The paper considers a method to reduce pressures at the time of cold run in non-isothermal hot main oil pipeline stopped for the repairing. The method is based on forming booster batches to displace and replace waxy oil. A review of the regulatory and technical base for the calculation of thermal-hydraulic parameters of pumping, the study of the viscosity-temperature properties of the flow and the rheological parameters of high-viscosity oils, including in the non-stationary cold run mode, has been carried out. An analysis of the operating experience and results of studies of oil blends pumped through domestic hot oil pipelines is presented. Peculiarities of the influence of the composition on the rheological properties of pumped blends are highlighted. A set of laboratory and numerical studies of the rheological parameters of the flow of mixtures of high-viscosity heavy and solidifying waxy oils in non-stationary start-up modes depending on the ratio of oils has been carried out. To calculate the value of the static shear stress and the effective viscosity of the mixture used to prepare the booster batch with the best starting characteristics, an equation was obtained in the form of a polynomial of the fourth degree with nine coefficients. In order to improve the accuracy of modeling, taking into account the physicality of the flow process and to reduce the complexity of calculations and the volume of tests associated with them, a previously developed universal model of an asymptotic form was proposed, using which a high convergence of calculated and experimental values was obtained. On the example of the blend of heavy oil of Yaregskoye field and waxy oil Kharyaginskoye field, the practical possibility and expediency of using booster batches for the period of scheduled shutdowns and cold start-up of non-isothermal sections of the hot main oil pipeline Usa – Ukhta – Yaroslavl are confirmed. The ratio of oils in the booster batch found with the help of the proposed method will make it possible to significantly reduce the static shear stress and loads at cold run.
References
1. Karimov R.M., Mastobaev B.N., Change of technology of swapping of oil on the oil pipeline "Uzen-Atyrau-Samara" with development of petrotransport system of the western Kazakhstan (In Russ.), Transport i khranenie nefteproduktov i uglevodorodnogo syr'ya, 2010, no. 2, pp. 9–14.
2. Karimov R.M., Mastobaev B.N., Rheologikal features of the West Kazakhstan oil blend (In Russ.), Transport i khranenine nefteproduktov i uglevodorodnogo sur’ya, 2011, no. 2, pp. 3–7.
3. Sunagatullin R.Z., Karimov R.M., Dmitriev M.E., Baykova M.I., Experimental studies of the operational properties of asphaltene-resin-paraffin deposits formed in main oil pipelines (In Russ.), Nauka i tehnologii truboprovodnogo transporta nefti i nefteproduktov = Science & Technologies: Oil and Oil Products Pipeline Transportation, 2018, V. 8, no. 4, pp. 398–406, DOI: 10.28999/2541-9595-2018-8-4-398-406
4. Karimov R.M., Zaplatin A.V., Tashbulatov R.R., The use of twisted heat exchangers from coils of small bend radius for heating and heat treatment of oil (In Russ.), Delovoy zhurnal Neftegaz.ru, 2018, no. 12, pp. 45–49.
5. Sunagatullin R.Z., Karimov R.M., Tashbulatov R.R., Mastobaev B.N., Modeling the thermal-hydraulic effect of wax layer (In Russ.), Nauka i tehnologii truboprovodnogo transporta nefti i nefteproduktov = Science & Technologies: Oil and Oil Products Pipeline Transportation, 2019, V. 9, no. 2, pp. 158–162, DOI: 10.28999/2541-9595-2019-9-2-158-162
6. Sunagatullin R.Z., Karimov R.M., Tashbulatov R.R., Mastobaev B.N., Study of the causes for wax deposition under the operating conditions of main oil pipelines (In Russ.), Nauka i tehnologii truboprovodnogo transporta nefti i nefteproduktov = Science & Technologies: Oil and Oil Products Pipeline Transportation, 2020, V. 10, no. 6, pp. 610–619, DOI: 10.28999/2541-9595-2020-10-6-610-619
7. Sunagatullin R.Z., Karimov R.M., Tashbulatov R.R., Mastobaev B.N., The study of the kinetics of the process of oil wax deposition in main pipeline operating conditions (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2020, no. 11, pp. 124–127, DOI: https://doi.org/10.24887/0028-2448-2020-11-124-127
8. Karimov R.M., Sunagatullin R.Z., Tashbulatov R.R., Dmitriev M.E., Study of wax deposition reasons in non-isothermal main pipelines for hot pumping of high-viscosity waxy oil (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2021, no. 1, pp. 87–91, DOI: https://doi.org/10.24887/0028-2448-2021-1-87-91
9. Tugunov P.I., Novoselov V.F., Korshak A.A. et al., Tipovye raschety pri proektirovanii i ekspluatatsiy neftebaz i nefteprovodov (Typical calculations in the design and operation of tank farms and oil pipelines), Ufa: Dizain-PoligrafServis Publ., 2002, 658 p.
10. Karimov R.M., Mastobaev B.N., Joint transportation of high-viscosity and highly solidifying oils from Western Kazakhstan via the Uzen-Atyrau-Samara oil pipeline (In Russ.), Transport i khranenie nefteproduktov i uglevodorodnogo syr'ya, 2012, no. 1, pp. 3–6.
11. Karimov R.M., Mastobayev B.N., Features of pipeline transport of multi-component systems (In Russ.), Azerbaydzhanskoe neftyanoe khozyaystvo, 2012, no. 1, pp. 60–63.
12. Revel'-Muroz P.A., Bakhtizin R.N., Karimov R.M., Mastobaev B.N., Joint usage of thermal and chemical stimulation technique for transportation of high viscosity and congealing oils (In Russ.), Socar Proceedings (Nauchnye trudy), 2017, no. 2, pp. 49-55, DOI: 10.5510/OGP20170200314
13. Revel'-Muroz P.A., Bakhtizin R.N., Karimov R.M., Mastobaev B.N., Joint transportation of heavy and wax oil blended (In Russ.), Socar Proceedings, 2018, no. 2, pp. 65-70, DOI: 10.5510/OGP20180200352
14. Revel'-Muroz P.A., Bakhtizin R.N., Karimov R.M., Mastobaev B.N., About the effectiveness of hydrocarbon diluents for pipeline transportation of high viscosity heavy and waxy oil (In Russ.), SOCAR Proceedings, 2021, Special Issue 1, pp. 148-155, DOI: 10.5510/OGP2021SI100521
15. Tashbulatov R.R., Karimov R.M., Valeev A.R., Mastobaev B.N., Approximation of the rheological curve in the low-temperature zones of the anomalous flow of non-Newtonian oils using the asymptotic model (In Russ.), Truboprovodnyy transport: teoriya i praktika, 2017, no. 4, pp. 19–22.
16. Tashbulatov R.R., Karimov R.M., Valeev A.R., Mastobaev B.N., Asymptotic model for describing the rheological curve of the non-Newtonian flow of oil mixtures (In Russ.), Transport i khranenie nefteproduktov i uglevodorodnogo syr'ya, 2017, no. 5, pp. 14–23.
17. Tashbulatov R.R., Karimov R.M., Mastobaev B.N., Valeev A.R., Analysis of changing viscosity-temperature dependence in binary mixture of oils (In Russ.), Transport i khranenie nefteproduktov i uglevodorodnogo syr'ya, 2018, no. 2, pp. 5–9, DOI: 10.24411/0131-4270-2018-10201
18. Tashbulatov R.R., Karimov R.M., Valeev A.R., Mastobaev B.N., Modeling rheological properties of thixotropic oils at direct measurements on a rotary viscometer for evaluating the start-up modes of the trunk oil pipeline (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2020, no. 4, pp. 80–84, DOI: https://doi.org/10.24887/0028-2448-2020-4-80-84
