CC BY
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Electrical facilmes and systems
Яхиббаева Л. М. Yakhibbaeva L. M.
кандидат филологических наук, доцент
кафедры «Иностранные языки», ФГБОУВО «Уфимский государственный нефтяной технический университет», г. Уфа, Российская Федерация
Cand. Sci. Philol., Assistant Professor of Foreign Languages Department, FSBEIHE «Ufa State Petroleum Technological University», Ufa, Russian Federation
УДК 622.692.4.07
Чатурова Д. И. Chaturova D. I.
магистрант кафедры электротехники и электрооборудования предприятий, ФГБОУ ВО «Уфимский государственный нефтяной технический университет», г. Уфа, Российская Федерация
Undergraduate Student of Electrical Engineering and Equipment of Enterprises Department, FSBEI HE «Ufa State Petroleum Technological University», Ufa, Russian Federation
TECHNOLOGICAL HEATING COMPLEX FOR SUBSEA PIPELINES BASED ON INDUCTION HEATING SYSTEM
Prospecting and exploration operations have increased in areas of seas and oceans as a result of intensive growth of raw hydrocarbons usage in all branches of industry. Hydrocarbon resources development in the north seas of the Arctic Ocean is becoming more and more relevant.
Oil product produced from the offshore field can be transported by means of tankers or a pipeline system. The latter method of transportation increases reliability and environmental friendliness of the technological process, however, the economic efficiency of oil-pipeline depends on physical and chemical properties of the oil pumped through the oil-pipeline. When transporting an oil product through a subsea pipeline, the oil product temperature drops because of the low environmental temperature. Therefore, oil product viscosity increases and cross-section of a pipeline decreases. All this results in pump load increase and electrical power costs. That is why it is necessary to decrease the parameter of the oil product viscosity. This problem can be solved by physical, chemical and thermal methods. But some of them are not applicable under water, and others are economically feasible.
The task of the oil product viscosity reduction and maintenance of its temperature at a desired level requires application of new technologies and systems. At the same time they must secure high reliability, long service life and the least capital expenditures. Such systems include electric heating systems. Nowadays direct electric heating has become rather popular, but this system is not suitable for distant pipelines and it has a number of significant disadvantages. And this is the reason why an effective heating system based on induction electrothermal technologies are required to be developed.
Key words: hydrocarbon resources, continental shelf, subsea pipeline, viscosity control, direct electric heating, induction-heating system, secondary power source.
ЭЛЕКТРОТЕХНИЧЕСКИЕ КОМПЛЕКСЫ И СИСТЕМЫ
ТЕХНОЛОГИЧЕСКИЙ КОМПЛЕКС ПОДОГРЕВА ДЛЯ ПОДВОДНЫХ ТРУБОПРОВОДОВ НА ОСНОВЕ ИНДУКЦИОННОЙ НАГРЕВАТЕЛЬНОЙ СИСТЕМЫ
В связи с интенсивным ростом потребления углеводородного сырья во всех сферах промышленности увеличились поисково-разведочные работы в акваториях морей и океанов. Все большую актуальность приобретает освоение углеводородных ресурсов северных морей Северного Ледовитого океана.
Добытый нефтепродукт с морского месторождения может транспортироваться танкерами или трубопроводной системой. Последний способ транспортировки повышает надежность и экологичность технологического процесса, однако экономическая эффективность нефтепровода зависит от физико-химических свойств перекачиваемой по нему нефти. При транспортировке нефтепродукта по подводному трубопроводу температура нефтепродукта падает из-за низких температур окружающей среды. Следовательно, увеличивается вязкость нефтепродукта и уменьшается рабочее сечение трубопровода. Все это приводит к увеличению нагрузки на насос и затрат на электроэнергию. Поэтому возникает необходимость в уменьшении параметра вязкости нефтепродукта. Данную проблему можно решить физическим, химическим и термическим методами. Однако некоторые из них неприменимы под водой, а другие экономически неэффективны.
Задача снижения вязкости нефтепродукта и поддержания его температуры на необходимом уровне требует применения новых технологий и систем. При этом они должны обеспечить высокую надежность, большой срок службы и наименьшие капитальные затраты. К таким системам относятся электрические системы нагрева. На сегодняшний день уже получил популярность прямой электрический нагрев, однако данная система не подходит для протяженных трубопроводов и имеет ряд существенных недостатков. В связи с этим возникает необходимость в создании эффективной системы нагрева на основе индукционных электротермических технологий.
Ключевые слова: углеводородные ресурсы, континентальный шельф, подводный трубопровод, регулирование вязкости, прямой электрический нагрев, индукционная нагревательная система, вторичный источник питания.
Nowadays the most part of oil and gas production is still carried out onshore.
Nevertheless, a large number of gas and oil is already being produced offshore. Now 30 % of the world's oil and gas development is carried out offshore — and this figure is rising with every passing year. Oil and gas are produced in offshore 35 countries, among which are such leading countries as Norway, Canada and the USA [1].
Russia has the largest continental shelf, the area of which is 6.3 million square kilometers, and 52 % of this territory is promising for oil and gas production. That is why the extraction of hydrocarbon resources on the continental shelf is considered to be one of the main strategic tasks of the Russian Federation [2]. In this case it is necessary to develop cost-effective technologies, capable of ensuring safe and effective oil and gas production [3].
One of the methods for increasing environmental security and flow capacity is the use of oil and gas pipeline transporting. However, during oil product delivery via a subsea pipeline, the oil product temperature decreases because of the low environmental temperature. As a result of this, pumped liquid viscosity increases and a pipeline cross-section decreases due to asphalt-resin-paraffin sediments, which lead to an increase of pump load and considerable energy expenditure. Consequently, the necessity occurs to regulate rheological properties of oil, namely — the viscosity reduction [4].
There are many different methods for regulating the rheological properties of pumped liquid: physical, chemical, thermal, electrical [4]. As for subsea pipelines heating, it is optimal to use the electrical method. Well-known methods of pipelines electrical heating by thermal field formation are shown in Table 1.
Электротехнические и информационные комплексы и системы. № 3, т. 13, 2017
Table 1. Electrical methods for regulating the rheological properties of pumped liquid
Heating method Heating source type
Resistive of constant power
of variable power
Inductive indirectly inductive (skin-system)
of commercial frequency
of semi-high frequency
Direct by alternating current
by direct current
Super-high frequency by electromagnetic field of super-high frequency
Direct electric heating is one of the widely used heating systems for subsea pipelines. When heating flow lines in offshore fields, direct electrical heating has been widely applied. The operating principle of the direct electrical heating is immediate passage of electric current through the material of a metal pipe (Figure 1) [5].
Heat removal in the pipe P is determined by the following relationship:
P = 12R, where I is the current in the pipe, A;
R is the pipe resistance, Ohm.
But such system has some disadvantages being as follows:
— high thermal-power losses in the pipe;
— high economic expenses involved in cable and supply systems;
— lack of heat-transfer process control;
— non-uniform current distribution in the area of welding joints;
— residual potential on the pipeline surface;
— negative impact of electric current on the environment.
Thus, from the foregoing we can conclude that this system is effective for short pipelines only.
In order to eliminate the disadvantages mentioned above, induction-heating system is offered to use; it consists of secondary power source and a heating element located on the facility — inductor (Figure 2) [6].
As an example, a process pipeline with a diameter of 526 mm and with the length of
Figure 1. Basic diagram of subsea pipelines direct electrical heating operation
1 — pumped liquid; 2 — pipeline; 3 — inductor; PS — power supply Figure 2. Induction-heating system
Электротехнические комплексы и системы
100 km was taken. The calculation showed that, the induction-heating system (IHS) with capacity of 34 kW maintains the temperature of oil in the range from +30 °C to +60 °C for the space of 60 km. For further efficient oil pumping, it is necessary to install one more IHS (on the pipeline section of 60 km) or to increase the capacity of initial IHS (Figure 3).
Figure 4 shows the induction-heating system layout on the underwater part of a pipeline with the local and stepped method. As for the secondary power source, it can be located both on the platform and in immediate vicinity from the inductor (under water), but when transferring the
energy, losses are usually reduced. In the first case, supply of secondary power source is carried out from the electric power substation; and in the second case, it is carried out from the power cable connected through the coupling [7].
As a result, induction-heating system is environmentally friendly, as heating isn't spread into environment from outside, and there is an opportunity to regulate the process of heating. This system is also adapted in various power supply circuits of an offshore oil and gas platform, such as centralized and autonomous, and induction-heating system power losses are parts per million per cent.
Figure 3. Diagram of pumped liquid temperature distribution with the induction-heating method
oïl ¿nid gas, plflifiwm
Receiver point
f 1__
Figure 4. Induction-heating system layout on the underwater part of a pipeline with the local and stepped method
Conclusion makes it possible to increase safety and effi-
Thus, we can conclude, that the use of the ciency of the technological process. induction-heating system for subsea pipelines
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Электротехнические и информационные комплексы и системы. № 3, т. 13, 2017
References
1. Philipov A.V. Oil and Gas — Marine Sequel of the Earth History // Oil and Gas Vertical. 2013. No. 12. P. 104-107.
2. Chaturova D.I. Heating Systems Analysis of Offshore Pipelines // Subsurface Management Problems: Collection of Research Papers of International Forum-Competition of Young Scientists. 2016. P. 190-191.
3. Chaturova D.I. Monitoring Complex of Offshore Oil and Gas Platform Facilities as a Part of Subsea Pipelines Heating System // Electric Drive, Electric Technologies and Electric Equipment of Enterprises: Collection of Research Papers of the III International (IV All-Russian) Scientific and Technical Conference, 2017. — P. 430-435.
4. Chaturova D.I. Heating Systems Analysis of Offshore Pipelines // Actual Problems of Science and Technology: Collection of Research Papers of the VIII International Scientific and Practical Conference of Young Scientists. 2015. P. 45-51.
5. Khrenkov N.N. Direct Electric Heating of Underwater Pipelines // Industrial Electric Heating and Electric Warming: Electronic Journal. M., 2013. Issue 2. URL: http://ru. calameo.com/read/0017674059a262e79f9cb (accessed: 01.10.2016).
6. Konesev S.G., Kirillov R.V., Kond-ratyev E.Yu., Sadikov M.R., Khazieva R.T., Khlyupin P.A. Induction Heating System for Length of the Pipeline // Oil and Gas Business. 2014. Part 12, No. 4. P. 40-47.
7. Chaturova D.I., Khlyupin P.A. Technological Complex of the Heating System of Underwater Field Pipelines // Actual Problems of Science and Technology: Materials of IX International Scientific-Practical Conference of Young Scientists. 2016. P. 324-326.
Список литературы
1. Филиппов А.В. Нефть и газ — морское продолжение земной истории // Нефтегазовая вертикаль. 2013. № 12. С. 104-107.
2. Чатурова Д.И. Анализ систем подогрева шельфовых трубопроводов // Проблемы недропользования: Сб. науч. тр. Междунар. форума-конкурса молодых ученых. 2016. С. 190-191.
3. Чатурова Д.И. Комплекс мониторинга объектов морской нефтегазовой платформы в составе системы нагрева подводных трубопроводов // Электропривод, электротехнологии и электрооборудование предприятий: сб.к науч. тр. III Междунар. (VI Всеросс.) науч.-техн. конф. 2017. С. 430-435.
4. Чатурова Д.И. Анализ систем подогрева шельфовых трубопроводов // Актуальные проблемы науки и техники: сб. матер. VIII Междунар. науч.-практ. конф. молодых ученых. 2015. С. 45-51.
5. Хренков Н.Н. Прямой электрический нагрев подводных трубопроводов // Промышленный электрообогрев и электроотопление: электрон. журн. 2013. Вып. 2. URL: http:// ru.calameo.com/read/0017674059 a262e79f9cb (дата обращения: 01.10.2016).
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