache P.J., Computational fluid dynamics, Hermosa Publishers, 1976, 446 p.
11. Bakhtizin R.N., Shutov A.A., Shtukaturov K.Yu., Simulation of pipeline operating modes using the NIPAL 3.0 (Non Isothermal Pipeline for Abnormal Liquids) software package (In Russ.), Neftegazovoe delo, 2004, no. 1, pp. 7, URL: http://ogbus.ru/files/ogbus/authors/Bahtizin/Bahtizin_1.pdf
12. Vakulin A.A., Shabarov A.B., Vakulin A.A., Cooling down of oil when the pipeline stops in frozen soil (In Russ.), Vestnik Tyumenskogo gosudarstvennogo universiteta. Fiziko-matematicheskoe modelirovanie. Neft’, gaz, energetika = Tyumen State University Herald. Physical and Mathematical Modeling. Oil, Gas, Energy, 2021, V. 7, no. 4(28), pp. 27–45, DOI: https://doi.org/10.21684/2411-7978-2021-7-4-27-45
