A fish-scale sand-proof air anchor
By combining a fish-scale-like structure with anti-backflow flow components, the problem of gas-liquid-solid three-phase mixing during coalbed methane well drainage is solved, achieving dynamic sand control and efficient gas-liquid separation, protecting the oil pump, and extending the service life of the equipment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- CHINA PETROLEUM & CHEMICAL CORP
- Filing Date
- 2025-09-08
- Publication Date
- 2026-06-30
AI Technical Summary
During the drainage process of coalbed methane wells, there is a mixture of gas, liquid and solid phases, which can lead to gas lock or sand blockage in the oil pump. Existing gas anchor devices are easily blocked by fine sand and coal dust, and cannot adapt to production fluctuations, resulting in tool erosion damage and sand entering the pump barrel, causing pump blockage.
It adopts a fish-scale-like scale structure, which automatically adjusts the gap according to the flow rate. It tightly blocks sand at low flow rates and expands to prevent blockage at high flow rates. Combined with anti-backflow flow components, it automatically works by utilizing the pressure difference of the oil pump to prevent sand particles from falling back, thereby enhancing gas-liquid separation efficiency and extending the life of the device.
It achieves dynamic sand prevention, automatically adjusts the opening and closing degree of the scales, improves gas-liquid separation efficiency, prevents sand particles from falling back, protects the oil pump, and extends the service life of the unit and the sand prevention effect.
Smart Images
Figure CN224432522U_ABST
Abstract
Description
Technical Field
[0001] This utility model specifically relates to the field of air anchor technology, and more specifically to a fish-scale sand-proof air anchor. Background Technology
[0002] During the production and drainage process of coalbed methane wells, there is a problem of three-phase mixing of gas, liquid, and solid. The production of coal dust and fracturing sand can easily lead to gas lock or sand blockage in the pumping unit. Sand particles can also exacerbate pump wear or clog the flow channels. Traditional gas anchors mostly use fixed screens or cyclone structures, which have the following drawbacks: static screens are easily clogged by fine sand and coal dust, requiring frequent replacement; cyclone separation is not efficient enough for separating particles smaller than 0.2mm; existing sand-blocking structures cannot adapt to the impact of sand particles caused by production fluctuations, which can easily cause tool erosion damage and pump blockage caused by sand entering the pump barrel. Utility Model Content
[0003] Therefore, this utility model proposes a fish-scale sand-proof air anchor to solve the problems mentioned in the background art.
[0004] To achieve the above objectives, this utility model provides the following technical solution: a fish-scale sand-proof air anchor, comprising:
[0005] The upper connector has an outlet channel and an inlet channel respectively at its left and right ends. The outlet channel is connected to the oil pump via an oil pipe, and a drain channel is connected between the outlet channel and the inlet channel.
[0006] Anti-backflow drainage components, whose seals are installed inside the drainage channel;
[0007] The lower connector connects to the bottom hole tubing.
[0008] The outer tube has its left end threaded to the outside of the upper connector extension, and its right end threaded to the inside of the lower connector. The side wall of the outer tube has multiple punches, and stainless steel wire is wound around the side wall of the outer tube.
[0009] The inner tube has a central flow channel inside. The left end of the inner tube is threaded to the inside of the upper connector extension. The right end of the inner tube is closed and sealed to the outer tube, so that an annular settling cavity is formed between the inner tube and the outer tube.
[0010] The inner tube has multiple evenly distributed liquid inlet holes on its side wall. Each liquid inlet hole is elastically connected to a scale on its side wall and to the left of the scale. Each scale is tilted relative to the liquid inlet hole to control the flow rate of the liquid inlet hole.
[0011] Optionally, an air guide hole is provided at the left end of the annular settling cavity between the inner tube and the outer tube.
[0012] Optionally, the anti-backflow flow element includes:
[0013] The drain cylinder is fitted into the drain channel, and the left end of the drain cylinder is engaged with the annular step of the drain channel.
[0014] A pressure ring, which is threadedly connected to the inside of the drainage channel, presses tightly against the drainage cylinder;
[0015] The sealing ring is fixed inside the right end of the drain cylinder;
[0016] A flow ring is fitted into a sealing ring, and the left end of the flow ring is sealed to a base located to the left of the sealing ring.
[0017] The support ring is fixed inside the drain cylinder;
[0018] And a sliding column, one end of which is slidably connected to a support ring, and the other end of which is fixedly connected to the chassis;
[0019] Multiple through holes are provided on the end face of the support ring and on the side wall of the flow ring.
[0020] Optionally, a compression spring is connected between the support ring and the chassis, and the compression spring is wound around the side wall of the slide column.
[0021] Optionally, the length of the sliding column is greater than the maximum travel distance of the flow ring.
[0022] Optionally, a sealing ring is connected between the drain cylinder and the pressure ring, and a sealing gasket is connected between the left end of the drain cylinder and the annular step of the drain channel.
[0023] Optionally, the spacing between the stainless steel wires is less than 2 mm.
[0024] Optionally, in the initial state, the gap between the scale and the liquid inlet hole is not less than 0.1 mm.
[0025] This utility model adopts the above technology and has the following beneficial effects compared with the existing technology:
[0026] 1. In this utility model device, the fish scales are distributed in a fish scale pattern, and the gap is automatically adjusted according to the pressure generated by the flow rate. When the flow rate is low, the scales tightly block sand, and when the flow rate is high, they expand to prevent blockage. The opening and closing degree of the scales is automatically adjusted to achieve dynamic gap adjustment.
[0027] 2. The anti-backflow flow component in this utility model device works automatically using the pressure difference generated by the oil pump, preventing sand particles from falling back to the bottom of the well or into the settling chamber, thus avoiding difficulties in starting the pump or damage to the equipment due to sand burial or blockage when restarting. Attached Figure Description
[0028] Figure 1A structural cross-sectional view of a fish-scale sand-proof air anchor;
[0029] Figure 2 for Figure 1 An enlarged schematic diagram of part A in the middle;
[0030] Figure 3 for Figure 1 Internal structure diagram of the anti-backflow flow component;
[0031] Figure 4 for Figure 3 Enlarged schematic diagram of part B.
[0032] In the diagram: 1. Upper connector; 2. Stainless steel wire winding; 3. Inner tube; 4. Lower connector; 5. Outer tube; 6. Liquid inlet; 7. Flakes; 8. Perforation; 9. Liquid inlet channel; 10. Liquid outlet channel; 11. Sealing ring; 12. Pressure ring; 13. Flow ring; 14. Base plate; 15. Compression spring; 16. Drain cylinder; 17. Support ring; 18. Sliding column. Detailed Implementation
[0033] With reference to the accompanying drawings of the embodiments of this utility model, the technical solutions of the embodiments of this utility model will be clearly and completely described below.
[0034] Example: Please refer to the appendix. Figure 1-4 This utility model provides a technical solution: a fish-scale sand-proof air anchor, which includes:
[0035] The upper connector 1 has an outlet channel 10 and an inlet channel 9 respectively at its left and right ends. The outlet channel 10 is connected to the oil pump via an oil pipe, and a drain channel is connected between the outlet channel 10 and the inlet channel 9.
[0036] Anti-backflow drainage components, whose seals are installed inside the drainage channel;
[0037] Lower connector 4, which connects to the bottom hole tubing;
[0038] The outer tube 5 has its left end threaded to the outside of the extension of the upper connector 1, and its right end threaded to the inside of the lower connector 4. The side wall of the outer tube 5 is provided with multiple punch holes 8, and the side wall of the outer tube 5 is wound with stainless steel wire 2.
[0039] And inner tube 3, which has a central flow channel. The left end of inner tube 3 is threaded to the inside of the extension of upper connector 1. The right end of inner tube 3 is closed and sealed to the outer tube 5, so that an annular settling cavity is formed between inner tube 3 and outer tube 5.
[0040] The inner tube 3 has multiple evenly distributed liquid inlet holes 6 on its side wall. Each side wall of the inner tube 3 is elastically connected to a scale 7 on the left side of each liquid inlet hole 6. Each scale 7 is tilted relative to the liquid inlet hole 6 next to it to control the flow rate of the liquid inlet hole 6.
[0041] In this embodiment, a gas guide hole is provided at the left end of the annular settling chamber between the inner tube 3 and the outer tube 5, which provides an outlet channel for the gas that accumulates at the left end of the settling chamber, so that the gas can be discharged from the annular settling chamber in time, avoiding the gas being carried back into the production liquid flow, and significantly improving the gas-liquid separation efficiency.
[0042] It should be noted that the fish scales are distributed in a fish scale pattern and the gap is automatically adjusted according to the flow rate. At low flow rates, they tightly block sand, and at high flow rates, they expand to prevent clogging. The opening and closing degree of the scales is automatically adjusted to achieve dynamic gap adjustment.
[0043] Specifically, at low flow rates, the fluid pressure is low, and the fish scales tend to close or the gaps become smaller under their own weight or slight pre-tightening force, forming a tight filter layer that effectively intercepts fine sand (even fine sand), preventing fine sand from entering the central flow channel and the oil pump, and protecting the pump valves and oil pipes.
[0044] At high flow rates, the fluid pressure increases, causing the fish scales to unfold and the gaps to widen. This prevents sand particles from accumulating rapidly in narrow gaps and causing blockages, ensuring the flow capacity under high discharge rates and significantly improving the anti-clogging performance and service life of the device.
[0045] Furthermore, the fluid flow and device vibration during use, combined with the elasticity of the scales, can effectively prevent sand particles from getting stuck in the gaps, maintain the unobstructed flow of the gaps, and solve the problem of easy clogging of traditional fixed filter holes.
[0046] In this embodiment, the anti-backflow flow component includes:
[0047] The drain cylinder 16 is fitted into the drain channel, and the left end of the drain cylinder 16 is engaged with the annular step of the drain channel.
[0048] The pressure ring 12 is threadedly connected to the inside of the drain channel and presses the drain cylinder 16 tightly.
[0049] The sealing ring 11 is fixed inside the right end of the drain cylinder 16;
[0050] The flow ring 13 is slidably fitted inside the sealing ring 11, and the left end of the flow ring 13 is sealed to the chassis 14 located to the left of the sealing ring 11.
[0051] The support ring 17 is fixed in the inner cavity of the drain cylinder 16;
[0052] And the sliding column 18, one end of which is slidably connected to the support ring 17, and the other end of the sliding column 18 is fixedly connected to the chassis 14.
[0053] Multiple through holes are provided on the end face of the support ring 17 and the side wall of the flow ring 13.
[0054] In this embodiment, a compression spring 15 is connected between the support ring 17 and the chassis 14, and the compression spring 15 is wrapped around the side wall of the slide column 18.
[0055] Specifically, when the oil pump is working, the pressure in the annular settling chamber is higher than the pressure in the central flow channel (suction effect). This pressure difference pushes the chassis, sliding column and flow ring to move to the left (compressing the spring), opening the through holes on the flow ring and support ring, allowing liquid to flow from the settling chamber into the central flow channel through the through holes;
[0056] When the oil pump stops working, the pressure difference disappears or reverses, and the elastic force of the pressure spring pushes the chassis, sliding column and flow ring to reset to the right. The flow ring moves to the right, and its side wall cooperates with the sealing ring to form a seal. At the same time, the chassis is tightly pressed against the left end face of the sealing ring. The double seal effectively blocks the backflow of liquid and sand from the central flow channel to the annular settling chamber or the upper connector inlet channel. This prevents sand from falling back to the bottom of the well or into the settling chamber, avoiding difficulties in starting or equipment damage due to sand burial or sand blockage when restarting the pump.
[0057] In this embodiment, the length of the sliding column 18 is greater than the maximum moving distance of the flow ring 13.
[0058] In this embodiment, a sealing ring is connected between the drain cylinder 16 and the pressure ring 12, and a sealing gasket is connected between the left end of the drain cylinder 16 and the annular step of the drain channel.
[0059] In this embodiment, the wire spacing of the stainless steel wire 2 is less than 2mm;
[0060] It should be noted that the stainless steel wire wrapped around the outer tube serves as the first sand barrier, effectively preventing most of the formation sand and larger particles from entering the annular settling chamber, reducing the sand-prevention burden on subsequent components, and preventing large particles from entering the core area and causing blockage or wear.
[0061] In this embodiment, when the scale 7 is in its initial state, the gap between it and the liquid inlet 6 is not less than 0.1 mm;
[0062] It should be noted that the pre-set micro-gap (≥0.1mm) between the scales and the inlet hole constitutes a second fine sand barrier, which can effectively prevent fine sand that the winding wire failed to intercept from entering the central flow channel of the inner tube, protecting the downstream oil pump from wear.
[0063] The above-described embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.
Claims
1. A fish-scale sand-proof air anchor, characterized in that, It includes: The upper connector (1) has an outlet channel (10) and an inlet channel (9) respectively at its left and right ends. The outlet channel (10) is connected to the oil pump by an oil pipe. A drain channel is connected between the outlet channel (10) and the inlet channel (9). Anti-backflow drainage components, whose seals are installed inside the drainage channel; The lower connector (4) is connected to the bottom hole tubing; The outer tube (5) has its left end threaded to the outside of the extension of the upper connector (1), and its right end threaded to the inside of the lower connector (4). The outer tube (5) has multiple punches (8) on its side wall, and stainless steel wire (2) is wound around its side wall. And an inner tube (3) with a central flow channel inside. The left end of the inner tube (3) is threaded to the inside of the extension of the upper connector (1). The right end of the inner tube (3) is closed and sealed to the outer tube (5), so that an annular settling cavity is formed between the inner tube (3) and the outer tube (5). The inner tube (3) has a plurality of uniformly distributed liquid inlet holes (6) on its side wall. Each of the inner tube (3) has a scale (7) elastically connected to the side wall of the inner tube (3) and to the left of each liquid inlet hole (6). Each scale (7) is tilted relative to the liquid inlet hole (6) adjacent to it in order to control the flow rate of the liquid inlet hole (6).
2. The fish-scale sand-proof air anchor according to claim 1, characterized in that: An air guide hole is provided at the left end of the annular settling cavity between the inner tube (3) and the outer tube (5).
3. The fish-scale sand-proof air anchor according to claim 2, characterized in that: The anti-backflow flow component includes: The drain cylinder (16) is matched and slid into the drain channel, and the left end of the drain cylinder (16) is engaged with the annular step of the drain channel; A pressure ring (12) is threaded onto the inside of the drain channel and presses against the drain cylinder (16); A sealing ring (11) is fixed inside the right end of the drain cylinder (16); A flow ring (13) is slidably fitted inside a sealing ring (11), and the left end of the flow ring (13) is sealed to a chassis (14) located to the left of the sealing ring (11). Support ring (17), which is fixed in the inner cavity of the drain cylinder (16); And a sliding column (18), one end of which is slidably connected to a support ring (17), and the other end of the sliding column (18) is fixedly connected to the chassis (14); Multiple through holes are provided on the end face of the support ring (17) and the side wall of the flow ring (13).
4. The fish-scale sand-proof air anchor according to claim 3, characterized in that: A compression spring (15) is connected between the support ring (17) and the chassis (14), and the compression spring (15) is wound around the side wall of the slide column (18).
5. A fish-scale sand-proof air anchor according to claim 4, characterized in that: The length of the slide bar (18) is greater than the maximum moving distance of the flow ring (13).
6. A fish-scale sand-proof air anchor according to claim 4, characterized in that: A sealing ring is connected between the drain cylinder (16) and the pressure ring (12), and a sealing gasket is connected between the left end of the drain cylinder (16) and the annular step of the drain channel.
7. The fish-scale sand-proof air anchor according to claim 1, characterized in that: The spacing between the stainless steel wires (2) is less than 2 mm.
8. The fish-scale sand-proof air anchor according to claim 1, characterized in that: In its initial state, the gap between the scale (7) and the liquid inlet (6) is not less than 0.1 mm.