CN212428759U - Self-cleaning type circular seam sand control filter unit and single sand control screen pipe - Google Patents

Abstract

The utility model relates to a self-cleaning type circular seam sand control filter unit and monomer formula sand control screen pipe, wherein, self-cleaning type circular seam sand control filter unit has seted up the through-hole including the shell that has the inner groovy on the shell, and nested has a stem, at least one intermediate ring and an outer ring in the inner groovy. The outer wall of the outer layer ring is attached to the wall of the inner groove, and the core column, the middle ring and the outer layer ring form an annular seam channel respectively. One end of each annular slit channel close to the bottom of the inner groove is respectively used as the inner end of the annular slit channel, and one end of each annular slit channel close to the notch of the inner groove is respectively used as the outer end of the annular slit channel. The longitudinal section of each annular slit passage along the axial direction of the shell is rectangular at the part close to the inner end of the annular slit passage, and the part close to the outer end of the annular slit passage is trapezoidal with large outside and small inside. The core column, the middle ring and the outer layer ring are fixed with each other through the clamping and locking piece respectively. The utility model discloses a self-cleaning type circular seam sand control filter unit and monomer formula sand control screen pipe have controllable and high-efficient self-cleaning advantage of sand control precision.

Description

Self-cleaning type circular seam sand control filter unit and single sand control screen pipe

Technical Field

The utility model relates to an oil gas exploitation technology technical field especially relates to a self-cleaning type circular seam sand control filter unit and monomer formula sand control screen pipe.

Background

The single sand control screen pipe generally comprises a pipe body and sand control filtering units arranged in holes of the pipe body, and different types of sand control screen pipes are formed according to different filtering structures of the sand control filtering units so as to meet the sand control requirements of different sand producing stratums.

However, the existing different single sand control screen pipes have the problem of narrow application range, and are difficult to simultaneously have the performances of controllable sand control precision, high-efficiency self-cleaning, erosion resistance and high external extrusion resistance.

Therefore, the inventor provides a self-cleaning type annular gap sand control filtering unit and a single sand control screen pipe by virtue of experience and practice of related industries for many years, so as to overcome the defects in the prior art.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a self-cleaning type circular seam sand control filter unit and monomer formula sand control screen pipe have controllable and high-efficient self-cleaning advantage of sand control precision.

The purpose of the utility model can be realized by adopting the following technical scheme:

the utility model provides a self-cleaning type circular seam sand control filter unit, which comprises a shell with an inner groove; a through hole is formed in the shell at the position corresponding to the bottom of the inner groove, and a core column, at least one middle ring and an outer layer ring are sequentially nested in the inner groove from the center to the periphery; the outer wall of the outer layer ring is attached to the wall of the inner groove, and an annular seam channel is formed among the core column, the middle ring and the outer layer ring; one end of each annular slit channel, which is close to the bottom of the inner groove, is respectively used as the inner end of the annular slit channel, and one end of each annular slit channel, which is close to the notch of the inner groove, is respectively used as the outer end of the annular slit channel; the part of the longitudinal section of each annular slit channel along the axial direction of the shell, which is close to the inner end of the annular slit channel, is rectangular, and the part, which is close to the outer end of the annular slit channel, is trapezoidal with large outside and small inside; the core column, the middle ring and the outer layer ring are fixed with each other through the clamping and locking piece respectively.

In a preferred embodiment of the present invention, the ends of the stem, the middle ring and the outer ring near the bottom of the inner groove are respectively used as the inner ends thereof, and the ends near the opening of the inner groove are respectively used as the outer ends thereof; the inner groove is a cylindrical groove, and the inner wall and the outer wall of the outer layer ring are both straight cylindrical surfaces; the part of the outer wall of the core column, which is close to the inner side end, forms a straight cylindrical surface, and the part of the outer wall, which is close to the outer side end, forms a conical surface which is gradually reduced from the inner side end to the outer side end; the inner wall of the middle ring is a straight cylindrical surface, the part of the outer wall of the middle ring, which is close to the inner side end, forms a straight cylindrical surface, and the part of the outer wall of the middle ring, which is close to the outer side end, forms a conical surface which is gradually reduced from the inner side end to the outer side end.

In a preferred embodiment of the present invention, the locking member is a lock cylinder and is embedded in two adjacent side walls of the core column, the middle ring and the outer ring.

In a preferred embodiment of the present invention, the inner wall of the outer ring has a semicircular inner counter bore from its inner end to its outer end, the outer wall of the intermediate ring has a semicircular outer counter bore from its outer end to its inner end, the inner wall of the intermediate ring has a semicircular inner counter bore from its inner end to its outer end, and the outer wall of the stem has a semicircular outer counter bore from its outer end to its inner end; the number of the semicircular outer counter bores is the same as that of the semicircular inner counter bores positioned on the periphery of the semicircular outer counter bores, the parts of the semicircular outer counter bores, which are opposite to the semicircular inner counter bores corresponding to the periphery of the semicircular outer counter bores, are respectively enclosed to form a cylindrical hole, and the lock column is embedded in the cylindrical hole.

In a preferred embodiment of the present invention, the inner wall of the outer ring is symmetrically provided with two semicircular inner counter bores; the outer wall of the middle ring is symmetrically provided with two semicircular outer counter bores, the inner wall of the middle ring is symmetrically provided with two semicircular inner counter bores, and the two semicircular outer counter bores and the two semicircular inner counter bores of the middle ring are distributed in a 90-degree staggered manner; the outer wall of the core column is symmetrically provided with two semicircular outer counter bores.

In a preferred embodiment of the present invention, a plurality of through holes are provided, and the cross section of each through hole is fan-shaped and arranged around the axis of the housing.

In a preferred embodiment of the present invention, the core column, the intermediate ring and the outer ring are made of cemented carbide or ceramic material.

The utility model also provides a monomer formula sand control screen pipe, include:

the outer wall of the pipe body is concavely provided with a plurality of sand prevention grooves along the radial direction, stepped holes with reduced diameters are formed in the bottom surfaces of the sand prevention grooves along the radial direction of the pipe body, and the stepped holes form hole shoulders facing the outer wall of the pipe body;

and a plurality of foretell type circular seam sand control filter unit separately, clean type circular seam sand control filter unit corresponds to inlay establishes at each sand control recess, and the notch of inner groovy sets up towards the body inner wall, shell and body fixed connection, and the outside end of outer ring supports and leans on the hole shoulder.

In a preferred embodiment of the present invention, the housing is welded to the pipe body.

In a preferred embodiment of the present invention, the tube body is made of carbon steel.

From top to bottom, the utility model provides a self-cleaning type circumferential weld sand control filter unit and monomer formula sand control screen pipe carries out special design through the annular joint passageway that forms each other to stem, intermediate ring and outer ring, makes it form a combination gap to trapezoidal seam passageway by the straight seam passageway, and this straight seam passageway's width is as this self-cleaning type circumferential weld sand control filter unit's fender sand particle diameter. During oil extraction, crude oil flows into the annular slit channels through the through holes on the shell, flows through the straight slit channels firstly and then flows through the trapezoidal slit channels. Because the sand grains are generally not uniform spherical, are basically elliptic cylindrical or other long strips with edges and corners, and can continuously rotate along with the liquid in the flowing process, if the annular seam channels are all straight seam channels, the sand grains are easily clamped in the straight seam channels and cannot flow out in the rotating process after entering the straight seam channels. And the utility model provides a circular seam passageway comprises straight seam passageway and trapezoidal seam passageway combination, and the sand grain that gets into in the straight seam passageway can the direct access trapezoidal seam passageway in, because trapezoidal seam passageway is close to outside end width more big more, and then more is favorable to the rotation of sand grain, effectively avoids the sand grain to play the in-process card of turning and causes the inside jam of circular seam passageway in the circular seam passageway.

Therefore, the utility model discloses the straight seam passageway of well annular seam passageway can play the effect of guaranteeing filter fineness, and trapezoidal seam passageway can play the effect that the discharge is not by filterable stratum solid particle to prevent that solid particle jam from in the annular seam passageway. Therefore, the utility model provides a self-cleaning type circular seam sand control filter unit can be less with keeping off the design of sand particle diameter, has efficient sand control ability, possesses high-efficient self-cleaning performance simultaneously, is difficult for causing the inside jam of circular seam passageway, keeps off sand precision controllability higher, and the performance of overflowing is more outstanding. The whole self-cleaning type circular seam sand-proof filtering unit is simple and compact in structure, scientific and effective, easy to process and low in cost.

Drawings

The drawings are only intended to illustrate and explain the present invention and do not limit the scope of the invention. Wherein:

FIG. 1: do the utility model provides a self-cleaning type circumferential weld sand control filter unit's top view.

FIG. 2: is a cross-sectional view taken along the line a-a in fig. 1.

FIG. 3: which is a cross-sectional view taken along the direction B-B in fig. 1.

FIG. 4: which is an enlarged view of a portion at D in fig. 3.

FIG. 5: for the utility model provides a front view cross-sectional view of shell.

FIG. 6: to the utility model provides a top view of shell.

FIG. 7: to the utility model provides a side view of shell.

FIG. 8: for the utility model provides a front view cross-sectional view of outer ring.

FIG. 9: to the utility model provides a top view of outer ring.

FIG. 10: for the utility model provides a side-looking cross-sectional view of outer ring.

FIG. 11: is the main view cross section of the intermediate ring provided by the utility model.

FIG. 12: is the top view of the intermediate ring provided by the utility model.

FIG. 13: for the utility model provides a side view cross-sectional view of intermediate ring.

FIG. 14: to the utility model provides a front view of stem.

FIG. 15: to the utility model provides a top view of stem.

FIG. 16: do the utility model provides a side-looking cross-sectional view of stem.

FIG. 17: to the utility model provides a front view of lock post.

FIG. 18: to the utility model provides a top view of lock post.

FIG. 19: is the structure schematic diagram of the single sand control screen pipe provided by the utility model.

FIG. 20: for the utility model provides a partial section view of pipe body.

FIG. 21: is a cross-sectional view taken along the direction C-C in fig. 19.

The reference numbers illustrate:

10. a self-cleaning type circular seam sand control filtering unit;

1. a housing; 11. an inner groove; 12. a through hole;

2. an outer ring; 21. a first semicircular inner counter bore;

3. an intermediate ring; 31. a first semicircular outer counter bore; 32. a second semicircular inner counter bore;

4. a stem; 41. a second semicircular outer counter bore;

5. a lock cylinder;

6. an annular slit passage; 61. a straight seam channel; 62. a trapezoidal slit channel;

20. a pipe body; 201. a sand prevention groove; 202. a stepped hole; 2021. a bore shoulder.

Detailed Description

In order to clearly understand the technical features, objects, and effects of the present invention, embodiments of the present invention will be described with reference to the accompanying drawings.

As shown in fig. 1 to 7, the present embodiment provides a self-cleaning type annular gap sand control filter unit 10, which includes a housing 1 having an inner groove 11, a through hole 12 is formed on the housing 1 at a position corresponding to a bottom of the inner groove 11, and a core column 4, at least one intermediate ring 3, and an outer ring 2 are sequentially nested in the inner groove 11 from the center to the outer periphery. The outer wall of the outer layer ring 2 is attached to the wall of the inner groove 11, and the core column 4, the middle ring 3 and the outer layer ring 2 form an annular seam channel 6. The end of each annular slit passage 6 near the bottom of the inner groove 11 serves as its inner end, and the end near the notch of the inner groove 11 serves as its outer end. The longitudinal section of each annular slit passage 6 in the axial direction of the housing 1 has a rectangular shape at a portion near the inner end thereof, and a trapezoidal shape at a portion near the outer end thereof. The stem 4, the middle ring 3 and the outer ring 2 are fixed with each other by a locking piece.

The core column 4 is of a solid structure, the outer ring 2 and the middle ring 3 are both of annular cylinder structures, and the outer wall of the outer ring 2 is in clearance fit with the wall of the inner groove 11. When in use, the self-cleaning type annular gap sand control filter unit 10 is embedded and fixed in a sand control groove 201 of a monomer type sand control screen pipe which is described below. The number of intermediate rings 3 can be determined according to the actual requirements, for example, three intermediate rings 3 are provided in the present embodiment.

In the self-cleaning type circular seam sand control filter unit 10 of the present embodiment (the circular seam is referred to as the circular seam channel 6) the circular seam channel 6 formed by the core column 4, the middle ring 3 and the outer layer ring 2 is specially designed to form a combined seam from the straight seam channel 61 to the trapezoid seam channel 62, and the width of the straight seam channel 61 is used as the sand blocking particle size of the self-cleaning type circular seam sand control filter unit 10. During oil extraction, crude oil flows into each annular slit passage 6 through the through holes 12 on the shell 1, flows through the straight slit passage 61 and then flows through the trapezoidal slit passage 62. Because the sand grains are generally not uniform spherical, are basically elliptic cylindrical or other long strips with edges and corners, and can continuously rotate along with the liquid in the flowing process, if the annular seam channel 6 is a straight seam channel, the sand grains are easily blocked in the straight seam channel and cannot flow out in the rotating process after entering the straight seam channel. The annular seam channel 6 in the embodiment is formed by combining the straight seam channel 61 and the trapezoid seam channel 62, sand entering the straight seam channel 61 can be directly connected into the trapezoid seam channel 62, the width of the trapezoid seam channel 62 is larger when the trapezoid seam channel 62 is closer to the outer side end, rotation of the sand is further facilitated, and blockage of the inner part of the annular seam channel 6 due to the fact that the sand is clamped in the annular seam channel 6 in the rotation process is effectively avoided.

Thus, the straight slit passage 61 of the annular slit passage 6 in this embodiment can play a role of ensuring the filtering accuracy, and the trapezoidal slit passage 62 can play a role of discharging the formation solid particles that are not filtered (i.e., sand particles that are not blocked by the straight slit passage 61), thereby preventing the solid particles from being clogged in the annular slit passage 6. Therefore, the self-cleaning type circular seam sand control filter unit 10 in the embodiment can design the sand blocking particle size to be smaller, has high-efficiency sand control capability, has high-efficiency self-cleaning performance, is not easy to cause blockage inside the circular seam channel 6, and has higher sand blocking precision controllability and more outstanding flow performance. The whole self-cleaning type circular seam sand-proof filtering unit 10 is simple and compact in structure, scientific and effective, easy to process and low in cost.

In a specific implementation, for ease of manufacture and installation, the annular slit passage 6 described above may be implemented as follows: as shown in fig. 1 to 16, the ends of the stem 4, the intermediate ring 3, and the outer ring 2 adjacent to the groove bottom of the inner groove 11 serve as the inner ends thereof, respectively, and the ends adjacent to the notch of the inner groove 11 serve as the outer ends thereof, respectively. The inner groove 11 is a cylindrical groove, and the inner wall and the outer wall of the outer ring 2 are both straight cylindrical surfaces. The part of the outer wall of the stem 4 near the inner end thereof forms a straight cylindrical surface, and the part near the outer end thereof forms a conical surface tapering from the inner end to the outer end thereof. The inner wall of the middle ring 3 is a straight cylindrical surface, the part of the outer wall of the middle ring 3 close to the inner side end forms a straight cylindrical surface, and the part close to the outer side end forms a conical surface gradually reduced from the inner side end to the outer side end.

In this way, the portions of the conical surfaces of the stem 4 and the intermediate ring 3 that oppose the straight cylindrical surfaces of the outer peripheries thereof constitute the trapezoidal cross-sectional portions (i.e., the trapezoidal slit passage 62 portions) of the annular slit passage 6, and the portions of the straight cylindrical surfaces of the stem 4 and the intermediate ring 3 that oppose the straight cylindrical surfaces of the outer peripheries thereof constitute the rectangular cross-sectional portions (i.e., the straight slit passage 61 portions) of the annular slit passage 6, in which case the trapezoidal slit passage 62 is a right-angled trapezoidal slit passage. Of course, the trapezoidal slit passage 62 may also be an isosceles trapezoid or a trapezoid with other shapes as required, as long as it forms a trapezoid with a large outside and a small inside, and this embodiment is merely for illustration.

The above-mentioned locking element is mainly to realize the gradual fixation among the stem 4, the middle ring 3 and the outer ring 2, and in practical application, for convenience of processing and installation, as shown in fig. 2, 3, 17 and 18, the locking element is a lock cylinder 5 and is embedded in two adjacent side walls among the stem 4, the middle ring 3 and the outer ring 2.

Specifically, as shown in fig. 2, 3 and 8 to 18, the inner wall of the outer ring 2 is formed with a semicircular inner counterbore, referred to as a first semicircular inner counterbore 21, from the inner end to the outer end thereof. A semicircular outer counter bore is formed in the outer wall of the middle ring 3 from the outer end to the inner end, and is marked as a first semicircular outer counter bore 31; the inner wall of the intermediate ring 3 is provided with a semicircular inner counter bore from the inner side end to the outer side end, and is marked as a second semicircular inner counter bore 32. A semicircular countersink is formed in the outer wall of the core column 4 from the outer end to the inner end, and is referred to as a second semicircular countersink 41. The number of the semicircular outer counter bores is the same as that of the semicircular inner counter bores positioned on the periphery of the semicircular outer counter bores, the parts of the semicircular outer counter bores, which are opposite to the semicircular inner counter bores corresponding to the periphery of the semicircular outer counter bores, are respectively enclosed to form a cylindrical hole, and the lock column 5 is embedded in the cylindrical hole.

In detail, the second semicircular outer counterbore 41 on the stem 4 and the second semicircular inner counterbore 32 on the intermediate ring 3 are enclosed to form a cylindrical hole, and the first semicircular outer counterbore 31 on the intermediate ring 3 and the first semicircular inner counterbore 21 on the outer ring 2 are enclosed to form a cylindrical hole; when the number of the middle rings 3 is more than or equal to two, the first semicircular outer counter bore 31 and the second semicircular inner counter bore 32 on two adjacent middle rings 3 are enclosed to form a cylindrical hole. The lock columns 5 are respectively embedded in the cylindrical holes to realize step-by-step locking.

In the specific implementation process, in order to facilitate installation, the inner wall of the outer layer ring 2 is symmetrically provided with two semicircular inner counter bores. The outer wall of the middle ring 3 is symmetrically provided with two semicircular outer counter bores, the inner wall of the middle ring 3 is symmetrically provided with two semicircular inner counter bores, and the two semicircular outer counter bores and the two semicircular inner counter bores of the middle ring 3 are distributed in a 90-degree staggered manner. The outer wall of the core column 4 is symmetrically provided with two semicircular outer counter bores.

Of course, the above-mentioned locking member may also adopt other manners as long as it is convenient to fix the stem 4, the middle ring 3 and the outer ring 2, and the present invention is not limited thereto.

Further, in order to allow the crude oil to flow into each annular slit passage 6 more smoothly through the through-holes 12 in the casing 1 at the time of oil extraction, as shown in fig. 6, a plurality of through-holes 12 are provided in total, and each through-hole 12 has a fan-shaped cross section and is arranged around the casing axis. The number of the through holes 12 may be determined as needed, for example, four through holes 12 are provided in the present embodiment.

Further, in order to ensure the sand prevention capability of the self-cleaning type circular seam sand prevention filter unit 10, the core column 4, the middle ring 3 and the outer layer ring 2 are all made of hard alloy or ceramic materials.

Thus, by adopting the harder material, the deformation of the core column 4, the middle ring 3 and the outer layer ring 2 can be avoided under the repeated impact of crude oil during oil extraction, and the gap width of the annular gap channel 6 is effectively prevented from being larger under the impact of fluid, so that the self-cleaning annular gap sand control filter unit 10 has stronger erosion resistance, and the sand blocking precision of the self-cleaning annular gap sand control filter unit 10 is ensured.

Further, as shown in fig. 19, 20 and 21, the present embodiment also provides a unitary sand screen including a tubular body 20 and a plurality of the self-cleaning annular gap sand control filter units 10. The outer wall of the pipe body 20 is provided with a plurality of sand control grooves 201 along the radial direction, the bottom surfaces of the sand control grooves 201 are provided with stepped holes 202 with reduced diameters along the radial direction of the pipe body 20, and the stepped holes 202 form hole shoulders 2021 facing the outer wall of the pipe body 20. The type circular seam sand control filter unit 10 that cleans separately is corresponding to be inlayed and is established at each sand control recess 201, and the notch of inner groovy 11 sets up towards body 20 inner wall, shell 1 and body 20 fixed connection, and the outside end of outer ring 2 supports and leans on hole shoulder 2021.

Wherein, general sand control recess 201 is circular recess, a plurality of sand control recess 201 evenly distributed on the outer wall of body 20 to make fluid can follow body 20 around each position evenly flow in the inside of body 20. The shell 1 and the pipe body 20 can be fixed by welding or other methods. Through the gradual kayser of kayser spare and the limiting displacement of hole shoulder 2021 to the shell 1 of outer ring 2, can prevent that self-cleaning type circumferential weld sand control filter unit 10 from droing to body 20 inner wall, guaranteed the stability of structure.

During oil recovery, crude oil flows in from the outside of the pipe body 20, flows into the inside of the pipe body 20 after the filtering action of the self-cleaning type circular seam sand control filtering unit 10, can not only ensure the sand control precision through the structural design of the self-cleaning type circular seam sand control filtering unit 10, but also can discharge sand grains entering the straight seam channel 61 to the inside of the pipe body 20, avoid the blockage inside the self-cleaning type circular seam sand control filtering unit 10, and have high-efficiency self-cleaning capability. Meanwhile, the whole single sand control screen pipe is provided with the sand control grooves 201 by processing the pipe body 20, and the respective clean circular seam sand control filtering units 10 are embedded in the sand control grooves 201, so that compared with a slotted screen pipe, the stress distribution is more uniform, and the stress concentration phenomenon does not exist basically, therefore, the single sand control screen pipe in the embodiment has high extrusion resistance.

Further, in order to facilitate the processing of the pipe body 20, it is convenient to process each sand-prevention groove 201 on the outer wall thereof, and the pipe body 20 is made of a relatively soft material, for example, the pipe body 20 is made of carbon steel.

In conclusion, the single sand control screen pipe in the embodiment has the advantages of controllable sand control precision, high efficiency, self-cleaning property, erosion resistance and high external extrusion resistance, and is simple in structure, convenient to process, easy to operate in site construction and low in cost.

The above description is only exemplary of the present invention, and is not intended to limit the scope of the present invention. Any person skilled in the art should also realize that such equivalent changes and modifications can be made without departing from the spirit and principles of the present invention.

Claims (10)

1. A self-cleaning type annular seam sand control filter unit is characterized by comprising a shell with an inner groove;

a through hole is formed in the shell at the position corresponding to the bottom of the inner groove, and a core column, at least one middle ring and an outer layer ring are sequentially nested in the inner groove from the center to the periphery;

the outer wall of the outer layer ring is attached to the wall of the inner groove, and an annular seam channel is formed among the core column, the middle ring and the outer layer ring; one end of each annular slit channel, which is close to the bottom of the inner groove, is respectively used as the inner end of the annular slit channel, and one end of each annular slit channel, which is close to the notch of the inner groove, is respectively used as the outer end of the annular slit channel; the part of the longitudinal section of each annular slit channel along the axial direction of the shell, which is close to the inner end of the annular slit channel, is rectangular, and the part, which is close to the outer end of the annular slit channel, is trapezoidal with large outside and small inside; the core column, the middle ring and the outer layer ring are fixed with each other through the clamping and locking piece respectively.

2. The self-cleaning, annular-gap, sand-controlling filter unit of claim 1,

the core column, the middle ring and the outer ring are respectively used as the inner side ends at the ends close to the bottom of the inner groove, and are respectively used as the outer side ends at the ends close to the notch of the inner groove;

the inner groove is a cylindrical groove, and the inner wall and the outer wall of the outer layer ring are both straight cylindrical surfaces; the part of the outer wall of the core column, which is close to the inner side end, forms a straight cylindrical surface, and the part of the outer wall, which is close to the outer side end, forms a conical surface which is gradually reduced from the inner side end to the outer side end; the inner wall of the middle ring is a straight cylindrical surface, the part of the outer wall of the middle ring, which is close to the inner side end, forms a straight cylindrical surface, and the part of the outer wall of the middle ring, which is close to the outer side end, forms a conical surface which is gradually reduced from the inner side end to the outer side end.

3. The self-cleaning, seam-type sand control filter unit of claim 2,

the locking piece is a lock column and is embedded in two adjacent side walls among the core column, the middle ring and the outer layer ring.

4. The self-cleaning, seam-type sand control filter unit of claim 3,

the inner wall of the outer layer ring is provided with a semicircular inner counter bore from the inner end to the outer end, the outer wall of the middle ring is provided with a semicircular outer counter bore from the outer end to the inner end, the inner wall of the middle ring is provided with a semicircular inner counter bore from the inner end to the outer end, and the outer wall of the core column is provided with a semicircular outer counter bore from the outer end to the inner end;

the number of the semicircular outer counter bores is the same as that of the semicircular inner counter bores positioned on the periphery of the semicircular outer counter bores, the parts of the semicircular outer counter bores, which are opposite to the semicircular inner counter bores corresponding to the periphery of the semicircular outer counter bores, are respectively enclosed to form a cylindrical hole, and the locking column is embedded in the cylindrical hole.

5. The self-cleaning, seam-type sand control filter unit of claim 4,

the inner wall of the outer layer ring is symmetrically provided with two semicircular inner counter bores; the outer wall of the middle ring is symmetrically provided with two semicircular outer counter bores, the inner wall of the middle ring is symmetrically provided with two semicircular inner counter bores, and the two semicircular outer counter bores and the two semicircular inner counter bores of the middle ring are distributed in a 90-degree staggered manner; the outer wall of the core column is symmetrically provided with two semicircular outer counter bores.

6. The self-cleaning, annular-gap, sand-controlling filter unit of claim 1,

a plurality of through holes are arranged in total, and the cross section of each through hole is fan-shaped and is arranged around the axis of the shell.

7. The self-cleaning, annular-gap, sand-controlling filter unit of claim 1,

the core column, the middle ring and the outer layer ring are all made of hard alloy or ceramic materials.

8. A unitary sand control screen, comprising:

the outer wall of the pipe body is concavely provided with a plurality of sand prevention grooves along the radial direction, stepped holes with reduced diameters are formed in the bottom surfaces of the sand prevention grooves along the radial direction of the pipe body, and the stepped holes form hole shoulders facing the outer wall of the pipe body;

and a plurality of self-cleaning type circular seam sand control filter units according to any one of claims 1 to 7, wherein the respective cleaning type circular seam sand control filter units are correspondingly embedded in the respective sand control grooves, the notch of the inner groove is arranged towards the inner wall of the pipe body, the outer shell is fixedly connected with the pipe body, and the outer side end of the outer layer ring is abutted against the hole shoulder.

9. The unitary sand control screen of claim 8,

the shell is welded and fixed with the pipe body.

10. The unitary sand control screen of claim 8,

the pipe body is made of carbon steel.

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