Gas leakage collecting device for sucker rod

Abstract

The utility model relates to a gas leakage collecting device for a sucker rod, which comprises a two-section device shell consisting of a left shell and a right shell, the opposite ends of the left shell and the right shell are communicated with each other, and the opposite sides of the left shell and the right shell are respectively provided with a gas outlet joint and a background gas inlet. An open hole longitudinally penetrating through the outer side of the left side shell or the right side shell is formed in the left side shell or the right side shell, and a sucker rod movably penetrates through the open hole. According to the gas leakage collecting device for the sucker rod, the capacity of the two-section type device shell is fixed, the sealed collecting capacity of leaked gas is achieved, and when the gas leakage collecting device for the sucker rod is used for field testing, collection of target testing gas and background gas can be guaranteed; and after collection, the two parts of gas can be fully mixed and input into detection equipment for detection, so that the problems of low precision and high risk of previous ground detection are effectively solved.

Description

Technical Field

[0001] This utility model relates to the field of oilfield pumping unit gas leakage detection technology, specifically a gas leakage collection device for sucker rods. Background Technology

[0002] The wellhead seal of an oilfield pumping unit mainly consists of a cross-shaped housing, a bottom base, a lower connector, a sealing gate valve, a sealing pin, a sealing cap, and rubber packing. During crude oil production, corrosion and wear of the polished rod can cause the packing seal to wear out, leading to leakage of oil, gas, and water. The main components of the leaked gas are natural gas, nitrogen, carbon dioxide, and hydrogen sulfide, which can pose a potential safety hazard. Methods for detecting wellhead gas leaks mainly include: Water detection method: This is a simple and primitive method suitable for detecting low-pressure gas systems. The workpiece is filled with gas at a pressure greater than atmospheric pressure and then placed in water. The location of the bubbles indicates the leak location. This method is inexpensive but has limited sensitivity and is not suitable for high-pressure or vacuum systems. Pressure decay method: The workpiece is filled with gas at a certain pressure and sealed for a period of time. The pressure gauge readings are then observed to determine if there is a leak. If there is a leak, the gas pressure will gradually decrease. This method is suitable for detecting larger leaks, but it cannot pinpoint the exact location of the leak and has low sensitivity to minor leaks. Pressure monitoring: By monitoring pressure changes at the wellhead tree, statistical methods are used to analyze the data and determine if a leak exists. When a leak occurs in the pipeline, the pressure at the leak point drops sharply, generating an expansion wave that propagates along the pipeline, causing pressure changes at various points along the line. Drone inspection: Combining high-definition cameras and infrared thermal imagers, drones can inspect gas pipelines from the air, promptly detecting and locating leaks. This method is efficient and has a wide coverage area, but it is limited by weather and flight conditions. Handheld instrument detection: Using handheld gas concentration detectors (based on infrared or thermal conductivity principles), personnel manually go to the wellhead tree to detect the gas concentration. If the concentration exceeds the normal environmental concentration, the specific concentration value can be displayed, and an audible and visual alarm can be generated.

[0003] The following problems exist in the current technology for detecting gas leaks in oilfield pumping units: 1. Generally, only the presence of gas leaks can be detected, but the amount of leakage cannot be determined; in short, it can only be qualitatively detected, not quantitatively measured. 2. Because the sucker rod interface of the wellhead pumping unit is a dynamic sealing structure, it is always in a state of relative motion, and its irregular shape makes it inconvenient for sealing and testing. 3. The internal pressure of the sucker rod packing is between 0-1 MPa. Due to the short-term expansion of the leaking gas and the fluctuations in pressure and leakage amount during the sucker rod's reciprocating cycle, the measurement results generally have large deviations. When general gas detection instruments are used for testing, the concentration and flow rate data are fluctuating, leading to inaccurate detection. 4. The commonly used method for measuring leakage is the bagging method. The disadvantages of the bagging method are: firstly, the bag is wrapped, but the volume of the bag cannot be kept constant each time, which affects the measurement results; secondly, the gas cannot be fully mixed, and the gas intake at the far and near ends cannot be guaranteed to be fully mixed, and the irregular volume and variable capacity have a significant impact on the measurement results. Utility Model Content

[0004] (a) Technical problems to be solved

[0005] This invention provides a gas leakage collection device for sucker rods, which solves the problems mentioned in the background art.

[0006] (II) Technical Solution

[0007] To achieve the above objectives, this utility model provides the following technical solution: a gas leakage collection device for sucker rods, comprising a two-section device housing consisting of a left outer shell and a right outer shell, wherein the opposite ends of the left and right outer shells are interconnected, and the opposite sides of the left and right outer shells are respectively provided with an outlet connector and a background gas inlet, and a longitudinal opening is formed on the left or right outer shell, which is penetrated by the sucker rod.

[0008] Preferably, the background gas inlet is connected to an external hose, and the background gas is introduced into the two-section device housing through the external hose.

[0009] In a further preferred embodiment, there is a gap between the opening and the sucker rod, through which leaked gas from the sucker rod packing is introduced into the two-section device housing.

[0010] In a further preferred embodiment, the inner cavity of the two-section device housing forms a gas mixing zone where the leaked gas and the background gas are mixed.

[0011] In a further preferred embodiment, a gas detection device is connected to the gas outlet connector, and the gas outlet connector outputs a mixed gas to the gas detection device.

[0012] In a further preferred embodiment, a connecting seam is formed at the junction of the left and right outer shells, the connecting seam being sealed with aluminum foil tape, and the two-section device housing is made of polyethylene terephthalate plastic shell.

[0013] (III) Beneficial Effects

[0014] Compared with the prior art, the present invention provides a gas leakage collection device for sucker rods, which has the following advantages:

[0015] 1. The two-section housing of the gas leak collection device for sucker rod has a fixed capacity and has the ability to seal and collect leaked gas. When the gas leak collection device for sucker rod is used for field testing, it can ensure the collection of target gas and background gas, and after collection, the two gases can be fully mixed and input into the detection equipment for detection.

[0016] 2. This gas leak collection device for sucker rods can be flexibly installed at the interface between the sucker rod and the lower packing, thereby collecting associated oil and gas leaking from the packing. It can be used in the field of leak detection at the working site of oil pumping units, effectively solving the problems of low accuracy and high danger of previous ground detection.

[0017] 3. The main body of the gas leakage collection device for sucker rods is made of polyethylene terephthalate plastic shell, which makes the design of the device take into account the use location at the well site and the existence of energized gas leakage, making the use of the device relatively safe. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of a gas leakage collection device for sucker rods according to the implementation plan;

[0019] Figure 2 for Figure 1 A schematic diagram of the cut-open structure of a gas leak collection device for sucker rods.

[0020] Figure 3 This is a simulation diagram of the gas flow trajectory in a gas leak collection device for sucker rods, according to the implementation plan.

[0021] In the diagram: 1. Gas outlet connector; 2. Two-section device housing; 3. Opening; 4. Connecting seam; 5. Background gas inlet; 6. Leaking gas; 7. Background gas; 8. Gas mixing zone; 9. Mixed gas; 10. Sucker rod. Detailed Implementation

[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0023] Please see Figure 1 and Figure 2 A gas leak collection device for sucker rods includes a two-section housing 2 consisting of a left outer shell and a right outer shell. The two-section housing 2 can be made of polyethylene terephthalate (PET) plastic, making it heat-resistant, corrosion-resistant, and possessing a certain pressure resistance. The opposing ends of the left and right outer shells are interconnected, and a connecting seam 4 is formed at the joint between the left and right outer shells. Aluminum foil tape can be used to tightly bind the connecting seam 4, ensuring a seal at the joint. An outlet connector 1 and a background gas inlet 5 are respectively formed on the opposite sides of the left and right outer shells. A flexible hose is connected to the background gas inlet 5, through which background gas 7 is introduced into the two-section housing 2. A gas detection device is connected to the outlet connector 1, and a mixed gas 9 is output to the gas detection device from the outlet connector 1. An opening 3 is formed on the left or right outer casing, extending longitudinally through the left or right outer casing. The opening 3 is movably passed through by the sucker rod 10, and there is a gap between the inner wall of the opening 3 and the outer wall of the sucker rod 10. This allows the leaked gas 6 leaking from the packing of the sucker rod to be introduced into the two-section device housing 2 through the gap between the opening 3 and the sucker rod 10. The inner cavity of the two-section device housing 2 forms a gas mixing zone 8 in which the leaked gas 6 and the background gas 7 are mixed.

[0024] In this embodiment, the leaking gas 6 leaks from the sucker rod seal. Its initial pressure is generally less than 1 MPa, but can reach 100 kPa after leakage. Therefore, the container must have a fixed volume to accommodate the leaked gas, and the volume of the two-section device shell 2 is set to have a capacity greater than 500 ml. The leaked gas is a flammable and explosive gas, with methane concentrations ranging from 0-100% and carbon dioxide concentrations ranging from 0-100%. Considering the accuracy requirements of subsequent testing instruments, it is necessary to achieve thorough mixing of the leaked gas and the mixed gas inside the collection device to avoid uneven mixing that could lead to significant deviations in test results. If the collection device is undersized, the mixed gas concentration will be uneven, resulting in jumps in concentration values ​​and data fluctuations in subsequent test results. If the collection device is too large, it will be inconvenient to carry during on-site testing. Therefore, the height and diameter of the collector need to be within a reasonable range.

[0025] Because the sucker rod moves up and down in actual operation, with a typical stroke rate of 4 to 12 times per minute, the connection between the entire device and the sucker rod is designed as a movable connection to avoid interference.

[0026] The working principle of the equipment is as follows:

[0027] The test gas to be tested is the target gas for leakage from the self-sucking rod, which is generally a complex gas. Assuming the volume is V1 and the concentration of gas 1 is... The gas volume percentages of each component are as follows:

[0028] Gas 11 volume percentage ,

[0029] 12% by volume of gas ,

[0030] 13% by volume of gas ,

[0031] ...

[0032] Gas 1N volume percentage ,

[0033] The background gas is also a complex gas, and the concentration of gas 2 is... The gas volume percentages of each component are as follows:

[0034] Background gas 21 volume percentage ,

[0035] Background gas 22 volume percentage ,

[0036] Background gas 23% by volume ,

[0037] ...

[0038] Background gas 2N volume percentage ,

[0039] The discharged mixture can also be a complex gas, with a gas concentration of 5. The gas volume percentages of each component are as follows:

[0040] 51% by volume of exhaust gas ,

[0041] 52% by volume of exhaust gas ,

[0042] 53% by volume of exhaust gas ,

[0043] ...

[0044] Exhaust gas 5N volume percentage ,

[0045] The purpose of the device is to thoroughly mix the leaked gas and the background gas. During the test, the gas is kept flowing at a certain velocity within the device to ensure uniform mixing. A simulation diagram of the flow trajectory is shown below. Figure 3 As shown.

[0046] This patented structure and collection device can be used for leak detection at oil pumping unit work sites, effectively solving the problems of low accuracy and high risk associated with previous surface detection methods. With the gradual promotion and implementation of CCUS projects, there are often multiple leak points detected on-site, including valves, sampling ports, flanges, etc., and the number of leak points gradually increases with the extension of working time. Since wellhead gas contains various gases such as carbon dioxide, methane, hydrogen sulfide, and nitrogen, detection and control are necessary to prevent related dangerous accidents.

[0047] Of all the solutions mentioned above, those involving the connection between two components can be selected according to the actual situation, such as bonding, welding, bolt and nut connection, bolt or screw connection, or other known connection methods, which will not be elaborated here. For all the fixed connections mentioned above, bonding is preferred. Although embodiments of this utility model have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this utility model. The scope of this utility model is defined by the appended claims and their equivalents.

Claims

1. A device for collecting gas leaks from sucker rods, characterized in that, The device includes a two-section housing (2) consisting of a left outer shell and a right outer shell. The opposite ends of the left and right outer shells are connected to each other. The opposite sides of the left and right outer shells are respectively formed with an air outlet connector (1) and a background gas inlet (5). A longitudinal opening (3) is formed on the left or right outer shell, and the opening (3) is movably passed through by the sucker rod (10).

2. The gas leakage collection device for sucker rod according to claim 1, characterized in that: The background gas inlet (5) is connected to an external hose, and the background gas (7) is introduced into the two-section device housing (2) through the external hose.

3. The gas leakage collection device for sucker rod according to claim 2, characterized in that: There is a gap between the opening (3) and the sucker rod (10), and the leaked gas (6) leaking from the packing of the sucker rod enters the two-section device housing (2) through the gap between the opening (3) and the sucker rod (10).

4. The gas leakage collection device for sucker rod according to claim 3, characterized in that: The inner cavity of the two-section device housing (2) forms a gas mixing zone (8) where the leaked gas (6) and the background gas (7) are mixed.

5. A gas leakage collection device for sucker rods according to claim 4, characterized in that: The gas outlet connector (1) is connected to an external gas detection device, and the gas outlet connector (1) outputs mixed gas (9) to the gas detection device.

6. A gas leakage collection device for sucker rods according to any one of claims 1-5, characterized in that: The connection between the left and right outer shells forms a seam (4), which is sealed with aluminum foil tape.

7. A gas leakage collection device for sucker rods according to claim 6, characterized in that: The outer shell (2) of the two-section device is made of polyethylene terephthalate plastic shell.

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