High-density solid layer filling backwashing valve for oil-water well

Abstract

The utility model discloses a high-density solid layer filling backwashing valve for an oil-water well, which comprises a central pipe, an outer backwashing mechanism and an inner backwashing mechanism, the outer backwashing mechanism and the inner backwashing mechanism are arranged on the central pipe in a sleeving manner, and the inner backwashing mechanism is arranged behind the outer backwashing mechanism; a one-way circulation sealing ring is arranged in the outer backwashing mechanism. According to the utility model, a backwashing fluid circulation channel is changed, the phenomenon that a formed filling layer is scattered or lost due to the fact that backwashing fluid scours and carries a stratum extrusion filling layer in a conventional backwashing mode is avoided, the compaction degree of the filling layer is improved, particularly precoated sand is filled, the later consolidation strength is ensured, and the service life of a sand prevention production well is prolonged. The internal backwashing mechanism not only can realize smooth steering of backwashing liquid, but also can meet the requirement of a normal stratum extrusion filling runner.

Description

Technical Field

[0001] The utility model relates to the technical field of oil exploitation, in particular to a high-density solid formation filling backwash valve for oil and water wells. Background Art

[0002] At present, the main method of sand control for oil and water wells is formation extrusion filling, which can make up for the formation deficit and improve the near-well seepage capacity. Due to the scouring and carrying of fluid on the filling layer during the construction process of the smooth oil pipe or when the well is backwashed after the construction, the compactness of the filling layer is difficult to ensure, which affects the effective period of sand control. Usually, after the formation filling of the smooth oil pipe, a pipe string with a sand control screen is lowered to circulate and fill the screen sleeve annulus, and a mechanical pipe string is left in the wellbore, which brings certain difficulties to the subsequent oil production, steam injection, water injection and failure treatment. In order to leave an empty wellbore space for later construction, another way is to add part or all of the coated sand to the formation extrusion filling for formation filling to form a high-strength filling layer. In this case, the conventional backwashing well scours and carries the filling layer, causing the coated sand to loosen and flow, seriously affecting the compactness and strength of the filling layer, causing sand control failure.

[0003] Publication (announcement) number: CN115126450B, discloses a bottom filling tool with self-reset and original position backwashing function, relates to the technical field of downhole operation tools for oil and gas wells, comprises an upper joint, a sealing assembly, a filling assembly, a well washer and a sealing filling pipe sleeved inside the sealing assembly connected in sequence from top to bottom; the filling assembly comprises a filling pipe, a leather cup seal, a leather cup protective sleeve, a ball seat and inner and outer reset springs, a plurality of filling ports are arranged in the middle of the filling pipe, the leather cup protective sleeve is fixed to the outside of the filling pipe by a first shear pin, the leather cup seal is located in the interlayer between the filling pipe and the leather cup protective sleeve, the ball seat is fixed to the inside of the filling pipe by a second shear pin, the outer reset spring is located at the lower part of the leather cup protective sleeve to support the leather cup protective sleeve; the inner reset spring is located at the lower part of the ball seat to support the ball seat; the well washer is fixedly mounted at the lower end of the filling pipe and is provided with a plurality of sand collecting ports; after the filling operation is completed, the well can be backwashed in the original position, saving operation time and cost.

[0004] The upper part of the upper joint of the prior art bottom filling tool is connected to the screen pipe. According to common sense, the sand-proof screen pipe is directly opposite to the filling position of the oil layer. Therefore, the bottom filling tool is located at the lower part of the oil layer. During filling, the gravel overcomes the gravity under the carrying effect of the sand-carrying fluid to reversely fill the screen pipe section from bottom to top, and the reverse circulation well washing liquid enters the backwash channel of the bottom filling tool from top to bottom through the oil casing annulus, so it is difficult to ensure the compactness of the filling.

[0005] Publication (Announcement) No.: CN219344643U, discloses a sand settling backwashing valve for improving the success rate of backwashing, comprising an outer cylinder with a shunt joint detachably mounted on the inner edge surface of one end, the shunt joint being detachably mounted on a lower joint at the end away from the outer cylinder, the O-ring five being detachably mounted on the inner edge surface of the end of the lower joint facing the O-ring five, the shunt joint being away from the outer cylinder at one end can be screwed into the lower joint and abutted against one side of the O-ring five, the O-ring five being arranged with a snap-fitting protrusion in an annular array on the outer edge surface, and a snap-fitting groove for positioning and snapping the snap-fitting protrusion in an annular array on the inner edge surface of the lower joint, the O-ring four being detachably mounted on the inner edge surface of the end of the outer cylinder facing the shunt joint, the shunt joint being away from the lower joint at one end can be screwed into the outer cylinder and abutted against one side of the O-ring four, the sand settling backwashing valve for improving the success rate of backwashing has a reasonable structure, is convenient for installing and removing the O-ring, and has strong practicality.

[0006] The cone head of the prior art can only play a sand prevention role in the oil production pipe column. If it is used in the sand flushing pipe column, gravel will be deposited on the valve ball and the spring during filling, so that the opening pressure during backwashing will become larger or even unable to open. Even if the backwash channel is successfully opened, a part of the cleaning fluid will enter the bottom of the well and destroy the compactness of the filling.

[0007] Publication (announcement) number: CN206737883U, discloses a repeatable switchable pressure-conducting backwashing valve, including an upper joint, a lower joint and a sleeve; one end of the sleeve is connected to the upper joint, and the other end is connected to the lower joint; the lower joint is provided with a spring seat near one end of the upper joint, a cavity is formed between the upper joint, the lower joint and the spring seat, a spring is provided on the spring seat, the spring is connected to a pressure rod, and the pressure rod is connected to a metal ball. The utility model solves the problems of short service life and small backwashing channel of the existing repeatable switchable pressure-conducting backwashing valve. When backwashing the well, the oil casing annulus is connected to the inner cavity of the tool and has a large liquid passage, and the channel can be automatically closed when the backwashing is ended. Metal balls are used to block and open the backwashing channel, which increases the service life of the tool, and a number of liquid passages are evenly distributed circumferentially to ensure the needs of large-displacement backwashing wells. The tool has a good application effect in backwashing unblocking and preventing drill jams under special working conditions.

[0008] If this prior art is used in a sand flushing column, gravel will be deposited on the metal balls during filling, increasing the opening pressure during backwashing or even making it impossible to open the channel. Even if the backwash channel is successfully opened, some cleaning fluid will enter the bottom of the well and destroy the compactness of the filling.

[0009] In short, the technical solutions of the above-disclosed technologies, the technical problems to be solved and the beneficial effects produced are all different from the present utility model. Regarding more technical features, technical problems to be solved and the beneficial effects of the present utility model, there is no technical inspiration in the above-disclosed technical documents. Utility Model Content

[0010] In view of the above-mentioned defects in the prior art, the purpose of the utility model is to provide a high-density formation filling backwash valve for oil and water wells. When sand blockage occurs during formation filling construction or the construction is completed, it is necessary to backwash the well to flush out excess gravel in the sand control pipe. The backwash valve is used to ensure that the formation squeeze filling forms a filling layer that is free from interference such as scouring and carrying of well washing fluid, thereby ensuring the density of the filling layer.

[0011] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0012] A high-density formation filling backwash valve for oil and water wells, 1. A high-density formation filling backwash valve for oil and water wells, including a central tube, an external backwash mechanism, and an internal backwash mechanism; the external backwash mechanism and the internal backwash mechanism are both mounted on the central tube, and the internal backwash mechanism is arranged behind the external backwash mechanism; a one-way flow sealing ring is arranged in the external backwash mechanism.

[0013] Further, the external backwash mechanism comprises an external backwash pipe and an external backwash seat, and the one-way flow sealing ring is an external backwash seal;

[0014] Specifically, the central tube is provided with a convex ring, and the front end of the outer backwash tube is connected to the outer circumferential surface of the convex ring;

[0015] Specifically, the external backwash pipe is provided with an external backwash port, and the external backwash seat is arranged on the outer wall of the central pipe and is located below the external backwash port;

[0016] Specifically, the external backwash seal is arranged on the external backwash seat.

[0017] Furthermore, the external backwash mechanism also includes an external spacer sleeve and an external adapter sleeve;

[0018] Specifically, the outer backwash seat is a stepped ring, which is divided into an outer large diameter ring and an outer small diameter ring, and the outer large diameter ring is in front of the outer small diameter ring;

[0019] Specifically, at least two external backwash seals are arranged on the outer small-diameter ring, and an external spacer sleeve is arranged between every two external backwash seals;

[0020] Specifically, the outer backwash seal is a first leather cup, and the mouth of the first leather cup faces forward;

[0021] Specifically, the outer fixing sleeve is arranged at the rear end of the outer small diameter ring to lock the outer backwash seal tightly.

[0022] Furthermore, the internal backwash mechanism includes a connecting pipe, an internal backwash seal, an internal backwash seat, and a blocking ring;

[0023] Specifically, the central tube is provided with at least two slits evenly distributed along the circumference of the central tube in the area corresponding to the inner backwash mechanism;

[0024] Specifically, the inner backwash seat is a stepped ring, which is divided into an inner large diameter ring and an inner small diameter ring, and the inner large diameter ring is arranged behind the inner small diameter ring;

[0025] Specifically, the inner backwash seat is connected to the central tube, and the inner large diameter ring covers the seam strips, and the inner large diameter ring is provided with an inner backwash port in the area corresponding to the seam strips, and the inner backwash port corresponds to at least one seam strip;

[0026] Specifically, the inner backwash seal is arranged on the inner small diameter ring;

[0027] Specifically, the inner backwash seal is covered with a connecting pipe, the connecting pipe covers the inner backwash seal, and the front end of the connecting pipe is connected to the rear end of the outer backwash pipe through a middle coupling;

[0028] Specifically, the blocking ring is connected to the rear end of the connecting pipe to seal the annular space between the connecting pipe and the inner backwash seat behind the inner backwash port.

[0029] Furthermore, the internal backwash mechanism also includes an internal fixing sleeve and an internal spacer sleeve;

[0030] Specifically, at least two inner backwash seals are arranged on the inner small diameter ring, and an inner spacer sleeve is arranged between every two inner backwash seals;

[0031] Specifically, the inner backwash seal is a second leather cup, and the mouth of the second leather cup faces backwards;

[0032] Specifically, the inner fixing sleeve is connected to the front end of the inner small-diameter ring to compress the inner backwash seal.

[0033] Furthermore, at least two external backwash ports are provided and are evenly distributed along the circumference of the external backwash pipe;

[0034] Specifically, the length of the outer spacer sleeve is 2 / 3-1 / 2 of the horizontal projection length of the outer cup;

[0035] Specifically, the horizontal angle of the mouth of the first leather cup is 160°-165°.

[0036] Furthermore, the cross section of the seam strip is a trapezoid that converges toward the center tube;

[0037] Specifically, at least two inner backwash ports are provided and are evenly distributed along the circumference of the inner large diameter ring;

[0038] Specifically, the length of the inner spacer sleeve is 1 to 2 times the horizontal projection length of the inner cup seal;

[0039] Specifically, the horizontal angle of the mouth of the second leather cup is 10°-15°;

[0040] Specifically, the diameter of the inner backwash port is smaller than the length of the slit.

[0041] Furthermore, the external backwash pipe and the connecting pipe are made in one piece.

[0042] Furthermore, the blocking ring includes a lower punch pipe and a connecting sleeve, the rear end of the inner backwash seat is inserted into the lower punch pipe, and the outer wall of the front end of the lower punch pipe is connected to the rear end of the connecting pipe through the connecting sleeve.

[0043] Furthermore, an upper coupling is provided at the front end of the central pipe.

[0044] Compared with the prior art, the utility model has the following beneficial effects:

[0045] 1. The utility model changes the backwash fluid flow channel, avoids the conventional backwashing method, which causes the already formed filling layer to be dispersed or lost due to the scouring and carrying of the backwash fluid on the formation to squeeze the filling layer, and improves the density of the filling layer, especially for the coated sand filling, to ensure the strength of the later consolidation and extend the life of the sand control production well.

[0046] 2. The outer cup seal mouth angle of the outer backwash mechanism of the utility model is large, the distance between the two outer cup seals is small, and the sealing performance is good.

[0047] 3. The internal backwash mechanism of the utility model can not only realize the smooth redirection of the backwash liquid, but also meet the requirements of the normal formation extrusion filling flow channel.

[0048] 4. The rear section of the central tube of the utility model is provided with circumferentially evenly distributed trapezoidal cross-section seams, which effectively block sand and gravel while ensuring smooth circulation of backwash liquid, ensuring safety and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 This is a structural schematic diagram of a high-density solid formation filling backwash valve for oil and water wells of the utility model;

[0050] Figure 2 It is a cross-sectional view of a slit of a central pipe of a high-density solid formation filling backwash valve for an oil-water well according to the utility model;

[0051] Figure 3 yes Figure 2 Enlarged view of point A in the middle;

[0052] In the figure: 1. upper coupling; 2. center pipe; 3. external backwash pipe; 4. external backwash port; 5. external backwash seat; 6. external backwash seal; 7. external spacer sleeve; 8. external fixing sleeve; 9. external backwash mechanism; 10. middle coupling; 11. connecting pipe; 12. internal fixing sleeve; 13. internal backwash seal; 14. internal spacer sleeve; 15. internal backwash seat; 16. internal backwash mechanism; 17. internal backwash port; 18. connecting sleeve; 19. lower flush pipe. DETAILED DESCRIPTION

[0053] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0054] Embodiment 1:

[0055] See also Figures 1 to 3 The utility model provides a high-density solid formation filling backwash valve for oil and water wells, comprising a central tube 2, an external backwash mechanism 9, and an internal backwash mechanism 16; the external backwash mechanism 9 and the internal backwash mechanism 16 are both mounted on the central tube, and the internal backwash mechanism 16 is arranged behind the external backwash mechanism 9.

[0056] The external backwash mechanism 9 includes an external backwash pipe 3, an external backwash seat 5, an external backwash seal 6, an external spacer sleeve 7, and an external fixing sleeve 8;

[0057] The center tube 2 is provided with a convex ring, the front end of the outer backwash tube 3 is connected to the outer circular surface of the convex ring, the outer backwash tube 3 is provided with an outer backwash port 4, the outer backwash seat 5 is arranged on the outer wall of the center tube 2, and is located below the outer backwash port 4. The outer backwash seat 5 is a stepped ring, which is divided into an outer large diameter ring and an outer small diameter ring. The outer large diameter ring is in front of the outer small diameter ring. At least two outer backwash seals 6 are arranged on the outer small diameter ring, and an outer spacer sleeve 7 is arranged between every two outer backwash seals 6. The outer backwash seal 6 is a first leather cup, and the bowl mouth of the first leather cup faces forward. The outer tightening sleeve 8 is arranged at the rear end of the outer small diameter ring to lock the outer backwash seal 6.

[0058] The internal backwash mechanism 16 includes a connecting pipe 11, an internal fixing sleeve 12, an internal backwash seal 13, an internal spacer sleeve 14, an internal backwash seat 15, and a blocking ring;

[0059] The center tube 2 is provided with at least two slits evenly distributed along the circumference of the center tube 2 in the area corresponding to the inner backwash mechanism 16. The inner backwash seat 15 is a stepped ring, which is divided into an inner large diameter ring and an inner small diameter ring. The inner large diameter ring is arranged behind the inner small diameter ring. The inner backwash seat 15 is connected to the center tube 2, and the inner large diameter ring covers the slit. The inner large diameter ring is provided with an inner backwash port 17 in the area corresponding to the slit. The inner backwash port corresponds to at least one slit. At least two inner backwash seals 13 are provided on the inner small diameter ring, and each two inner backwash seals 13 are provided with inner backwash ports 17. An inner spacing sleeve 14 is arranged between the backwash seals 13, the inner backwash seal 13 is a second leather cup, the mouth of the second leather cup faces backwards, the inner tightening sleeve 12 is connected to the front end of the inner small diameter ring to compress the inner backwash seal 13, the inner backwash seal 13 is outerly covered with a connecting pipe 11, the connecting pipe 11 covers the inner backwash seal 13, the front end of the connecting pipe 11 is connected to the rear end of the outer backwash pipe 3 through the middle coupling 10, the blocking ring is connected to the rear end of the connecting pipe 11, and the annular space between the connecting pipe 11 and the inner backwash seat 15 behind the inner backwash port 17 is closed.

[0060] An upper coupling 1 is provided at the front end of the central pipe 2 .

[0061] Compared with existing technologies:

[0062] 1. Change the flow channel of the backwash fluid to avoid the conventional backwashing method, which will cause the already formed filling layer to be dispersed or lost due to the scouring and carrying of the backwash fluid on the formation to squeeze the filling layer, and improve the density of the filling layer, especially for the coated sand filling, to ensure the strength of the later consolidation and extend the life of the sand control production well.

[0063] 2. The internal backwash mechanism 16 can not only realize the smooth diversion of the backwash liquid, but also meet the requirements of normal formation squeezing and filling the flow channel.

[0064] Embodiment 2:

[0065] Based on Example 1, at least two external backwash ports 4 are provided and evenly distributed along the circumference of the external backwash pipe 3. The length of the external spacer sleeve 7 is 2 / 3-1 / 2 of the horizontal projection length of the outer leather cup 6. The horizontal angle of the first leather cup is 160°-165°.

[0066] The cross-section of the seam strip is a trapezoid that converges toward the center tube 2. At least two internal backwash ports are provided and are evenly distributed along the circumference of the inner large diameter ring. The length of the inner spacer sleeve 14 is 1 to 2 times the horizontal projection length of the inner leather cup seal 13. The horizontal angle of the bowl mouth of the second leather cup is 10°-15°. The diameter of the internal backwash port 17 is smaller than the length of the seam strip.

[0067] To improve the integrity of the device, the external backwash pipe 3 and the connecting pipe are made in one piece.

[0068] The blocking ring includes a connecting sleeve 18 and a lower flushing pipe 19 . The rear end of the inner backwash seat 15 is inserted into the lower flushing pipe 19 . The outer wall of the front end of the lower flushing pipe 19 is connected to the rear end of the connecting pipe through the connecting sleeve 18 .

[0069] Compared with existing technologies:

[0070] 1. The bowl angle of the external backwash seal 6 on the external backwash mechanism 9 is large, the distance between the two external backwash seals 6 is small, and the sealing performance is good.

[0071] 2. The rear section of the central pipe 2 is provided with circumferentially evenly distributed trapezoidal cross-section seams, which effectively block sand and gravel while ensuring smooth circulation of backwash liquid, ensuring safety and reliability.

[0072] Embodiment 3:

[0073] Based on Example 1 or Example 2, this embodiment provides a method for using the backwash valve.

[0074] S1. During the filling construction process, the inner backwash mechanism 16 outside the central tube 2 blocks the sand-carrying fluid from entering the pipe column clamp wall, and the sand-carrying fluid flow pumped from the oil pipe can only flow downward through the central tube 2 of the present invention to implement extruded gravel filling of the formation;

[0075] S2. When sand blockage occurs (especially when filling with coated sand), or after filling is completed, the backwash liquid reaches the position of the external backwash mechanism 9 on the backwash valve through the casing annulus, enters the sandwich wall between the external backwash pipe 3 and the central pipe 2 through the external backwash port 4, flows through the internal backwash mechanism 16, and enters the interior of the central pipe 2 through the internal backwash port 17, and backwashes the excess gravel out of the ground through the oil pipe.

[0076] All components and connection methods of components not discussed in this application belong to the known technologies in this technical field and can be directly applied without further explanation.

[0077] In the present invention, the term "plurality" means two or more than two, unless otherwise clearly defined. The terms "install", "connect", "connect", "fix" and the like should be understood in a broad sense. For example, "connect" can be a fixed connection, a detachable connection, or an integral connection; "connected" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0078] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by terms such as "up", "down", "left", "right", "front" and "back" are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific orientation, and therefore, cannot be understood as a limitation on the present invention.

[0079] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0080] The above description is only the preferred embodiment of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A high-density formation filling backwash valve for oil and water wells, comprising a central pipe, It is characterized in that It also includes an external backwash mechanism and an internal backwash mechanism; The external backwash mechanism and the internal backwash mechanism are both mounted on the central tube, and the internal backwash mechanism is arranged behind the external backwash mechanism; A one-way flow sealing ring is arranged in the external backwash mechanism.

2. The high-density solid formation filling backwash valve for oil and water wells according to claim 1, characterized in that: The external backwash mechanism includes an external backwash pipe and an external backwash seat, and the one-way flow sealing ring is an external backwash seal; The central tube is provided with a convex ring, and the front end of the outer backwash tube is connected to the outer circumferential surface of the convex ring; The external backwash pipe is provided with an external backwash port, and the external backwash seat is arranged on the outer wall of the central pipe and is located below the external backwash port; The external backwash seal is arranged on the external backwash seat.

3. The high-density formation filling backwash valve for oil and water wells according to claim 2, characterized in that: The external backwash mechanism also includes an external spacer sleeve and an external adapter sleeve; The outer backwash seat is a stepped ring, which is divided into an outer large diameter ring and an outer small diameter ring, and the outer large diameter ring is in front of the outer small diameter ring; At least two external backwash seals are arranged on the outer small diameter ring, and an external spacer sleeve is arranged between every two external backwash seals; The outer backwash seal is a first leather cup, and the mouth of the first leather cup faces forward; The outer fixing sleeve is arranged at the rear end of the outer small diameter ring to lock the outer backwash seal tightly.

4. The high-density formation filling backwash valve for oil and water wells according to claim 2, characterized in that: The internal backwash mechanism comprises a connecting pipe, an internal backwash seal, an internal backwash seat and a blocking ring; The central tube is provided with at least two slits evenly distributed along the circumference of the central tube in the area corresponding to the inner backwash mechanism; The inner backwash seat is a stepped ring, which is divided into an inner large diameter ring and an inner small diameter ring, and the inner large diameter ring is arranged behind the inner small diameter ring; The inner backwash seat is connected to the central tube, and the inner large diameter ring covers the seam strips. The inner large diameter ring is provided with an inner backwash port in the area corresponding to the seam strips, and the inner backwash port corresponds to at least one seam strip. The inner backwash seal is arranged on the inner small diameter ring; The inner backwash seal is covered with a connecting pipe, the connecting pipe covers the inner backwash seal, and the front end of the connecting pipe is connected to the rear end of the outer backwash pipe through a middle coupling; The blocking ring is connected to the rear end of the connecting pipe to seal the annular space between the connecting pipe and the inner backwash seat behind the inner backwash port.

5. The high-density solid formation filling backwash valve for oil and water wells according to claim 4, characterized in that: The internal backwash mechanism also includes an internal fixing sleeve and an internal spacing sleeve; At least two inner backwash seals are arranged on the inner small diameter ring, and an inner spacer sleeve is arranged between every two inner backwash seals; The inner backwash seal is a second leather cup, and the mouth of the second leather cup faces backwards; The inner fixing sleeve is connected to the front end of the inner small diameter ring to compress the inner backwash seal.

6. The high-density solid formation filling backwash valve for oil and water wells according to claim 3, characterized in that: At least two external backwash ports are provided and are evenly distributed along the circumference of the external backwash pipe; The length of the outer spacer sleeve is 2 / 3-1 / 2 of the horizontal projection length of the outer cup; The horizontal angle of the mouth of the first leather cup is 160°-165°.

7. The high-density formation filling backwash valve for oil and water wells according to claim 5, characterized in that: The cross section of the seam strip is a trapezoid that converges toward the center tube; At least two inner backwash ports are provided and are evenly distributed along the circumference of the inner large diameter ring; The length of the inner spacer sleeve is 1 to 2 times the horizontal projection length of the inner cup seal; The horizontal angle of the mouth of the second leather cup is 10°-15°; The diameter of the inner backwash port is smaller than the length of the seam strip.

8. The high-density formation filling backwash valve for oil and water wells according to claim 4, characterized in that: The external backwash pipe and the connecting pipe are made in one piece.

9. The high-density solid formation filling backwash valve for oil and water wells according to claim 5, characterized in that: The blocking ring comprises a lower flush pipe and a connecting sleeve. The rear end of the inner backwash seat is inserted into the lower flush pipe, and the outer wall of the front end of the lower flush pipe is connected to the rear end of the connecting pipe through the connecting sleeve.

10. A high-density solid formation filling backwash valve for oil and water wells according to any one of claims 1 to 9, characterized in that: An upper coupling is arranged at the front end of the central pipe.

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