Safe operation optimization method and device based on speed of plunger reaching wellhead

Abstract

The invention discloses a safe operation optimization method and device based on the speed of a plunger reaching a wellhead, and belongs to the technical field of oil and gas production of oil and gas fields, and the method comprises the following steps: S1, installing a first plunger reaching sensor and a second plunger reaching sensor on a gas production tree, the vertical distance between the first plunger and the sensor and the vertical distance between the second plunger and the sensor are measured; s2, judging whether the first plunger arrival sensor and the second plunger arrival sensor monitor the arrival of the plunger or not, and acquiring the arrival moments of the plunger detected by the first plunger arrival sensor and the second plunger arrival sensor; according to whether the two plunger arrival sensors monitor the arrival of the plunger and the arrival time, detected by the plunger arrival sensors, of the plunger, the speed of the plunger reaching the wellhead is calculated; and S3, a plunger well operation scheme is determined according to the speed of the plunger reaching the wellhead. The speed of the plunger reaching the wellhead is accurately detected in real time, and the problem that an existing average speed detection method is prone to distortion, and consequently the dangerous speed reaches misjudgment and shutdown is caused is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas production in oil and gas fields, and in particular relates to a safe operation optimization method and device based on the speed at which a plunger reaches a wellhead. Background Art

[0002] As the development of natural gas reservoirs enters the middle and late stages, the gas well production capacity declines, the gas liquid carrying capacity is insufficient, and the wellbore liquid accumulation aggravates the restriction of gas well production capacity. Taking effective drainage and gas production measures to discharge the accumulated liquid is the key to extending the life cycle of the gas well. The plunger gas lift process is an important means of drainage and gas production in the middle and late stages of gas wells. The technical feature is that it is easy to form an isolation interface inside the wellbore, reduce gas upward and liquid slippage during the liquid lifting process, and improve the lifting efficiency. At present, it has been applied to more than 7,000 wells in major gas fields.

[0003] The plunger running speed is a key parameter for judging the running state of the plunger and the safety of the wellhead. Studies have shown that the arrival sensor installed at the wellhead blowout preventer can sense the arrival of the plunger, judge the state of the plunger discharge, and obtain the plunger rising time, thereby calculating the plunger running speed (well depth / rising time). The plunger running speed obtained by the existing method is the average speed of the plunger rising from the bottom of the well to the wellhead, but the actual plunger is not moving at a uniform speed during the upward movement. It is generally believed that the upward speed of the plunger is the highest in a short time when the plunger reaches the wellhead, and the impact on the wellhead is the most serious. The plunger arrives too quickly, which will cause damage to the blowout preventer, buffer spring and other devices, reduce the service life of the wellhead device, increase related maintenance costs, and easily cause safety accidents. In addition, there is a situation where the plunger does not fall to the bottom of the well after the actual well is closed, and reaches the wellhead quickly after the well is opened. The calculated running speed is too distorted, causing the control system to misjudge that the plunger has reached the wellhead at a dangerous speed, resulting in an emergency shutdown and well closing. It is necessary to manually verify the safety before optimizing the system to execute the plunger operation, which affects the normal production of the gas well.

[0004] Therefore, how to accurately obtain the speed at which the plunger reaches the wellhead, and then analyze the plunger's operating status and optimize the plunger's safe operation, is an important reference for judging the safety of the plunger hitting the wellhead blowout preventer, and is an important basis for ensuring the safe operation of the plunger well and reducing the production cost of drainage and gas production. Summary of the invention

[0005] The present invention provides a safe operation optimization method and device based on the speed of the plunger arriving at the wellhead, which can realize real-time and accurate detection of the speed of the plunger arriving at the wellhead, avoid the problem that the existing average speed detection method is prone to distortion and leads to misjudgment and shutdown of dangerous speed arrival, and reduce the related costs of manual inspection in the production process.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A safe operation optimization method based on the speed of the plunger reaching the wellhead comprises the following steps:

[0008] S1. Install a first plunger arrival sensor and a second plunger arrival sensor on the gas tree, and measure the vertical distance between the first plunger arrival sensor and the second plunger arrival sensor;

[0009] S2, judging whether the first plunger arrival sensor and the second plunger arrival sensor detect the arrival of the plunger, and obtaining the time of the plunger arrival detected by the first plunger arrival sensor and the second plunger arrival sensor, and calculating the plunger arrival speed at the wellhead according to whether the two plunger arrival sensors detect the arrival of the plunger and the time of the plunger arrival detected by the plunger arrival sensors;

[0010] S3. Determine the plunger well operation plan based on the plunger's arrival speed at the wellhead.

[0011] Further, in step S2, when the first plunger arrival sensor and the second plunger arrival sensor detect that the plunger 7 has arrived:

[0012] The speed V of the plunger reaching the wellhead is calculated according to the following formula 柱塞到达井口速度 :

[0013]

[0014] Wherein, h is the vertical distance between the first plunger arrival sensor and the second plunger arrival sensor, t1 is the moment when the plunger arrives at the second plunger arrival sensor, and t2 is the moment when the plunger arrives at the first plunger arrival sensor.

[0015] Furthermore, when the second plunger arrival sensor detects the arrival of the plunger, but the first plunger arrival sensor does not detect the arrival of the plunger, the average running speed of the plunger is calculated based on the actual well depth divided by the plunger rise time, and the obtained average running speed is regarded as the plunger arrival speed at the wellhead.

[0016] Furthermore, in step S2, when both the first plunger arrival sensor and the second plunger arrival sensor fail to detect the plunger, the plunger is judged as not arriving, and the shut-in time is extended additionally to ensure that the plunger can reach the wellhead in the next cycle.

[0017] Further, determining the plunger well operation plan according to the plunger reaching the wellhead speed includes the following steps:

[0018] Determine the relationship between the speed at which the plunger reaches the wellhead and the first calibration value:

[0019] When the speed of the plunger arriving at the wellhead is less than or equal to the first calibration value, the plunger is judged to be operating normally, and the speed of the plunger arriving at the wellhead is used to optimize the plunger safety operation system in the next cycle; and the relationship between the speed of the plunger arriving at the wellhead and the third calibration value is judged: if the speed of the plunger arriving at the wellhead is greater than the third calibration value, the plunger maintains the existing system operation; otherwise, the well shut-in time is extended;

[0020] When the speed at which the plunger reaches the wellhead is greater than the first calibration value, the magnitude relationship between the speed at which the plunger reaches the wellhead and the second calibration value is determined:

[0021] When the plunger reaches the wellhead at a speed less than or equal to the second calibration value, an "overspeed" alarm is issued, and the plunger is operated after reducing the well shut-in time;

[0022] When the plunger reaches the wellhead at a speed greater than the second calibration value, a "dangerous speed" alarm is triggered, the solenoid valve is closed, and operation can only continue after a manual on-site inspection to eliminate the danger.

[0023] Furthermore, while the "excessive speed" alarm is being issued, the number of "excessive speed" alarms is recorded. When the number of consecutive "excessive speed" alarms reaches the set number, a shutdown command is executed and the machine is operated after manual verification of safety.

[0024] Furthermore, the first calibration value is the upper limit of the reasonable value of the plunger reaching the wellhead speed, and the third calibration value is the lower limit of the reasonable value of the plunger reaching the wellhead speed.

[0025] A safe operation optimization device based on the speed of the plunger reaching the wellhead, comprising:

[0026] Plunger arrival time acquisition module: used to obtain the moment when the plunger arrival sensor detects the arrival of the plunger;

[0027] Plunger arrival time difference determination module: used to determine the time difference between the plunger passing through two plungers and reaching the sensor;

[0028] A plunger arrival speed determination module: used to determine the plunger arrival speed at the wellhead according to the plunger arrival time difference;

[0029] The first determination module is used to determine the relationship between the speed of the plunger arriving at the wellhead and the first calibration value: when the speed of the plunger arriving at the wellhead is less than the first calibration value, the plunger is determined to be operating normally and the third determination module is started; otherwise, the second determination module is started; the second determination module is used to determine the relationship between the speed of the plunger arriving at the wellhead and the second calibration value: when the speed of the plunger arriving at the wellhead is greater than the first calibration value and less than the second calibration value, an "excessive speed" alarm signal is output; when the speed of the plunger arriving at the wellhead is greater than the second calibration value, the valve is closed;

[0030] The third judgment module is used to judge the relationship between the speed at which the plunger reaches the wellhead and the third calibration value: if the speed at which the plunger reaches the wellhead is greater than the third calibration value, the plunger maintains the existing system operation; if the speed at which the plunger reaches the wellhead is less than the third calibration value, the well shut-in time is extended.

[0031] Furthermore, the plunger arrival time difference determination module includes:

[0032] The first time unit is used to determine the moment when the plunger reaches the second plunger arrival sensor as the first moment; the second time unit is used to determine the moment when the plunger reaches the first plunger arrival sensor as the second moment; the plunger arrival time difference determination unit is used to determine the plunger arrival time difference according to the difference between the first moment and the second moment.

[0033] Furthermore, it also includes a first alarm module: for the plunger "excessive speed" alarm; a first execution module: for determining that the number of consecutive "excessive speed" alarms reaches a set number, executing a shutdown command, and operating after manual verification of safety; a second alarm module: for the plunger "dangerous speed" alarm; a second execution module: for closing the valve when it is determined that the plunger running speed has reached the "dangerous speed", and opening the valve after manual on-site inspection to eliminate the danger.

[0034] Compared with the prior art, the present invention has at least the following beneficial technical effects:

[0035] The present invention provides a method for optimizing a safe operation system based on the speed at which a plunger reaches a wellhead: the present invention starts with changing a method for detecting the plunger's running speed, and calculates the time difference by acquiring the moment at which two plunger arrival sensors detect the plunger's arrival; at the same time, the vertical distance between the two plunger arrival sensors is measured, and the speed at which the plunger reaches the wellhead detected by the double arrival sensors is calculated, and a new concept of "double arrival sensors detecting the speed at which the plunger reaches the wellhead" is creatively proposed. Because this speed is independent of the starting position of the plunger, real-time and accurate detection of the speed at which the plunger reaches the wellhead is achieved, thereby avoiding the problem of serious distortion of the plunger's average speed, solving the problem of misjudgment of shutdown due to dangerous arrival, and ensuring safe production of gas wells.

[0036] In addition, the accurately detected plunger arrival speed at the wellhead is used to reasonably evaluate the safety risks of the wellhead blowout preventer, better guide the optimization of the plunger safety operation system, avoid the occurrence of wellhead blowout preventer failure caused by the plunger reaching the wellhead too fast, improve the plunger wellhead safety, ensure the safe production of the gas field, and improve the plunger operation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A flow chart of a safe operation optimization method based on the speed of the plunger reaching the wellhead;

[0038] Figure 2aThis is a schematic diagram of the first installation method of two plunger arrival sensors;

[0039] Figure 2b This is a schematic diagram of the second installation method of the two plunger arrival sensors;

[0040] Figure 2c This is a schematic diagram of the third installation method of two plunger arrival sensors;

[0041] Figure 3 Schematic diagram of the human-machine interface for setting the "double arrival distance" parameter;

[0042] Figure 4 Schematic diagram of the device structure optimized for safe operation.

[0043] In the attached figure: 1—blowout preventer; 2—solenoid valve; 3—first plunger arrival sensor; 4—digital pressure gauge; 5—plunger controller; 6—second plunger arrival sensor; 7—plunger; 8—downhole limiter; 9—data forwarding system. DETAILED DESCRIPTION

[0044] In order to make the purpose and technical solution of the present invention clearer and easier to understand, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0045] Example 1

[0046] Figure 1 The present invention provides a method for optimizing a safe operation system based on the speed at which the plunger reaches the wellhead, which specifically includes the following steps:

[0047] S1: Install a plunger arrival wellhead speed detection device to obtain the plunger arrival time detected by the plunger arrival sensor.

[0048] The plunger arrival wellhead speed detection device mainly includes: a first plunger arrival sensor 3, a second plunger arrival sensor 6 and a plunger controller 5. The plunger controller 5 is installed outside the 5# gate valve or 6# gate valve of the gas tree, and the two plunger arrival sensors are fixed at two different positions of the gas tree to monitor the plunger arrival respectively. According to the different wellhead structures of the plunger gas well, the installation methods of the two plunger arrival sensors are also different, including but not limited to the following three installation methods:

[0049] (1) The first plunger arrival sensor is installed on the lubricator 1; the second plunger arrival sensor is installed in the large cross-piece, such as Figure 2a shown.

[0050] (2) The first plunger arrival sensor is installed on the lubricator 1; the second plunger arrival sensor is installed in the small four-way, such as Figure 2b shown.

[0051] (3) The first plunger arrival sensor is installed in the small four-way; the second plunger arrival sensor is installed in the large four-way, such as Figure 2c shown.

[0052] In this embodiment, the plunger controller 5 is installed outside the pipeline where the 5# gate valve of the gas tree is located, the first plunger arrival sensor 3 is fixed on the blowout preventer 1, and the second plunger arrival sensor 6 is fixed at the large four-way position.

[0053] Add "Dual Arrival Distance" parameter setting in the original plunger controller menu. Figure 3 ), measure the vertical distance h between the two plunger arrival sensors, and set the "double arrival spacing" to h. The plunger controller 5 communicates bidirectionally with the first plunger arrival sensor 3, the second plunger arrival sensor 6, the digital pressure gauge 4 and the solenoid valve 2. The data forwarding system 9 is connected to the plunger controller 5 through a communication cable to transfer data instructions for remote monitoring. The digital pressure gauge 4 is used to measure and record the wellhead pressure. A downhole limiter 8 is installed under the plunger 7, and the downhole limiter 8 is used to prevent the plunger 7 from falling to the bottom of the well.

[0054] After the opening command is issued by the plunger controller 5, the solenoid valve 2 is started to perform the well opening operation. The plunger moves upward from the bottom of the well to the wellhead, passing through the second plunger arrival sensor 6 and the first plunger arrival sensor 1 in turn, and the plunger arrival times are correspondingly determined as t1 and t2, respectively.

[0055] S2: Determine the speed at which the plunger reaches the wellhead based on the plunger arrival time difference.

[0056] ① When plunger 7 reaches the first plunger arrival sensor and the second plunger arrival sensor

[0057] According to the detection of the two plunger arrival sensors, the times when the plunger passes through the two plunger arrival sensors in sequence are determined to be t1 and t2, and the time signals are communicated to the plunger controller 5 to calculate the time difference t between the two plunger arrival sensors, t=t2-t1.

[0058] According to the time difference t, the speed V of the plunger reaching the wellhead is calculated according to formula (1): 柱塞到达井口速度 :

[0059]

[0060] Wherein, h is the vertical distance between the two plungers and the sensor, t1 is the time when the plunger reaches the second plunger and the sensor, and t2 is the time when the plunger reaches the first plunger and the sensor.

[0061] ② When plunger 7 reaches the second plunger arrival sensor but does not reach the first plunger arrival sensor, the average plunger running speed is calculated based on the actual well depth divided by the plunger rising time, and the obtained average running speed is regarded as the plunger arrival speed at the wellhead;

[0062] ③ When neither the first plunger arrival sensor nor the second plunger arrival sensor detects the plunger 7, it is determined as the plunger has not arrived, and the shut-in time is extended to ensure that the plunger can reach the wellhead in the next cycle;

[0063] S3: Determine the plunger well operation plan based on the plunger reaching the wellhead speed.

[0064] Determine the relationship between the speed at which the plunger reaches the wellhead and the first calibration value:

[0065] When the speed at which the plunger reaches the wellhead is less than or equal to the first calibration value, it is determined that the plunger 7 is operating normally, and the speed at which the plunger reaches the wellhead is used to optimize the plunger safety operation system in the next cycle; and the relationship between the speed at which the plunger reaches the wellhead and the third calibration value is determined: if the speed at which the plunger reaches the wellhead is greater than the third calibration value, the plunger maintains the existing system operation; if the speed at which the plunger reaches the wellhead is less than the third calibration value, the well shut-in time is extended;

[0066] When the speed at which the plunger reaches the wellhead is greater than the first calibration value, the magnitude relationship between the speed at which the plunger reaches the wellhead and the second calibration value is determined:

[0067] When the plunger reaches the wellhead at a speed less than or equal to the second calibration value, the plunger controller 5 outputs an "excessive speed" alarm and records the number of "excessive speed" alarms, reduces the well shut-in time and runs the plunger. When the number of consecutive "excessive speed" alarms reaches the set number, a shutdown command is executed, and manual verification of safety is required before operation;

[0068] When the plunger reaches the wellhead at a speed greater than the second calibration value, the plunger controller 5 outputs a "dangerous speed" alarm, and the plunger controller issues a command to close the valve. Manual on-site inspection is required to eliminate the danger before continuing to operate.

[0069] Among them, according to the actual production situation of the gas field, the first calibration value is set to 300m / min, the second calibration value is set to 600m / min, and the third calibration value is set to 200m / min. When the speed at which the plunger reaches the wellhead is less than the first calibration value, it is determined that the plunger is operating normally, and the speed at which the plunger reaches the wellhead is used to optimize the plunger operation system for the next cycle, wherein when the speed at which the plunger reaches the wellhead is within a reasonable speed range (200-300m / min), the plunger maintains the existing system operation, and when the speed at which the plunger reaches the wellhead is less than 200m / min, the shut-in time is extended to ensure that the speed at which the plunger reaches the wellhead in the next cycle is within a reasonable speed range; when the speed at which the plunger reaches the wellhead is greater than the first calibration value and less than the second calibration value, the plunger controller 5 outputs an "excessive speed" alarm, reduces the shut-in time and then operates the plunger, and when the number of consecutive "excessive speed" alarms reaches the set number, a shutdown command is executed, and manual verification of safety is required before operation; when the speed at which the plunger reaches the wellhead is greater than the second calibration value, the plunger controller 5 outputs a "dangerous speed" alarm, and the plunger controller issues a command to close the solenoid valve 2, and manual on-site inspection is required to eliminate the danger before continuing to operate.

[0070] In this embodiment, the vertical distance h=2.7m between the two plungers of a plunger well A in an oil field is first measured, and then the plunger arrival speed at the wellhead is tested and counted for 60 operation cycles, of which 54 cycles are normal operation data, and 6 cycles are artificial tests of dangerous arrival conditions, that is, the plunger 7 starts to manually execute the well opening command before it falls to the bottom of the well, so that the plunger 7 quickly reaches the wellhead. At this time, the average speed calculated by the conventional method is greater than the dangerous speed value, and the gas well executes the emergency well closing command, but the plunger arrival speed at the wellhead measured by the plunger arrival speed detection device of the present invention is less than the dangerous speed, and the dangerous well closing command is not executed, which effectively solves the problem of misjudgment and well closing of the plunger gas well "dangerous arrival" caused by serious distortion of the average speed. The safe operation system optimization method in this embodiment effectively controls the plunger arrival speed at the wellhead within a safe range, and there is no situation where the "dangerous speed" alarm causes emergency well closing.

[0071] Table 1 Data of the plunger reaching the wellhead speed in Well A

[0072]

[0073]

[0074]

[0075] Example 2

[0076] The safe operation optimization device provided in the embodiment of the present invention can execute the safe operation optimization method provided in the embodiment of the present invention, and has the functional modules and beneficial effects corresponding to the execution method. Figure 4Schematic diagram of the structure of a device for detecting the speed of a plunger reaching a wellhead provided in Example 2 of the present invention. Figure 4 As shown, the device comprises:

[0077] Plunger arrival time acquisition module 10: used to obtain the moment when the plunger arrival sensor detects the arrival of the plunger;

[0078] The plunger arrival time difference determination module 20 is used to determine the time difference between the plunger passing through two plungers and reaching the sensor;

[0079] The plunger arrival speed determination module 30 is used to determine the plunger arrival speed at the wellhead according to the plunger arrival time difference;

[0080] The first determination module 40 is used to determine the relationship between the speed at which the plunger reaches the wellhead and the first calibration value: when the speed at which the plunger reaches the wellhead is less than the first calibration value, the plunger is determined to be operating normally and the third determination module 60 is started; otherwise, the second determination module 50 is started; the second determination module 50 is used to determine the relationship between the speed at which the plunger reaches the wellhead and the second calibration value: when the speed at which the plunger reaches the wellhead is greater than the first calibration value and less than the second calibration value, the plunger controller outputs an "excessive speed" alarm and records the number of "excessive speed" alarms. When the number of consecutive "excessive speed" alarms reaches the set number, a shutdown command is executed; when the speed at which the plunger reaches the wellhead is greater than the second calibration value, the plunger controller issues a command to close the valve.

[0081] The third determination module 60 is used to determine the relationship between the speed at which the plunger reaches the wellhead and the third calibration value: if the speed at which the plunger reaches the wellhead is greater than the third calibration value, the plunger maintains the existing system operation; if the speed at which the plunger reaches the wellhead is less than the third calibration value, the well shut-in time is extended.

[0082] Optionally, the plunger arrival time difference determination module includes:

[0083] The first time unit is used to determine the moment when the plunger reaches the second plunger arrival sensor as the first moment; the second time unit is used to determine the moment when the plunger reaches the first plunger arrival sensor as the second moment; the plunger arrival time difference determination unit is used to determine the plunger arrival time difference according to the difference between the first moment and the second moment.

[0084] Optionally, the device further comprises:

[0085] The first alarm module: used for the plunger "excessive speed" alarm; the first execution module: used to determine that the number of consecutive "excessive speed" alarms has reached the set number, and execute the shutdown command, which requires manual verification of safety before operation; the second alarm module: used for the plunger "dangerous speed" alarm; the second execution module: used to determine that when the plunger running speed reaches the "dangerous speed", the plunger controller issues a command to close the valve, and manual on-site inspection is required to eliminate the danger before continuing to operate.

[0086] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A safe operation optimization method based on the speed of the plunger reaching the wellhead, characterized in that: The following steps are involved: S1. Install a first plunger arrival sensor and a second plunger arrival sensor on the gas tree, and measure the vertical distance between the first plunger arrival sensor and the second plunger arrival sensor; S2, judging whether the first plunger arrival sensor and the second plunger arrival sensor detect the arrival of the plunger, and obtaining the time of the plunger arrival detected by the first plunger arrival sensor and the second plunger arrival sensor, and calculating the plunger arrival speed at the wellhead according to whether the two plunger arrival sensors detect the arrival of the plunger and the time of the plunger arrival detected by the plunger arrival sensors; S3. Determine the plunger well operation plan based on the plunger's arrival speed at the wellhead.

2. A safe operation optimization method based on the speed of the plunger reaching the wellhead according to claim 1, characterized in that: In step S2, when the first plunger arrival sensor and the second plunger arrival sensor detect that the plunger 7 has arrived: The speed V of the plunger reaching the wellhead is calculated according to the following formula 柱塞到达井口速度 : Wherein, h is the vertical distance between the first plunger arrival sensor and the second plunger arrival sensor, t1 is the moment when the plunger arrives at the second plunger arrival sensor, and t2 is the moment when the plunger arrives at the first plunger arrival sensor.

3. A safe operation optimization method based on the speed of the plunger reaching the wellhead according to claim 1, characterized in that: When the second plunger arrival sensor detects the arrival of the plunger, but the first plunger arrival sensor does not detect the arrival of the plunger, the average plunger running speed is calculated based on the actual well depth divided by the plunger rising time, and the obtained average running speed is regarded as the plunger arrival speed at the wellhead.

4. A safe operation optimization method based on the speed of the plunger reaching the wellhead according to claim 1, characterized in that: In step S2, when the first plunger arrival sensor and the second plunger arrival sensor both fail to detect the plunger, the plunger is judged as not arriving, and the shut-in time is extended additionally to ensure that the plunger can reach the wellhead in the next cycle.

5. A safe operation optimization method based on the speed of the plunger reaching the wellhead according to claim 1, characterized in that: Determining the plunger well operation plan based on the plunger arrival speed at the wellhead includes the following steps: Determine the relationship between the speed at which the plunger reaches the wellhead and the first calibration value: When the speed of the plunger arriving at the wellhead is less than or equal to the first calibration value, the plunger is judged to be operating normally, and the speed of the plunger arriving at the wellhead is used to optimize the plunger safety operation system in the next cycle; and the relationship between the speed of the plunger arriving at the wellhead and the third calibration value is judged: if the speed of the plunger arriving at the wellhead is greater than the third calibration value, the plunger maintains the existing system operation; otherwise, the well shut-in time is extended; When the speed at which the plunger reaches the wellhead is greater than the first calibration value, the magnitude relationship between the speed at which the plunger reaches the wellhead and the second calibration value is determined: When the plunger reaches the wellhead at a speed less than or equal to the second calibration value, an "overspeed" alarm is issued, and the plunger is operated after reducing the well shut-in time; When the plunger reaches the wellhead at a speed greater than the second calibration value, a "dangerous speed" alarm is triggered, the solenoid valve is closed, and operation can only continue after manual on-site inspection to eliminate the danger.

6. A safe operation optimization method based on the speed of the plunger reaching the wellhead according to claim 5, characterized in that: While issuing an "overspeed" alarm, the number of "overspeed" alarms is recorded. When the number of consecutive "overspeed" alarms reaches the set number, the shutdown command is executed and the machine is operated after manual verification of safety.

7. A safe operation optimization method based on the speed of the plunger reaching the wellhead according to claim 5, characterized in that: The first calibration value is the upper limit of the reasonable value of the plunger reaching the wellhead speed, and the third calibration value is the lower limit of the reasonable value of the plunger reaching the wellhead speed.

8. A safe operation optimization device based on the speed of the plunger reaching the wellhead, characterized in that: include: A plunger arrival time acquisition module (10): used to acquire the time when the plunger arrival sensor detects the arrival of the plunger; A plunger arrival time difference determination module (20): used to determine the time difference between the plunger passing through two plungers and arriving at the sensor; A plunger arrival speed determination module (30) is used to determine the plunger arrival speed at the wellhead according to the plunger arrival time difference; A first determination module (40) is used to determine the magnitude relationship between the speed at which the plunger reaches the wellhead and the first calibration value: when the speed at which the plunger reaches the wellhead is less than the first calibration value, it is determined that the plunger is operating normally, and the third determination module (60) is started; otherwise, the second determination module (50) is started; A second determination module (50) is used to determine the magnitude relationship between the speed at which the plunger reaches the wellhead and a second calibration value: when the speed at which the plunger reaches the wellhead is greater than the first calibration value and less than the second calibration value, an "excessive speed" alarm signal is output; when the speed at which the plunger reaches the wellhead is greater than the second calibration value, the valve is closed; A third determination module (60): used to determine the magnitude relationship between the speed at which the plunger reaches the wellhead and a third calibration value: if the speed at which the plunger reaches the wellhead is greater than the third calibration value, the plunger maintains the existing system operation; If the plunger reaches the wellhead at a speed less than the third calibration value, the shut-in time is extended.

9. A safe operation optimization device based on the speed of the plunger reaching the wellhead according to claim 8, characterized in that: The plunger arrival time difference determination module (20) comprises: The first time unit is used to determine the moment when the plunger reaches the second plunger arrival sensor as the first moment; the second time unit is used to determine the moment when the plunger reaches the first plunger arrival sensor as the second moment; the plunger arrival time difference determination unit is used to determine the plunger arrival time difference according to the difference between the first moment and the second moment.

10. The safe operation optimization device based on the speed of the plunger reaching the wellhead according to claim 8, characterized in that: It also includes a first alarm module: used for the plunger "excessive speed" alarm; a first execution module: used to determine that the number of consecutive "excessive speed" alarms reaches the set number, execute the shutdown command, and run after manual verification of safety; a second alarm module: used for the plunger "dangerous speed" alarm; a second execution module: used to close the valve when it is determined that the plunger running speed has reached the "dangerous speed", and open the valve after manual on-site inspection to eliminate the danger.

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