The study of the kinetics of the process of oil wax deposition in main pipeline operating conditions

UDK: 658.5:622.692.4
DOI: 10.24887/0028-2448-2020-11-124-127
Key words: intensity of wax deposition, oil, main pipeline, dynamic tests, kinetics of the process, thermohydraulic testing installation, wax inhibitor, flow mode
Authors: R.Z. Sunagatullin (The Pipeline Transport Institute LLC, RF, Moscow), R.M. Karimov (Ufa State Petroleum Technical University, RF, Ufa), R.R. Tashbulatov (Ufa State Petroleum Technical University, RF, Ufa), B.N. Mastobaev (Ufa State Petroleum Technical University, RF, Ufa)

A comparative analysis of the instrumental base and test methods for qualitative and quantitative studies of waxing processes and the selection of wax inhibitors is presented. The drawbacks of the static test methods used are substantiated, which allow, at best, to estimate the intensity or indirect indicators characterizing the dynamics of the pipe waxing process in model laboratory conditions, the results of which are suitable only for solving a narrow range of problems – comparing the tendency of different oil composition to form wax deposits and the effectiveness of wax inhibitors. The data obtained in this way, even in a wide temperature range, do not effectively predict the course and development of the process under conditions of various regimes of oil flow modes through non-isothermal pipelines. In particular, the ineffectiveness of the used depressor inhibitors on commercial oils under prolonged test conditions has been experimentally proved, where the latter can act as surfactants that, on the one hand, reduce the amount of deposits in the flow and at the same time prevent the washout of the already formed layer in the near-wall zone. It is noted that temperature conditions are only a factor in the formation of the deposits themselves, and do not determine the dynamics of their accumulation on the inner surface of the pipe wall. To assess the kinetics of the waxing process in time, only methods based on in-line tests are applicable. A thermohydraulic testing installation is proposed, developed for carrying out in-line experimental studies of the dynamics and kinetics of the wax deposition process of non-isothermal main oil pipelines, which reproduces conditions close to operating ones, not only taking into account unsteady heat-mass transfer and the level of shear stresses, but also flow regime modes, up to developed turbulent ones, at which they have the place where the surface layer of sediments was washed away due to pulsations in the wall zone for the possibility of applying the results of experimental studies from lab and testing installation data to the operating modes of oil pipelines, the boundary test conditions have been determined.

References

1. Armenskiy E.A., Novoselov V.F., Tugunov P.I., Study of thermal phenomena and dynamics of wax deposition in oil pipelines (In Russ.), Neft' i gaz, 1969, no. 10, pp. 77–80.

2. Voznyak M.P., Khizgilov I.Kh., Voznyak L.V., Changes in the thickness of paraffin deposits along the length of the pipeline and in time  (In Russ.), Razvedka i razrabotka neftyanykh i gazovykh mestorozhdeniy, 1975, no. 12, pp. 113–116.

3. Kolesnik I.S., Lukashevich I.P., Susanina O.G., Study of the adhesion of paraffin deposits to a steel surface (In Russ.), Transport i khranenie nefteproduktov i uglevodorodnogo syr'ya, 1972, no. 5, pp. 17–20.

4. Kolesnik I.S., Lukashevich I.P., Susanina O.G., Influence of temperature on the waxing process (In Russ.), Neft' i gaz, 1971, no. 2, pp. 85–88.

5. Tronov V.P., Teoreticheskaya otsenka vliyaniya fizicheskikh svoystv poverkhnostey kachestva obrabotki i drugikh faktorov na intensivnost' otlozheniy parafina (Theoretical assessment of the influence of the physical properties of surfaces, processing quality and other factors on the intensity of wax deposits), Proceedings of TatNIPI, 1962, V. 4, pp. 400–412.

6. Tronov V.P., O mekhanizme vliyaniya prirody poverkhnostey na ikh zaparafinivanie (On the mechanism of the effect of the nature of surfaces on their waxing), Proceedings of TatNIPI, 1968, V. 11, pp. 191–200. 

7.  Tronov V.P., Mekhanizm obrazovaniya smolo-parafinovykh otlozheniy i bor'ba s nimi (Mechanism of formation of resin-paraffin deposits and its control), Moscow: Nedra Publ., 1970, 192 p.

8. Sunagatullin R.Z., Karimov R.M., Mastobaev B.N., Vliyanie temperaturnogo gradienta na granitse razdela "potok – stenka" na intensivnost' parafinootlozheniy (Influence of the temperature gradient at the "flow - wall" interface on the intensity of paraffin deposition), Proceedings of  XIV International educational, scientific and practical conference "Truboprovodnyy transport – 2019" (Pipeline Transport – 2019), Ufa: Publ. of USPTU, 2019, pp. 132–133.

9. 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.

10. 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.

11.  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.), Nauchnye trudy NIPI Neftegaz GNKAR = SOCAR Proceedings, 2017, no. 2, pp. 49–55.

12. Revel'-Muroz P.A., Bakhtizin R.N., Karimov R.M., Mastobaev B.N., Joint transportation of heavy and wax oil blended (In Russ.), Nauchnye trudy NIPI Neftegaz GNKAR = SOCAR Proceedings, 2018, no. 2, pp. 65–70.

13. Patent RU2650727S1, Stand for research of transportation processes of black and bituminous oil, Inventors: Chuzhinov S.N., Sunagatullin R.Z., Zverev F.S., Nesyn G.V., Avdej A.V.

A comparative analysis of the instrumental base and test methods for qualitative and quantitative studies of waxing processes and the selection of wax inhibitors is presented. The drawbacks of the static test methods used are substantiated, which allow, at best, to estimate the intensity or indirect indicators characterizing the dynamics of the pipe waxing process in model laboratory conditions, the results of which are suitable only for solving a narrow range of problems – comparing the tendency of different oil composition to form wax deposits and the effectiveness of wax inhibitors. The data obtained in this way, even in a wide temperature range, do not effectively predict the course and development of the process under conditions of various regimes of oil flow modes through non-isothermal pipelines. In particular, the ineffectiveness of the used depressor inhibitors on commercial oils under prolonged test conditions has been experimentally proved, where the latter can act as surfactants that, on the one hand, reduce the amount of deposits in the flow and at the same time prevent the washout of the already formed layer in the near-wall zone. It is noted that temperature conditions are only a factor in the formation of the deposits themselves, and do not determine the dynamics of their accumulation on the inner surface of the pipe wall. To assess the kinetics of the waxing process in time, only methods based on in-line tests are applicable. A thermohydraulic testing installation is proposed, developed for carrying out in-line experimental studies of the dynamics and kinetics of the wax deposition process of non-isothermal main oil pipelines, which reproduces conditions close to operating ones, not only taking into account unsteady heat-mass transfer and the level of shear stresses, but also flow regime modes, up to developed turbulent ones, at which they have the place where the surface layer of sediments was washed away due to pulsations in the wall zone for the possibility of applying the results of experimental studies from lab and testing installation data to the operating modes of oil pipelines, the boundary test conditions have been determined.

References

1. Armenskiy E.A., Novoselov V.F., Tugunov P.I., Study of thermal phenomena and dynamics of wax deposition in oil pipelines (In Russ.), Neft' i gaz, 1969, no. 10, pp. 77–80.

2. Voznyak M.P., Khizgilov I.Kh., Voznyak L.V., Changes in the thickness of paraffin deposits along the length of the pipeline and in time  (In Russ.), Razvedka i razrabotka neftyanykh i gazovykh mestorozhdeniy, 1975, no. 12, pp. 113–116.

3. Kolesnik I.S., Lukashevich I.P., Susanina O.G., Study of the adhesion of paraffin deposits to a steel surface (In Russ.), Transport i khranenie nefteproduktov i uglevodorodnogo syr'ya, 1972, no. 5, pp. 17–20.

4. Kolesnik I.S., Lukashevich I.P., Susanina O.G., Influence of temperature on the waxing process (In Russ.), Neft' i gaz, 1971, no. 2, pp. 85–88.

5. Tronov V.P., Teoreticheskaya otsenka vliyaniya fizicheskikh svoystv poverkhnostey kachestva obrabotki i drugikh faktorov na intensivnost' otlozheniy parafina (Theoretical assessment of the influence of the physical properties of surfaces, processing quality and other factors on the intensity of wax deposits), Proceedings of TatNIPI, 1962, V. 4, pp. 400–412.

6. Tronov V.P., O mekhanizme vliyaniya prirody poverkhnostey na ikh zaparafinivanie (On the mechanism of the effect of the nature of surfaces on their waxing), Proceedings of TatNIPI, 1968, V. 11, pp. 191–200. 

7.  Tronov V.P., Mekhanizm obrazovaniya smolo-parafinovykh otlozheniy i bor'ba s nimi (Mechanism of formation of resin-paraffin deposits and its control), Moscow: Nedra Publ., 1970, 192 p.

8. Sunagatullin R.Z., Karimov R.M., Mastobaev B.N., Vliyanie temperaturnogo gradienta na granitse razdela "potok – stenka" na intensivnost' parafinootlozheniy (Influence of the temperature gradient at the "flow - wall" interface on the intensity of paraffin deposition), Proceedings of  XIV International educational, scientific and practical conference "Truboprovodnyy transport – 2019" (Pipeline Transport – 2019), Ufa: Publ. of USPTU, 2019, pp. 132–133.

9. 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.

10. 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.

11.  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.), Nauchnye trudy NIPI Neftegaz GNKAR = SOCAR Proceedings, 2017, no. 2, pp. 49–55.

12. Revel'-Muroz P.A., Bakhtizin R.N., Karimov R.M., Mastobaev B.N., Joint transportation of heavy and wax oil blended (In Russ.), Nauchnye trudy NIPI Neftegaz GNKAR = SOCAR Proceedings, 2018, no. 2, pp. 65–70.

13. Patent RU2650727S1, Stand for research of transportation processes of black and bituminous oil, Inventors: Chuzhinov S.N., Sunagatullin R.Z., Zverev F.S., Nesyn G.V., Avdej A.V.


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