Spiral gas anchor with sand prevention structure

Abstract

The present application relates to the technical field of oil exploitation, and particularly relates to a spiral gas anchor with a sand prevention structure. The spiral gas anchor comprises an outer pipe, a spiral blade fixedly connected in the outer pipe, a central pipe fixedly connected to the middle part of the spiral blade, and a spiral channel formed by cooperation of the outer pipe, the spiral blade and the central pipe. A separation cavity is arranged above the spiral blade in the outer pipe. The outer pipe is provided with an oil discharge hole in communication with the separation cavity, an oil pumping channel in communication with the oil discharge hole, and oil discharge holes in spiral distribution and located outside the spiral blade. In the upstroke process, part of the oil in the spiral channel is discharged into the oil pumping channel in advance through the oil discharge holes, the speed of oil discharge is increased, the oil flow discharged into the oil pumping channel through the oil discharge hole is shared, and the separated oil can be quickly discharged into the oil pumping channel even when the oil-gas mixture contains more oil.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil exploitation, and in particular to a spiral gas anchor with a sand prevention structure. BACKGROUND

[0002] In the mechanical oil production process of an oil field, especially in the middle and late development stage, the produced liquid of an oil well is often accompanied by a large amount of associated gas and sand particles. The gas entering the oil pump will reduce the pump efficiency, causing "gas locking", and in severe cases, the oil pump cannot work normally. The sand particles will aggravate the wear and tear of key components such as pump cylinder and plunger. Generally, a spiral gas anchor is installed below the oil pipe to solve such problems.

[0003] The core structure of the spiral gas anchor usually includes a central pipe and an outer pipe sleeved outside the central pipe. The annulus between the outer pipe and the central pipe is provided with continuous spiral blades, thereby forming a spiral channel. The working principle is as follows: the oil, gas, water and sand mixture enters the spiral channel from the liquid inlet at the bottom of the gas anchor. During the upward rotation in the channel, due to the density differences of oil, gas, water and sand, the centrifugal force, gravity and buoyancy jointly act on the mixture to achieve preliminary separation. The liquid with higher density (oil and water) is thrown to the outside of the spiral channel, while the gas with lower density is gathered on the inside of the spiral channel. Above the spiral channel, a separation chamber (or a settling chamber) is usually designed, which is a relatively open cavity providing further settling and separation space for the mixture coming out of the spiral channel. The separated gas is located at the top of the separation chamber and is guided out to the annular space between the oil pipe and the casing through a specific structure (such as a hole communicating with the central pipe). The separated oil and sand particles then settle downward.

[0004] In the prior art, in order to guide the separated oil in the separation chamber into the central oil pumping pipe, a plurality of oil discharge holes are usually opened in the separation chamber. The separated oil flows upward through these oil discharge holes and is finally sucked into the bottom oil pump. However, when the proportion of oil in the oil-gas mixture is large (i.e. high liquid-gas ratio or low gas-liquid ratio working condition), the amount of liquid settling in the separation chamber is large and the flow rate is fast. At this time, the limited number of oil discharge holes with fixed total cross-sectional area is not enough to discharge the separated oil from the separation chamber in time and in sufficient quantity. This will cause the liquid level in the separation chamber to accumulate and rise, even flooding the upper space originally used for gas separation and guiding, which will damage the gas-liquid separation effect. More importantly, the "pressure build-up" and poor discharge of the separation chamber will hinder the flow of fluid in the spiral channel in the opposite direction, increase the flow resistance of the mixture, and make the subsequent oil-gas mixture unable to smoothly enter the spiral channel for efficient separation, forming a vicious cycle and reducing the oil pumping efficiency. SUMMARY

[0005] In order to overcome the shortcomings that the existing spiral gas anchor cannot quickly discharge oil from the separation cavity for the oil-gas mixture with high liquid proportion, the application provides a spiral gas anchor with sand prevention structure and auxiliary exhaust function.

[0006] The technical scheme of the application is: a spiral gas anchor with sand prevention structure, comprising an outer pipe, a sand prevention cylinder with sand prevention holes is fixedly connected and communicated at the lower end of the outer pipe, a spiral fin is fixedly connected in the outer pipe, a center pipe is fixedly connected at the middle part of the spiral fin, the outer pipe, the spiral fin and the center pipe cooperate to form a spiral channel, a separation cavity is arranged above the spiral fin in the outer pipe, the outer pipe is provided with an oil discharge hole communicated with the separation cavity, the outer pipe is provided with an oil pumping channel communicated with the oil discharge hole, the outer pipe is provided with an exhaust channel communicated with the oil jacket annulus, a pipe sleeve is fixedly connected to the outer pipe near the separation cavity, the pipe sleeve is provided with an air inlet groove for discharging gas in the separation cavity, a reverse flow surface in the shape of an inverted horn is arranged on one side of the outer pipe near the separation cavity, the outer pipe is provided with oil leakage holes in a spiral distribution and located outside the spiral fin, and the oil leakage holes in a spiral distribution are communicated with the spiral channel and the oil pumping channel.

[0007] Further, the hole diameters of the oil leakage holes in a spiral distribution gradually decrease from top to bottom.

[0008] Further, the center pipe and the pipe sleeve are jointly sealed and rotationally connected with a one-way shaft sleeve, the one-way shaft sleeve is composed of an inner ring and an outer ring, and the outer ring of the one-way shaft sleeve is fixedly connected with circumferentially distributed flow guide plates.

[0009] Further, the flow guide plates are provided with rectangular through grooves on the side close to the one-way shaft sleeve for gas flow.

[0010] Further, the side of the flow guide plates away from the one-way shaft sleeve is deflected along the spiral direction of the spiral fin for guiding the oil discharged above the spiral channel to the oil discharge hole.

[0011] Further, the outer pipe is sealingly and limitingly slidingly connected with a sliding rod, the sliding rod is provided with a spiral groove, and the inner ring of the one-way shaft sleeve is fixedly connected with a guide rod sliding in the spiral groove.

[0012] Further, the sliding rod is fixedly connected with a pressure disc located on the upper side of the oil pumping channel, a tension spring is fixedly connected between the pressure disc and the outer pipe, and the outer pipe is provided with a variable diameter part above the pressure disc.

[0013] Further, the pitch of the spiral groove gradually increases from bottom to top.

[0014] Further, a sealing plug fixedly connected with the sliding rod is sealingly and slidingly connected in the center pipe, and the center pipe is provided with an oil guide hole.

[0015] Further, the diameter of the oil guide hole is smaller than the inner diameter of the central pipe.

[0016] The beneficial effects are: the present application can increase the speed of oil discharge by discharging part of the oil in the spiral channel into the oil pumping channel through the oil discharge hole in the upstroke process, share the oil flow discharged into the oil pumping channel by the oil discharge hole, ensure that the separated oil can be quickly discharged into the oil pumping channel even if the oil is more in the oil-gas mixture, filter the oil through the sand prevention hole on the sand prevention cylinder before the oil enters the outer pipe, reduce the amount of sand entering the outer pipe, keep the oil rotating by rotating the oil in the separation chamber through the flow guide plate in the early downstroke process, so that the rotating oil blocks the oil discharge hole, thereby reducing the amount of gas entering the oil pumping channel through the oil discharge hole, prolonging the time of gas discharge into the oil jacket annulus, and assisting the gas to discharge from the separation chamber, reducing the amount of gas in the separation chamber by storing part of the gas in the separation chamber by moving the sealing plug downward in the early downstroke process, ensuring that the oil in the separation chamber will be located above the oil discharge hole even if it does not rotate again, and reducing the amount of gas discharged into the oil pumping channel through the oil discharge hole. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a schematic diagram of the three-dimensional structure of the present application;

[0018] Figure 2 is a sectional view of the three-dimensional structure of the present application;

[0019] Figure 3 is a schematic diagram of the three-dimensional structure of the oil-gas interface A of the present application;

[0020] Figure 4 is a schematic diagram of the three-dimensional structure of the spiral groove and guide rod of the present application;

[0021] Figure 5 is an exploded view of the tube sleeve and one-way shaft sleeve of the present application.

[0022] In the drawing: 1-outer pipe, 101-spiral channel, 111-separation chamber, 102-oil discharge hole, 1021-oil discharge hole, 103-oil pumping channel, 104-gas discharge channel, 105-variable diameter, 2-sand prevention cylinder, 3-spiral piece, 4-central pipe, 401-oil guide hole, 5-tube sleeve, 501-gas inlet groove, 6-one-way shaft sleeve, 7-flow guide plate, 8-sliding rod, 801-spiral groove, 9-guide rod, 10-pressure disc, 11-tension spring, 12-sealing plug. DETAILED DESCRIPTION

[0023] The embodiments of the present application will be described in detail below with reference to the accompanying drawings, and the direction of rotation described in the following embodiments is Figure 1 the direction of the top view. Example 1

[0024] The existing spiral gas anchor opens an oil outlet hole outside the separation cavity (that is, the cavity above the spiral channel) to facilitate the discharge of the separated oil into the oil pumping channel. However, when the oil accounts for a large proportion in the oil-gas mixture, the oil outlet hole is insufficient to discharge the separated oil out of the separation cavity, and the oil pumping efficiency is low. During the downstroke process, the oil in the spiral gas anchor is in a stationary state, and the oil and gas in the separation cavity no longer rotate, thereby causing the oil-gas interface to become flat. At this time, the gas in the separation cavity has not been completely discharged into the oil jacket annulus. Therefore, during the process of the oil-gas interface becoming flat, part of the gas is discharged into the oil pumping channel through the oil outlet hole and enters the subsequent oil pipe upward, affecting the oil pumping process.

[0025] A spiral gas anchor with a sand prevention structure, please refer to Figures 1-3Reading this paragraph, including the outer tube 1, the upper side of the outer tube 1 is installed at the lower end of the oil pipe through the threaded joint, the lower end of the outer tube 1 is fixed and communicated with the sand prevention cylinder 2 with sand prevention hole, the fixed method can be selected by bolt connection, the sand carried in the oil is intercepted through the sand prevention hole on the sand prevention cylinder 2 before the oil enters the outer tube 1, the amount of sand entering the outer tube 1 is reduced, the outer tube 1 is fixed with the spiral blade 3, the center tube 4 is fixed at the middle part of the spiral blade 3, the outer tube 1, the spiral blade 3 and the center tube 4 cooperate to form the spiral channel 101, the upward flowing oil gas mixture is guided to rotate along the spiral channel 101 by the spiral blade 3, the density of the oil in the oil gas mixture is greater than that of the gas, the centrifugal force of the oil is greater than that of the gas, therefore, the oil in the oil gas mixture will gather on one side of the spiral channel 101 away from the center tube 4, and the gas will gather on the side of the spiral channel 101 close to the center tube 4, the outer tube 1 is provided with a separation chamber 111 located above the spiral blade 3, the outer tube 1 is provided with an oil discharge hole 102 communicating with the separation chamber 111, the outer tube 1 is provided with an oil pumping channel 103 communicating with the oil discharge hole 102, the oil and gas in the separation state entering the separation chamber 111 along the spiral channel 101 continue to rotate and separate, the oil enters the oil pumping channel 103 through the oil discharge hole 102, the outer tube 1 is provided with a gas discharge channel 104 communicating the separation chamber 111 with the oil sleeve annulus, the gas in the separation chamber 111 enters the oil sleeve annulus (the annular space of the oil pipe and the casing) through the gas discharge channel 104, the outer tube 1 is fixed with the pipe sleeve 5 at the position close to the separation chamber 111, the pipe sleeve 5 is provided with the air inlet groove 501 for discharging the gas in the separation chamber 111, the outer tube 1 is provided with an inverted flow surface in the shape of inverted horn at the side close to the separation chamber 111, which is convenient for collecting the gas at the top of the separation chamber 111, the outer tube 1 is provided with the oil discharge hole 1021 in the shape of spiral and located outside the spiral blade 3, the oil discharge hole 1021 in the shape of spiral communicates the spiral channel 101 with the oil pumping channel 103, in the process of the oil flowing upward along the spiral channel 101, part of the oil close to the outside in the spiral channel 101 will enter the oil pumping channel 103 in advance through the oil discharge hole 1021, which increases the speed of oil discharge, shares the oil flow discharged into the oil pumping channel 103 through the oil discharge hole 102, ensures that the oil can be quickly discharged into the oil pumping channel 103 after separation even in the case of more oil in the oil gas mixture, the diameter of the oil discharge hole 1021 in the shape of spiral decreases from top to bottom, which ensures the oil discharge in the spiral channel 101 and reduces the discharge amount of the gas in the spiral channel 101.

[0026] Please refer to Figures 2-5In this paragraph, the center tube 4 and the sleeve 5 are jointly sealed and rotationally connected with the one-way sleeve 6, which is composed of an inner ring and an outer ring. The outer ring of the one-way sleeve 6 can rotate counterclockwise relative to the inner ring, and the inner ring of the one-way sleeve 6 can rotate clockwise relative to the outer ring. The inner ring of the one-way sleeve 6 can drive the outer ring to rotate counterclockwise. The outer ring of the one-way sleeve 6 is fixedly connected with the circumferentially uniformly distributed guide plates 7. The guide plates 7 are provided with rectangular through grooves on the side close to the one-way sleeve 6 for gas flow. The guide plates 7 reduce the volume occupied in the middle part of the separation cavity 111, facilitating the upward transportation of the gas in the middle part of the separation cavity 111. The side of the guide plates 7 away from the one-way sleeve 6 is deflected along the spiral direction of the spiral blade 3, for guiding the oil discharged from above the spiral channel 101 to the oil discharge hole 102. The outer tube 1 is sealingly and limitingly connected with the slide rod 8 (the limitation here is to limit the slide rod 8 to only longitudinally slide relative to the outer tube 1 and not to rotate relative to the outer tube 1, and the slide rod 8 and the outer tube 1 can be considered as a spline connection). The lower side of the slide rod 8 is provided with a spiral groove 801. The inner ring of the one-way sleeve 6 is fixedly connected with the guide rod 9 sliding in the spiral groove 801. In the initial state, the guide rod 9 is located on the upper side of the spiral groove 801. The upward movement of the slide rod 8 through the spiral groove 801 limits the clockwise rotation of the guide rod 9. The guide rod 9 drives the inner ring of the one-way sleeve 6 to rotate clockwise. The inner ring of the one-way sleeve 6 rotates clockwise relative to the outer ring. The upper end of the slide rod 8 is fixedly connected with the pressure disc 10 located on the upper side of the oil pumping channel 103. The pressure disc 10 and the outer tube 1 are fixedly connected with the tension spring 11. The outer tube 1 is provided with a variable diameter portion 105 located above the pressure disc 10. In the initial state, the pressure disc 10 is located below the variable diameter portion 105. During the upward stroke, the upward flowing oil in the oil pumping channel 103 drives the pressure disc 10 to move upward, and the tension spring 11 is stretched.

[0027] The traditional oil pumping process is divided into two parts, namely the upward stroke and the downward stroke. In the upward stroke process, the oil in the well enters the oil pipe and flows upward. In the downward stroke process, the oil in the well is in a static state and no oil enters the oil pipe.

[0028] In the upward stroke process, the oil-gas mixture enters the lower part of the outer tube 1 through the sand prevention holes of the sand prevention cylinder 2. The sand carried in the oil is intercepted through the sand prevention holes on the sand prevention cylinder 2 before the oil enters the outer tube 1, reducing the amount of sand entering the outer tube 1. The oil-gas mixture flows upward along the spiral channel 101 under the guidance of the spiral blade 3. The density of oil in the oil-gas mixture is greater than that of gas, and the centrifugal force of oil is greater than that of gas. Therefore, the oil in the oil-gas mixture will gather on the side of the spiral channel 101 away from the center tube 4, and the gas will gather on the side of the spiral channel 101 close to the center tube 4. Finally, the oil-gas mixture in a separated state rotates counterclockwise into the separation cavity 111 from above the spiral channel 101. The oil in the separation cavity 111 is located on the outer side of the separation cavity 111, and the gas is close to the one-way sleeve 6 and constantly moves upward.Figure 3 The middle oil-gas interface A is a cone surface placed upside down, the height of the oil outside the separation chamber 111 is higher than that of the inside and exceeds the oil discharge hole 102, the oil rotating in the separation chamber 111 is close to the outside of the separation chamber 111 and is discharged from the oil discharge hole 102 into the oil pumping channel 103, the oil in the oil pumping channel 103 flows upward and is discharged out of the outer tube 1, and the gas in the middle part of the separation chamber 111 enters the gas inlet groove 501 after contacting the reverse flow surface of the upside-down horn-shaped outer tube 1 and then flows upward through the gas discharge channel 104 into the oil jacket annulus.

[0029] In the process of the oil flowing upward along the spiral channel 101, part of the oil close to the outside in the spiral channel 101 will enter the oil pumping channel 103 in advance through the oil discharge hole 1021, increasing the speed of the oil discharge, sharing the oil flow discharged from the oil discharge hole 102 into the oil pumping channel 103, and ensuring that the oil can be quickly discharged into the oil pumping channel 103 after being separated in the case of more oil in the oil-gas mixture. Since the rotation speed of the oil-gas mixture just entering the spiral channel 101 is low, and the rotation speed of the oil-gas mixture increases continuously as it flows upward, the oil-gas separation effect is poor under low rotation speed conditions. Therefore, the diameter of the spiral distribution oil discharge hole 1021 gradually decreases from top to bottom, so that the speed of the oil discharged from the lower part of the spiral channel 101 is less than that of the oil discharged from the upper part, thereby ensuring that the oil separated in the spiral channel 101 is discharged into the oil pumping channel 103 through the oil discharge hole 1021, and reducing the amount of gas discharged into the oil pumping channel 103 from the oil discharge hole 1021 (for the oil-gas mixture below the spiral channel 101, under low rotation speed conditions, the gas content in the middle part of the spiral channel 101 is low, and part of the gas is still in the oil and has not been separated. If the diameter of the lower oil discharge hole 1021 is large, the gas will also be discharged with the oil during the oil discharge process, which will affect the oil pumping process).

[0030] The oil rotating counterclockwise in the separation chamber 111 will impact the flow guide plate 7, the flow guide plate 7 drives the outer ring of the one-way shaft sleeve 6 to rotate counterclockwise, and the outer ring of the one-way shaft sleeve 6 rotates counterclockwise relative to the inner ring. Since the flow guide plate 7 is passively rotating, the rotation speed of the flow guide plate 7 is less than that of the oil in the separation chamber 111, so that the flow guide plate 7 produces a guiding effect on the oil rotating in the separation chamber 111, and the oil in the separation chamber 111 is guided by the flow guide plate 7 to approach the oil discharge hole 102 after contacting the flow guide plate 7, thereby assisting the oil to enter the oil discharge hole 102 and accelerating the speed of the oil discharge from the separation chamber 111.

[0031] During the upstroke, the upward flowing oil in the oil extraction channel 103 pushes the pressure disc 10 to move upward, the tension spring 11 is stretched, the pressure disc 10 drives the sliding rod 8 to move upward, the helical groove 801 of the sliding rod 8 drives the guide rod 9 to rotate clockwise, the guide rod 9 drives the inner ring of the one-way sleeve 6 to rotate clockwise, the inner ring of the one-way sleeve 6 rotates clockwise relative to the outer ring, when the guide rod 9 is located at the lower side of the helical groove 801, the guide rod 9 is limited by the helical groove 801 and cannot move upward, the pressure disc 10 is aligned with the variable diameter portion 105 in the horizontal direction, the upward flowing oil in the oil extraction channel 103 continues to flow upward through the space between the pressure disc 10 and the variable diameter portion 105, and the increased inner diameter of the variable diameter portion 105 ensures the smooth upward flow of the oil, thereby making up for the flow area of the oil extraction channel 103 occupied by the pressure disc 10.

[0032] During the downstroke, the oil in the helical gas anchor is in a static state, the oil and gas in the separation chamber 111 no longer rotate, thereby making the oil-gas interface A flat, and at this time, the gas in the separation chamber 111 has not been completely discharged into the oil jacket annulus through the gas inlet groove 501 and the gas discharge channel 104, so during the process of the oil-gas interface becoming flat, part of the gas is discharged into the oil extraction channel 103 through the oil discharge hole 102 and enters the subsequent oil pipe upward, affecting the oil extraction process, in order to solve this problem, it is necessary to continue to keep the separated oil in the separation chamber 111 in a rotating state at the initial stage of the downstroke, so as to prolong the discharge time of the gas in the separation chamber 111, facilitate the gas to enter the oil jacket annulus, and the specific operation is as follows: at the initial stage of the downstroke process, the oil in the oil extraction channel 103 no longer flows upward, so there is no oil impacting the pressure disc 10, the tension spring 11 in the force storage state drives the pressure disc 10 to move downward, the pressure disc 10 drives the sliding rod 8 to move downward, the helical groove 801 of the sliding rod 8 drives the guide rod 9 to rotate counterclockwise, the guide rod 9 drives the inner ring of the one-way sleeve 6 to rotate counterclockwise, the inner ring of the one-way sleeve 6 drives the outer ring to rotate counterclockwise, and the outer ring of the one-way sleeve 6 drives the guide plate 7 to rotate counterclockwise to push the oil in the separation chamber 111 to rotate, so that the oil in the separation chamber 111 remains in a rotating state, and the rotating oil blocks the oil discharge hole 102, thereby reducing the amount of gas entering the oil extraction channel 103 through the oil discharge hole 102, prolonging the time of discharging the gas into the oil jacket annulus, and assisting the gas to discharge from the separation chamber 111, when the tension spring 11 resets, the guide rod 9 is located at the upper side of the helical groove 801. Example 2

[0033] On the basis of example 1, a helical gas anchor with a sand prevention structure, please refer to Figure 4 Reading this paragraph, the pitch of the helical groove 801 gradually increases from bottom to top, the center pipe 4 is sealingly and slidingly connected with the sealing plug 12 fixedly connected with the lower end of the sliding rod 8, the center pipe 4 is provided with a guide hole 401, the diameter of the guide hole 401 is smaller than the inner diameter of the center pipe 4, and the guide hole 401 is used to control the moving speed of the sealing plug 12 in the center pipe 4.

[0034] In the embodiment 1, the oil in the separation chamber 111 is kept in a rotating state before the early stage of the down stroke, and the gas in the separation chamber 111 is discharged. In this embodiment, part of the gas in the separation chamber 111 is stored, so as to reduce the amount of gas entering the oil pumping passage 103. The specific operation is as follows: during the up stroke, the sliding rod 8 drives the sealing plug 12 to move upward, and the upward movement of the sealing plug 12 draws part of the oil below the outer tube 1 into the center tube 4 below the sealing plug 12 through the oil guide hole 401. During the early stage of the down stroke, the sliding rod 8 drives the sealing plug 12 to move downward, and the downward movement of the sealing plug 12 reduces the pressure above the center tube 4. At this time, the gas in the separation chamber 111 enters the sleeve 5, the one-way shaft sleeve 6 and the space above the sealing plug 12 in the center tube 4 through the gas inlet groove 501, so as to reduce the amount of gas in the separation chamber 111. Even if the oil in the separation chamber 111 does not rotate, the oil-gas interface will be above the oil outlet hole 102 after the oil-gas interface is flat, so as to reduce the amount of gas discharged into the oil pumping passage 103 through the oil outlet hole 102. During the downward movement of the sealing plug 12, the sealing plug 12 pushes the oil below it out of the center tube 4 through the oil guide hole 401. Due to the limitation of the diameter of the oil guide hole 401, the speed of the oil discharged from the center tube 4 through the oil guide hole 401 is constant, so the downward movement speed of the sealing plug 12 is constant, and the downward movement speed of the sliding rod 8 and the pressure disc 10 is constant. The pitch of the helical groove 801 gradually increases from bottom to top, so the counterclockwise rotation speed of the guide rod 9 gradually decreases, and the counterclockwise rotation speed of the flow guide plate 7 gradually decreases. The rotation speed of the oil in the separation chamber 111 gradually decreases, so that the oil-gas interface gradually flattens and the sealing plug 12 discharges the gas in the separation chamber 111, so that the oil-gas interface gradually approaches the middle part, and the auxiliary gas is discharged.

[0035] The above only describes the embodiments of the present application and is not used to limit the present application. Any equivalent replacement within the principles of the present application shall be included in the protection scope of the present application. The contents not described in detail in the present application belong to the prior art known by the technical personnel in the field.

Claims

1. A spiral air anchor with a sand-proof structure, comprising an outer tube (1), the lower end of which is fixedly connected to and communicates with a sand-proof cylinder (2) having sand-proof holes, a spiral blade (3) fixedly connected inside the outer tube (1), a central tube (4) fixedly connected to the middle of the spiral blade (3), the outer tube (1), the spiral blade (3) and the central tube (4) forming a spiral channel (101), a separation chamber (111) located above the spiral blade (3) is provided inside the outer tube (1), and a drain is provided in the outer tube (1) communicating with the separation chamber (111). Oil hole (102), the outer tube (1) is provided with an oil extraction channel (103) communicating with the oil drain hole (102), the outer tube (1) is provided with an exhaust channel (104) communicating with the separation chamber (111) and the oil sleeve annulus, a sleeve (5) is fixedly connected to the outer tube (1) near the separation chamber (111), the sleeve (5) is provided with an air inlet groove (501) for discharging gas in the separation chamber (111), and an inverted trumpet-shaped backflow surface is provided on the side of the outer tube (1) near the separation chamber (111), characterized in that: The outer tube (1) is provided with oil drain holes (1021) arranged in a spiral pattern and located outside the spiral blade (3). The oil drain holes (1021) arranged in a spiral pattern connect the spiral channel (101) and the oil extraction channel (103). The central tube (4) and the tube sleeve (5) are sealed together and rotatably connected to a one-way bushing (6). The one-way bushing (6) is composed of an inner ring and an outer ring. The outer ring of the one-way bushing (6) is fixed with circumferentially distributed guide plates (7). The outer tube (1) A sliding rod (8) is sealed and limited to slide. The sliding rod (8) is provided with a spiral groove (801). The inner ring of the one-way bushing (6) is fixedly connected to a guide rod (9) that slides in the spiral groove (801). The sliding rod (8) is fixedly connected to a pressure plate (10) located on the upper side of the oil extraction channel (103). A tension spring (11) is fixedly connected between the pressure plate (10) and the outer tube (1). The outer tube (1) is provided with a diameter change point (105) located above the pressure plate (10).

2. A spiral air anchor with a sand-proof structure according to claim 1, characterized in that: The diameter of the oil drain holes (1021) that are spirally distributed decreases from top to bottom.

3. A spiral air anchor with a sand-proof structure according to claim 1, characterized in that: The guide plate (7) has a rectangular through groove for gas flow on the side near the one-way bushing (6).

4. A spiral air anchor with a sand-proof structure according to claim 3, characterized in that: The guide plate (7) is deflected along the spiral direction of the spiral blade (3) on the side away from the one-way bushing (6) to guide the oil discharged above the spiral channel (101) to the oil discharge hole (102).

5. A spiral air anchor with a sand-proof structure according to claim 1, characterized in that: The pitch of the spiral groove (801) gradually increases from bottom to top.

6. A spiral air anchor with a sand-proof structure according to claim 5, characterized in that: The central tube (4) is sealed and slidably connected to a sealing plug (12) that is fixed to the slide rod (8), and the central tube (4) is provided with an oil guide hole (401).

7. A spiral air anchor with a sand-proof structure according to claim 6, characterized in that: The diameter of the oil guide hole (401) is smaller than the inner diameter of the central tube (4).

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