Rod Pumping Unit Research Articles

Express-diagnostics of rods’ parting-twist off at wells equipped with sucker rod pump

The development of fields that are at a late or final stage of operation is carried out mainly with the use of downhole sucker rod pumps. The most characteristic failures for these installations are rods parting-twist off and malfunctions of pump valves. The methods of eliminating these accidents vary significantly the parting or twist off of the rods involves lifting of the downhole equipment, and the "sticking" of the shut-off valve assembly of the pump is eliminated by "resuscitation" of the downhole equipment (flushing with water, hot oil or solvent). An error in fault identification leads to incorrect planning of work to restore the operability of the downhole equipment and, as a result, to economic losses.
 The cause of malfunctions of the downhole equipment of downhole rod pumping units, as a rule, is determined by analyzing dynamograms. However, in many cases dynamograms do not allow to distinguish the lower twist off of the rods from the malfunction of the valves of the rod pump. In the presented work, a method for the operational determination of the parting or twist off of rods in the well is considered, which consists in creating an electrical circuit "rod string tubing string" and monitoring its integrity. To determine the type of malfunction, the synchronization unit measures the resistance of the system on the dielectric insert via the electromagnetic channel. In case of parting or twist off of the rods, the electrical resistance of the "tubing-pump-rod string" circuit will be much higher (more than 2 ohms) than in the absence of this failure (0...2 ohms).

Statistical analysis of the relative position of the rod hanger and the wellhead

One of the leading methods of exploitation of oil fields is oil production with the help of downhole rod pumping units (DRPU). Over 80 % of the operating well stock of Azneft PA is equipped with deep well pumps and about 30 % of oil is produced in the country with their help.
 The widespread use of DRPU is associated with a fairly high maturity of installations, simplicity of its design and maintenance, repair in field conditions, ease of adjustment, the possibility of servicing the installation by unskilled workers, a small effect on the operation of DRPU of the physical and chemical properties of the pumped liquid, as well as high efficiency.
 However, along with the high efficiency of the applied DRPU, there are also complaints regarding the need to increase the reliability and resource of wellhead equipment, including in order to improve the environmental situation in the oil fields.
 One of the conditions for ensuring high reliability of the ground equipment of the DRPU is to ensure the tightness of the wellhead rod-wellhead stuffing box assembly, the violation of which is not only a failure of the installation, but also leads to environmental pollution.
 This is facilitated by inaccuracies in the assembly and installation of DRPU at the wellhead. When mounting the pumping unit, for many reasons, the tolerance of the wellhead rod with the suspension point of the rod string to the balancer head is not ensured.
 In this regard, in the requirements for the accuracy of mounting the pumping unit at the point of application, a certain mismatch of the axes within the circular coordinates is allowed. So, for widely used pumping units of the CK8 type, the permissible mismatch between the axis of the wellhead rod and the suspension point of the rods is determined by the conditions under which the projection of the suspension point of the rods onto the plane of the base of the pumping unit at any position of the balancer is allowed within a circle with a diameter of 25 mm.

Determination of lower break-out of the boom on wells equipped plunger pump

Development of fields at a late or final stage of exploitation of the Ural-Volga region is carried out mainly with the use of downhole sucker rod pumping units. The most typical failures for these installations are rods breaks and breaks and pump valve malfunctions. Methods for eliminating these accidents vary significantly: a break or a breakaway of the rods involves lifting the downhole equipment, and the "sticking" of the shut-off element of the pump valve assembly is eliminated by the "resuscitation" of the downhole equipment (flushing with water, hot oil or solvent). An error in recognizing a malfunction leads to incorrect planning of work to restore the operability of downhole equipment, and, as a result, to economic losses.The cause of the downhole equipment malfunctions of the sucker rod pumping units is usually determined by analyzing the dynamogram. However, in many cases dynamometer charts don't distinguish between the bottom flap of the rods and the failure of the sucker rod pump valves. In the article, a method of prompt determination of rod breakage and breakaway in a well is considered, which consists in creating an electrical circuit "rod string - tubing string" and monitoring its integrity. To determine the type of malfunction, the synchronization unit via the electromagnetic channel measures the resistance of the system on the dielectric insert. In case of break-off of rods, the electrical resistance of the "tubing-pump-rod string" circuit will be much higher (more than 2 ohms) than in the absence of this failure (0...2 ohms).

Technology for the NOISE Control of Oil Wells by Wattmeter Card of the Electric Motor of Sucker Rod Pumping Units

The possibility of using measuring information on the power consumption (watt-metrogram) by the electric motor of a sucker rod pumping unit for diagnosing the technical condition of oil well equipment is considered. It is shown that one of the possible ways in this case can be the application of Noise technology to the processing of wattmetrogram signals.A technology is proposed for forming a set of combinations of reference and current informative attributes from the estimates of the normalized correlation functions of the useful signal of a wattmeter card; it is shown that they are equivalent to informative attributes of a dynamometer card received from a force transducer installed on the hanger of a sucker rod pumping unit. It is also shown that they equally reflect the technical condition of the well, due to which the informative attribute of the wattmeter card can be used to solve the problems of control, identification and management the oil production process with a sucker rod pumping unit. Variants of decreasing the error in the results of correlation analysis of the watt-metrogram and a variant of using the normalized correlation functions of the useful signal of the watt-metrogram for solving problems of identifying the technical state of the equipment of sucker rod pumping stations are proposed. To increase the effectiveness of monitoring systems, it is proposed to duplicate the system diagnostic function using the spectral technology for the control of the onset and dynamics of development of faults. The features of implementation in the fields are given. Possible options for using the normalized correlation functions of the useful signal of the wattmetrogram for solving the problems of identifying the technical state of wells during its operation are considered. A simplified structural diagram of the remote monitoring and control system of the sucker rod pumping unit based on the wattmetrogram signals, which has been introduced at the wells of the oil production department "Bibiheybatneft" in Azerbaijan, is presented. It is shown that the algorithms and technologies for analyzing the interference of wattmetrograms proposed in the work, in principle, can be widely used in many areas of the economy where electric motors are used.

Ways to Increase the Efficiency of Sucker Rod Pump Units in Oil Production

Ways to Increase the Efficiency of Sucker Rod Pump Units in Oil Production by Aliev Telman Abbas1, Guluyev Gambar Agaverdi1, Rzayev Asif Haji1, Aliyev Yaver Gabil1, Rezvan Mahammad Huseyn1, Yashin Anton Nikolaevich2, Khakimyanov Marat Ilgizovich1,* 1 Laboratory “Control, diagnostics and management system for oil extracting facilities”, Institute of Control Systems of ANAS, Baku, 1141, Azerbaijan

ИСПЫТАТЕЛЬНЫЙ СТЕНД ДЛЯ МОДЕЛИРОВАНИЯ РЕЖИМОВ РАБОТЫ ЭЛЕКТРОПРИВОДА ШТАНГОВОЙ ГЛУБИННОЙ НАСОСНОЙ УСТАНОВКИ

Relevance In the practice of designing and developing high-tech types of equipment for electrical complexes, it often becomes necessary to conduct tests in the absence of access to existing equipment, for example, due to the specifics of oil production facilities. To assess energy efficiency, study diagnostic problems, and develop the functions of control stations for sucker-rod pumping units, it is advisable to use laboratory test benches allowing to perform these works in stationary conditions and significantly reduce the cost of their implementation. Aim of Research Development of a test bench for the study of dynamic processes in electric drives of sucker-rod pumping units for oil production. Research methods The following methods were used: mathematical and computer modeling, including real-time modeling; physical modeling based on a test bench. Results A test bench has been developed that, with a given scale, implements the electromechanical processes occurring in the electric drive of a sucker-rod pumping unit; the use of experimental power diagrams as training sets for diagnostic problems by machine learning is proposed; the possibility of creating and debugging control systems for the technological process of oil production on a test bench was demonstrated. Keywords: test bench, sucker rod pumping unit, load simulation, electric drive, oil production

Research of carbon fiber plastic rod connections with steel heads at the action of bending loads

To increase the efficiency of the use of a sucker rod pumping unit (SRPU) today the columns of sucker rods of fiberglass and carbon fiber are used. Such polymer composites have a number of advantages over steel, but they have a significant drawback in the design of a sucker rod - a high concentration of stresses at the point where theyare connected to a steel head containing a thread. Many constructive solutions to this problem have been developed, but maintaining the connection of a fiberglass or carbon-plastic barrel with a metal head remains quite a challenge. As practice shows, the bending of the pump rods in the well are also subjected to bending loads, torque, friction to the column of tubing (tubing) and the like. Therefore, a comparative analysis of the parts of the pump rod structures: traditional steel and combined (metal tip with composite rod) should be carried out. In this work, such joints were subjected only to bending loads, which are particularly dangerous when passing through a rod of bent sections of a well and when running down the bar. It is established that at the time of bending the maximum normal stresses are distributed along the length of the pump rod unevenly and are concentrated in the transition between the head and the rod. The maximum normal stresses occurring in the transition between the steel tip and the carbon-plastic core, which are jointed without structural features (galtels, different transitions, etc.), have been determined to be greater than 1600 MPa. Such value of stress is undesirable when cycling the connection in well. For example, the design of a metal head was proposed, which allows reducing the stresses arising from bending and distribute them on the connection more evenly, compared to the traditional sucker rod.

Comparative evaluation of the executive mechanism of the balancing drive of the rocking machine equipped with a long-running stand

The article studies long-running drive of a downhole rod pumping unit, the design of which combines a traditional two-arm balancing drive (rocking machine) and a long-running stand. Modern downhole rod pumping units can extract oil, usually from one or two layers of wells up to 3500 m deep with a liquid flow rate from a cubic meter to several hundred cubic meters per day. It is investigated that the characteristics of balancing drives, performed by a number of world manufacturers allow the usage of pumping equipment in the range of fluid flow rate from the well from 1 to 40 m3 day. There is a general global trend of reducing the oil wells’ flow, as most oil fields are in the late stage of development, and therefore most traditional rocking machines are operated with low efficiency. Because the vast majority of of Ukrainian oil-production enterprises’ wells are equipped with beam pumping units their replacement by other types of the downhole rod pumps' drives requires significant investments. Equipping of a traditional balancing drive with a long-travel stand can improve drive’s technical characteristics. Determination of the design changes’ influence on kinematic and dynamic characteristics has been performed for two balancing options: 1 – traditional balancing of the drive with crank counterweights, placed on the cranks of the rocking machine in combination with a long-running stand and 2 – when the balance drive is used only to convert movement of a rope suspension bracket, and counterweights are placed on a long-running stand. It has been calculated that the first balancing variant allows to reduce the maximum torque up to 27.7 %, and by the counterweights placing on a long-running stand, the reduction of the maximum torque can be up to 62 %. It is proposed to use the standard deviation of the torque as a criterion for assessing the quality of balance.

Determination of the state and functioning of the equipment of rod well pumping units in the operation process by the parameters of the wattmetrogram

TARGET.The purpose ofthis work is to develop a method for diagnostics of equipment of sucker rod pumping units (SRPU) during operation according to the parameters of the wattmetrogram. A wattmetering module is used as a measuring element, the developed software in the MatLab software package serves as a tool for processing vibration signals. The technical condition of the sucker rod pumping unit is analyzed by the parameters of the wattmetrogram and the amplitude spectra of the object under study, formed using the fast Fourier transform procedure in the MatLab software environment.METHODS.Thewattmeteringmethodallowsyouto control the sucker rod-pumping unit during its operation under voltage. This control method is highly accurate, sensitive to developing defects, and allows the use of computer technologies for signal processing and analysis.RESULTS.The wattmetering method is fully disclosed. The construction of the spectrum is considered. The relationship between the wattmetrogram and the dynamogram has been established. The removal and evaluation of experimental data from the operating sucker-rod pumping unit during its operation was carried out. A wattmetrogram and a dynamogram were built, a spectrum was also built, which showed the presence of defects in this installation.CONCLUSION.ThismethodofwattmeteringwiththeMatLabsoftwareallowsyoutomonitorthetechnicalconditionofthesuckerrod pumping unit according to the amplitude-frequency characteristics of the wattmetrogram parameters.

Determination of the state and functioning of the equipment of rod well pumping units in the operation process by the parameters of the wattmetrogram

TARGET.The purpose ofthis work is to develop a method for diagnostics of equipment of sucker rod pumping units (SRPU) during operation according to the parameters of the wattmetrogram. A wattmetering module is used as a measuring element, the developed software in the MatLab software package serves as a tool for processing vibration signals. The technical condition of the sucker rod pumping unit is analyzed by the parameters of the wattmetrogram and the amplitude spectra of the object under study, formed using the fast Fourier transform procedure in the MatLab software environment.METHODS.Thewattmeteringmethodallowsyouto control the sucker rod-pumping unit during its operation under voltage. This control method is highly accurate, sensitive to developing defects, and allows the use of computer technologies for signal processing and analysis.RESULTS.The wattmetering method is fully disclosed. The construction of the spectrum is considered. The relationship between the wattmetrogram and the dynamogram has been established. The removal and evaluation of experimental data from the operating sucker-rod pumping unit during its operation was carried out. A wattmetrogram and a dynamogram were built, a spectrum was also built, which showed the presence of defects in this installation.CONCLUSION.ThismethodofwattmeteringwiththeMatLabsoftwareallowsyoutomonitorthetechnicalconditionofthesuckerrod pumping unit according to the amplitude-frequency characteristics of the wattmetrogram parameters.

Analysis and improvement of the design of uninterrupted connection of pump rods

Based on the field data, numerous failures of the downhole equipment of sucker rod pumping units occur, especially of the sucker rod strings. They are subject to corrosion, wear and alternating loads. The stress-strain state of the threaded connection elements is determined by the nature of the distribution of loads along the threads, which is uneven and depends on many factors. Despite this, the development of new designs of sucker rod connections and measures to improve the efficiency of operation and their research is an urgent task. In addition to the threaded connections of the sucker rods, there were a number of threadless designs that were not used in the fields, but they passed certain tests. The article presents these connection designs and discusses their advantages and disadvantages in comparison with standard threaded connections. Simulation modeling of a standard connection of sucker rods made it possible to investigate its stress-strain state and identify hazardous areas (stress concentrators). The stress-strain state of the threaded connection of the sucker rods has been investigated, the design of this connection has been improved and it has been established that, in comparison with the standard threaded connection of the sucker rods, the investigated has certain advantages. It was found that with an increase in the number of protrusions and depressions in a threaded joint, stresses decrease, which are concentrated in dangerous sections and along the contact planes. Convex contact planes also reduce stress, especially at the joint surface. Research has shown that the stresses generated in a threadless sucker rod joint are less than the stresses generated in a standard sucker rod and sleeve joint. Although the difference between these stresses is insignificant, attention should be paid to changing the geometric parameters of the threadless connection of the sucker rods, thereby reducing the maximum stresses.

Mechanisms and consequences of flooding of lubricating oils in transmissions of rod well pumping units

In ensuring the trouble-free and long-term operation of artificial lift facilities, an important role is played by the condition of lubricants and, in particular, oils. The operating conditions of sucker rod pumping units have their own characteristics - the equipment is operated daily and around the clock, its operation is characterized by temperature drops, humidity, significant and uneven loads, vibrations, high contact pressures, etc. there is a gradual accumulation of water in various forms: dissolved, in the form of an emulsion or in a free state. The presence of water is undoubtedly destructive; it naturally intensifies the aging process of lubricants and accelerates the wear of parts in friction pairs. On the basis of scientific papers, the mechanisms, patterns and consequences of the harmful effects of flooding of lubricating oils are analyzed, taking into account the specifics of the operating conditions of oilfield equipment. The regularities of changes in the state of the properties of oils, depending on the form of the presence of water in the lubricating medium: free, emulsified and dissolved, are separately considered and analyzed. The ways and mechanisms of flooding have been investigated and analyzed, which are conditionally divided into three groups: absorption of atmospheric moisture by oil components, condensation of atmospheric moisture on the inner surfaces of the gearbox and the mirror of the lubricant bath, and direct ingress of water into the gearbox due to technical imperfections and equipment defects. Particular attention is paid to the regularities of atmospheric moisture condensation, as the main path of flooding and the factors affecting the intensity of this process in the industrial operating conditions of the gearboxes of sucker rod pumping units. The main directions of the fight against flooding of both design and technical and organizational nature have been formulated.

Investigating the Techno-economic Utility of Integrating an Optimized PV/diesel Hybrid System in an Entire Oil Field in the Western-dessert in Egypt

Artificial lifting is considered as the most common technique in oil and gas production industry. However, from the electrical energy consumption prospective, artificial lifting is a heavy consumer. In the absence of a grid, oil and gas stack holders are forced to utilize diesel generator for energy production. Herein, an added cost of operation and maintenance is included in the oil production cost. The purpose of this work is to develop a systematic optimization methodology for utilizing renewable energy resources, specifically Photovoltaic (PV), in Oil & Gas Industry. The study has been applied on an entire oil field in the Egyptian western dessert. The load is operated with an integrated solar-assisted system and stand-alone diesel generator. The annual energy requirements using the Levelized cost of energy (LCOE) for ten sucker rod pumping units have been evaluated. A metaheuristic optimizer (Water Cycle Optimization Technique WCOT) has been utilized to optimize the PV contribution in the hybrid PV/diesel system proposed. Moreover, centralized, and distributed generation systems have been investigated technically and economically. The results have shown that the hybrid centralized system can provide up to 62% reduction in the LCOE with respect to the running diesel generator 24/7 system.

Application of Linear Valve Submersible Electric Motors in Oil Production Units for Marginal Wells

In recent years, the share of marginal wells has been steadily increasing in the structure of the mechanized stock. But traditional types of artificial lift, such as sucker rod pumping units, have many disadvantages. Therefore, manufacturers of oil equipment are faced with the urgent tasks of creating innovative products that allow efficient production of fluid in wells with low flow rates. The article presents a diagram and components of the installation of an EP01 submersible electric plunger pump with a linear valve motor. A description of her work is given. The advantages of using the unit during the operation of marginal oil wells are shown.

Use of hydraulic drive of sucker-rod pump 120-6-24 in oil and gas industry as an alternative to import substitution of small-sized pumps

The purpose of this article is the research aimed at the improvement of the quality of hydraulic equipment, namely, investigation of the use of hydraulic drive of sucker-rod pump 120-6-24 in oil and gas industry as an alternative to import substitution of small-sized pumps. Nowadays, at the fields of Western Siberia, it is necessary to replace outmoded and worn-out equipment with modern equipment of proven efficiency. To a greater extent, the imported equipment is used in oil industry. For Russian industry import substitution is one of the key tasks. This article considers the task of wells operation with sucker rod pumping units with a surface hydraulic drive with an analysis of its performance. As an alternative to import substitution for small-sized pumps, it is recommended to use innovative equipment - a highly efficient hydraulic drive of a sucker rod pumping unit, which provides a general increase in the efficiency of production processes during operation, increasing oil production during well operation in optimal mode. The use of this drive leads to a decrease in the costs of oil and gas production enterprises by reducing the level of oil deficit and prevents equipment failure in oil fields. The method of oil production with a hydraulic drive hydraulic drive of sucker-rod pump 120-6-24 considered in this article is widely applied in oil and gas industry and became a valid alternative to small-sized pumps.

Design and Implementation of a Laboratory Sucker Rod Pumping Unit Using Industry 4.0 Concepts

The Industry 4.0 is here, and advanced technologies are widely available for domains such oil and gas which are traditionally slow in adopting extreme new technologies. This paper presents the design architecture and implementation of effective data acquisition (DAQ) and monitoring system applied to an experimental sucker rod pumping unit for both event occurrence and educational purpose using latest technological advancements and industry 4.0 principles. The designed framework allows control and monitoring of analog and digital sensors configured in a decentralized generation structure. This system controls the values of the sampling frequency, range of channels, the number of points to acquire and then retrieves the data acquired from the operation of a sucker rod pump setup. National Instruments LabVIEW was used for the solution architecture presented in this study data collection and diagnostic analysis. Some of the operational physical parameters analysed and monitored include pressure, fluid production rate, valve leakage, pump efficiency, vibrations and energy consumption. The proposed architecture can be built easily with very low energy consumption, high reliability, ample flexibility for quicker data retrieval and prospective future modifications.

Расчет нагрузки на штанговую подвеску при неустановившемся колебательном движении штанг скважинной насосной установки

The efficiency of a rod pumping unit is determined by the straightness of its rod string, which is impacted by the load when the rod string is in motion. Determining the dependence of the load impacting the rod suspension on the dynamic forces is one of the major issues in ensuring its straightness. In order to provide equal distribution of the stresses along the entire length of the polished rod under dynamic loading, it is necessary to determine the load on its surface, which is impossible without the equation of unsteady motion of the rod string. To this end, the article examines the issues related to the equation of unstable motion of well pumping unit rods. Formulae for calculating the loads acting on the rod suspension point are derived, and the equation of the rod string motion and load on the polished rod after the initial deformation is obtained.

RESEARCH CONCERNING THE SIMULATION OF THE OPERATION OF CONVENTIONAL SUCKER ROD PUMPING UNITS

In the paper is presented a method for obtaining the variation during a cinematic cycle of the motor torque at the crankshaft in the case of the conventional sucker rod pumping units. The calculation method has been transposed into a computer program which allows establishing the influence of different constructive and operating parameters of the pumping units on the variation of the motor torque at the crankshaft. Finally, a series of results of the simulations performed in the case of a C-640D-305-120 pumping unit are presented.

Kinematic and kinetostatic analysis of the six-link straight-line generating converting mechanism of the unbalanced sucker rod pumper drive

The results of kinematic and force analysis of the new six-link converting mechanism of the sucker rod pumper drive (SRPD) are presented in this paper and the advantages of the alternative design are substantiated. Using a straight-line generating mechanism allows reducing essentially converting mechanism dimensions and metal consumption as compared with traditionally used SRPD with swinging balancer and crank-based counterweight, first of all, due to eliminating the complicated arc head (so-called «horse-head») of the existing units. However, in order to make sure the working capacities of non-balancer mechanism, kinematic and force characteristics have to be studied. The results of mathematical modeling of the six-link mechanism confirm the qualitative advantages of the straight-line generator. As a result of the study of the rectilinear-guiding mechanism as a transforming mechanism for the drive of sucker rod pumping units, the laws of motion of the links, position, speed and acceleration of all points were determined. To solve the problem of kinematic analysis, the method of closed vector contours was used, which makes it possible to determine the functions of the position of links and analogs of speeds and accelerations. When solving the problem of strength analysis, the equilibrium of each link was considered. As a result of force analysis, jointly solving the equilibrium equations of the links of the six-link hinge-lever mechanism, the reactions of the hinges of the mechanism are determined. A computer model for studying the kinematics and kinetostatics of the converting mechanism of the sucker rod pumping unit drive has been developed

Development of a stand for researching electric drives of pumping units

In the modern oil industry, the vast majority of oil production units are represented by sucker rod pumping units, driven mainly by asynchronous electric motors without using any monitoring, control and regulation means. Studies carried out on such installations show their low energy efficiency and reliability. Therefore, the issue of developing complex electric drives of a new generation based on the use of synchronous valve electric motors is relevant allowing to significantly increase the energy efficiency and reliability of both individual installations and to ensure the creation of "smart" oil field control systems. The paper discusses new technical solutions of the experimental stand which makes it possible to study the energy characteristics of electric drives based on asynchronous and synchronous valve electric motors, as well as allowing to create conditions as close as possible to real field conditions with imitation of the operation of an oil pumping unit of a sucker rod pumping unit. In modern test equipment systems, devices are often used to create a mechanical load on the shaft of the electric motor under study. The system proposed and implemented as such a device is "a frequency converter - load asynchronous electric motor", which has been tested on a stand and has proven to be the best in comparison with traditional circuits using DC motors. But using of a load asynchronous electric motor as part of the test stand has revealed a number of disadvantages: overheating of the electric motor operating in the opposing mode, low accuracy of creating the load torque and the speed of the system's response. The problem of overheating of the load electric motor has been solved by transferring the frequency converter to the direct torque control mode, while a significant decrease in the motor current and stabilization of the temperature regime have been detected. The low accuracy and response speed of the system have been increased by introducing feedback and a PID controller into the stand control system.