Gas well closed swabbing safety guard device

Abstract

The utility model discloses a gas well closed swabbing safety guard device which comprises an anti-channeling damping module, a control device and an overload pressure relief module. The anti-upward-moving damping module comprises a fishing head, a damping clamping jaw and a center shaft. The control device comprises a control chip, a voltage stabilizing / reducing module and a battery, the overload pressure relief module is connected in series after the control device is controlled, and the first telescopic motor and the second telescopic motor are controlled to act through the control chip; the overload pressure relief module comprises a second telescopic motor, a valve and two rubber cylinders, the two rubber cylinders are assembled in series through a steel center shaft, the metal shell is connected with the steel center shaft and the second telescopic motor, the valve is located behind the second telescopic motor, and the valve is located behind the second telescopic motor. And the second telescopic motor controls the valve to control the opening and closing of the central channel of the steel central shaft, so that the phenomena of upward movement and blowout of the swabbing device caused by sudden increase of well pressure in the swabbing process of the swabbing equipment are effectively solved.

Description

Technical Field

[0001] The utility model belongs to the field of oil and natural gas exploitation, relates to oil and natural gas exploitation equipment technology and circuit control technology, and is specifically a gas well closed pumping safety guard device. Background Art

[0002] Stabilizing and increasing natural gas production is the primary task of natural gas extraction. Typical natural gas extraction processes include plunger drainage, foam drainage, and closed pumping. Production practices in low-yield wells both domestically and internationally demonstrate that closed pumping is an effective method for recovering gas from low-yield wells. Traditional closed pumping is evolving into a key technology for dewatering and recovering natural gas wells, crucial for restoring production in low-yield, inefficient, and severely liquid-loaded wells. Existing closed pumping techniques, adapted from traditional oil recovery techniques, are primarily designed for use in oil-water mixed fluid lubrication environments. They are less adaptable to the fluid drainage environments of gas wells with high salinity, high water content, and high formation pressure. Furthermore, the pump and tool string have poor anti-swelling capabilities, making them inadequate for safe gas well operations and refined drainage and gas recovery. To address these challenges, through research into closed pumping technology, a series of safe and environmentally friendly closed pumping tools for oil and gas wells have been developed.

[0003] Prior art publication number CN218324832U discloses an electronic gas lift plunger with temperature and pressure data collection and positioning capabilities. This addresses the problem of traditional plungers being unable to collect downhole temperature, pressure, acceleration, fluid accumulation height, and other data, and unable to monitor and calculate the plunger's position and depth in the wellbore. Prior art publication number CN114439435A discloses a downhole crawling powered gas lift plunger. Its four-crank slider buffer mechanism cushions the impact force on the drive motor when it stops sliding upward, reducing the chance of damage from impact.

[0004] The research on downhole tool strings of existing closed pumping and drainage processes aims to improve the pumping efficiency, sewage discharge effect and closed sealing capability of the process. Utility Model Content

[0005] In response to the problems existing in the above-mentioned prior art, the purpose of the present utility model is to provide a gas well closed pumping safety guard device, which automatically controls the pump to prevent it from rising and overload pressure relief, improves the performance of the tool string, and achieves more efficient liquid extraction and sewage discharge.

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

[0007] A gas well closed pumping safety guard device includes an anti-upward damping module, a control device, and an overload pressure relief module;

[0008] The anti-channeling damping module includes a fishing head, a damping claw and a center shaft;

[0009] The fishing head for placing and lifting the scavenging tool is fixedly connected to the front end of the central shaft. The central shaft is a cylindrical structure. The damping claw base is sleeved on the central shaft. The damping claw base and the central shaft are clearance-matched and can slide axially along the central shaft. A sliding groove is provided on the central shaft along the axial direction. The end of the pin shaft radially penetrating the side wall of the damping claw base is placed in the sliding groove. The cylindrical surface of the central shaft is milled with three flat surfaces along the axial direction at equal angles for accommodating the damping claws.

[0010] The three damping claws are arranged at three planes milled on the central axis, one end of which is connected to one end of the damping claw base through respective shafts and can swing along the axis. A clearance-matched reset spring is sleeved on the central axis, and the reset spring is located between the scoop head and the damping claw base; the tail cylinder is sleeved on the central axis and located behind the damping claw, and the front end of the tail cylinder is milled into an inclined surface to form a damping expansion wedge. When the tail cylinder slides along the central axis toward the damping claw, it pushes the damping claw to open; a weighting rod connector for installing a weighting rod is connected to the rear of the tail cylinder, and a first telescopic motor is installed in the central axis. The central axis is pulled back by the first telescopic motor, and the damping expansion wedge opens the damping claw;

[0011] The control device includes a control chip, a voltage stabilizing / reducing module and a battery. An overload pressure relief module is connected in series with the control device to control the movement of the first telescopic motor and the second telescopic motor through the control chip.

[0012] The overload pressure relief module includes a second telescopic motor, a valve and two rubber cylinders. The two rubber cylinders are assembled in series through a steel center shaft. The metal shell is connected to the steel center shaft and the second telescopic motor. The valve is located behind the second telescopic motor. The second telescopic motor controls the valve to control the opening and closing of the central channel of the steel center shaft.

[0013] Furthermore, the fishing head is a cylindrical structure, with a threaded hole radially opened from the cylindrical surface, and the fishing head is fixed to the central shaft by a bolt passing through the threaded hole.

[0014] Furthermore, the middle cylinder of the fishing head has two sides cut off, so that the fishing head is smaller at the top and larger at the bottom.

[0015] Furthermore, a guide groove is provided on the surface of the central shaft where the tail cylinder is sleeved, and a protrusion is provided on the inner side of the tail cylinder wall. The protrusion is placed in the guide groove to form a tail cylinder positioning structure.

[0016] Furthermore, a serrated damping tooth structure is provided on the outer side of the damping claw.

[0017] Furthermore, a ferrule is sleeved on the central shaft, which is installed at the tail of the central shaft and fixed by screws to prevent the tail cylinder from slipping off the central shaft.

[0018] Furthermore, the weight rod connector is a cylindrical structure threadedly connected to the tail end of the central shaft, and an adjustment short section is installed in the central shaft through threads, and the adjustment short section can adjust its position through threads in the weight rod connector.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] 1. The utility model provides a closed gas well pumping safety guard device, which utilizes a metal frame and rubber tube structure design. This device minimizes pumping losses, reduces the probability of encountering resistance, and provides overall stability and reliability. This device effectively addresses the issues of pumping device updrafts and blowouts caused by sudden increases in well pressure during the pumping process. It implements a pressure monitoring function and effectively controls the telescopic motor to adjust the pumping device's operating state based on feedback from the pressure sensor, effectively avoiding pumping overloads and ensuring normal underground production.

[0021] 2. The utility model improves the performance of the tool string by optimizing the design and operation of the tool string, which can achieve more efficient liquid extraction and sewage discharge, while effectively maintaining the closed environment of the underground well. It also has digital control to achieve automatic control of the pump to prevent it from rising and overload pressure relief. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the main view of the utility model;

[0023] Figure 2a This is the structural diagram of the anti-upward damping module of the utility model;

[0024] Figure 2b This is the structural diagram of the anti-upward damping module of the utility model;

[0025] Figure 3 This is a structural diagram of the control device of the utility model;

[0026] Figure 4 This is the structural diagram of the overload pressure relief module of the utility model;

[0027] Figure 5 This is the force analysis diagram of the slips of the utility model;

[0028] Figure 6 This is a force analysis diagram of the utility model when moving upward;

[0029] Figure 7 This is a working state diagram of the utility model when the well pressure is different;

[0030] Figure 8 This is the tension curve of different liquid column heights during the test process of the utility model;

[0031] In the figure: 1. Fishing head; 2. Buffer spring; 3. Damping claw; 4. Damping expansion wedge; 5. First telescopic motor; 6. Control chip; 7. Voltage stabilization / reduction module; 8. Battery; 9. Sensor hole; 10. Second telescopic motor; 11. Valve; 12. Center flow channel; 13. Rubber cylinder; 2a. Center shaft; 5a. Tail cylinder; 6a. Ferrule; 9a. Pin shaft. DETAILED DESCRIPTION

[0032] The present invention will be further described in detail below with reference to specific embodiments, which are intended to explain rather than limit the present invention.

[0033] like Figure 1 As shown, the gas well closed pumping safety guard device of the present invention includes an anti-upward damping module, a control device, and an overload pressure relief module.

[0034] like Figure 2a As shown, the anti-upward damping module includes a fishing head 1, a buffer spring 2, a damping claw 3, a damping expansion wedge 4, and a first telescopic motor 5. The fishing head 1 has a groove at its bottom, the damping claw 3 is mounted on a damping claw base, and the buffer spring 2 is located between the fishing head bottom and the damping claw base. The damping expansion wedge 4 is attached to the outer wall of the central shaft, and the first telescopic motor 5 is installed inside the central shaft. The damping expansion wedge 4 is driven by the first telescopic motor 5, and a control device is connected in series with the rear of the central shaft.

[0035] like Figure 2b As shown, the fishing head 1 used for placing and fishing out the scavenging tool is cylindrical, with a threaded hole radially extending from the cylindrical surface. The fishing head is fixed to the central axis 2a by bolts passing through the threaded hole. To prevent backlash during the lifting and lowering operation, the two sides of the middle cylinder are cut off, making the fishing head 1 smaller at the top and larger at the bottom, making fishing more convenient.

[0036] The center shaft 2a is a cylindrical structure, and the damping claw base is sleeved on the center shaft 2a. The center shaft and the damping claw base are clearance-matched, and the damping claw base can slide axially along the center shaft 2a. In order to avoid the circumferential rotation of the damping claw base and affect the position of the damping claw 3, a slide groove is opened axially on the center shaft 2a, and the end of the pin shaft 9a that radially penetrates the side wall of the damping claw base along the damping claw base is placed in the slide groove. Under the action of the pin shaft 9a, the damping claw base determines the trajectory on the center shaft 2a; three planes for accommodating the damping claw 3 are milled at equal angles along the axial direction on the cylindrical surface of the center shaft 2a.

[0037] The three damping claws 3 are set at three planes milled on the surface of the central shaft 2a. One end of each is connected to one end of the damping claw base via a respective shaft, allowing it to swing along the axis. A gap exists between the damping claw 3 and the damping claw base, which facilitates the opening of the damping claw 3. The buffer spring 2 is sleeved on the central shaft 2a and located between the scoop head and the damping claw base. The buffer spring 2 has a slightly larger diameter than the central shaft 2a, achieving a clearance fit and facilitating the smooth extension and retraction of the damping claw 3. To increase the friction of the damping claw 3, a serrated damping tooth structure is provided on the outside of the damping claw 3. When the damping claw 3 is opened, the anchoring effect with the inner wall of the oil pipe is more prominent.

[0038] The tailpiece 5a is sleeved onto the central shaft 2a, positioned behind the damping claw 3. The front end of the tailpiece 5a is milled with an inclined surface to form a damping expansion wedge 4. As the tailpiece 5a slides along the central shaft 2a toward the damping claw 3, it pushes the damping claw 3 open. A guide groove is defined on the surface of the central shaft 2a where the tailpiece 5a is sleeved. A protrusion is provided on the inner wall of the tailpiece 5a, which fits within the guide groove to form a positioning structure for the tailpiece 5a. A collar 6a is mounted on the central shaft 2a and secured to the rear of the central shaft with screws. This collar 6a limits the sliding distance of the tailpiece 5a and prevents it from slipping off the central shaft 2a.

[0039] Connected to the rear of the tail cylinder 5a is a weighted rod connector. This cylindrical structure is threaded onto the tail end of the central shaft 2a. A first telescopic motor 5 is mounted within the central shaft 2a. This motor retracts the central shaft 2a, causing the damping expansion wedge 4 to open the damping claws 3. The upper end of the central shaft 2a is connected to the fishing head, and the lower end to the tail cylinder 5a. As the swabbing tool ascends, the damping claws 3 open and become firmly engaged with the inner wall of the damping claw base, preventing it from moving upward. The damping claws 3 are released by pulling the tool upward.

[0040] like Figure 3 As shown, the control device includes a control chip 6, a voltage stabilizing / reducing module 7, a battery 8 and a sensor hole 9. An overload pressure relief module is connected in series behind the control device. The voltage provided by the battery 8 is reduced by the voltage stabilizing / reducing module 7 and then supplied to the control chip 6 and the first telescopic motor 5 and the second telescopic motor 10. The control chip 6 makes a judgment based on the signal detected by the sensor and controls the operation of the first telescopic motor 5 and the second telescopic motor 10 through the control chip 6.

[0041] like Figure 4As shown, the overload pressure relief module includes a second telescopic motor 10, a valve 11, a central flow channel 12, and a rubber cylinder 13. The overload pressure relief module body is composed of two sealed rubber cylinders 13 assembled in series via a steel central shaft. A fixed metal housing connects the second telescopic motor 10 and the overload pressure relief module body. The valve 11 is located behind the second telescopic motor 10. The second telescopic motor 10 controls the valve 11 to open and close the central flow channel 12 of the steel central shaft. This opens and closes the valve 11 by the second telescopic motor 10, achieving pressure relief.

[0042] like Figure 7 As shown, in order to address the problems that may exist during traditional closed pumping operations, the utility model has "triple protection" to ensure the safety of the closed pumping operations in gas wells. Figure 7 Figure a is the normal pumping state (no obvious abnormality in well pressure), b is the high liquid column above the tool string and the pressure relief valve is open (small abnormality in well pressure), c is the pressure relief valve open and the claws are expanded (obvious abnormality in well pressure), and d is the pressure relief valve open and the claws expansion is ineffective, hitting the buffer spring (high abnormality in well pressure).

[0043] The anti-upward damping module primarily functions through the damping claws and their expansion wedges. During the lowering and raising of the swab tool string, the damping claws remain retracted; during normal lowering and raising of the swab, the slips remain retracted. During a blowout, the gas and liquid below push the swab upward against the swab. When the swab's upward movement exceeds the normal speed of the wireline, the slips move relative to the cone, pushing the slips out and anchoring them to the inner wall of the tubing. This significantly increases friction between the tool string and the tubing, effectively preventing the wireline from twisting due to rapid upward swab movement, and ultimately preventing upward swab movement of the swab tool string.

[0044] In addition, when the well pressure is too high and does not push the claws to expand, pushing the electric pole will sense the pressure and push out the expansion wedge, allowing the claw expansion tool string to move upward; when the wire rope continues to be pulled up, the cava retracts relative to the cone, releasing the anchor, and can continue to move upward to the wellhead.

[0045] The overload pressure relief module is primarily designed to address situations where the tool string is lowered too deep and pumping overload occurs when the bottomhole liquid level is uncertain. The overload pressure relief module adds a motor-controlled valve to the traditional oil recovery pump. The oil recovery pump's rubber seal and guide block, after assembly, slide back and forth on the plunger rod to achieve the pumping and drainage function. The overload pressure relief nipple structural design primarily optimizes and innovates the internal structure of the oil recovery pump, resolving technical issues associated with traditional oil recovery pumps and achieving overload pressure relief technology. When the pumping tool is raised, if the pressure of the liquid column above the pump exceeds 8MPa, the electric push rod will drive the valve to open, allowing the liquid column to flow out of the pump's central channel, achieving automatic unloading. When the pressure is less than 6MPa, the electric push rod will close the valve.

[0046] The process of the slips holding the casing string is a process of interaction between the slips and the pipe string. At the initial moment when the slips hold the pipe body, the main force comes from the slips. Under the action of its own weight and the downward impact force, the slips are magnified by the conical surface and hold the pipe string in the radial direction. Under the action of the initial holding force, in order to make the slips hold the casing tightly without slipping, it is necessary to ensure that the friction between the casing and the slips can overcome the tensile stress of the casing after being stretched and the weight of the casing, so as to achieve safe suspension. Figure 5 shown.

[0047] In the vertical direction (axial direction), there is a mechanical equilibrium relationship:

[0048] F1+N2 sinα=F2 cosα

[0049] The projections of the forces in the horizontal direction (radial direction) are balanced, and we get:

[0050] N1=N2cosα+F2sinα

[0051] Where: F1 is the friction between the slips and the outer cylinder; F2 is the friction between the slips and the cone surface; α is the cone angle of the slips.

[0052]

[0053] Solving the above equations together, we can obtain the conditions that the design angle α must meet:

[0054]

[0055] Where: f1 and f2 are friction coefficients, which are 0.25 and 0.15 respectively; the final calculated α is 7°.

[0056] According to the Lame formula for thick-walled cylinders, the maximum tangential stress (on the inner wall) is calculated as:

[0057]

[0058] Where: a, b are the inner and outer radii of the casing, mm; p is the unit pressure borne by the clamping surface of the casing, MPa.

[0059]

[0060] Where: K is the lateral load coefficient; F is the total axial load on the pipe body, N; A l The theoretical contact area between the slips and the pipe is mm 2 The axial tensile stress of the casing is:

[0061]

[0062] Where: A is the cross-sectional area of the pipe wall (mm) 2 .

[0063] Substituting the above formula into the intensity condition equation of energy intensity theory is:

[0064]

[0065] After simplification, we get:

[0066]

[0067] Where: is the service strength of the casing, MPa; is the theoretical contact area A between the slips and the casing l =2πal,A l is the clamping length of the cava in mm; K is the lateral load coefficient and the average value is 3.

[0068] Advantages of the slip type extractor: The advantages of the slip type extractor are quite obvious. It has the characteristics of simple structure, easy operation, high extraction efficiency, reliable sealing, safe operation, etc. It is suitable for various pipeline pressure environments and can greatly improve the extraction efficiency of traditional extraction equipment.

[0069] The upward resistance of the pumping device includes friction when the pumping equipment is lifted, pressure of the liquid column on the tool string, pressure of the gas on the tool string, and the gravity of the tool string and wire rope. The upward forces include tension, buoyancy, and downhole thrust.

[0070] Liquid tool string pressure:

[0071] F1=P 液 S1=ρghS1

[0072] Where: F1 is the pressure of the liquid on the pump; ρ is the density of water, 1×10 kg / m 3 g is the acceleration due to gravity, 9.8 N / kg; h is the height of the liquid column, 200 m; S1 is the surface area of the pump, 0.00302 m 2 .

[0073] Gas pressure on tool string:

[0074] F2=P 气 S1

[0075] Where: F2 is the pressure of the gas on the tool string; P is the gas pressure, 3 MPa; S1 is the surface area of the drawer, 0.00302 m 2 .

[0076] Friction between the tool string and the tubing wall during lifting: The tool string mainly contacts the tubing wall with the two puller sealant cylinders, and there is friction between the tool string and the tubing wall. The friction is:

[0077] F3=μPS=μ×P×2πRh

[0078] Where: F3 is the friction between the puller and the tubing wall when lifting; μ is the friction coefficient between steel and rubber, 0.1; P is the pressure of the puller on the tubing wall, 5 MPa; S is the contact area between the two pullers and the tubing wall, 0.027789 m 2 ;

[0079] Tool string's own gravity:

[0080] G=mg

[0081] Where: G is the weight of the tool string itself; m is the mass of the tool string, 60 kg; g is the acceleration due to gravity, 9.8 N / kg;

[0082] The total buoyancy of the upward force tool string and the steel rope is:

[0083] F4=ρ 液 gV 排 =ρ 液 gπr 2 h

[0084] Where: F4 is the total buoyancy of the tool string and the steel rope; ρ is the density of water, 1×10 kg / m 3 ; g is the acceleration due to gravity, 9.8N / kg; V is the sum of the rough volume of the tool string and the volume of the steel rope, 0.013m 3 ;

[0085] Thrust of downhole gas and liquid on tool string:

[0086] F5=PS3

[0087] Where: F5 is the upward thrust of the downhole gas and liquid on the tool string; P is the total downhole pressure, 5 MPa; S3 is the bottom area of the tool string;

[0088] The total pulling force is currently calculated as:

[0089] F 拉 =F1+F2+F3+G-F4-F5

[0090] Where: F1 is the pressure of the liquid on the puller; F2 is the pressure of the gas on the tool string; F3 is the friction between the puller and the tubing wall during lifting; G is the weight of the tool string itself; F4 is the total buoyancy of the tool string and the steel rope; F5 is the upward thrust of the gas and liquid on the tool string. After calculation, the total pulling force is 13961.66N.

[0091] Due to the changes in the liquid column generated by downhole pumping, Figure 8 The corresponding pulling force required to extract different liquid column heights.

Claims

1. A gas well closed pumping safety guard device, characterized by: Including anti-upward damping module, control device, overload pressure relief module; The anti-upward damping module comprises a fishing head (1), a damping claw (3) and a central shaft (2a); A fishing head (1) for placing and fishing up a pumping tool is fixedly connected to the front end of the central shaft. The central shaft (2a) is a cylindrical structure. The damping claw base is sleeved on the central shaft (2a). The damping claw base and the central shaft (2a) are clearance-matched and can slide axially along the central shaft (2a). A sliding groove is provided on the central shaft (2a) along the axial direction. The end of a pin shaft (9a) radially penetrating a side wall of the damping claw base is placed in the sliding groove. Three planes for accommodating the damping claw (3) are milled at equal angles along the axial direction on the cylindrical surface of the central shaft (2a). Three damping claws (3) are arranged at three planes milled on the central shaft (2a), one end of which is installed on one end of the damping claw base through respective shaft connections and can swing along the axis. A clearance-matching reset spring is sleeved on the central shaft (2a), and the reset spring is located between the scoop head and the damping claw base; a tail cylinder (5a) is sleeved on the central shaft (2a) and located behind the damping claw (3); a front end of the tail cylinder (5a) is milled into an inclined surface to form a damping expansion wedge; when the tail cylinder (5a) slides along the central shaft (2a) toward the damping claw (3), it pushes the damping claw (3) to open; a weighting rod connector for installing a weighting rod is connected to the rear of the tail cylinder (5a); a first telescopic motor (5) is installed in the central shaft (2a); the central shaft (2a) is pulled back by the first telescopic motor (5), and the damping expansion wedge (4) opens the damping claw (3); The control device comprises a control chip (6), a voltage stabilizing / reducing module (7) and a battery (8); an overload pressure relief module is connected in series to the control device, and the control chip (6) controls the movement of the first telescopic motor (5) and the second telescopic motor 10; The overload pressure relief module comprises a second telescopic motor (10), a valve (11) and two rubber cylinders (13), the two rubber cylinders being assembled in series through a steel central shaft, the metal shell being connected through the steel central shaft and the second telescopic motor (10), the valve being located behind the second telescopic motor (10), and the second telescopic motor (10) controlling the valve (11) to control the opening and closing of the central channel (12) of the steel central shaft.

2. The gas well closed pumping safety guard device according to claim 1, characterized in that: The fishing head (1) is a cylindrical structure, with a threaded hole radially opened from the cylindrical surface. The fishing head (1) is mounted and fixed to the central shaft (2a) via a bolt passing through the threaded hole.

3. The gas well closed pumping safety guard device according to claim 2, characterized in that: The middle cylinder of the fishing head has two sides cut off, so that the fishing head (1) is smaller at the top and larger at the bottom.

4. The gas well closed pumping safety guard device according to claim 2 or 3, characterized in that: A guide groove is provided on the surface of the central shaft (2a) where the tail cylinder (5a) is sleeved, and a protrusion is provided on the inner side of the wall of the tail cylinder (5a). The protrusion is placed in the guide groove to form a positioning structure of the tail cylinder (5a).

5. The gas well closed pumping safety guard device according to claim 4, characterized in that: A sawtooth-shaped damping tooth structure is provided on the outer side of the damping claw (3).

6. The gas well closed pumping safety guard device according to claim 4, characterized in that: The central shaft (2a) is sleeved with a ferrule (6a), which is installed at the tail of the central shaft and fixed by screws, and is used to prevent the tail cylinder (5a) from slipping off the central shaft (2a).

7. The gas well closed pumping safety guard device according to claim 4, characterized in that: The weighting rod connecting piece is a cylindrical structure threadedly connected to the tail end of the central shaft (2a); an adjusting short section is threadedly installed in the central shaft (2a); and the adjusting short section can be adjusted in position in the weighting rod connecting piece through the thread.

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