Composite cavity completion sand screen

Abstract

The present application relates to sand control screen pipe technical field, especially to composite cavity type well completion sand filter pipe, including: screen pipe, the screen pipe is provided with the filter hole of uniform distribution, the screen pipe is provided with the flow collection cavity that communicates with all filter hole, the screen pipe is provided with the annular uniform distribution of lower lug and annular uniform distribution of upper lug, the lower lug with the upper lug one to one, the lower lug and corresponding upper lug are jointly fixed with extrusion strip, the screen pipe, all lower lug, all upper lug and all extrusion strip jointly constitute the primary filter cavity, the present application relies on the interception of screen pipe to gravel and forms sand layer, and uses extrusion strip to extrude the sand layer of screen pipe periphery side, makes sand layer form stable, so using sand layer carries out sand control, eliminates the step of additional filling sandstone, simplifies installation process, shortens the time length required for installation, further improves installation efficiency.

Description

Technical Field

[0001] This invention relates to the field of sand control screen pipe technology, and more particularly to composite cavity well completion sand filter pipe. Background Technology

[0002] Well completion filter pipes, commonly known as sand screens or oil well sand filters, are key downhole tools installed at the bottom of oil wells in the reservoir area during oil and gas extraction. They allow crude oil to flow into the wellbore through physical filtration while effectively blocking sand and gravel. Traditional screens rely on the screen mesh to directly intercept sand and gravel, but under the impact of high-speed sand-laden fluids, the sand particles have high kinetic energy and continuously impact the screen surface, leading to material wear and ultimately erosion damage. To solve this problem, gravel packing completion is often used in the field: after the screen pipe is lowered into the well, sand and gravel are filled into the annulus between the screen pipe and the wellbore to form an outer sand layer. This sand layer acts as a pre-filtration barrier, intercepting large sand particles in the fluid and significantly reducing the fluid velocity and kinetic energy, thereby reducing the direct erosion of the screen mesh by the sand-laden fluid. However, this packing operation is relatively cumbersome, resulting in a long installation time for the screen pipe and affecting operational efficiency. Summary of the Invention

[0003] This invention provides a composite cavity well completion filter pipe to overcome the shortcomings of existing filter pipes, such as long installation time and low operation efficiency.

[0004] The technical implementation scheme of the present invention is as follows: a composite cavity well completion sand filter pipe, comprising: a screen pipe, wherein the screen pipe is provided with uniformly distributed filter holes, and a confluence cavity is provided inside the screen pipe that communicates with all the filter holes. A ring-shaped, uniformly distributed lower connecting plate and a ring-shaped, uniformly distributed upper connecting plate are provided on the outer side of the screen pipe. The lower connecting plate corresponds one-to-one with the upper connecting plate. Both the lower connecting plate and the upper connecting plate are capable of swinging relative to the screen pipe. An extrusion strip is fixedly connected to the lower connecting plate and the corresponding upper connecting plate. The screen pipe, all the lower connecting plates, all the upper connecting plates, and all the extrusion strips together form a primary filtration cavity. The primary filtration cavity is used to contain gravel to form a sand layer for sand control. A power assembly is provided inside the screen pipe for controlling the movement of all the extrusion strips to change the volume of the primary filtration cavity.

[0005] Furthermore, the power assembly includes: a connecting ring slidably connected inside the screen tube; a traction rope fixedly connected to one end of the upper connecting piece near the extrusion strip; a connecting hole provided on the screen tube near all the traction ropes; the traction rope passing through adjacent connecting holes and then fixedly connected to the connecting ring; and a ring-shaped distribution of shielding plates provided inside the connecting ring, the shielding plates being used to shield the middle part of the connecting ring; the movement of the connecting ring being powered by the fluid drag force of the crude oil flowing in the manifold on the shielding plates.

[0006] Furthermore, both ends of the connecting hole are provided with annular arc surfaces, which are used to reduce the friction when the traction rope slides in the connecting hole.

[0007] Furthermore, the connecting ring is fixedly connected with a number of hinged rods equal to the number of the shielding fan plates. The hinged rods are rotatably connected to the shielding fan plates. Elastic sheets are fixedly connected to the connecting ring near all the shielding fan plates. The end of the elastic sheet away from the connecting ring is fixedly connected to the corresponding shielding fan plate. The shielding fan plate is provided with a sliding groove. A sliding block is slidably connected to the sliding groove. The sliding block is threadedly connected to a fixing bolt. The fixing bolt is rotatably connected to a pressure plate. The pressure plate is used to compress the corresponding elastic sheet.

[0008] Furthermore, the shielding fan plate is provided with a hinge portion near the adjacent hinge rod. The hinge portion is cylindrical, and the hinge rod is not coaxial with the adjacent hinge portion. The hinge portion is used to compress the adjacent elastic sheet when the adjacent shielding fan plate rotates.

[0009] Furthermore, a connecting block is fixedly connected to each of the positions corresponding to all the shielding fan plates inside the connecting ring. The connecting block is threaded with an adjusting bolt, which is used to press against the adjacent shielding fan plates.

[0010] Furthermore, both the lower and upper connecting pieces are made of elastic material, and both always tend to pull the adjacent extrusion strip away from the screen tube.

[0011] Furthermore, the sieve tube is fixedly connected to a dissolving column, which is fixedly connected to the connecting ring.

[0012] Furthermore, the side of the extrusion bar away from the screen tube is provided with several grooves, which are used to enhance the bending strength of the extrusion bar.

[0013] Furthermore, the extrusion bar has an arc-shaped surface on the side near the screen tube, which is used to help gather the sand and gravel in the primary filtration chamber.

[0014] Overall, compared with the prior art, the above-mentioned technical solutions conceived by the present invention can achieve the following beneficial effects: The present invention relies on the interception of sand and gravel by the screen tube to form a sand layer, and uses the extrusion strip to extrude the sand layer on the outer periphery of the screen tube to keep the sand layer shape stable. In this way, the sand layer is used for sand prevention, eliminating the need for additional filling of sand and gravel, simplifying the installation process, shortening the installation time, and thus improving the installation efficiency.

[0015] By limiting the length of the free part of the elastic sheet with a pressure plate, the length of the part where the elastic sheet bends during the swing of the baffle plate is adjusted, thereby changing the magnitude of the elastic force that the elastic sheet needs to overcome when it deforms. This changes the threshold at which the baffle plate swings relative to the connecting ring, thereby changing the maximum extrusion force of the extrusion strip on the sand layer and reducing the probability of the extrusion strip damaging the sand layer structure.

[0016] Relying on the elasticity of the lower and upper connecting plates, after the sand layer has been used for a long time, by stopping oil production, the connecting ring and the shielding fan plate are no longer affected by the fluid drag force. Under the elastic force of the lower and upper connecting plates, the extrusion bar moves away from the screen pipe and releases the extrusion on the sand layer. In this way, the original sand layer collapses on its own under the action of gravity. After oil production is resumed, the sand and gravel are re-adsorbed to form a new sand layer. This makes it easy to replace the sand layer, improves oil production efficiency, and does not affect the casing, well wall, etc. Attached Figure Description

[0017] Figure 1 This is a three-dimensional structural diagram of the present invention;

[0018] Figure 2 This is a three-dimensional structural diagram of the sieve tube and extrusion bar of the present invention;

[0019] Figure 3 This is a three-dimensional structural diagram of the lower and upper connectors of the present invention;

[0020] Figure 4 This is a three-dimensional structural diagram of the upper connector and connecting ring of the present invention;

[0021] Figure 5 This is a three-dimensional structural diagram of the shielding fan plate and the dissolving column of the present invention;

[0022] Figure 6 This is a three-dimensional structural cross-sectional view of the connecting ring and the shielding fan plate of the present invention;

[0023] Figure 7 This is a three-dimensional structural diagram of the lower connecting piece and the extrusion strip of the present invention.

[0024] The meanings of the reference numerals in the figure are as follows: 1-sieve tube, 101-filter hole, 102-combination cavity, 2-lower connecting plate, 3-upper connecting plate, 4-extrusion strip, 401-primary filtration cavity, 402-groove, 403-arc strip surface, 5-traction rope, 501-connecting hole, 502-annular arc surface, 6-connecting ring, 7-shielding fan plate, 701-hinge part, 8-connecting block, 9-adjusting bolt, 10-hinge rod, 11-elastic plate, 12-sliding block, 121-sliding groove, 13-fixing bolt, 14-pressure plate, 15-dissolving column. Detailed Implementation

[0025] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments. Example 1

[0026] This embodiment provides a composite cavity well completion filter pipe to solve the problems of long installation time and low operation efficiency of existing filter pipes.

[0027] See Figures 1 to 4 A composite cavity well completion filter pipe includes: a screen pipe 1, on which uniformly distributed filter holes 101 are provided. The filter holes 101 are used to intercept gravel and allow crude oil to pass through the screen pipe 1; a confluence cavity 102 is provided inside the screen pipe 1, which is connected to all the filter holes 101; and annularly distributed lower connecting plates 2 and annularly distributed upper connecting plates 3 are provided on the outside of the screen pipe 1. In the axial direction of the screen pipe 1, the lower connecting plates 2 and the upper connecting plates 3 correspond one-to-one. Both the lower connecting plates 2 and the upper connecting plates 3 can swing relative to the screen pipe 1. The lower connecting plates 2 and the corresponding upper connecting plates 3 are fixedly connected to the extrusion strips 4. The screen pipe 1, all the lower connecting plates 2, all the upper connecting plates 3 and all the extrusion strips 4 together form a primary filter cavity 401. The primary filter cavity 401 is used to contain gravel to form a sand layer for sand control. A power component is provided inside the screen pipe 1 to control the movement of all the extrusion strips 4 to change the volume of the primary filter cavity 401.

[0028] The above setup enables the formation of a sand layer by intercepting gravel with the screen tube 1, and the sand layer is kept stable by the compression of the outer periphery of the screen tube 1 by the extrusion strip 4. This sand layer is used for sand prevention, eliminating the need for additional filling of sand and gravel, simplifying the installation process, shortening the installation time, and thus improving installation efficiency.

[0029] It should be noted that in this embodiment, the arrangement of the lower connecting piece 2 and the upper connecting piece 3 with the screen tube 1 can be regarded as a rotatable connection.

[0030] See Figure 4 and Figure 5 The power assembly includes: a connecting ring 6, which is slidably connected inside the screen tube 1, and a clamp is fitted inside the screen tube 1 (see...). Figure 4 The clamp is used to limit the lower limit position of the connecting ring 6; the upper connecting piece 3 is fixedly connected to the end near the extrusion strip 4 with a traction rope 5. The screen tube 1 is provided with a connecting hole 501 near all the traction ropes 5. The upper end of the traction rope 5 passes through the adjacent connecting hole 501 and is fixedly connected to the connecting ring 6. Three shielding fan plates 7 are arranged in a ring inside the connecting ring 6. The shielding fan plates 7 are used to shield the middle part of the connecting ring 6. There is a gap between the shielding fan plates 7 and the connecting ring 6 to reduce the flow area when the fluid flows upward along the manifold 102. The fluid drag force of the crude oil on the shielding fan plates 7 when it flows in the manifold 102 provides power for the movement of the connecting ring 6. Then, the traction rope 5 pulls the extrusion strip 4 to swing, so that the extrusion strip 4 extrudes the sand layer.

[0031] The number and area of ​​the shielding fan 7 are determined based on the optimal oil production rate (corresponding to the maximum flow velocity of the fluid) and the viscosity of the fluid in the well to be installed. Under the optimal oil production rate, the upward force provided by the fluid drag on the shielding fan 7 is sufficient to move the connecting ring 6, the traction rope 5 and the compression bar 4 together. However, under the condition of less than the optimal oil production rate, the upward force provided by the fluid drag on the shielding fan 7 is insufficient to overcome the gravity of the connecting ring 6, that is, it is impossible to move the connecting ring 6.

[0032] It should be noted that in this embodiment, the arrangement of the shielding fan plate 7 and the connecting ring 6 can be considered as a fixed connection; and in this embodiment, the lower connecting piece 2, the upper connecting piece 3, and the extrusion strip 4 are initially attached. Figure 3 As shown, the connecting ring 6 is initially in contact with the clamp on its lower side.

[0033] Workflow: After the casing is run into the oil well, this device is installed at the designated position on the casing using tools. Oil production then begins, and the production rate is controlled to be lower than the optimal production rate. During oil production, due to the pressure difference between the inside and outside of the casing, the fluid in the formation will continuously flow into the casing. Specifically, the sand-bearing fluid in the formation enters the primary filter chamber 401 through the gap between two adjacent extrusion strips 4. Then, the sand-bearing fluid passes through the filter hole 101 and enters the manifold 102, and begins to flow upward along the manifold 102. During the process of the sand-bearing fluid passing through the filter hole 101, the filter hole 101... 1. Sand and gravel larger than the pore size in the sand-containing fluid are intercepted. The intercepted sand and gravel are stably adhered to the outer periphery of the screen tube 1 by the fluid drag, gravity, and the interlocking force between the sand and gravel, that is, they are kept in the primary filtration chamber 401. Since the filter holes 101 are evenly distributed on the outer periphery of the screen tube 1, the sand and gravel will be evenly deposited and accumulated in the primary filtration chamber 401, eventually forming a continuous annular sand layer that wraps around the outer periphery of the screen tube 1. The sand-containing fluid flows upward in the confluence chamber 102 and continues to flow upward after passing through the gap between the connecting ring 6 and the three baffle plates 7. During this process, the connecting ring 6 remains stationary.

[0034] After a specified time (the time is determined based on the sand content in the sand-laden fluid, aiming to wait until the sand layer thickness on the outer periphery of the screen tube 1 reaches the ideal thickness), the oil production rate is increased to the optimal oil production rate. This increases the fluid drag force on the baffle plate 7 as the fluid flows in the confluence cavity 102. The baffle plate 7 drives the connecting ring 6 to move upward. The connecting ring 6 drives all the upper connecting plates 3 to swing upward together through all the traction ropes 5. The upper connecting plates 3 drive the adjacent extrusion strips 4 and the adjacent lower connecting plates 2 to move. Since the screen tube 1, lower connecting plates 2, upper connecting plates 3 and extrusion strips 4 form a near-parallelogram structure, the extrusion strips 4 will move closer to the screen tube 1 during the swinging of the upper connecting plates 3, reducing the volume of the primary filtration cavity 401. The extrusion strips 4 extrude the sand layer formed in the primary filtration cavity 401, stabilizing the sand layer. In this way, a stable sand layer can be formed without additional sand filling. This sand layer is used to pre-filter the sand-laden fluid, reducing the kinetic energy of the sand-laden fluid and reducing the direct erosion of the screen tube 1 by the sand-laden fluid. Example 2

[0035] This embodiment is a further optimization based on Embodiment 1.

[0036] See Figure 4 Both ends of the connecting hole 501 are provided with annular arc surfaces 502, which are used to reduce the friction force when the traction rope 5 slides in the connecting hole 501. Example 3

[0037] This embodiment is a further optimization based on embodiment 2, in order to limit the maximum extrusion force of the extrusion strip 4 on the sand layer.

[0038] See Figure 5 and Figure 6The connecting ring 6 is fixedly connected with a number of hinge rods 10 equal to the number of shielding fan plates 7. The hinge rods 10 are rotatably connected to the shielding fan plates 7, allowing the shielding fan plates 7 to swing relative to the connecting ring 6. Elastic plates 11 are fixedly connected to the connecting ring 6 near all the shielding fan plates 7. The elastic plates 11 are made of high-temperature resistant elastic metal. The end of the elastic plate 11 furthest from the connecting ring 6 is fixedly connected to the corresponding shielding fan plate 7. The force required for the deformation of the three elastic plates 11 is greater than the weight of the connecting ring 6, meaning that the fluid drag force will first drive the connecting ring 6 to move before causing the elastic plates 11 to deform. Two symmetrically distributed... The sliding groove 121 has a sliding block 12 that is slidably connected within it. The sliding block 12 is threadedly connected to a fixing bolt 13. Two fixing bolts 13 on the same shielding fan plate 7 are rotatably connected to a pressure plate 14. The pressure plate 14 is used to compress the corresponding elastic sheet 11 (hereinafter, the part of the elastic sheet 11 located between the pressure plate 14 and the connecting ring 6 will be referred to as the free part. This free part will deform when the shielding fan plate 7 swings. The part of the elastic sheet 11 located on the side of the pressure plate 14 near the axis of the connecting ring 6 is in contact with the adjacent shielding fan plate 7. This part will not deform when the shielding fan plate 7 swings).

[0039] The above settings can restrict the length of the free part of the elastic sheet 11 by the pressure plate 14, thereby adjusting the length of the part of the elastic sheet 11 that bends during the swinging process of the baffle plate 7, changing the magnitude of the elastic force that the elastic sheet 11 needs to overcome when it deforms, thus changing the threshold of the baffle plate 7 swinging relative to the connecting ring 6, thereby changing the maximum extrusion force of the extrusion strip 4 on the sand layer and reducing the probability of the extrusion strip 4 damaging the sand layer structure.

[0040] During oil production operations at the optimal oil recovery rate, the fluid, through its drag force, moves the shielding fan 7 and connecting ring 6 upwards. Once the extrusion strip 4 contacts the sand layer, the extrusion strip 4 and connecting ring 6 stop moving. In this state, the fluid drag force is directly converted into the extrusion force of the extrusion strip 4 on the sand layer. To prevent the extrusion force of the extrusion strip 4 from being too great, which could lead to tight bonding of the sand layer or crushing of the gravel, the following measures are taken: After the connecting ring 6 stops moving, the shielding fan 7 swings under the action of the fluid drag force. The shielding fan 7 causes the adjacent elastic sheet 11 to bend. After the shielding fan 7 swings, the gap between the shielding fan 7 and the connecting ring 6, as well as the gap between two adjacent shielding fan 7, increases. The fluid drag force acting on the shielding fan 7 decreases, thus reducing the extrusion force of the extrusion strip 4 on the sand layer and reducing the probability of damaging the sand layer.

[0041] See Figure 5The shielding fan plate 7 is provided with a hinge part 701 near the adjacent hinge rod 10. The hinge part 701 is cylindrical, and the hinge rod 10 and the adjacent hinge part 701 are not coaxial. Initially, the distance between the side of the hinge part 701 away from the axis of the connecting ring 6 and the hinge rod 10 is the smallest. When the shielding fan plate 7 swings, the hinge part 701 rotates around the hinge rod 10, so that the distance between the side of the hinge part 701 away from the axis of the connecting ring 6 and the hinge rod 10 gradually increases. The hinge part 701 presses the adjacent elastic sheet 11, so that the compressive force between the elastic sheet 11 and the screen tube 1 increases, thereby increasing the friction between the elastic sheet 11 and the screen tube 1. This friction is used to maintain the stability of the relative position between the connecting ring 6 and the screen tube 1. Example 4

[0042] This embodiment is a further optimization based on embodiment 3, to improve the ease of adjusting the flow area in the middle of the connecting ring 6.

[0043] See Figure 5 and Figure 6 Connecting blocks 8 are fixedly connected to the positions corresponding to all the shielding fan plates 7 inside the connecting ring 6. The connecting blocks 8 are threadedly connected to adjusting bolts 9, which are used to press the adjacent shielding fan plates 7.

[0044] The above settings enable the initial position of the shielding fan plate 7 to be changed by adjusting the bolt 9 to squeeze the shielding fan plate 7, thereby changing the projected area of ​​the shielding fan plate 7 on the horizontal plane. This adjusts the flow area between the shielding fan plate 7 and the connecting ring 6 at the initial stage, thus adapting to oil wells with different oil production rates. Example 5

[0045] This embodiment is a further optimization based on embodiment 4.

[0046] After long-term use, the amount of fine sand and gravel accumulated inside the sand layer increases, which reduces the porosity of the sand layer and causes blockage, affecting the flow rate of formation fluid into the casing. When this problem occurs, physical flushing is usually used to backflush out the fine sand and gravel blocking the sand layer. However, this method is time-consuming, easily damages the original sand layer structure, and causes erosion and wear to the screen pipe, well wall, and casing.

[0047] See Figure 3 Both the lower connecting piece 2 and the upper connecting piece 3 are made of elastic material, and both always have a tendency to pull the adjacent extrusion strip 4 away from the screen tube 1, that is, when the extrusion strip 4 is in the attached position... Figure 3 In the state shown, the lower piece 2 and the upper piece 3 still have the tendency to drive the extrusion strip 4 to move outward.

[0048] It should be noted that in this embodiment and subsequent embodiments, when the fluid drag force drives the connecting ring 6 and the shielding fan plate 7 to move, it needs to overcome the sum of the gravity of the connecting ring 6 and the elastic force of the lower connecting piece 2 and the upper connecting piece 3.

[0049] The above setup enables the connection ring 6 and the shielding fan 7 to be freed from the influence of fluid drag by stopping oil production after the sand layer has been used for a long time, relying on the elasticity of the lower connecting plate 2 and the upper connecting plate 3. This allows the extrusion strip 4 to move away from the screen pipe 1 under the elastic force of the lower connecting plate 2 and the upper connecting plate 3, thus releasing its extrusion on the sand layer. In this way, the original sand layer will collapse on its own under the action of gravity. After oil production is resumed, the sand and gravel will be reabsorbed to form a new sand layer. This makes it easy to replace the sand layer, improves oil production efficiency, and will not affect the casing, well wall, etc. Example 6

[0050] This embodiment is a further optimization based on embodiment 5.

[0051] See Figure 4 and Figure 5 The screen tube 1 is fixedly connected to a dissolving column 15, which is made of a soluble material (such as a soluble magnesium alloy or a polymer material) and can slowly dissolve on its own in the downhole fluid; the dissolving column 15 is fixedly connected to the connecting ring 6.

[0052] The above setup enables the dissolving column 15 to limit the connecting ring 6, allowing the extrusion strip 4 to remain close to the screen tube 1 during installation, thereby reducing the outer diameter of the device and facilitating installation. After the device is installed, the dissolving column 15 gradually dissolves, eventually releasing the limit on the connecting ring 6. Under the elastic force of the lower connecting piece 2 and the upper connecting piece 3, as well as the gravity of the connecting ring 6, the connecting ring 6 moves downward and contacts the clamp. Example 7

[0053] This embodiment is a further optimization based on embodiment 6.

[0054] See Figure 7 The side of the extrusion strip 4 away from the screen tube 1 is provided with several grooves 402, which are used to enhance the bending strength of the extrusion strip 4; the side of the extrusion strip 4 close to the screen tube 1 is provided with an arc-shaped strip surface 403, which is used to assist in the agglomeration of sand and gravel in the primary filtration chamber 401.

[0055] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention.

Claims

1. A composite cavity type well completion filter pipe, comprising: A sieve tube (1) is provided with uniformly distributed filter holes (101), and a confluence cavity (102) is provided inside the sieve tube (1) that communicates with all the filter holes (101). The sieve tube (1) is characterized by having annularly distributed lower connecting pieces (2) and annularly distributed upper connecting pieces (3) on its outer side. The lower connecting pieces (2) and the upper connecting pieces (3) correspond one-to-one, and both the lower connecting pieces (2) and the upper connecting pieces (3) are capable of moving relative to the sieve tube (1). The lower connecting piece (2) and the corresponding upper connecting piece (3) are fixedly connected to the extrusion strip (4). The screen tube (1), all the lower connecting pieces (2), all the upper connecting pieces (3) and all the extrusion strips (4) together form the primary filtration chamber (401). The primary filtration chamber (401) is used to contain sand and gravel to form a sand layer for sand prevention. The screen tube (1) is provided with a power component for controlling the movement of all the extrusion strips (4) to change the volume of the primary filtration chamber (401). The power assembly includes: The connecting ring (6) is slidably connected inside the screen tube (1). The upper connecting piece (3) is fixedly connected to a traction rope (5) at one end near the extrusion strip (4). A connecting hole (501) is provided on the screen tube (1) near all the traction ropes (5). The traction rope (5) passes through the adjacent connecting hole (501) and is fixedly connected to the connecting ring (6). A ring-shaped shielding fan (7) is provided inside the connecting ring (6). The shielding fan (7) is used to shield the middle part of the connecting ring (6). The fluid drag force of the crude oil on the shielding fan (7) when it flows in the manifold (102) provides power for the movement of the connecting ring (6).

2. The composite cavity well completion filter pipe according to claim 1, characterized in that: Both ends of the connecting hole (501) are provided with annular arc surfaces (502), which are used to reduce the friction force when the traction rope (5) slides in the connecting hole (501).

3. The composite cavity well completion filter pipe according to claim 1, characterized in that: The connecting ring (6) is fixedly connected with a number of hinge rods (10) equal to the number of shielding fan plates (7). The hinge rods (10) are rotatably connected to the shielding fan plates (7). Elastic plates (11) are fixedly connected to the connecting ring (6) near all the shielding fan plates (7). The end of the elastic plate (11) away from the connecting ring (6) is fixedly connected to the corresponding shielding fan plate (7). The shielding fan plate (7) is provided with a sliding groove (121). A sliding block (12) is slidably connected in the sliding groove (121). A fixing bolt (13) is threadedly connected to the sliding block (12). A pressure plate (14) is rotatably connected to the fixing bolt (13). The pressure plate (14) is used to squeeze the corresponding elastic plate (11).

4. The composite cavity well completion filter pipe according to claim 3, characterized in that: The shielding fan plate (7) is provided with a hinge part (701) near the adjacent hinge rod (10). The hinge part (701) is cylindrical, and the hinge rod (10) is not coaxial with the adjacent hinge part (701). The hinge part (701) is used to press the adjacent elastic sheet (11) when the adjacent shielding fan plate (7) rotates.

5. A composite cavity well completion filter pipe according to claim 4, characterized in that: A connecting block (8) is fixedly connected to each of the positions corresponding to all the shielding fan plates (7) in the connecting ring (6). The connecting block (8) is threaded with an adjusting bolt (9). The adjusting bolt (9) is used to press the adjacent shielding fan plates (7).

6. The composite cavity well completion filter pipe according to claim 1, characterized in that: Both the lower connecting piece (2) and the upper connecting piece (3) are made of elastic material, and both of them always have the tendency to drive the adjacent extrusion strip (4) away from the screen tube (1).

7. A composite cavity well completion filter pipe according to claim 5, characterized in that: The sieve tube (1) is fixedly connected to a dissolving column (15), and the dissolving column (15) is fixedly connected to the connecting ring (6).

8. A composite cavity well completion filter pipe according to claim 7, characterized in that: The extrusion strip (4) has several grooves (402) on the side away from the screen tube (1), and the grooves (402) are used to enhance the bending strength of the extrusion strip (4).

9. A composite cavity well completion filter pipe according to claim 8, characterized in that: The extrusion bar (4) has an arc-shaped strip surface (403) on the side near the screen tube (1), and the arc-shaped strip surface (403) is used to assist the sand and gravel in the primary filtration chamber (401) to gather.

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