RU2806837C1 - Control system for hydraulic drives of two sucker rod pumps - Google Patents

Abstract

FIELD: mechanical engineering.

SUBSTANCE: invention relates to control and monitoring systems for hydraulic drives of sucker rod pumps. The control system for the hydraulic drive of the sucker rod pump contains a programmable logic controller (PLC) connected through discrete inputs of the discrete input module to the outputs of two oil level sensors in the oil tank of the hydraulic pumping station of the sucker rod pump and connected through the analogue inputs of the analogue input module to the analogue outputs of two temperature sensors and two pressure sensors, and through the corresponding discrete outputs of the discrete output module and analogue outputs of the analogue output module connected to the corresponding inputs of two frequency converters of each of the two asynchronous motors of the two pressure lines of the pumping station, based on the settings pre-set by the operator separately for each of the two sets of electro-hydraulic equipment each of two circuits of pressure lines that connect the hydraulic pumping station with the corresponding hydraulic cylinders of the rod strings of sucker rod pumps, based on data on the level of formation fluid in the wells and the volume of raised formation fluid, obtained separately from the first echo sounder and the first flow meter and the second echo sounder and the second flow meter, a programmable logic controller through an analogue output module is made with the ability to separately regulate the speed characteristics of each of the two asynchronous motors to ensure independent operation of deep-well equipment with a given number of double strokes of each of the two hydraulic cylinder rods.

EFFECT: increase in formation fluid production per unit of time without increasing the number of surface equipment due to automatic control of electro-hydraulic equipment.

2 cl, 2 dwg

Description

Field of technology to which the invention relates

The invention relates to mechanical engineering, namely to control and monitoring systems for hydraulic drives of sucker rod pumps.

State of the art

A known control system for the hydraulic drive of a rod pump, which contains a set of electro-hydraulic equipment (patent 2767669, published 03/18/2022, the patent holder of which is the applicant of this application). The control system for the hydraulic drive of the sucker rod pump contains a programmable logic controller connected through discrete outputs to at least two intermediate relays connected to at least two electromagnets; the discrete inputs of the programmable logic controller are connected to the outputs of at least two working fluid level sensors (for example, oil) in the hydraulic tank (hydraulic tank), the analog inputs of the programmable logic controller are connected to the analog outputs of at least two temperature sensors and at least two pressure sensors. The programmable logic controller receives signals about the malfunction of the mentioned sensors through discrete and analog inputs; based on these signals, it switches to the corresponding backup sensor. The corresponding discrete and analog outputs of the programmable logic controller are connected to the corresponding inputs of two frequency converters of each of the two asynchronous electric motors, connected, in turn, to the corresponding hydraulic motors of the pressure lines of the pumping station. Based on the operator’s settings or when a malfunction is detected in the electro-hydraulic equipment of one of the pressure lines, the programmable logic controller, through discrete and analog outputs, regulates the frequency of asynchronous electric motors and controls their activation or deactivation to ensure the operation of deep-well equipment with a specified number of double strokes of the hydraulic cylinder rod. Thus, the control system changes the rotation speed of asynchronous electric motors that control the movement of the hydraulic cylinder rod of the deep-well sucker-rod pump drive, which leads to an increase in the volume of formation fluid lifting, an increase in the range of regulation of the operating parameters of the deep-well sucker-rod pump and an increase in the reliability of the system as a whole.

The disadvantage of the known control system is the narrow range of control of the characteristics of the hydraulic equipment, which does not provide the possibility of simultaneous operation of two separate wells, and requires the installation of additional surface equipment to control each of the exploited formations or wells, or ensures the production of a small volume of formation fluid.

The essence of the invention

The problem that the claimed invention is aimed at solving is the insufficient efficiency of the operation of deep-well equipment, such as sucker-rod pumps, and the need to increase the number of sets of surface equipment, as well as change the operating parameters of each sucker-rod pump based on data from auxiliary equipment, such as an echo sounder and a flow meter.

The technical result achieved by implementing the claimed invention is an increase in formation fluid production per unit of time without increasing the amount of surface equipment due to the automatic control of electro-hydraulic equipment (hydraulic blocks, hydraulic motors, hydraulic valves, sensors, electric motors and other equipment of a hydraulic pumping station), which is included in drive composition, which increases the efficiency of formation fluid production by ensuring the operation of several simultaneously operating deep-rod pumps with one drive.

The specified technical result is achieved by the fact that the control system for the hydraulic drive of the sucker rod pump contains a programmable logic controller (PLC), connected through discrete inputs of the discrete input module with the outputs of two oil level sensors in the oil tank of the hydraulic pumping station of the sucker rod pump, and connected through analog inputs of the analog input module. input with analog outputs of two temperature sensors and two pressure sensors, and through the corresponding discrete outputs of the discrete output module and analog outputs of the analog output module connected to the corresponding inputs of two frequency converters, each of two asynchronous motors of two pressure lines of the pumping station, based on those previously specified by the operator settings separately for each of the two sets of electro-hydraulic equipment for each of the two pressure line circuits that connect the hydraulic pumping station with the corresponding hydraulic cylinders of the rod strings of sucker rod pumps, based on data on the level of formation fluid in wells and the volume of lifted formation fluid, obtained separately from the first echo sounder and the first flow meter, and the second echo sounder and the second flow meter, the programmable logic controller through the analog output module is configured to separately regulate the speed characteristics of each of the two asynchronous motors to ensure independent operation of the deep equipment with a given number of double strokes of each of the two hydraulic cylinder rods. The programmable logic controller (PLC) is connected to the first and second echo sounders, and the first and second flow meters via the RS-485 network interface using the Modbus RTU protocol.

Brief description of drawings

In fig. Figure 1 shows a functional diagram of the control system for the hydraulic drive of a sucker rod pump;

Figure 2 shows a block diagram of a programmable logic controller.

Carrying out the invention

When operating one well, it may be necessary to extract formation fluid from two closely spaced adjacent wells, in which case the question arises about the placement of surface equipment in the most optimal way, taking into account the necessary measurements required for the best operation of the wells. This is the installation of a single set of surface equipment capable of automatically controlling two deep-rod pumps, taking into account the well condition indicators.

Rod pumps together with tubing and a string of rods are lowered into the corresponding wells, the plungers of the sucker rod pumps are connected through the rod strings to the rods of the corresponding hydraulic cylinders, echo sounders are fixed to the wellhead equipment connected to the annulus of the well, and flow meters are installed in the line of downhole equipment connected to Tubing, while echo sounders and flow meters are connected via a coded communication line to the PLC. The PLC evaluates the operation of deep-well equipment through sensors of the rod rotator position, temperature, pressure, working fluid level, and frequency converters, with which it is connected via a wired communication line.

The control system for the hydraulic drive of a sucker rod pump contains a programmable logic controller (1) (hereinafter referred to as PLC), containing a central processor (2), a discrete input module (3), an analog input module (4), a discrete output module (5), an analogue module 6 output, memory (7), network interface (8), and operator console (9) connected to the PLC (1) (Figs 1, 2).

According to figure 1, the analog output of the analog output module (5) and the discrete output of the discrete (6) output module are connected to the corresponding inputs of frequency converters (10-1,10-2), the output power bus of which is connected to the corresponding electric motors (11-1 ,11-2) hydraulic motors of hydraulic drives of two deep-rod pumps, and the input power bus to the mains switch 12. In the PLC discrete input module (3) (1), the first discrete input is connected to switch 13, the second and third discrete inputs are connected to the first and the second output of the frequency converter (10-1), and the sixth and seventh discrete inputs are connected to the first and second output of the frequency converter (10-2). The second and fourth discrete outputs of the PLC discrete output module (5) (1) are connected to intermediate relays (14-1,14-2) connected to electromagnets (15-1,15-2), respectively, that control hydraulic units of pressure lines. The first and second analog inputs of the PLC analog input module (4) (1) are connected to pressure sensors (16-1, 16-2), which are installed in the first and second pressure lines, respectively, the third and fourth analog inputs are connected to sensors (17- 1.17-2) temperatures that are installed in the oil tank and are designed to control the temperature of the working fluid. The eighth and ninth discrete inputs of the discrete input module (3) are connected to the first sensor (18-1) of the working fluid level in the oil tank and the second sensor (18-2) of the working fluid level in the oil tank. The fourth and fifth discrete inputs of the PLC discrete input module (3) (1) are connected to two rod rotator position sensors (19-1), located on the support of the first hydraulic cylinder and designed to determine the corresponding position of the rod rotator relative to the support. The tenth and eleventh discrete inputs of the PLC discrete input module (3) (1) are connected to two rod rotator position sensors (19-2), located on the support of the second hydraulic cylinder and designed to determine the corresponding position of the rod rotator relative to the support. Echo sounders (20-1,20-2) and flow meters (21-1,21-2) for each well or for each formation of one well are connected to the network interface (8) RS-485 PLC (1), for example, via the Modbus RTU protocol .

The control system works as follows.

The PLC (1) begins operation (under normal operating conditions) when a discrete signal is supplied from a constant voltage source (not shown in the diagram) to the first discrete input of the discrete input module (3) via the “Start/Stop” switch (13). The voltage of the power supply network, as well as the voltage to the power sources of the drive sensors of the sucker rod pump and the PLC (1) (not shown in the diagram), is supplied through the input switch (12). The rod rotator position sensors (19-1) are located on the support of the first hydraulic cylinder, and the rod rotator position sensors (19-1,19-2) are located on the support of the second hydraulic cylinder and are designed to determine the corresponding position of each rod rotator relative to the corresponding support. Sensors (19-1,19-2) are installed in twos for the upper and lower positions of the rod rotator, respectively. The activation of the sensors (19-1,19-2) of the rod rotator confirms the fact of a change in the direction of its movement downwards or upwards, respectively.

Electromagnets (15-1,15-2), which control the opening/closing of hydraulic valves in the hydraulic blocks of the corresponding pressure lines, are configured to open/close the corresponding pressure line for each of the two hydraulic cylinders separately in accordance with the number of double strokes of the rods specified through the operator's console hydraulic cylinders. The PLC (1) monitors the state of the temperature sensor (17-1) and the working fluid level sensor (18-1) in the hydraulic tank when a malfunction of any of the listed sensors is detected (for example, no signal from the sensor, signal value exceeding the permissible minimum or maximum values ), The PLC (1) switches to working with the corresponding backup sensors (17-2, 18-2).

When starting operation, the PLC (1) works through a frequency converter (10-1) with the electrohydraulic equipment of the first pressure line and through a frequency converter (10-2) with the electrohydraulic equipment of the second pressure line. Frequency converters (10-1,10-2) are connected through the corresponding current protection circuit breakers (not shown in the diagram).

The PLC (1), through the first discrete output of the discrete output module (5), which is connected to the first discrete input of the frequency converter (10-1), provides a signal about the direction of movement of the asynchronous motor (11-1), and through the first analog output of the module ( 6) analog output, which is connected to the first analog input of the frequency converter (10-1), by setting a preset value of the specified frequency (number of revolutions) of the asynchronous motor (11-1), checks the possibility of output to the preset ones through the operator’s console (9) the speed parameters of the movement of the first hydraulic cylinder of the first sucker rod pump, in other words, determines whether a predetermined number of engine revolutions (11-1) allows the drive of the first sucker rod pump to provide a predetermined number of double strokes per minute. Double stroke is defined as the passage of the rod from the lower to the upper position sensor of the rod rotator and back. If the achievement of the preset speed parameters of the movement of the first hydraulic cylinder of the first sucker-rod pump does not occur, that is, the drive cannot provide a preset number of double strokes per minute, the PLC (1) changes the AC frequency values of the asynchronous motor (11-1) in the range allowed for the engines used, in order to provide the required speed parameters for the movement of the first hydraulic cylinder.

Then the PLC (1) proceeds to check the speed parameters of the movement of the second hydraulic cylinder of the second sucker rod pump by issuing a signal about the direction of movement of the asynchronous engine (11-2), and setting a preliminary value of the specified frequency (number of revolutions) through the first analog output of the analog output module (6), which is connected to the first analog input of the frequency converter (10-2), and if they do not correspond to the preset through the operator's remote control (9) parameters, changes the speed parameters of the movement of the second hydraulic cylinder of the second deep-rod pump by changing the set frequency of the asynchronous motor (11-2).

The first and second discrete outputs of the frequency converter (10-2) are connected to the fourth and sixth discrete inputs of the PLC discrete input module (3) (1). In the process of changing the speed characteristics of the movement of the hydraulic cylinders of the first and second sucker rod pumps, the PLC (1) with a predetermined frequency evaluates the levels of formation fluid in the wells, using survey data from the first and second echo sounders (20-1,20-2), respectively, as well as volume of lifted formation fluid using data from the first and second flow meters (21-1,21-2), respectively. PLC (1) in the process of controlling the electrohydraulic equipment of the first and second sucker rod pumps for lifting formation fluid, with a frequency preset by the operator, interrogates the flow meters (21-1, 21-2) of the first one via a coded communication line (for example, using the MOLBUS RTU protocol) and second wells, respectively, for the volume of raised formation fluid and an echo sounder (20-1, 20-2) for the level of formation fluid in the first and second wells, and, by changing the predetermined number of double strokes of the hydraulic cylinder rod, ensures maximum formation flow rate liquid and does not allow a critical decrease in the liquid level in the well. Depending on the change in data received from the first and second echo sounders (20-1, 20-2) and the first and second flow meters (21-1, 21-2), the PLC (1) changes the specified speed parameters of each hydraulic cylinder based on the preliminary the limits of possible changes in the number of double strokes of the hydraulic cylinder rod of the corresponding sucker rod pumps, specified through the operator's console.

In the control system of the hydraulic drive of a deep-rod pump, when operating with two hydraulic cylinders (i.e., two deep-rod pumps), the electromagnets (15-1, 15-2) of the hydraulic valves ensure the operation of the hydraulic units of the electro-hydraulic equipment of the hydraulic pumping station along two separated pressure lines separately in accordance with the specified number of double strokes of the hydraulic cylinder rods. The movement of the first and second hydraulic cylinders is controlled through frequency converters (10-1, 10-2) of each of the two asynchronous motors of the two pressure lines of the pumping station, and the engine (11-1, 11-2) with a hydraulic motor, which belong to the electrohydraulic equipment of the hydraulic pumping station and are connected to each other by half-couplings, respectively. The PLC (1), receiving a signal about the rod rotator passing the upper and lower sensors (19-1,19-2) of the rod rotator position, calculates the number of double strokes of the hydraulic cylinder rod per minute based on the time of passage between the rod rotator position sensors (19-1,19-2), if this value does not correspond to the one previously set through the operator’s console, then the PLC (1) outputs a changed value of the alternating current frequency to the frequency converter (10-1,10-2) of the asynchronous motor, which changes the engine rotation speed and, accordingly, the rotation speed of the hydraulic motor, which changes the volume of working fluid transferred from the oil tank to the hydraulic cylinder, i.e. changes the speed of reciprocating movement of the hydraulic cylinder rod.

Thus, the control system, by separately changing the rotation speed of the asynchronous motors of the first and second pressure lines, independently controls the first and second hydraulic cylinders and, accordingly, two deep-rod pumps, which leads to optimization of the volumes of lifted reservoir fluid without installing additional surface equipment, reducing metal consumption of surface equipment and increasing the efficiency of formation fluid production.

Claims (2)

1. A control system for the hydraulic drives of two sucker rod pumps, containing a programmable logic controller (PLC) configured to separately control the operation of the hydraulic drive of each of the two sucker rod pumps, wherein the PLC contains a discrete input module connected through discrete inputs to the outputs of two sensors working fluid level in the oil tank of the hydraulic pumping station of a sucker rod pump, an analog input module connected via analog inputs to the analog outputs of two temperature sensors installed in the oil tank, and analog outputs of two pressure sensors of the pressure lines of the pumping station, a discrete output module connected via discrete outputs with corresponding inputs of frequency converters of each of two asynchronous motors of two pressure lines of the pumping station and with two intermediate relays connected to two electromagnets, configured to open and close the corresponding pressure line for each of the two hydraulic cylinders separately in accordance with the number specified through the operator's console double strokes of the hydraulic cylinder rods, and an analog output module connected through analog outputs to the corresponding inputs of the frequency converters of each of the two asynchronous motors of the two pressure lines of the pumping station, while the PLC is connected to the first echo sounder and the first flow meter, the second echo sounder and the second flow meter, and the PLC is made with the ability to separately regulate the speed characteristics of each of the two asynchronous motors of the pressure lines of the pumping station based on the number of double strokes of the hydraulic cylinder rod per minute, preset via the operator’s console separately for the hydraulic drive of each of the two deep-rod pumps, and data on the level of formation fluid in the wells and the volume of lifted formation fluid, obtained separately from the first echo sounder and the first flow meter and the second echo sounder and the second flow meter. 2. The control system according to claim 1, in which the PLC is connected to the first echo sounder and the first flow meter, the second echo sounder and the second flow meter via the RS-485 network interface via the Modbus RTU protocol.