Variable pitch type spiral gas anchor

Abstract

The invention relates to the technical field of gas anchors, in particular to a variable pitch type spiral gas anchor. Comprising an anchor body, a sand prevention cylinder is installed on the lower side of the anchor body, a sand prevention hole is formed in the sand prevention cylinder, a spiral piece is fixedly connected into the anchor body, a center pipe fixedly connected with the anchor body is fixedly connected to the middle of the spiral piece, and the anchor body, the spiral piece and the center pipe are matched to form a spiral channel. A separation cavity is formed in the upper side of the spiral piece in the anchor body, the screw pitch of the lower side of the spiral piece is smaller than that of the upper side of the spiral piece, the screw pitch of the upper side of the spiral piece is gradually increased from bottom to top, and exhaust holes which are distributed in a spiral shape and located in the inner side of the spiral piece are formed in the center pipe. Petroleum pushes gas to the middle by setting the screw pitch of the spiral piece, the gas in the spiral channel is exhausted in advance in cooperation with the exhaust hole, the amount of the gas accumulated in the separation cavity is reduced, and it is guaranteed that the oil pumping process is conducted smoothly.

Description

Technical Field

[0001] This invention relates to the field of air anchor technology, and more particularly to a variable pitch helical air anchor. Background Technology

[0002] During oilfield development, especially when using pumps for mechanical oil production, the well fluid (i.e., the fluid produced from the oil layer) is usually a gas-liquid mixture. If gas enters the pump, it will reduce pump efficiency and cause problems such as gas lock and stroke loss, which will seriously affect the efficiency and stability of the pumping system. In order to reduce the impact of gas on the pump, gas anchors are often used as downhole gas-liquid separation devices. Their core function is to separate free gas as much as possible before the well fluid enters the pump.

[0003] In existing technologies, the spiral gas anchor is a common gas-liquid separation device. Its basic working principle is as follows: spiral blades guide the well fluid to rotate, and centrifugal force causes the denser liquid to move towards the pipe wall, while the less dense gas accumulates at the center. The separated gas is discharged into the annulus through a dedicated exhaust channel, while the degassed liquid enters the lower liquid collection chamber and then enters the oil pump suction port through the oil outlet. However, when the gas content in the oil-gas mixture is too high, although the spiral blades can achieve initial gas-liquid centrifugal separation, the subsequent exhaust capacity of the separation chamber is insufficient, and the gas remains trapped during separation. If the rising speed inside the chamber is too fast, it cannot be completely discharged through the exhaust channel in time, causing the gas to accumulate at the top of the separation chamber, forming an air cap. This air cap will compress the liquid level in the separation chamber, causing it to drop or even fall below the height of the oil drain port. Once the oil drain port is exposed within the air cap area, the separated gas will directly enter the oil drain channel instead of the designed exhaust channel. This gas will eventually be sucked into the oil pump along with the liquid, affecting the oil extraction process. During the oil extraction process, the oil will carry impurities such as sand. Prolonged extraction will cause the sand to clog the mesh of the sandproof cylinder, resulting in low oil extraction efficiency. Summary of the Invention

[0004] This invention provides an auxiliary exhaust variable pitch spiral gas anchor to solve the technical problem that when existing spiral gas anchors handle oil-gas mixtures with a high gas content, the separation chamber on the anchor cannot discharge the gas in time, and the sand carried in the oil clogs the mesh of the sand-proof cylinder, resulting in low oil extraction efficiency.

[0005] The technical solution of the present invention is as follows: a variable pitch helical gas anchor, comprising an anchor body, a sand-proof cylinder installed on the lower side of the anchor body, the sand-proof cylinder having sand-proof holes, a helical blade fixedly connected to the anchor body, a central tube fixedly connected to the middle of the helical blade and fixedly connected to the anchor body, the anchor body, the helical blade and the central tube cooperating to form a helical channel, a separation chamber provided on the upper side of the helical blade in the anchor body, an oil drain port communicating with the separation chamber in the anchor body, an oil drain channel communicating with the oil drain port in the anchor body, an exhaust channel communicating with the central tube in the anchor body, an exhaust groove communicating with the separation chamber in the central tube, an inverted trumpet-shaped guide surface provided on the anchor body near the exhaust groove, the pitch of the lower side of the helical blade being smaller than the pitch of the upper side, the pitch of the upper side of the helical blade gradually increasing from bottom to top, and the central tube having exhaust holes distributed in a helical pattern.

[0006] A further preferred embodiment of the present invention is that the diameter of the exhaust holes, which are distributed in a spiral shape, increases sequentially from bottom to top.

[0007] A further preferred embodiment of the present invention is that the anchor body is provided with symmetrically distributed sealing cavities, a sealing plug is slidably connected to the sealing cavity, the sealing plug is fixedly connected to a sliding rod slidably connected to the anchor body, the sliding rod is fixedly connected to a connecting plate, and the symmetrically distributed connecting plates are jointly fixedly connected to a ring slidably connected to the sand-proof cylinder.

[0008] A further preferred embodiment of the present invention is that the diameter of the outer ring surface gradually decreases from the middle to both sides.

[0009] A further preferred embodiment of the present invention is that the anchor body has symmetrically distributed fixed rods respectively located in the corresponding sealed cavities, the sliding rod is slidably connected to the adjacent fixed rod, and a first spring sleeved on the outside of the adjacent fixed rod is fixed between the sliding rod and the anchor body.

[0010] A further preferred embodiment of the present invention is that the symmetrically distributed sliding rods are all fixedly connected to a fixing ring, a tension spring is fixedly connected between the fixing ring and the sand-proof cylinder, and the sand-proof cylinder is slidably connected to the anchor body.

[0011] In a further preferred embodiment of the present invention, the lower part of the anchor body is provided with symmetrically distributed through holes, the sand-proof cylinder is provided with a shoulder on the side near the fixing ring, a limiting rod for limiting the shoulder is slidably connected in the through holes of the anchor body, a limiting member is slidably connected in the through holes of the anchor body away from the shoulder, and a second spring is fixedly connected between the limiting member and the adjacent limiting rod.

[0012] In a further preferred embodiment of the present invention, the slide bar is provided with a guide groove, and the limiting member is provided with a rectangular limiting part, the limiting part of the limiting member sliding within the adjacent guide groove.

[0013] A further preferred embodiment of the present invention is that the limiting rod has an inclined surface on the side near the fixing ring, the shoulder portion is used to press the inclined surface of the limiting rod, and the elastic coefficient of the first spring is greater than that of the second spring.

[0014] In a further preferred embodiment of the present invention, the guide groove is composed of a vertical groove and an inclined groove, wherein the vertical groove of the guide groove is located above its inclined groove, and the distance between the inclined grooves of the guide grooves gradually increases from top to bottom.

[0015] Beneficial effects: This invention uses the pitch of the spiral blades to push the oil and gas towards the center, and with the help of the exhaust port to discharge the gas in the spiral channel in advance, the amount of gas accumulating in the separation chamber is reduced, ensuring the smooth progress of the oil extraction process. The connecting plate drives the ring to move longitudinally back and forth to scrape off the sand isolated outside the sandproof cylinder, ensuring the flow of oil. The diameter of the outer ring surface gradually decreases from the center to both sides, so that the scraped sand is guided away from the sandproof cylinder, assisting in scraping off the sand outside the sandproof cylinder. By releasing the elastic force of the tension spring, the sandproof cylinder is moved upward, so that the oil inside the sandproof cylinder backflushs against the sandproof holes on it, ensuring that the subsequent oil can pass smoothly through the sandproof holes of the sandproof cylinder, thus ensuring the smooth progress of the oil extraction process. Attached Figure Description

[0016] Figure 1 This is a three-dimensional structural diagram of the present invention; Figure 2 This is a three-dimensional structural cross-sectional view of the present invention; Figure 3 This is a three-dimensional structural diagram of the oil-gas interface a of the present invention; Figure 4 For the present invention Figure 3 A schematic diagram of the three-dimensional structure at point A in the middle; Figure 5 For the present invention Figure 3 A schematic diagram of the three-dimensional structure at point B in the middle; Figure 6 This is a three-dimensional structural diagram of the present invention where the limiting rod no longer limits the shoulder of the platform.

[0017] The markings in the diagram are as follows: 1-Anchor body, 11-Spiral channel, 111-Separation chamber, 12-Oil drain port, 13-Oil drain channel, 14-Exhaust channel, 15-Sealing chamber, 2-Sandproof cylinder, 21-Shoulder, 3-Spiral blade, 4-Central tube, 41-Exhaust groove, 42-Exhaust hole, 501-Sealing plug, 502-Sliding rod, 51-Guide groove, 503-Connecting plate, 504-Ring, 601-Fixing rod, 602-First spring, 701-Fixing ring, 702-Tension spring, 801-Limiting rod, 802-Limiting component, 803-Second spring. Detailed Implementation

[0018] The present invention will be further described below with reference to the embodiments shown in the accompanying drawings. Example 1

[0019] The existing spiral gas anchor further separates the gas and oil after the spiral blades have separated them in the separation chamber. When the gas content is high, the gas cannot be discharged into the annulus through the exhaust channel in a short time. The gas will occupy the upper part of the separation chamber, causing the oil level on the outside to be lower than the oil outlet. The gas will be discharged into the oil outlet channel through the oil outlet that is not blocked by oil, and then enter the subsequent oil pipe, affecting the oil pumping process.

[0020] A variable pitch helical gas anchor, such as Figures 1-3 As shown, the system includes an anchor body 1, which is installed at the lower end of the tubing. A sand-proof cylinder 2 is installed on the lower side of the anchor body 1. In this embodiment, the connection between the sand-proof cylinder 2 and the anchor body 1 is considered to be fixed. A sand-proof hole is provided at the lower part of the sand-proof cylinder 2. During the upstroke, the downhole oil-gas mixture passes through the sand-proof hole of the sand-proof cylinder 2 and enters the sand-proof cylinder 2. Sand in the oil-gas mixture is intercepted on the outside of the sand-proof cylinder 2. A spiral blade 3 is fixedly connected inside the anchor body 1, and a central tube fixedly connected to the anchor body 1 is fixedly connected to the middle of the spiral blade 3. 4. The anchor body 1, spiral blade 3, and central tube 4 cooperate to form a spiral channel 11. The oil-gas mixture enters the channel through the lower side of the anchor body 1 and is guided by the spiral blade 3 to spiral upward along the spiral channel 11. Due to the different densities of the gas and petroleum in the oil-gas mixture, the centrifugal force experienced by the gas during rotation is less than that experienced by the petroleum, thus separating the gas and petroleum. A separation chamber 111 is provided on the upper side of the spiral blade 3 inside the anchor body 1. The oil-gas interface of the rotating gas and petroleum in the separation chamber 111 is as follows: Figure 3As shown in Figure 'a', 'a' is an inverted conical surface with the outer oil level higher than the inner oil level. Anchor body 1 has an oil drain port 12 connected to separation chamber 111, an oil drain channel 13 connected to the oil drain port 12, and an exhaust channel 14 connected to the central pipe 4. The central pipe 4 has an exhaust groove 41 connected to separation chamber 111. The rotating gas in separation chamber 111 flows upward through exhaust groove 41 into exhaust channel 14 and is discharged into the oil sheath. The rotating oil in separation chamber 111 flows upward through oil drain port 12 into oil drain channel 13 and flows upward into the subsequent oil pipe. An inverted trumpet-shaped guide surface is provided on anchor body 1 near exhaust groove 41. In the gas collection and separation chamber 111, the pitch of the lower side of the spiral blade 3 is smaller than that of the upper side, so that the oil-gas mixture has already undergone high-speed rotation and oil-gas separation in the lower side of the spiral channel 11. The pitch of the upper side of the spiral blade 3 gradually increases from bottom to top. The separated gas and oil move upward along the spiral channel 11 and the rotation speed gradually decreases. The central tube 4 is provided with exhaust holes 42 distributed in a spiral shape. The separated gas in the spiral channel 11 enters the central tube 4 in advance through the exhaust holes 42. The diameter of the exhaust holes 42 distributed in a spiral shape increases from bottom to top, which is adapted to the characteristic of the increased gas content between adjacent blades due to the increased pitch of the spiral blade 3, so that more gas is discharged from the upper spiral channel 11.

[0021] Oil extraction consists of two processes: the upstroke and the downstroke. During the upstroke, the downhole oil-gas mixture passes through the sand-proof holes of the sand-proof cylinder 2 and enters the sand-proof cylinder 2. Sand in the oil-gas mixture is intercepted on the outside of the sand-proof cylinder 2. The oil-gas mixture enters through the lower side of the anchor body 1 and is guided by the spiral blades 3 to spirally rise along the spiral channel 11. Due to the different densities of gas and oil in the oil-gas mixture, the centrifugal force experienced by the gas during rotation is less than that experienced by the oil, thus separating the gas and oil. As the oil moves upward in the spiral channel 11, it gradually accumulates on the outside of the spiral channel 11, while the gas mainly accumulates on the side of the spiral channel 11 closer to the central tube 4. Finally, the separated gas and oil rotate into the separation chamber 111. The oil-gas interface of the rotating gas and oil in the separation chamber 111 is as follows: Figure 3 As shown in Figure 'a', 'a' is an inverted conical surface with the outer liquid level of the petroleum being higher than the inner liquid level. The rotating gas in the separation chamber 111 enters the exhaust channel 14 through the exhaust groove 41 and is discharged into the air of the oil sheath. The rotating petroleum in the separation chamber 111 enters the exhaust channel 13 through the oil outlet 12 and flows upward into the subsequent oil pipe.

[0022] As the oil-gas mixture moves upward along the spiral channel 11, the pitch of the lower side of the spiral blade 3 is smaller than the pitch of the upper side. This causes the oil-gas mixture to undergo high-speed rotation and complete oil-gas separation on the lower side of the spiral channel 11. When entering the upper side of the spiral channel 11, the oil and gas in the mixture move upward with the middle part being gas and the outer part being petroleum. After the gas and petroleum enter the upper side of the spiral channel 11, the rotation speed of the separated gas and petroleum decreases because the pitch of the upper side of the spiral blade 3 gradually increases from bottom to top. As a result, the oil-gas liquid surface a gradually flattens (this flattening is only relative to the high-speed rotating oil-gas interface; in reality, the tilt angle of the oil-gas liquid surface a will only decrease slightly). As the oil-gas interface a gradually flattens, the oil on the outer side will squeeze the gas in the middle, causing the gas to enter the central tube 4 through the exhaust port 42. In addition, some gas will actively enter the central tube 4 through the exhaust port 42, thereby assisting the discharge of gas in the spiral channel 11. Since the upper pitch of the spiral blade 3 is greater than the lower pitch, the diameter of the spirally distributed exhaust port 42 is set to gradually increase from bottom to top, so that more gas is discharged from the upper spiral channel 11. By changing the pitch of the spiral blade 3, the oil pushes the gas towards the middle, and in conjunction with the exhaust port 42, the gas in the spiral channel 11 is discharged in advance, preventing most of the gas from accumulating in the separation chamber 111, and instead being discharged into the oil discharge channel 13 with the oil.

[0023] After the upstroke ends, the downstroke begins. During the downstroke, the oil no longer flows upward, and the separation speed of the gas and oil in the separation chamber 111 decreases. The gas moves upward only by utilizing its own density, which is less than that of the oil seal, and continues to be discharged into the air of the oil sleeve through the exhaust channel 14. The above operation is repeated after the downstroke ends. Example 2

[0024] During oil extraction, sand carried in the oil can clog the sand-proof holes of the sand-proof cylinder, resulting in a small amount of oil entering the oil pipe and low oil extraction efficiency.

[0025] Based on Example 1, a variable pitch helical air anchor, such as Figures 1-6As shown, the anchor body 1 has two symmetrically distributed sealing cavities 15. A sealing plug 501 is slidably connected within each sealing cavity 15. During the upstroke, the pressure inside the anchor body 1 decreases, causing the adjacent sealing plugs 501 to move upwards. Each sealing plug 501 is fixedly connected to a sliding rod 502 (composed of two vertical rods of different lengths and a horizontal plate connecting the two vertical rods) that is slidably connected to the anchor body 1. The upward movement of the sealing plug 501 allows the downhole oil to slowly flow upwards through the sliding connection between the sliding rod 502 and the anchor body 1. Within the adjacent sealed cavity 15, the longitudinal movement speed of the sealing plug 501 is restricted. A connecting plate 503 is fixedly connected to the slide rod 502. The two connecting plates 503 are jointly fixedly connected to a ring 504 that is slidably connected to the sandproof cylinder 2. The diameter of the outer ring surface of the ring 504 gradually decreases from the middle to both sides. The two connecting plates 503 drive the ring 504 to move longitudinally back and forth to scrape the sand from the sandproof cylinder 2, ensuring the flow of oil. The diameter of the outer ring surface of the ring 504 gradually decreases from the middle to both sides, so that the scraped sand is guided away from the sandproof cylinder 2, assisting in scraping the sand on the outside of the sandproof cylinder 2.

[0026] like Figure 2 , Figure 3 , Figure 5 and Figure 6As shown, the anchor body 1 has fixed rods 601 symmetrically distributed on the left and right sides and located in corresponding sealed cavities 15. A sliding rod 502 is slidably connected to the adjacent fixed rod 601. A first spring 602, sleeved on the outside of the adjacent fixed rod 601, is fixed between the sliding rod 502 and the anchor body 1. Both sliding rods 502 are jointly fixed to a fixing ring 701 located above the sand-proof cylinder 2. A tension spring 702 is fixed between the fixing ring 701 and the sand-proof cylinder 2. The sand-proof cylinder 2 is slidably connected to the anchor body 1. The lower part of the anchor body 1 has two symmetrically distributed through holes. A shoulder 21 is provided on the upper side of the sand-proof cylinder 2. A limiting rod 801 for limiting the shoulder 21 is slidably connected inside the through hole of the anchor body 1. In the initial state, the two limiting rods 801 together limit the shoulder 21, preventing the sand-proof cylinder 2 from moving upwards. A limiting element 802 is slidably connected inside the through hole of the anchor body 1 on the side away from the shoulder 21. A second spring 803 is fixedly connected between the limiting element 802 and the adjacent limiting rod 801. Spring 803 is located in the adjacent through hole of anchor body 1. Slide rod 502 is provided with guide groove 51. Limiting member 802 is provided with a rectangular limiting part. The limiting part of limiting member 802 slides in the adjacent guide groove 51. The guide groove 51 is composed of a vertical groove and an inclined groove. The vertical groove of the guide groove 51 is located above its inclined groove. In the initial state, the limiting part of limiting member 802 is located above the vertical groove of the adjacent guide groove 51. The distance between the inclined grooves of the two guide grooves 51 gradually decreases from top to bottom. As the limit rod 801 enlarges, an inclined surface is provided on the side of the limit rod 801 near the fixed ring 701. The shoulder 21 is used to press the inclined surface of the limit rod 801. The elastic coefficient of the first spring 602 is greater than that of the second spring 803. During the process of the shoulder 21 moving downward from above the limit rod 801 and contacting the inclined surface of the limit rod 801, the lower side of the shoulder 21 presses the inclined surfaces of the two limit rods 801, causing the two limit rods 801 to move away from each other, and the two second springs 803 are compressed.

[0027] Before oil extraction, the condition was as follows: Figure 2 and Figure 3As shown, during the upward stroke, the pressure inside the anchor body 1 decreases, causing a decrease in the pressure inside the sealing cavity 15. The two sealing plugs 501 drive the two sliding rods 502 to move upwards. This upward movement of the sealing plugs 501 allows the downhole oil to slowly flow upwards through the sliding connection between the sliding rods 502 and the anchor body 1 into the sealing cavity 15 below the sealing plugs 501. Therefore, under the negative pressure within the anchor body 1, the sealing plugs 501 slowly move upwards. The two sliding rods 502, through the two connecting plates 503, drive the two rings 504 to move upwards. The sand adhering to the outside of the sand-proof cylinder 2 is scraped off by the rings 504, and the sliding rods 502 move upwards... The upward movement compresses the adjacent first spring 602. During the upward movement of the two slide rods 502, the two slide rods 502 drive the fixed ring 701 to move upward. Since the two limiting rods 801 limit the shoulder 21, the sand-proof cylinder 2 cannot move upward, and the tension spring 702 is stretched. The limiting part of the limiting member 802 is located in the vertical groove of the guide groove 51. If most of the sand-proof holes of the sand-proof cylinder 2 are not blocked (the anchor body 1 is in a low negative pressure state), oil will normally enter the sand-proof cylinder 2 through the unblocked sand-proof holes. However, the negative pressure in the anchor body 1 will not cause the two sealing plugs 501 to reach the required level. Figure 6 The location shown.

[0028] During the downstroke, the negative pressure inside the anchor body 1 gradually disappears. The tension of the tension spring 702 is released, causing the fixed ring 701 to move downwards. The fixed ring 701 causes the two sliding rods 502 to move downwards. At the same time, the elastic force of the two first springs 602 is released, pushing the adjacent sliding rods 502 downwards. The two sliding rods 502 cause the two sealing plugs 501 to move downwards. The sealing plugs 501 allow the oil below them to slowly drain into the well through the sliding connection between the adjacent sliding rods 502 and the anchor body 1. The two sealing plugs 501 slowly move downwards. The two sliding rods 502, through the two connecting plates 503, cause the ring 504 to move downwards again, scraping away the sand on the outside of the sand-proof cylinder 2. When the elastic force of the tension spring 702 and the two first springs 602 returns to their initial state, the state is as follows: Figure 2 As shown, the two connecting plates 503 drive the ring 504 to move longitudinally back and forth to scrape the sand off the sand-proof cylinder 2, ensuring the flow of oil. The diameter of the outer ring surface of the ring 504 gradually decreases from the middle to both sides, so that the scraped sand is guided away from the sand-proof cylinder 2, which helps to scrape the sand off the outside of the sand-proof cylinder 2.

[0029] During the upward stroke, if most of the sand-proof holes in the sand-proof cylinder 2 are blocked, the negative pressure inside the anchor body 1 causes the two sealing plugs 501 to continue moving upward at the position mentioned above during the upward stroke. Taking the sealing plug 501 on the right as an example, when the limiting part of the limiting member 802 enters the inclined groove from the vertical groove of the guide groove 51, the limiting member 802 is limited to the right by the inclined groove of the guide groove 51. The limiting member 802 drives the limiting rod 801 to move to the right through the second spring 803. When the limiting part of the limiting member 802 is located on the lower side of the inclined groove of the guide groove 51, the limiting rod 801 no longer limits the shoulder 21, and the state is as follows. Figure 6 As shown, the tension of the tension spring 702 in the stretched state releases the tension, causing the sand-proof cylinder 2 to move upward. The oil in the anchor body 1 is discharged in the reverse direction through the sand-proof hole of the sand-proof cylinder 2, which flushes out the sand blocking the sand-proof hole of the sand-proof cylinder 2, thereby ensuring that the sand-proof hole of the sand-proof cylinder 2 is not blocked. During the upward movement of the sand-proof cylinder 2, since the oil is difficult to pass through the sliding connection between the slide rod 502 and the anchor body 1 in a short time, the slide rod 502 remains almost stationary. At the same time, the fixing ring 701 remains stationary, allowing the tension spring 702 to drive the sand-proof cylinder 2 to move upward. When the tension of the tension spring 702 returns to its initial state, the sand-proof cylinder 2 no longer moves upward. At this time, the pressure in the anchor body 1 returns to a low negative pressure state.

[0030] After the upstroke ends, the first spring 602, which is in a stored state, releases its elasticity. The two first springs 602 drive the two slide rods 502 to move downwards. The two slide rods 502 drive the fixing ring 701, tension spring 702, and sandproof sleeve 2 to move downwards. Taking the right slide rod 502 as an example, the inclined groove of the guide groove 51 causes the limiting member 802 to move to the left. The limiting member 802 drives the limiting rod 801 to move to the left through the second spring 803. The inclined surface of the limiting rod 801 is located on the path of the shoulder 21 moving downwards. When the limiting part of the limiting member 802 enters the vertical groove from the inclined groove of the guide groove 51, the limiting member 802 and the limiting rod 801 no longer move to the left. When the lower side of the shoulder 21 contacts the inclined surface of the limiting rod 801, because the elastic coefficient of the first spring 602 is greater than that of the second spring... The elastic coefficient of 803 is used. The shoulder 21 squeezes the inclined surface of the limiting rod 801, causing the limiting rod 801 to move to the right. The second spring 803 is compressed. When the shoulder 21 is lower than the limiting rod 801, the elastic force of the second spring 803 in the compressed state is released, causing the limiting rod 801 to move to the left. When the elastic force of the second spring 803 is restored, the limiting rod 801 limits the shoulder 21, and the elastic force of the first spring 602 is restored. When most of the sandproof holes of the sandproof cylinder 2 are blocked again, the above steps are repeated. When the sandproof holes of the sandproof cylinder 2 are blocked, the elastic force of the tension spring 702 is released, causing the sandproof cylinder 2 to move upward, so that the oil in the sandproof cylinder 2 backflushes against the sandproof holes on it, ensuring that the subsequent oil passes smoothly through the sandproof holes of the sandproof cylinder 2, so that the oil pumping process can proceed smoothly.

[0031] Those skilled in the art should understand that the above embodiments do not limit the present invention in any way, and all technical solutions obtained by equivalent substitution or equivalent transformation fall within the protection scope of the present invention.

Claims

1. A variable pitch helical gas anchor, comprising an anchor body (1), a sand-proof cylinder (2) installed on the lower side of the anchor body (1), the sand-proof cylinder (2) having sand-proof holes, a helical blade (3) fixedly connected inside the anchor body (1), a central tube (4) fixedly connected to the middle of the helical blade (3) and fixedly connected to the anchor body (1), the anchor body (1), the helical blade (3) and the central tube (4) forming a helical channel (11), and a separation cavity ( ) provided on the upper side of the helical blade (3) inside the anchor body (1). 111), the anchor body (1) is provided with an oil drain port (12) communicating with the separation chamber (111), the anchor body (1) is provided with an oil drain channel (13) communicating with the oil drain port (12), the anchor body (1) is provided with an exhaust channel (14) communicating with the central pipe (4), the central pipe (4) is provided with an exhaust groove (41) communicating with the separation chamber (111), and the anchor body (1) is provided with an inverted trumpet-shaped guide surface near the exhaust groove (41), characterized in that: The pitch of the lower side of the spiral blade (3) is smaller than that of the upper side, and the pitch of the upper side of the spiral blade (3) gradually increases from bottom to top. The central tube (4) is provided with exhaust holes (42) distributed in a spiral shape. The anchor body (1) is provided with symmetrically distributed sealing cavities (15). A sealing plug (501) is slidably connected in the sealing cavity (15). The sealing plug (501) is fixedly connected to a slide rod (502) that is slidably connected to the anchor body (1). The slide rod (502) is fixedly connected to a connecting plate (503). The symmetrically distributed connecting plates (503) are jointly fixedly connected to a circular ring that is slidably connected to the sandproof cylinder (2). Ring (504); The anchor body (1) is fixedly connected with symmetrically distributed fixed rods (601) respectively located in the corresponding sealing cavity (15), the sliding rod (502) is slidably connected to the adjacent fixed rod (601), and the sliding rod (502) and the anchor body (1) are fixedly connected with a first spring (602) sleeved on the outside of the adjacent fixed rod (601); The symmetrically distributed sliding rods (502) are jointly fixedly connected with a fixed ring (701), and the fixed ring (701) and the sandproof cylinder (2) are fixedly connected with a tension spring (702), and the sandproof cylinder (2) and the anchor body (1) are slidably connected.

2. The variable pitch helical gas anchor according to claim 1, characterized in that: The diameter of the exhaust holes (42) distributed in a spiral shape increases from bottom to top.

3. A variable pitch helical gas anchor according to claim 1, characterized in that: The diameter of the outer ring (504) gradually decreases from the middle to both sides.

4. A variable pitch helical gas anchor according to claim 1, characterized in that: The lower part of the anchor body (1) is provided with symmetrically distributed through holes. The sand-proof cylinder (2) is provided with a shoulder (21) on the side near the fixing ring (701). A limiting rod (801) for limiting the shoulder (21) is slidably connected in the through hole of the anchor body (1). A limiting member (802) is slidably connected in the through hole of the anchor body (1) on the side away from the shoulder (21). A second spring (803) is fixed between the limiting member (802) and the adjacent limiting rod (801).

5. A variable pitch helical gas anchor according to claim 4, characterized in that: The slide bar (502) is provided with a guide groove (51), and the limiting member (802) is provided with a rectangular limiting part, and the limiting part of the limiting member (802) slides in the adjacent guide groove (51).

6. A variable pitch helical gas anchor according to claim 4, characterized in that: The limiting rod (801) has an inclined surface on the side near the fixing ring (701), and the shoulder (21) is used to press the inclined surface of the limiting rod (801). The elastic coefficient of the first spring (602) is greater than that of the second spring (803).

7. A variable pitch helical gas anchor according to claim 5, characterized in that: The guide groove (51) is composed of a vertical groove and an inclined groove. The vertical groove of the guide groove (51) is located above its inclined groove. The guide groove (51) is symmetrically distributed. The distance between the inclined grooves gradually increases from top to bottom.

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