RU2457456C1 - System for diagnosing submersible electric motors - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: invention relates to methods and apparatus for checking the technical state of downhole electric centrifugal pump units when conducting maintenance work. The system has in its downhole part measurement modules connected by a data bus which is connected to a communication channel, whose output is connected through a first interface unit to the first input/output of a control device, and the second input/output is connected to an operator's panel, and the third input/output is connected through a second interface unit to external devices or systems. Each measurement module has vibration sensors and temperature sensors, connected to an analogue-to-digital converter whose output is connected to a controller which is connected to the data bus through an interface unit.

EFFECT: high reliability of acceptance tests.

3 cl, 3 dwg

Description

The invention relates to the oil and gas field, in particular to means for checking the technical condition of well installations of electric centrifugal pumps (ESP) when carrying out maintenance activities.

High requirements for the quality of maintenance work, in particular for acceptance testing (PSI) of the ESP, are determined by the requirements for the reliability of this installation in conditions of long-term operation in the well. PSI is carried out using specialized bench equipment.

Known stands for conducting PSI submersible electric motors (PED) at idle [RU 21455, IPC G01M 10/00, 2002; RU 33224, IPC G01M 10/00, 2003; LLC Kamtehnopark [Electronic resource]. [2009] URL: http://www.kamtehnopark.ru/ (accessed: 11/25/2010); GK Novomet [Electronic resource]. [2010] URL: http://www.novomet.ru (accessed: 11.24.2010); CJSC Mehta [Electronic resource]. [2009] URL: http://www.mehta.ru/ (accessed: 11.24.2010)], consisting of a slipway with clamps for placing and fixing the electric motor in a horizontal position and instrumentation for measuring and recording control parameters. The advantage of this stand is ease of implementation, the disadvantages include the lack of a load simulator.

Known stands for the PSI of submersible electric motors (PED) under real load [LLC Kamtehnopark [Electronic resource]. [2009] URL: http://www.kamtehnopark.ru/ (accessed: 11/25/2010); GK Novomet [Electronic resource]. [2010] URL: http://www.novomet.ru (accessed: 11.24.2010)]. The composition of these stands is similar to the previous ones, but differs by the presence of a load simulator - a load DC generator. The advantage of these stands is the simplicity of implementation and the ability to simulate the load of the SEM.

A common disadvantage of the known stands is the horizontal arrangement of the SEM on the slipway, which does not correspond to the working location of the SEM in the production well.

A well-known stand for conducting PSI submersible electric motors (PED) under real load in a vertical position [LLC Kamtehnopark [Electronic resource]. [2009] URL: http://www.kamtehnopark.ru/ (accessed: 11/25/2010)]. This sample differs from the previous ones in the presence of a hydraulic lift, with which it is possible to set the vertical position of the SEM during testing. The advantages of the stand are imitation of engine load, vertical arrangement of the SEM during the test.

Common shortcomings of the equipment listed are the inability to take into account the mutual influence of the operating ESP units and their interaction with the production casing, as well as the mismatch of the air environment with the actual operating conditions.

There is a well-known test bench for PED diagnostics as part of the ESP operation layout when it is lowered into a vertical test well filled with a working fluid (for example, transformer oil), while a small part of the engine remains on the surface for measuring vibration parameters [Bocharnikov V.F., Vedernikov V. BUT. The results of experimental studies of the vibration of submersible centrifugal electric pumps of the ETsNM type with a frequency-controlled drive // Oilfield Equipment. 2007. No. 12. S.92-93]. The advantage of the stand is the vertical location of the tested SEM and the most complete simulation of the working environment and real load. The disadvantage of the stand is that the readings are taken only at one point from a portable device (for example, "Peony"), which does not allow to obtain reliable information about the technical condition of the SEM.

The objective of the invention is to improve the quality of maintenance work on the SEM by increasing the reliability of the results of PSI.

The problem is solved by means of a diagnostic system for a submersible electric motor (SEM), as part of the working layout of a borehole installation of an electric centrifugal pump in a vertical test well during acceptance tests, containing measurement modules in its borehole part, connected by an information bus that is connected to the communication channel, output which through the first interface unit is connected to the first input / output of the control device, and the second input / output of which is connected to the remote control an amplifier, and the third input / output through the second interface unit is connected to external devices or systems, each measuring module containing vibration sensors and temperature sensors connected to an analog-to-digital converter, the output of which is connected to the controller, which is connected to the information bus through the interface node .

According to the invention, in the system, the number of measuring modules and the number of sensors in the measuring modules can be different, depending on the design of the SEM.

According to the invention, the communication channel may be wired or wireless, depending on the conditions of use.

The proposed diagnostic system allows you to monitor and measure the parameters of the vibration and temperature fields of the SEM directly in the process of running the SEM as part of the ESP working layout in real time in an automated mode. The effectiveness of the proposed solution is due to: the simplicity of its implementation, the vertical arrangement of the layout in the PSI process, which allows you to take into account the mutual influence of the ESP units and their interaction with the production string, work in real load conditions and conditions closest to the production well. In the presence of defects, it is possible to accurately identify the faulty SEM unit due to the presence of a large number of measuring modules fixed along the entire length of the SEM.

Measuring modules mounted on the surface of the SEM body in the most informative places (bearings and heel assemblies) allow monitoring of vibration and temperature parameters. The presence of the control device allows the conversion of the temporary vibration signal into the frequency spectrum based on the fast Fourier transform. Spectrum analysis, for similarity with a certain set of diagnostic features (the presence or absence of certain frequency components, as well as the ratio of their amplitudes) for each defect, serves as the basis for forming a conclusion on the technical condition of each SEM unit. The measured temperature prevents overheating of the SEM; in addition, by measuring the temperature at different points of the SEM, it is possible to identify its local maximums, which indirectly serve as an indicator of the potential location of the malfunction.

An illustration of the claimed system is the drawings, in which Fig. 1 is a structural diagram of a diagnostic system, and Fig. 2 is a structural diagram of a measuring module.

The diagnostic system (Fig. 1) contains measuring modules 1 and 2 (in general, there can be several), an information bus 3, a communication channel 4, a first interface unit 5, a control device 6, an operator console 7 and a second interface unit 8. Measuring modules 1 and 2, related to the downhole part of the system, are mounted on the surface of the SEM. They are combined by an information bus 3, which is connected to the borehole part of the equipment of the communication channel 4. The ground part of the system has a control device 6 connected through the first interface unit 5 to the communication channel 4 and through the second interface unit 8 with external devices (systems) 9. The operator panel 7 provides a human-machine interface for operating and testing the system.

The system operates as follows. Before launching the ESP unit into the test well, the measuring modules 1 and 2, combined by the information bus 3, and the borehole part of the communication channel equipment 4 are mounted directly on the surface of the SEM. Each measuring module contains a certain set of spatially distributed (at characteristic points) vibration and temperature sensors 13-16 on the PED housing. Information bus 3 is made protected from mechanical and electromagnetic influences. The system is initiated by the control device 6 transmitting the corresponding command through the first interface unit 5 and communication channel 4. Measuring modules 1 and 2 interrogate all the sensors, receive, pre-process and store the measurement information in their RAM. Upon completion of the measurement cycle, the control device 6 reads the information stored in the measurement modules 1 and 2, performs the necessary calculations, displays the result on the display of the operator console 7 and stores an array of results. The control device 6 can be implemented on the basis of programmable logic, including a central processing unit, random access memory and input / output devices [Guk M. Hardware PC. Encyclopedia - St. Petersburg: Peter Kom, 1988. - 816 s: ill.]. If necessary, through the second interface unit 8, communication with external devices or systems 9 is carried out.

The measuring module (Fig. 2) contains an interface node 10, a controller 11, an analog-to-digital converter (ADC) 12, the first and second acceleration sensors 13, 14, the first and second temperature sensors 15, 16 (in the general case, there can be several sensors ) The acceleration sensors 13, 14 generate analog signals that are encoded by a multi-channel ADC 12. The controller 11 provides control of all nodes of the measuring module, receives, preprocesses and stores measurement information. The controller 11 interacts with the ground part through the interface node 10, information bus 3 and communication channel 4.

The implementation of controllers, their combination, interfaces and other circuitry issues are known from many sources [for example, B. Shevkoplyas Microprocessor structures. Engineering Solutions: Reference. - 2 ed. Re-worker. and add. - M .: Radio and communications, 1990. - 512 p.: Ill.].

Communication channel 4 can be performed on a wired and wireless circuit. In the event that the ground equipment is located close to the well, and the stand design allows unhindered cable routing, it is possible to use a wired communication channel as the simplest and most reliable. In other cases, the channel can be implemented wirelessly, for example using a radio channel [PROSOFT Company [Electronic resource]. [2010] URL: http://www.prosoft.ru/ (accessed: December 6, 2010)]. Moreover, with a wired channel, the power of the downhole part is remote using wires, with a wireless one - from an autonomous power source.

The implementation of ground-based software and hardware environments is also known. These tools are made using programmable logic, for example, based on an industrial computer [PROSOFT Company [Electronic resource]. [2010] URL: http://www.prosoft.ru/ (accessed: December 6, 2010)].

An example of a specific implementation. In the process of testing PEM using the proposed system, the temperature and vibration fields at the points of location of the bearing assemblies were simultaneously measured.

Based on the data obtained from each measuring module, time dependences and spectra of vibration signals were constructed. By measuring the vibration of one of the points of the SEM, the time dependence and the vibration spectrum shown in Fig. 3 are plotted. In the given spectrum, dominant components are observed at a frequency of 50 Hz and at a frequency of 25 Hz. According to characteristic diagnostic features [Goldin A.S. Vibration of rotary machines. M .: Mechanical Engineering, 1999.344 s .; Shirman A.R., Soloviev B.S. Practical vibration diagnostics and monitoring of the state of mechanical equipment. M., 1996. 276 pp.], Namely: the appearance of a component at the rotational speed of the engine rotor (50 Hz), together with the appearance of a component at the frequency of movement of the lubricant in the bearing clearance (22-28 Hz), we can conclude that there is a bearing in this bearing poor bearing capacity of the lubricating layer of the bearing. In addition, the degree of development of the specified defect can be judged by the ratio of amplitudes at the indicated frequencies. If the ratio of the amplitude of the component at 25-28 Hz to the component at 50 Hz exceeds 0.5, we can talk about the loss of the bearing capacity of the lubricating layer. In this case, the ratio of amplitudes is 0.44, which indicates a highly developed defect. The specified defect is confirmed by a local increase in temperature, which also confirms the presence of a developed defect.

According to the tests performed, the SEM is analyzed and the condition of the friction material of the bearing is checked. In the event of unacceptable wear, the bearing must be replaced.

Thus, the proposed system allows to improve the quality of maintenance work on the SEM by increasing the reliability of the results of PSI.

Claims (3)

1. Diagnostic system of a submersible electric motor (SEM) as part of the working layout of a borehole installation of an electric centrifugal pump in a vertical test well during acceptance tests, containing in its borehole measuring modules connected by an information bus that is connected to the communication channel, the output of which is through the first interface unit connected to the first input / output of the control device, the second input / output of which is connected to the operator console, and the third input / output through the second interface the interface unit is connected to external devices or systems, and each measuring module contains vibration sensors and temperature sensors connected to an analog-to-digital converter, the output of which is connected to the controller, which is connected to the information bus through the interface node. 2. The system according to claim 1, characterized in that the number of measuring modules and the number of sensors in the measuring modules can be different depending on the design of the SEM. 3. The system according to claim 1, characterized in that the communication channel can be wired or wireless, depending on the conditions of use.

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