Automatic control system for carbon dioxide booster pump pry

Abstract

The utility model relates to the field of oil-gas field development, and discloses an automatic control system for a carbon dioxide booster pump pry, which comprises a carbon dioxide gas-liquid separation tank and a booster pump, the carbon dioxide gas-liquid separation tank is connected with a carbon dioxide storage tank through a suction pipeline and is connected with the booster pump through a conveying pipeline, and the booster pump is connected with the carbon dioxide gas-liquid separation tank. The booster pump is connected with the fracturing truck through a discharge pipeline, an emptying ball valve is arranged on the carbon dioxide gas-liquid separation tank, a pressure difference liquid level sensor and a radar liquid level sensor are arranged in the carbon dioxide gas-liquid separation tank, the booster pump is further connected with the carbon dioxide gas-liquid separation tank through a return pipeline, and the carbon dioxide gas-liquid separation tank is connected with the pressure difference liquid level sensor. The booster pump, the emptying ball valve, the differential pressure liquid level sensor, the radar liquid level sensor and the return valve are respectively connected with the controller. The utility model not only solves the problem of automatic control of the discharge pressure of the carbon dioxide supercharging device, but also realizes the automation of liquid level control of the booster pump prying device.

Description

Technical Field

[0001] The utility model relates to the technical field of oil and gas field development, in particular to oil and gas field development fracturing operations, and more specifically to a carbon dioxide booster pump skid automatic control system. Background Art

[0002] At present, the scale of carbon dioxide fracturing will increase significantly, and carbon dioxide boosting equipment has become one of the indispensable equipment for this process. Through the investigation of the current use of carbon dioxide boosting devices on site, it is found that the structure design of the device is relatively complex, the degree of automation is low, especially the control system has not yet realized automatic control, and personnel need to operate in a high-pressure environment, which poses safety risks and is difficult to meet the existing construction needs.

[0003] At present, the liquid level control system of the booster pump skid is mainly controlled manually, and the three liquid level ball valves of the separator tank of the booster pump skid are manually controlled locally to observe and control the liquid level height of the separator tank. Due to the lack of remote liquid level display and automatic control functions, the measurement error is large. At the same time, the personnel are operating in a high-pressure area, which poses a great safety hazard. Furthermore, the discharge pressure control of the booster pump skid adopts the method of controlling the discharge output pressure by adjusting the speed of the booster pump. Since the medium passed by the booster pump is ultra-low temperature carbon dioxide, adjusting the speed of the booster pump back and forth is not conducive to the stability of the booster pump skid and reduces the service life of the seal of the booster pump.

[0004] For example, the invention patent with publication number CN114893160A discloses a carbon dioxide fracturing medium phase change control system and method, which has the problems described in the background technology. Utility Model Content

[0005] In view of the problems and defects existing in the above-mentioned prior art, the utility model provides an automatic control system for a carbon dioxide booster pump skid, which not only solves the problem of automatic control of the discharge pressure of the carbon dioxide booster device, but also solves the problem of automatic liquid level control of the booster pump skid, thereby ensuring that the liquid carbon dioxide in the separation tank always has a certain liquid level height.

[0006] In order to achieve the above utility model purpose, the technical solution of the utility model is as follows:

[0007] A carbon dioxide booster pump skid automatic control system, the system includes a booster pump skid device, a booster pump skid discharge pressure automatic control subsystem and a booster pump skid liquid level automatic control subsystem, the booster pump skid discharge pressure automatic control subsystem and the booster pump skid liquid level automatic control subsystem are respectively connected to a controller, and the controller is connected to a human-computer interaction interface via Ethernet; the specific structure is as follows:

[0008] The booster pump skid device provided by the utility model comprises a carbon dioxide gas-liquid separation tank, a booster pump, a liquid carbon dioxide suction pipeline and a liquid carbon dioxide discharge pipeline, one end of the liquid carbon dioxide suction pipeline is connected to the outlet of the carbon dioxide storage tank, and the other end is connected to the inlet of the carbon dioxide gas-liquid separation tank, the outlet of the carbon dioxide gas-liquid separation tank is connected to the inlet of the booster pump through a delivery pipeline, one end of the liquid carbon dioxide discharge pipeline is connected to the inlet of a fracturing vehicle, and the other end is connected to the outlet of the booster pump, the delivery pipeline is provided with a suction pressure sensor and a suction temperature sensor connected to a controller, the discharge pipeline is provided with a discharge temperature sensor and a discharge pressure sensor connected to the controller, and the booster pump is also connected to the controller of the system; during the construction process, the carbon dioxide in the storage tank enters the carbon dioxide gas-liquid separation tank through the suction pipeline for gas-liquid separation, and then the separated liquid carbon dioxide is introduced into the booster pump, and is pressurized by the booster pump to provide a phase-stable liquid carbon dioxide medium for the fracturing vehicle.

[0009] The booster pump skid discharge pressure automatic control subsystem provided by the utility model includes a reflux valve connected to a controller, a reflux inlet is provided on the carbon dioxide gas-liquid separation tank, the outlet of the booster pump is also connected to the reflux inlet through a reflux pipeline, and the reflux valve is provided on the reflux pipeline; the operator sets the pressure value through the human-computer interaction interface, the controller collects the pressure value of the pressure gauge at the discharge end in real time, compares and calculates the set value with the collected value, and outputs a corresponding control signal according to the calculation, thereby controlling the booster pump speed and the opening of the reflux valve at the discharge end. The specific control method is: before the booster pump speed reaches the theoretical displacement required for construction, the controller controls the discharge pressure by controlling the booster pump speed; after the booster pump speed reaches the theoretical displacement required for construction, the controller adjusts the discharge pressure by controlling the opening of the reflux valve, so that part of the pressurized carbon dioxide flows back to the carbon dioxide gas-liquid separation tank through the reflux pipeline, and the speed of the booster pump remains unchanged at this time.

[0010] The booster pump skid liquid level automatic control subsystem provided by the utility model comprises a pressure differential liquid level sensor and a radar liquid level sensor, wherein the pressure differential liquid level sensor and the radar liquid level sensor are arranged in a carbon dioxide gas-liquid separation tank, and the pressure differential liquid level sensor and the radar liquid level sensor measure the liquid level of the liquid carbon dioxide in the separation tank in real time, and output a measurement signal to a controller, and the controller calculates a control amount according to the received liquid level signal, thereby outputting a corresponding control signal, controlling the opening degree of the vent ball valve, and thus controlling the liquid level in the separation tank.

[0011] The radar level sensor used in the utility model is FMP54 guided wave radar level gauge, the differential pressure level sensor model is PMD75, the suction temperature sensor and the discharge temperature sensor model are TM131, the suction pressure sensor and the discharge pressure sensor model are PMP71B, which are explosion-proof pressure sensors, and the controller is a PLC controller. The conveying pipeline used is a stainless steel metal hose.

[0012] Beneficial effects of the utility model:

[0013] 1. In the utility model, the discharge pressure automatic control system of the carbon dioxide booster pump skid provides a stable output through the stable speed of the booster pump skid and controls the reflux speed of the liquid carbon dioxide by adjusting the switch size of the reflux valve on the reflux pipeline, thereby achieving the displacement and discharge pressure required for the work. This method innovatively achieves that the booster pump always maintains a stable speed when the displacement fluctuates, prolongs the maintenance time of the booster pump seal, and increases the service life of the booster pump.

[0014] 2. In the utility model, the automatic control system of the liquid level of the carbon dioxide booster pump skid adopts two different sensors to detect the liquid level height in the carbon dioxide separation tank, and controls the switch size of the drain ball valve by setting the liquid level to realize automatic control of the liquid level, which can avoid the safety hazards caused by manual operation in the high-pressure area. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The above and following detailed description of the present invention will become more clear when read in conjunction with the following drawings, in which:

[0016] Figure 1 This is a schematic diagram of the structure of the carbon dioxide booster pump skid device of the utility model;

[0017] Figure 2 This is a block diagram of automatic control of discharge pressure of the carbon dioxide booster pump of the utility model;

[0018] Figure 3 This is a block diagram of the automatic liquid level control of the carbon dioxide booster pump skid of the utility model.

[0019] In the figure:

[0020] 1. Carbon dioxide gas-liquid separation tank; 2. Booster pump; 3. Reflux valve; 4. Vent ball valve; 5. Differential pressure level sensor; 6. Radar level sensor; 7. Controller; 8. Suction pressure sensor; 9. Suction temperature sensor; 10. Flow meter; 11. Discharge temperature sensor; 12. Discharge pressure sensor 13. Pump inlet valve. DETAILED DESCRIPTION

[0021] At present, the liquid level control system of the booster pump skid is mainly controlled manually, and the three liquid level ball valves of the separator tank of the booster pump skid are manually controlled locally to observe and control the liquid level height of the separator tank. Due to the lack of remote liquid level display and automatic control functions, the measurement error is large. At the same time, the personnel are operating in a high-pressure area, which poses a great safety hazard. Furthermore, the discharge pressure control of the booster pump skid adopts the method of controlling the discharge output pressure by adjusting the speed of the booster pump. Since the medium passed by the booster pump is ultra-low temperature carbon dioxide, adjusting the speed of the booster pump back and forth is not conducive to the stability of the booster pump skid and reduces the service life of the seal of the booster pump.

[0022] Based on this, the utility model proposes a carbon dioxide booster pump skid automatic control system, which uses a sensor to detect the liquid level height in the carbon dioxide gas-liquid separation tank in real time, and controls the switch size of the vent ball valve by setting the liquid level to achieve automatic control of the liquid level. At the same time, the stable output is provided by the stable speed of the booster pump, and the switch size of the remote-controlled reflux valve on the reflux pipeline is used to jointly control the reflux speed of the liquid carbon dioxide, thereby achieving the displacement and discharge pressure required for work. This method innovatively achieves that the booster pump always maintains a stable speed when the displacement fluctuates, extends the maintenance time of the booster pump seal, and increases the service life of the booster pump.

[0023] The technical solution for achieving the purpose of the utility model is further described below through specific embodiments. It should be noted that the technical solution claimed for protection by the utility model includes but is not limited to the following embodiments.

[0024] The present embodiment discloses a carbon dioxide booster pump skid automatic control system, the system is composed of a booster pump skid device, a booster pump skid discharge pressure automatic control subsystem, a booster pump skid liquid level automatic control subsystem, a controller and a human-computer interaction interface. The booster pump skid discharge pressure automatic control subsystem and the booster pump skid liquid level automatic control subsystem are respectively connected to the controller, and the controller is connected to the human-computer interaction interface via Ethernet.

[0025] Refer to the instruction manual Figure 1 As shown, the booster pump skid device mainly includes a carbon dioxide gas-liquid separation tank 1, a booster pump 2, a liquid carbon dioxide suction pipeline and a liquid carbon dioxide discharge pipeline. The liquid carbon dioxide suction pipeline is connected to the carbon dioxide storage tank and the carbon dioxide gas-liquid separation tank 1 respectively. The booster pump 2 is connected to the carbon dioxide gas-liquid separation tank 1 and the liquid carbon dioxide discharge pipeline respectively through a delivery pipeline, and the carbon dioxide discharge pipeline is also connected to the fracturing vehicle; the delivery pipeline is provided with an intake temperature sensor 9, an intake pressure sensor 8 and a pump inlet valve 13 respectively connected to the controller 7; the discharge pipeline is provided with a discharge temperature sensor 11, a discharge pressure sensor 12 and a flow meter 10 connected to the controller 7.

[0026] Refer to the instruction manual Figure 2 As shown, the booster pump skid discharge pressure automatic control subsystem mainly includes a reflux valve 3 connected to a controller 7, and the outlet of the booster pump 2 is also connected to the reflux inlet of the carbon dioxide gas-liquid separation tank 1 through a reflux pipeline, and the reflux valve 3 is arranged on the reflux pipeline.

[0027] Refer to the instruction manual Figure 3 As shown, the booster pump skid liquid level automatic control subsystem mainly includes a differential pressure level sensor 5 and a radar level sensor 6 connected to a controller 7. The radar level sensor 6 is located at the top of the separation tank, and the differential pressure level sensors 5 are distributed at the top and bottom of the separation tank.

[0028] During the construction process, the carbon dioxide in the carbon dioxide storage tank enters the gas-liquid separation tank through the suction pipeline, and the gaseous and liquid carbon dioxide are separated in the separation tank. The gaseous carbon dioxide is located at the upper part of the separation tank, and the liquid carbon dioxide is located at the bottom of the separation tank. The top of the separation tank is provided with a vent ball valve 4 connected to the controller 7, and the bottom is provided with a liquid outlet. The liquid carbon dioxide is discharged from the liquid outlet into the booster pump 2 through the delivery pipeline for pressurization, and the pressurized carbon dioxide is then delivered to the fracturing truck through the discharge pipeline.

[0029] In the present invention, the process of realizing automatic control of discharge pressure by the booster pump skid discharge pressure automatic control subsystem is as follows:

[0030] The operator inputs the preset displacement output pressure value in the human-machine interface (control panel) and transmits it to the controller. The PLC controller collects the instantaneous pressure value of the discharge pressure sensor 12 on the discharge pipeline. The controller 7 compares and calculates the set value with the collected value, calculates the corresponding control quantity according to the PID algorithm, and outputs the corresponding control signal, thereby controlling the speed of the booster pump 2 and the opening of the return valve 3. The discharge pressure is jointly controlled by the speed of the booster pump 2 and the switch size of the return valve 3 to provide a phase-stable liquid carbon dioxide medium for the fracturing truck.

[0031] In the present invention, the process of the booster pump skid liquid level automatic control subsystem to realize automatic control of the liquid level height in the separation tank is as follows:

[0032] The operator inputs the preset separation tank liquid level value (liquid part) in the human-machine interaction interface (control panel) and transmits it to the controller 7; the liquid level signal measured by the differential pressure level sensor 5 and the ball valve angle signal measured by the angle sensor on the drain ball valve 4 are respectively output to the controller 7. After receiving the liquid level detected by the liquid level sensor, the controller 7 calculates the control quantity through the PID algorithm and outputs the corresponding control signal to the drain ball valve 4. The opening of the drain ball valve 4 is controlled by the output control signal, thereby controlling the liquid level in the separation tank.

[0033] In the utility model, when monitoring the liquid level, the controller usually uses the liquid level signal collected by the pressure difference liquid level sensor 5 in the separation tank as the basis for calculation, and the signal collected by the radar liquid level sensor 6 is used as an auxiliary. When the sensors are normal, the difference between the two data calculated by the controller 7 based on the signals collected by the two sensors is within the set range. When one of the sensors is damaged, the difference between the two calculated data exceeds the set range. At this time, the ball valve 4 can be manually operated to release all the gas in the separation tank. Only liquid exists in the tank. At this time, it can be determined which sensor is damaged based on the value calculated based on the data collected by the two liquid level sensors. If it is determined that the pressure difference liquid level sensor 5 is damaged, the controller 7 uses the data collected by the radar liquid level sensor 6 as the basis for data calculation. Therefore, the complementary effect is achieved by the two sensors. When one of the sensors has a problem, the entire system can still operate normally and continue to provide the pressure required for the fracturing operation without affecting production efficiency.

[0034] In the utility model, the controller 7 can monitor in real time whether the temperature and pressure of the carbon dioxide output from the separation tank meet the requirements through the suction temperature sensor 9 and the suction pressure sensor 8 arranged on the delivery pipeline, and then control the opening of the pump inlet valve 13; further, the liquid flow can also be monitored in real time through the flow meter 10 arranged on the discharge pipeline.

[0035] In the present invention, the PID algorithm is a prior art and will not be elaborated in detail here.

[0036] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the scope of protection of the present invention.

[0037] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "setting", "installation" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A carbon dioxide booster pump skid automatic control system, comprising a carbon dioxide gas-liquid separation tank (1) and a booster pump (2), wherein the inlet of the carbon dioxide gas-liquid separation tank (1) is connected to the outlet of a carbon dioxide storage tank via a suction pipeline, the outlet of the carbon dioxide gas-liquid separation tank (1) is connected to the inlet of the booster pump (2) via a delivery pipeline, the outlet of the booster pump (2) is connected to the inlet of a fracturing vehicle via a discharge pipeline, and the carbon dioxide gas-liquid separation tank (1) is provided with a venting ball valve (4), characterized in that: The carbon dioxide gas-liquid separation tank (1) is provided with a differential pressure level sensor (5) and a radar level sensor (6); the outlet of the booster pump (2) is also connected to the reflux inlet of the carbon dioxide gas-liquid separation tank (1) via a reflux pipeline; a reflux valve (3) is provided on the reflux pipeline; the vent ball valve (4), the differential pressure level sensor (5), the radar level sensor (6) and the reflux valve (3) are respectively connected to a controller (7); and the booster pump (2) is connected to the controller (7).

2. The automatic control system of a carbon dioxide booster pump skid according to claim 1, characterized in that: The delivery pipeline is provided with a suction pressure sensor (8) and a suction temperature sensor (9) connected to the controller (7).

3. The automatic control system of a carbon dioxide booster pump skid according to claim 1, characterized in that: The discharge pipeline is provided with a flow meter (10) connected to the controller (7), a discharge temperature sensor (11) and a discharge pressure sensor (12).

4. The automatic control system of a carbon dioxide booster pump skid according to claim 1, characterized in that: The radar liquid level sensor (6) is an FMP54 guided wave radar liquid level meter.

5. The automatic control system of a carbon dioxide booster pump skid according to claim 1, characterized in that: The delivery pipeline is a stainless steel metal hose.

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