Submersible Electric Motor Research Articles

Investigation of transients in a submersible electric motor with a downhole compensator

Currently, the energy efficiency improving into the oil production is an important task. The main electricity consumer in the electrical complex structure of the electric centrifugal pumps’ installation is a submersible asynchronous electric motor. The power factor of these electric motors varies from 0.75 to 0.85. It leads to the losses’ increasing in the conductive elements of the complex. The use of downhole reactive power compensators is the most potential way to increase the power factor into the submersible asynchronous electric motors. In the course of pilot tests there are some cases of the protection devices for downhole compensators’ false triggering. It is recorded when the control station is switched off. It leads to the energy efficiency decreasing into the oil production. The purpose of this study is to research the transients in a submerged asynchronous electric motor equipped by the downhole compensator when the power supply is switched off. The task of the study is to determine the transient process’ parameters, in order to prevent false triggering of the downhole compensator protection devices. Simulation modeling of a submerged electric motor with a downhole compensator is performed in the Matlab Simulink. A simulation model of a submerged electric motor with a downhole compensator is developed to study transients when the power supply is switched off. The characteristics for the transient process of the voltage and current into the downhole compensator are obtained during the simulation modeling. The current surge for the capacitors’ discharge of the downhole compensator is 260.7% relative to the rated current at the time of the power supply disconnection. Prevention measures off false triggering for automatic shutdown devices of the downhole compensator are proposed.

Повышение качества электроэнергии для потребления в нефтедобывающей отрасли

Currently, 50-60 percents of power consumption in oil fields falls on mechanized oil production. The specificity of the operation of a submersible electric centrifugal pump (ESP), powered by a submersible electric motor (SEM) as consumers of electricity, is due to their operation at a considerable distance from the earth’s surface, the variable nature of the load, the aggressiveness of the produced fluid, and the presence of an extended cable line. (Research objective) To study devices for improving the quality of electricity in the oil industry. (Materials and methods) The results of the survey of the parameters of power consumption of the Novoportovskoe oil and gas condensate field of the PREO «Yamal» Network district No. 1 Kust 18 KTP 10 / 0.4 kV No. 1 input-2. (Results and discussion) The results of studies of the parameters of electricity at the Novoportovskoye oil and gas condensate field have shown that it is advisable to use devices that improve the quality of electricity. Devices can be different, both in design and in scope. Such as voltage stabilizers, phase voltage balancing devices, reactive power compensation devices, filter compensating devices, active mains filters. (Conclusions) Having considered the variety of devices on the market that improve the quality of electricity, as well as devices that compensate for reactive power, it is advisable to use static thyristor reactive power compensators manufactured by JSC Electrointer, Serpukhov.

Тепловой расчет погружных электродвигателей

The paper proposes a method of thermal calculation of submersible electric motors intended for use at the stage of their conceptual design. The model is based on the complete system of hydrodynamic equations averaged over the motor cross section and the annular channel through which coolant is pumped. All geometric dimensions and properties of the substance are set. The temperature distribution over the cross section and along the length of the motor is calculated. Two approximations are used. In the first one, the temperature distribution in the cross section of the electric motor was averaged over the corners, which requires setting an effective coefficient of thermal conductivity inside the stator grooves filled with winding wires and electrical insulation. In the second approximation, the heat transfer at the solid – liquid interface was specified through the empirical dependence of the Nusselt number on the Reynolds and Prandtl numbers. To verify the model, the results obtained were compared with calculations by the method of computational fluid dynamics in the ANSYS Fluent software package. The error in calculating the insulation temperature was not more than 5%.

Design of energy efficient electrotechnical complexes with an autonomous electric supply system

Improving energy efficiency and reducing the costs of creating an autonomous power supply complex for an oil production enterprise is an urgent problem and requires a rational solution. At each stage of the electrical complex development of the oil production enterprise, the purpose is to increase energy efficiency in order to reduce the unit cost of electricity per unit of produced well fluid volume. The electrical complex energy efficiency assessment of the oil production enterprise can be determined by the classical methodology of the energy balance. The task of increasing the energy efficiency of the electrical complex with an autonomous power supply system is to ensure a minimum of fuel costs while maintaining current oil production. Two types of the electrical complex models are proposed: with an individual electricity source and a generation center based on individual diesel generators. A method for calculating the energy parameters of the electrical complex components with installations of different types of pumps is presented. In this case, the energy efficiency is improved due to joint deep and group reactive power compensation and power factor correction by reducing the harmonic components of the current. The electrical complex simulation of a submersible electric motor has been carried out in order to determine the values of voltage and current during switching processes. The autonomous power supply system modeling of an oil production enterprise in case of voltage losses and the simulation of diesel generators with a frequency deviation of the generated voltage during load surges was carried out.

Calculation of winding temperature of a submersible motor

The article is devoted to the issue of control and regulation of the high-quality operation of a submersible motor with a long overhaul period. There are some complications of operating the electric submersible pump. One of them is the thermal interaction of the borehole fluid and components and parts of the electric submersible pump that leads to failure and repair. It is necessary to conduct research in the field of physical and hydrodynamic calculations to determine the effect of heat exposure. The article reveals one of the approaches to solving the problem of thermal interaction between a well and the electric submersible pump. We describe calculations of the winding temperature of a submersible electric motor for specific conditions in a particular well, including different modes of fluid flow, different loads of the submersible motor, and different concentrations of oil in water. The development of the described technique will allow creating special software aimed at determining the areas with the highest temperature of the motor winding, taking into account various parameters that affect the heat transfer process.

Prospects for the use of high-speed ESP for oil production

Increasing the ESP speed allows for a reduction in the linear dimensions of the units and the number of standard sizes. By reducing the length, wear resistant materials can be used in each pump stage. However, with an increase in the rotational speed to 10000 rpm, the head of the pumping stage increases significantly (> 35m) and the processes of friction and wear intensify. Test benches for wear testing of pump stages and thrust bearings of hydraulic protectors and submersible electric motors with a rotation speed of up to 12000 rpm have been developed. It was revealed that the greatest change in mass is observed in the guide vane due to erosive wear, which varies depending on the rotational speed in a power-law dependence with an exponent of ∼ 3.4. When testing a thrust bearing made of SiC with a rotational speed of 10800 rpm and an axial force of 6000N, the friction coefficient varied in the range 0.028 ... 0.008. Bearing made of hard alloy WC-8Co scored at 4.92MPa load. It is necessary to determine the optimal area of application of high-speed ESPs and the allowable wear values of the pump stages.

Using Metal-Sprayed Coatings to Protect Submersible Electric Pump Motors from the Impact of Complicating Factors in Oil Wells

This paper presents an overview of the results of the application of metal-sprayed coatings to protect the outer surface of electric submersible pumps (ESP) from the effects of complicating factors in oil wells. The metal-sprayed coating is applied using hot spraying, and the choice of the method is based on the chemical composition, the materials that are used, and the properties of the finished coating. The most common coatings on the Russian market include monel and austenitic stainless-steel alloys applied by arc metallization or high velocity spraying. Traditional coatings obtained by thermal spraying are characterized by an insufficiently high level of physical, mechanical, and chemical properties. Studies of the abnormal cases of submersible electric motors (SEMs) have shown that the most significant disadvantages of the applied coatings include insufficient resistance to mechanical shock, as well as abrasive wear; higher electrochemical potential in relation to the base metal; violations of the application technology; and significant coating porosity. One of the main reasons for the observed disadvantages is a limited number of traditionally used methods and materials. To solve the problem of using protective SEM coatings and significantly increase their properties, service life, and economic efficiency, it is necessary to use modern scientific achievements in the development of coatings to protect metal surfaces from wear and corrosion, namely, to expand the number of coating methods and materials, work out a methodology for assessing the quality of coatings, and develop a methodology for assessing the economic efficiency of protective coatings. Solving these problems will allow us to make a reasonable technical and economic choice of a specific SEM coating for specific operating conditions.

Performance characteristics’ study of a submersible electric motor based on the bench tests results

Currently, the majority of electric centrifugal pump installations are equipped with submersible induction motors. The simulation models’ development and the study of operating modes based on them should be accompanied by verification of the data obtained with experimental results. It is due to the design features of this electric motors’ type. Therefore, the aim of the article is to study the performance of submersible induction motor with a power of 70 kW. The performance is obtained on simulation model and their verification with experimental results. The simulation model of SEM-YA 70-117 M5B5 submersible induction electric motor is developed in the MATLAB/Simulink software environment during the research. The performance characteristics are also built. It is established that the relative error of the values obtained during simulation to the experimental data does not exceed 10 %.

Application of metallization coatings for protection of submersible electric motors of pumping equipment from influence of complicating factors in oil wells

The paper provides a review of results obtained when using metallization coatings to protect the outer surface of electric centrifugal pump (ECP) equipment against the complicating factors in oil wells. Metallization coating is applied by thermal spraying using the method selected based on the chemical composition, materials used and properties of the finished coating. The most common coatings on the Russian market are Monel and alloys based on austenitic stainless steel applied by methods of electric arc metallization or high-speed spraying. Traditional coatings obtained by thermal spraying feature by insufficiently high level of physical, mechanical and chemical properties. The studies of failed cases of submersible motors show that most critical shortcomings of the coatings used include insufficient resistance to mechanical impact and abrasive wear, higher electrochemical potential in relation to the base metal, application technology violations, and significant coating porosity. One of the main reasons for the observed shortcomings is the limited number of traditionally used methods and materials. In order to solve the problem of using protective coatings for submersible motors, significantly improve their properties, service life and economic efficiency, it is necessary to use modern achievements of science in the development of coatings to protect metal surfaces from wear and corrosion, namely: to expand the number of methods and materials for coating application; to develop a methodology for coating quality assessment; to develop a methodology for assessing the economic efficiency of protective coatings. Solving these tasks will enable a reasonable technical and economic choice of a specific submersible motor coating for specific operating conditions.

ПУТИ ПОВЫШЕНИЯ ЭФФЕКТИВНОСТИ УСТАНОВОК ЭЛЕКТРОЦЕНТРОБЕЖНЫХ НАСОСОВ ДОБЫЧИ НЕФТИ

Актуальность работы обусловлена необходимостью верификации данных узла «погружной электродвигатель – внутрискважинный компенсатор», полученных на имитационной модели с результатами стендовых испытаний. Внутрискважинная компенсация реактивной мощности является относительно новой технологией повышения энергетической эффективности нефтедобывающих объектов по сравнению с существующими способами. Ввиду технических особенностей размещения внутрискважинных компенсаторов реактивной мощности в эксплуатационной колонне нефтедобывающей скважины, в некоторых случаях, экономически не целесообразно исследование установки электроцентробежного насоса с внутрискважинным компенсатором, с целью определения оптимальных параметров работы установки на реальном объекте. Поэтому разработка адекватной имитационной модели узла «погружной электродвигатель – внутрискважинный компенсатор» является важной задачей, позволяющей при минимальных материальных затратах решить проблемы построения, функционирования и модернизации установок электроцентробежных насосов. Цель: исследование внутрискважинного компенсатора реактивной мощности в программной среде Matlab Simulink и экспериментальные исследования погружного асинхронного электродвигателя с внутрискважинным компенсатором на лабораторном стенде. Объект: погружной асинхронный электродвигатель с внутрискважинным компенсатором реактивной мощности. Методы. При разработке имитационной модели погружного асинхронного электродвигателя использованы готовые блоки библиотеки SimPowerSystem программного комплекса MATLAB Simulink. Для проверки адекватности имитационной модели изготовлен погружной асинхронный электродвигатель и опытный образец внутрискважинного компенсатора реактивной мощности. Стендовые испытания проведены на заводе ООО «Алмаз», имеющем лицензированные лаборатории и аттестованных специалистов. Результаты. Разработана имитационная модель узла нагрузки «ПЭД-ВКРМ» для моделирования электромеханических процессов узла. Разработан опытный образец внутрискважинного компенсатора реактивной мощности. По результатам стендовых испытаний получены рабочие характеристики погружного асинхронного электродвигателя с внутрискважинным компенсатором. Проведена верификация данных, полученных на имитационной модели, с результатами эксперимента. Расхождения между расчетными и экспериментальными данными составили менее 10 %. Таким образом, разработанная имитационная модель узла нагрузки «ПЭД-ВКРМ» адекватно отображает электромеханические процессы узла. Определены перспективы проведения опытно-промышленных испытаний погружного асинхронного электродвигателя с внутрискважинным компенсатором реактивной мощности.

Control over parameters of ESCP unit to improve efficiency in bringing wells to stable production using a frequency-controlled drive on R. Trebs oil field

The article deals with the results of technological process of bringing an oil well to stable production; the well is equipped with an electric submersible centrifugal pump unit, its drive function is changed by a frequency-controlled drive. The paper presents data obtained while bringing an oil well to stable production: the liquid flow rate, oil flow rate, operating current, submersible electric motor loading, current frequency, water content of the products. The authors describe the process and specific aspects of bringing an oil well to stable production, conditions necessary for the process, variation of operation parameters. Recommendations were developed to ensure optimal operation of oil wells equipped with electric submersible centrifugal pump units considering technological and economic costs.

Verification for the simulation model of submersible electric motor with downhole compensator based on the bench tests results

The bench tests results of submersible electric motor with downhole reactive power compensator are presented in this study. The decrease in the current consumption by 13 % and the increase in the power factor from 0.84 to 0.95 are recorded according to the test results. A simulation model of a submersible electric motor with a downhole reactive power compensator is developed. The data obtained on the simulation model are compared with the bench tests results. It is found that the discrepancy between the calculated and experimental data is less than 10 %. Consequently, the simulation model adequately reflects the electromechanical processes of the real object.

Новое поколение гидрозащиты погружных электрических двигателей с динамическим лабиринтом для эксплуатации осложненных месторождений с высоким содержанием свободного газа и механических примесей

In this work, the authors study the problems associated with the operation of oil wells using electric centrifugal pumps. The authors acknowledge the negative factors that lead to an increase in solids concentration in the upper part of the submersible electric motor protectors, higher possibility of end seal failures and shortening of service life of serial products. The replacement of a gravitational labyrinth by a dynamic one in the upper part of the motor seal protector is one of the ways to improve the reliability of the protector in the operational environment with high concentration of gas and solids. The proposed seal protector design makes it possible to considerably increase the estimated efficiency of solids separation (by 300 times), improve reliability, as stable running is ensured even after the failure of end seals, and reduce the mounting length by 25–40 %, resulting in cost saving and improved maintainability as fewer parts are used. This conceptually new operation principle facilitates the creation of a new generation of highly reliable seal protectors, capable of working effectively in challenging well conditions. Thus, the new design should supersede all serial motor seal protectors in conventional wells and add a market segment in complicated wells.

More Efficient Machining by Modifying the Shaping Cycles on a CNC Machine Tool

The efficiency in machining the nipple of a submersible electric motor may be increased by modifying the machining cycles for the elementary surfaces on a WFL M35-G CNC machine tool.

Temperature Estimation and Vibration Monitoring for Induction Motors and the Potential Application in Electrical Submersible Motors

Condition monitoring is essential for the reliable operation of induction motors. Temperature estimation serves as a basis for motor protection. Developing accurate and real-time temperature calculation algorithms is critical for thermal and overload protection for induction motors. Vibration monitoring is a widely used approach for induction motors' fault diagnosis. Vibration signals are usually analyzed by time-, frequency-, or time-frequency-domain signal processing methods. Recent advancement of fault diagnosis by machine learning makes intelligent approaches feasible. Although decades of efforts have been put on condition monitoring of regular induction motors, electrical submersible motors operating in a very unique downhole environment in the oil industry have not received much attention. Currently, electrical submersible motors rely on downhole monitoring tools to transmit temperature and vibration data measured by sensors from downhole to the surface; however, such data are transmitted at a slow rate, and there are no fault diagnosis algorithms in place. An advanced condition monitoring and fault diagnosis method for electrical submersible motors is needed in the near future. In this paper, a literature review is conducted on temperature estimation and vibration monitoring techniques for induction motors, the state-of-the-art methods are summarized, and their potential application in electrical submersible motors are recommended.

Operational Parameters Affecting Harmonic Resonance in Electrical Submersible Pump Systems

Electrical submersible pump (ESP) systems in the oil field have unique features due to the long cabling effect. The electrical system for a typical ESP installation consists of a variable frequency drive (VFD), a multi-tap step-up transformer, a surface cable, a downhole main cable, a motor lead extension (MLE) cable, and an electrical submersible motor. A load filter is usually required in a VFD-ESP system. In this paper, several operational parameters that can significantly affect operating conditions of an ESP system are demonstrated through field measurements and simulation of a practical ESP system currently in operation in Alberta, Canada. The simulation model is also validated by comparing with field measurement data. This analysis is beneficial to field engineers and ESP system operators to understand better the impacts of equipment parameter settings.

Justification of the active method of protecting the insulation of submersible electric motors

The article provides an analysis of the properties of the working environment of submersible electrical equipment. The influence of the operating parameters of electrical equipment on the physical properties of the fluid (its electrically conductive properties) is considered. Mathematical confirmation of the implementation of electroosmosis in the capillaries of the insulation of submersible electric motors is given. The rationale for the active method of protecting submersible electrical equipment from reducing insulation resistance and preventing electrical breakdown is given.

Designing a New Artificial Lift Method Using Computational Simulation and Evolutionary Optimization

Oil exploitation has moved into deeper reservoirs with the advances in drilling techniques and thus the development of new pumping techniques has become a challenge to improve production. The positive displacement pumping system proposed in this paper is presented as an artificial lift technique. Here we present a new pumping device, its estimated operational curves through numerical simulations and a prototype of the device, denominated a Double Acting Submersible Linear Pump (SLP), which is a hydraulic system adapted for inside well operations. Design parameters used in the tests were optimized using the Particle Swarm Optimization (PSO) algorithm to maximize oil production while optimizing the parameters (characterstics) of the pump, such as maximum pump diameters and submersible electric motor power, pressure and volumetric displacement of the hydraulic pump. Also presented are the operating curves estimated from the numerical simulation of the power and pump modules, as well as the SLP0 and SLP1 experimental test curves in a controlled environment using the optimized parameters obtained using PSO The data obtained were compared to the computational simulations performed with the Automation Studio™ software. The SLP0 and SLP1 optimal design tests showed the importance to delimit the range of operation within which the SLP must operate, since the pipes and hydraulic components must be suitable for the flow of hydraulic oil and the production oil. The findings presented here play an important role in the production process of a fully operational SLP prototype.

A simulation model of electric actuator unit of electric centrifugal pump with a submersible individual compensation installation

The substitution scheme and the system of differential equations for electrotechnical complex of producing well are given. The mathematical and simulation models of electric drive of electric centrifugal pump installation with submersible individual compensating installation are developed. The scheme of inclusion and practical realization of individual compensating installation consisting of the static capacitor battery with non-standard nominal voltage which is connected directly to the stator clips of submersible electric motor in a well is proposed. The simulation model of electric actuator of the electric centrifugal pump allows one to simulate the operation mode of electric actuator in steady-state and transient modes, as well as the group start of electric drives of electrical complex of the producing well. The optimal level of outgoing line voltage, energy parameters and the optimal parameters of individual, node and centralized compensating installations, as well as the rational voltage level of the main substation were determined from simulation.

Влияние внутрискважинного компенсатора на падение напряжения в элементах электротехнического комплекса добывающей скважины

Актуальность исследования обусловлена необходимостью определения требуемого напряжения на выходе питающего трансформатора с учетом компенсации реактивной мощности внутри скважины, с целью предотвращения аварийных ситуаций в процессе эксплуатации установок электроцентробежных насосов. Цель исследования: оценить изменение величины падения напряжения в токопроводящих элементах электротехнического комплекса установки электроцентробежного насоса для добычи нефти при использовании внутрискважинного компенсатора реактивной мощности. Объект исследования: электротехнический комплекс установок электроцентробежных насосов для добычи нефти. Методы. При разработке математической модели электротехнического комплекса погружной установки для добычи нефти использованы положения теоретических основ электротехники, корректные допущения при составлении математических моделей и компьютерное моделирование в программном пакете символьной математики Wolfram Mathematica. Результаты. Разработана схема замещения и математическая модель электротехнического комплекса установки электроцентробежных насосов с внутрискважинным компенсатором реактивной мощности. С помощью качественной векторной диаграммы напряжений и токов в ветвях и узлах схемы замещения показано распределение величин падений напряжений на элементах комплекса. Анализ векторной диаграммы показал, что внутрискважинный компенсатор уменьшает продольную и поперечную составляющие падения напряжения, что положительно влияет на режим работы установки для добычи нефти. Получены поверхности требуемого напряжения на выходе питающего трансформатора в зависимости от мощности погружного электродвигателя для различных длин и сечений кабельной линии. Установлено, что использование внутрискважинного компенсатора позволяет уменьшить падение напряжения в токопроводящих элементах электротехнического комплекса установки для добычи нефти до 50 В.