Sand prevention injection and production valve

Abstract

The utility model relates to the technical field of thickened oil recovery, in particular to a sand prevention injection and production valve which comprises a central pipe, a steam injection hole and an oil inlet hole are formed in the pipe wall of the central pipe, a sand filtering assembly is sleeved outside the central pipe, the central pipe is in sealed butt joint with the upper end and the lower end of the sand filtering assembly, and an annular space is formed between the central pipe and the sand filtering assembly. A one-way oil inlet valve communicated with the oil inlet hole is arranged in the annular space, the center pipe is further connected with a blocking structure used for blocking the steam injection hole, and the blocking structure can slide in the axial direction of the center pipe to expose the steam injection hole under well outside hydraulic operation. When the sand prevention injection and production valve is assembled into an injection and production pipe column for layered injection and production operation, steam injection, oil production and sand filtering can be achieved at the same time, additional oil inlet or sand prevention devices do not need to be arranged on the injection and production pipe column, and therefore the assembled injection and production pipe column is short in axial length, simple in structure and capable of being suitable for injection and production operation of oil layers with different layered thicknesses.

Description

Technical Field

[0001] The utility model relates to the technical field of heavy oil exploitation, and particularly relates to a sand control injection-production valve. Background Art

[0002] Heavy oil (also known as thick oil), due to its high viscosity, high density, high asphaltene and resin content, and strong sand-carrying capacity, currently mainly adopts the steam huff and puff development method. However, due to the strong heterogeneity of heavy oil reservoirs and the repeated utilization during steam injection in high-permeability oil layers, while the gas intake in low-permeability oil layers is less or even zero, the original general steam injection development method exacerbates the interlayer contradiction of the reservoir, resulting in uneven utilization degrees of each layer of the reservoir, reducing the vertical steam sweep efficiency, and affecting the development efficiency of the oil. Based on this, the heavy oil reservoir layered steam injection technology uses the mechanical sealing effect of packers to divide the steam injection units of the reservoir, divides the reservoirs with similar physical properties into one layer, that is, one steam injection unit, and reasonably injects steam into each steam injection layer as needed. This can reduce the mutual interference between steam injection layers, improve the steam intake profile. The prior art, such as the utility model patent with the authorization announcement number CN205382911U, discloses a high-temperature steam injection valve, specifically including a main body provided with a channel, steam injection holes for communicating the channel with the outside of the main body are provided on the wall of the main body, a sliding sleeve for blocking the steam injection holes is provided in the channel, and the upper end of the sliding sleeve can be blocked by a valve ball, so as to slide along the extension direction of the main body under the action of external pressure outside the well to open the steam injection holes for steam injection.

[0003] During the steam injection exploitation operation, it is necessary to successively assemble the high-temperature steam injection valve and the oil inlet valve to form an injection-production string and then lower it to the expected position (the position of the oil layer to be injected with steam) for steam injection and oil production. However, the injection-production string is arranged with a steam injection valve, an oil inlet valve and other accessories axially in sequence. The axial length of the injection-production string is relatively long and the structure is complex. When lowering it into an oil layer with a relatively thin layered thickness, the length of the injection-production string may exceed the thickness of the layered oil layer, and layered injection-production operations cannot be carried out. And with the high-temperature steam injection and blowdown of the oil well, the exploitation degree of the near-well formation increases, and due to factors such as the change of the production pressure difference, the formation sand production becomes more serious. To prevent the formation sand from entering through the steam injection holes in the oil inlet valve and the high-temperature steam injection valve of the above-mentioned layered injection-production string, resulting in serious consequences such as the reduction of the diameter or even blockage of the steam injection channel and the liquid inlet channel, it is also necessary to set sand control screen meshes and other components on both the high-temperature steam injection valve and the oil inlet valve, which will make the structure of the injection-production string more complex, and make the processes of string assembly and lowering into the well consume too much time, affecting the exploitation efficiency of heavy oil reservoirs. Content of the Utility Model

[0004] The purpose of the utility model is to provide a sand control injection-production valve to solve the problems that the steam injection valve in the prior art causes the structure of the layered injection-production string to be relatively complex and cannot be used in oil layers with relatively thin layered thickness during injection-production operations.

[0005] To achieve the above object, the technical solution of the sand control injection-production valve provided by the present utility model is as follows: It includes a central pipe, steam injection holes and oil inlet holes are opened on the pipe wall of the central pipe, a sand filtering assembly is sleeved outside the central pipe, the upper and lower ends of the central pipe and the sand filtering assembly are hermetically butted, and there is an annular space between the central pipe and the sand filtering assembly. A one-way oil inlet valve communicated with the oil inlet hole is arranged in the annular space. A plugging structure for plugging the steam injection hole is also connected to the central pipe. The plugging structure can slide axially along the central pipe under the hydraulic operation outside the well to expose the steam injection hole.

[0006] As a further improvement, the aperture of the oil inlet hole is larger than that of the steam injection hole.

[0007] As a further improvement, annular retaining platforms are arranged on the outer sides of the pipe walls at both ends of the central pipe, a sealing ring is sleeved on the central pipe to achieve the seal between it and the sand filtering assembly, connectors are connected to both ends of the sand filtering assembly, and the connectors cooperate with the annular retaining platforms to achieve axial limit of the sealing ring.

[0008] As a further improvement, the plugging structure is a sliding sleeve arranged on the inner side of the pipe wall of the central pipe, and the upper end of the sliding sleeve can be used for ball plugging.

[0009] As a further improvement, the plugging structure is a sliding ring connected to the outer side of the pipe wall of the central pipe through shear pins, and the sliding ring has an axial pressure-bearing surface.

[0010] As a further improvement, the cross-section of the sliding ring is L-shaped, a convex platform is arranged on the outer side of the pipe wall of the central pipe, the axial section of the sliding ring is connected to the convex platform through shear pins, and the radially extending section of the sliding ring constitutes the axial pressure-bearing surface.

[0011] As a further improvement, the one-way oil inlet valve includes an axially extending tubular valve seat and a valve ball installed in the tubular valve seat, and flow holes corresponding to and communicated with the oil inlet hole are arranged on the side wall of the tubular valve seat.

[0012] As a further improvement, the sand filtering assembly includes a perforated base pipe and a wire-wound sand control screen sleeve.

[0013] As a further improvement, the wire-wound sand control screen sleeve is formed by winding stainless steel wires, and a liquid flow channel with a smaller outer diameter and a larger inner diameter is formed in the radial direction.

[0014] The beneficial effects are as follows: The present utility model provides a sand control injection-production valve improved on the basis of the injection valve in the prior art. After the component string is lowered to the expected position, during the steam injection operation, first, hydraulic operation is carried out outside the well to make the plugging structure slide axially along the central pipe to expose the steam injection holes, the steam injection channel is unsealed, and high-pressure steam enters the inner cavity of the central pipe along the pipe string and is then injected into the expected formation through the steam injection holes. At the same time, the sand filtration component can block formation sand from entering the sand control injection-production valve through the steam injection holes, avoiding the situation of formation sand blocking the sand control injection-production valve, ensuring the long-term normal use of the sand control injection-production valve, and thus ensuring the normal progress of the stratified steam injection operation. After the steam injection is completed, the oil liquid carrying sand grains is filtered by the sand filtration component and enters the central pipe through the oil inlet valve and the steam injection holes, and then is pumped out.

[0015] During the injection-production operation, according to the number of oil layers to be injected with gasoline, the same number of sand control injection-production valves are selected and assembled to form an injection-production pipe string. Through the sand control injection-production valve provided by the present utility model, steam injection, oil production, and sand filtration can be achieved simultaneously, without the need to set additional oil inlet or sand control devices on the injection-production pipe string. The steam injection, oil production, and sand control components on the injection-production pipe string are integrated into the same valve body, making the assembled injection-production pipe string have a shorter axial length, a simple structure, and being able to adapt to the injection-production operations of oil layers with different stratified thicknesses; and it shortens the assembly time of the injection-production pipe string, as well as the operation time for lowering and pulling out the injection-production pipe string, and significantly improves the production efficiency. Brief Description of the Drawings

[0016] Figure 1 It is a schematic structural diagram when the sand control injection-production valve provided by the present utility model is assembled into a stratified sand control injection-production pipe string;

[0017] Figure 2 It is a schematic structural diagram of an embodiment of the sand control injection-production valve provided by the present utility model;

[0018] Figure 3 It is a schematic structural diagram of another embodiment of the sand control injection-production valve provided by the present utility model;

[0019] Figure 4 It is a schematic diagram of the wire winding and liquid flow channels in the wire-wound sand screen sleeve in the sand control injection-production valve provided by the present utility model;

[0020] In the figure: 1. Upper joint; 2. Lower joint; 3. Upper sealing ring; 4. Lower sealing ring; 5. Central pipe; 6. Oil inlet hole; 7. Steam injection hole; 8. Drilled base pipe; 9. Wire-wound sand control screen sleeve; 10. Valve seat; 11. Valve ball; 12. Flow hole; 13. Sleeve; 14. Boss; 15. Slip ring; 16. Shearing pin; 17. Telescopic pipe; 18. Thickening pump; 19. Safety joint; 20. Steam injection packer; 21. Plug; 22. Upper sand control injection-production valve; 23. Lower sand control injection-production valve; 24. First oil layer; 25. Second oil layer; 26. Wire winding; 27. Liquid flow channel; 28. Annular retaining platform. Detailed implementation mode

[0021] The features and performance of the present utility model will be further described in detail below in conjunction with the embodiments.

[0022] In the oilfield, the formation of heavy oil reservoirs is shallowly buried, loosely cemented, with high viscosity of the oil liquid and strong sand-carrying capacity. The steam flooding injection technology is a widely used technology for extracting heavy oil at present. In the prior art, such as the high-temperature steam injection valve disclosed in the authorized publication number CN205382911U, when carrying out steam injection production operations, it is necessary to be assembled with components such as an oil inlet device to form an injection-production string. However, the axial length of the injection-production string formed by assembling this high-temperature steam injection valve is relatively long. When operating on some oil layers with relatively thin layered thicknesses, the length of the injection-production string even exceeds the thickness of the layered oil layer to be steam-injected and produced, and it is simply impossible to carry out injection-production operations on oil layers with relatively thin layered thicknesses. Moreover, the injection-production string itself has many components and is relatively long. However, due to the strong sand-carrying capacity of heavy oil, it is also necessary to separately set up sand control screens on the steam injection valve and the oil inlet device. Although it can avoid the situation of the injection channel and the oil production channel being reduced in diameter and blocked by formation sand, it further increases the complexity of the string. Assembling the string and the string entering and exiting the well all consume too much time, and the practicability is poor, seriously affecting the efficiency of heavy oil production operations. Based on this, the present utility model improves the steam injection valve in the prior art and provides a sand control injection-production valve.

[0023] The overall design concept of the sand control injection-production valve provided by the present utility model is as follows:

[0024] As Figures 1 - 4 shown, a sand control injection-production valve includes a central pipe 5. Steam injection holes 7 and oil inlet holes 6 are provided on the pipe wall of the central pipe 5. A sand filtration assembly is sleeved outside the central pipe 5. The upper and lower ends of the central pipe 5 are hermetically butted with the sand filtration assembly. At the same time, the upper and lower ends of the sand filtration assembly are connected with an upper joint 1 and a lower joint 2 by screw threads. There is an annular space between the central pipe 5 and the sand filtration assembly. A one-way oil inlet valve communicated with the oil inlet hole 6 is arranged in the annular space, so that the oil liquid passes upward unidirectionally, flows into the oil inlet valve and then passes through the oil inlet hole 6 to the inner cavity of the central pipe 5 to be pumped and produced. A blocking structure for blocking the steam injection hole 7 is also connected to the central pipe 5.

[0025] When conducting layered steam injection production, the same number of sand control injection-production valves are selected according to the number of oil layers that need steam injection. The telescopic pipe 17, the heavy oil extraction pump 18, the safety joint 19, and the sand control injection-production valves are connected in sequence. And an injection steam packer 20 is connected between two adjacent sand control injection-production valves, and a plug 21 for plugging is also connected at the bottom. After being connected to form a layered injection-production string, it is lowered into the heavy oil well, so that the position of the sand control injection-production valve underground corresponds to the oil layer that needs steam injection, and a packer corresponds to the string between two adjacent oil layers. When steam injection is required after the layered sand control injection-production string is lowered to the expected position, first, hydraulic operation is carried out outside the well. At this time, the plugging structure on the sand control injection-production valve at the bottom of the string first slides axially along the central pipe 5 under the hydraulic operation, and the plugging structure moves away from the steam injection hole 7 to expose the steam injection hole 7. At this time, steam injection operation can be carried out on the oil layer corresponding to this sand control injection-production valve. High-temperature steam is injected into the oil layer through the steam injection hole 7 from the inner cavity of the central pipe 5. And during the steam injection operation, the steam injection hole 7 is inside the sand filtration component, and formation sand is blocked by the sand filtration component and will not enter the steam injection hole 7 to cause blockage of the sand control steam injection valve or even the steam injection channel, which can ensure the long-term normal use of the sand control injection-production valve, and then ensure the normal progress of the layered steam injection operation.

[0026] After the layered steam injection operation is completed, during the operation of the heavy oil extraction pump 18, the oil fluid flows through the one-way oil inlet valve through the oil inlet hole 6 into the inner cavity of the central pipe 5, and then is pumped and produced. At the same time, the oil fluid can also enter the inner cavity of the central pipe 5 from the steam injection hole 7 and be produced under the action of the heavy oil extraction pump 18. During the oil production process, the formation sand carried in the oil fluid is resisted by the sand filtration component of the sand control injection-production valve, which can, to a certain extent, prevent the sand grains carried by the heavy oil from entering the sand control injection-production valve from the steam injection hole 7 and the oil inlet valve, thereby being able to, to a certain extent, avoid the consequences of sand grains blocking the sand control injection-production valve or even jamming the pump, and ensure the normal progress of the oil production operation.

[0027] The sand control injection-production valve provided by the present utility model can be assembled with other tools through its upper joint 1 and lower joint 2 to form a layered sand control injection-production string, integrating the functions of sand blocking, fluid passing, and pressure bearing, and realizing the integration of steam injection, production, and sand filtration in the same valve body. There is no need to additionally set an oil inlet or sand control device on the string, which simplifies the structure of the layered sand control injection-production string, makes the axial length of the assembled layered sand control injection-production string shorter, can adapt to the steam injection and production operations of oil layers with different layered thicknesses, and because there are fewer tools on the string, the structure is simpler, the assembly time required for assembling the string is reduced, the process is saved, and the construction cost is effectively controlled; and during the actual injection-production operation, the time for the string to enter and exit the well is shortened, and the heavy oil production efficiency is significantly improved.

[0028] Based on the above overall introduction of the present utility model, the following provides a more specific embodiment on the basis of the overall introduction:

[0029] During the oil production process, the oil fluid first enters the one-way oil inlet valve after passing through the filter sand assembly. The one-way oil inlet valve allows the oil fluid to pass upward unidirectionally, not only shortening the oil inlet flow path, reducing the oil inlet resistance, but also effectively preventing the oil fluid from flowing back into the wellbore, thereby effectively improving the pump efficiency. And to ensure the heavy oil production efficiency, the aperture of the oil inlet hole 6 is larger than that of the steam injection hole 7, and the amount of oil fluid entering through the oil inlet hole 6 is greater than that entering through the steam injection hole 7. At this time, even if there is a situation where the oil fluid flows back from the steam injection hole 7, more oil fluid will be pumped out by the one-way oil inlet valve.

[0030] As Figures 1 - 3 shown, the one-way oil inlet valve includes an axially extending tubular valve seat 10 and a valve ball 11 installed inside the tubular valve seat. The inner cavity of the valve seat 10 forms an oil inlet channel, and a flow-through hole 12 corresponding to and communicating with the oil inlet hole 6 is provided on the side wall of the tubular valve seat 10. The oil inlet channel is communicated with the oil inlet hole 6 through the flow-through hole 12. After the steam injection operation is completed, during the operation of the heavy oil pump 18, the oil fluid carrying formation sand passes through the filtration of the filter sand assembly, pushes open the valve ball 11 and enters the oil inlet channel, and enters the central tube 5 through the flow-through hole 12 and the oil inlet hole 6, and is thus pumped out during the operation of the heavy oil pump 18. At the same time, the filter sand assembly prevents the oil fluid from carrying formation sand into the sand control injection-production valve, thereby preventing the sand control injection-production valve and even the central tube 5 from being blocked and affecting the production operation. The one-way oil inlet valve is provided with one valve ball 11, with higher reliability, further ensuring the normal operation of the sand control injection-production valve.

[0031] To ensure the pressure-bearing performance of the sand control injection-production valve so that the plugging structure no longer plugs the steam injection hole 7 during the hydraulic operation outside the well, a sealing ring is sleeved on the central tube 5 to achieve the seal between it and the filter sand assembly. Specifically, annular retaining platforms 28 are provided at both the upper and lower ends of the tube wall of the central tube 5. The upper sealing ring 3 and the lower sealing ring 4 are both arranged inside the annular retaining platform 28, and then the upper joint 1 and the lower joint 2 are connected to the filter sand assembly by threads to compress the upper sealing ring 3 and the lower sealing ring 4, thereby axially limiting the sealing ring and pressing the sealing ring in the annular retaining platform 28 to ensure the sealed butt joint between the central tube 5 and the filter sand assembly; and both ends of the central tube 5 and the filter sand assembly are axially pressed by the upper joint 1 and the lower joint 2, further ensuring the sealing pressure-bearing of the sand control injection-production valve. Preferably, inner rubber ring grooves are provided on the inner sides of the upper sealing ring 3 and the lower sealing ring 4 to fill with sealing rubber rings, and outer rubber ring grooves are provided on the outer sides of the upper sealing ring 3 and the lower sealing ring 4 to fill with sealing rubber rings, thereby further ensuring the sealed butt joint between the central tube 5 and the filter sand assembly.

[0032] Based on the above overall introduction of the present invention, the following provides a more specific embodiment on the basis of the overall introduction:

[0033] This embodiment focuses on a detailed description of the plugging structure.

[0034] To ensure the steam injection efficiency, a plurality of steam injection holes 7 are provided on the pipe wall of the central pipe 5, and the plurality of steam injection holes 7 are evenly spaced along the circumferential direction of the central pipe 5. A plugging member is provided on the central pipe 5 to plug the steam injection holes 7, and the steam injection holes 7 are exposed when steam needs to be injected into the formation. The plugging structure can be a sliding sleeve 13 connected to the inner side of the pipe wall of the central pipe through a shear pin 16, and the upper end of the sliding sleeve 13 can be used for ball plugging; of course, the plugging structure can also be a sliding ring connected to the outer side of the pipe wall of the central pipe 5 through a shear pin 16. When the shear pin 16 is cut by hydraulic operation outside the well, the sliding ring 15 or the sliding sleeve 13 can move to expose the steam injection holes 7.

[0035] When assembling a sand control injection-production valve string with the corresponding number according to the number of layers that need to be steam injected in layers, the plugging structure of the sand control injection-production valve can be the above-mentioned sliding sleeve 13 or sliding ring 15. Taking the steam injection and production of two oil layers in this case as an example, the sand control injection-production pipe string for layered use includes an upper sand control injection-production valve 22 and a lower sand control injection-production valve 23 arranged adjacent to each other. After the sand control injection-production pipe string for layered use is assembled, it is lowered into the well, so that the positions of the upper sand control injection-production valve 22 and the lower sand control injection-production valve 23 in the well correspond to the first oil layer 24 and the second oil layer 25, and a steam injection packer 20 is provided on the pipe string between the first oil layer 24 and the second oil layer 25. The entire sand control injection-production pipe string for layered use is in a sealed and pressure-bearing state. At this time, the plugging structure of the lower sand control injection-production valve 23 is a sliding ring 15 arranged on the outer side of the pipe wall of the central pipe 5. Through hydraulic operation outside the well, the sliding ring 15 on the lower sand control injection-production valve 23 slides axially along the central pipe 5 to expose the steam injection holes 7, and the steam injection channel is opened. Subsequently, high-pressure steam enters the inner cavity of the central pipe 5 along the pipe string and is injected into the second oil layer 25 through the steam injection holes 7. The steam flooding operation continues. Since the steam injection holes 7 in the lower sand control injection-production valve 23 have been opened, the entire sand control injection-production pipe string for layered use cannot be pressure-held at this time, that is, the steam injection holes 7 in the upper sand control injection-production valve 22 cannot be opened by pressure-holding. At this time, the plugging structure of the upper sand control injection-production valve 22 is a sliding sleeve 13 arranged on the inner side of the pipe wall of the central pipe 5. The upper end of the sliding sleeve 13 is plugged during the ball dropping operation, and then the sliding sleeve 13 is moved downward by hydraulic operation to expose the steam injection holes 7 in the upper sand control injection-production valve 22, so that high-pressure steam can be injected into the first formation through the steam injection holes 7 of the central pipe 5 of the upper sand control injection-production valve 22 to complete the steam injection. At the same time, since the upper end of the sliding sleeve 13 is plugged by the dropped ball, the steam cannot flow through the sliding sleeve 13 and into the lower part of the sliding sleeve 13, thereby preventing the steam injected during the steam flooding operation of the first formation 24 from being injected into the second formation 25. Of course, the plugging structures on the upper sand control injection-production valve 22 and the lower sand control injection-production valve 23 can also both be sliding sleeves 13, so as to open the steam injection holes 7 by sliding in the central pipe 5 through ball dropping and hydraulic operation outside the well, and the upper end of the sliding sleeve 13 can be plugged by the dropped ball, thereby preventing high-temperature steam from flowing along the pipe string and being injected into adjacent oil layers.

[0036] Preferably, to ensure that the slip ring 15 can be opened more quickly to ensure the normal progress of the steam injection operation, a boss 14 is provided on the outer wall of the central pipe 5. The cross-section of the slip ring 15 is L-shaped. The axial section of the slip ring 15 is connected to the boss 14 through a shear pin 16. At this time, there is a gap between the slip ring 15 and the steam injection hole 7. The radial extension section of the slip ring 15 forms an axial pressure-bearing surface. Thus, the hydraulic pressure is transmitted through the steam injection hole 7 to the space between the slip ring 15 and the steam injection hole 7, and the radial extension section of the slip ring 15 is pressed, causing the shear pin 16 between the slip ring 15 and the boss 14 to be cut off, and the slip ring 15 to fall off the boss 14 and slide axially along the central pipe 5.

[0037] To ensure the sealing and pressure-bearing performance of the high-temperature steam injection valve and enable the plugging structure to be opened during hydraulic operation outside the well, outer rubber ring grooves are provided at both the upper and lower ends of the sliding sleeve 13. An outer rubber ring groove is provided between the outer side of the boss 14 and the slip ring 15, and an inner rubber ring groove is provided between the inner side of the slip ring 15 and the central pipe 5 for installing the sealing rubber ring, thereby ensuring the sealed installation of the plugging structure and causing the shear pin 16 to be cut off due to pressure buildup during hydraulic operation, exposing the steam injection hole 7.

[0038] In this embodiment, to improve the connection strength between the central pipe 5 and the sliding sleeve 13, the sliding sleeve 13 and the central pipe 5 can be connected through multiple shear pins 16. The number of shear pins 16 can be set to 2, 3, or other numbers, which are not limited herein. The installation height of the shear pins 16 can be higher than that of the one-way oil inlet valve, or the installation height of the shear pins 16 can be lower than that of the one-way oil inlet valve, which is also not limited herein.

[0039] Based on the above overall introduction of the present invention, or on the basis of the embodiments of the present invention introduced above, the following provides a more specific embodiment on the basis of the overall introduction:

[0040] This embodiment focuses on a detailed description of the sand filtration assembly.

[0041] As Figures 2 - 4 shown, the sand filtration assembly includes a perforated base pipe 8 and a wire-wound sand control screen sleeve 9. The perforated base pipe 8 adopts a spiral hole distribution method, which not only meets the requirements of the opening ratio but also meets the requirements of the base pipe strength. The wire-wound sand control screen sleeve 9 is a screen sleeve wound by a stainless steel wire 26. And to ensure the sand filtration effect, the wound screen sleeve is provided with a liquid flow channel 27 that is smaller on the outside and larger on the inside in the radial direction. In this embodiment, as Figure 4 shown, the cross-section of the wire 26 is triangular, and the wound liquid flow channel 27 has a trapezoidal cross-section. During the operation, the larger particles retained on the surface of the screen sleeve are washed away by the flowing pressure of the oil layer, increasing the self-cleaning ability of the screen sleeve for formation sand, reducing the sedimentation of sediment in the central pipe 5, and delaying or even preventing blockage. Of course, in other embodiments, the cross-section of the wire 26 is trapezoidal, and after winding, a liquid flow channel 27 that is smaller on the outside and larger on the inside can also be formed.

[0042] It should be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. To avoid unnecessary repetition, the present utility model will not separately describe various possible combination manners.

[0043] In addition, any combination can be made among various different embodiments of the present utility model as long as it does not violate the idea of the present utility model, and it should also be regarded as the content disclosed by the present utility model.

[0044] The above is only the preferred embodiment of the present utility model and is not intended to limit the present utility model. The patent protection scope of the present utility model is subject to the claims. Any equivalent structural changes made by using the description and drawings of the present utility model shall be included in the protection scope of the present utility model by the same token.

Claims

1. A sand prevention injection valve, comprising a central tube, characterized in that: A steam injection hole and an oil inlet hole are provided on the wall of the center tube, and a sand filter assembly is provided on the outer sleeve of the center tube. The center tube and the sand filter assembly are sealed and connected at the upper and lower ends, and an annular space is provided between the center tube and the sand filter assembly. A one-way oil inlet valve connected to the oil inlet hole is provided in the annular space. A sealing structure for sealing the steam injection hole is also connected to the center tube, and the sealing structure can slide axially along the center tube under hydraulic operation outside the well to expose the steam injection hole.

2. The sand prevention injection and production valve according to claim 1 is characterized in that: The diameter of the oil inlet hole is larger than the steam injection hole.

3. The sand prevention injection and production valve according to claim 1 is characterized in that: Annular baffles are provided on the outer side of the tube wall at both ends of the central tube. A sealing ring is sleeved on the central tube to achieve sealing between it and the sand filter assembly. Joints are connected at both ends of the sand filter assembly. The joints cooperate with the annular baffles to achieve axial limitation of the sealing ring.

4. The sand prevention injection and production valve according to any one of claims 1 to 3, characterized in that: The plugging structure is a sliding sleeve connected to the inner side of the pipe wall of the central pipe through a shear pin, and the upper end of the sliding sleeve can be used for ball throwing and plugging.

5. The sand prevention injection and production valve according to any one of claims 1 to 3, characterized in that: The plugging structure is a slip ring connected to the outer side of the pipe wall of the central pipe through a shear pin, and the slip ring has an axial pressure-bearing surface.

6. The sand prevention injection and production valve according to claim 5 is characterized in that: The cross section of the slip ring is L-shaped, a boss is provided on the outer side of the tube wall of the central tube, the axial section of the slip ring is connected to the boss through a shear pin, and the radial extension section of the slip ring constitutes the axial pressure-bearing surface.

7. The sand prevention injection and production valve according to any one of claims 1 to 3, characterized in that: The one-way oil inlet valve comprises an axially extending tubular valve seat and a valve ball installed in the tubular valve seat. A flow hole corresponding to the oil inlet hole is arranged on the side wall of the tubular valve seat.

8. The sand prevention injection and production valve according to any one of claims 1 to 3, characterized in that: The sand filter assembly includes a perforated base pipe and a wire-wrapped sand screen sleeve.

9. The sand prevention injection and production valve according to claim 8 is characterized in that: The wire wound sand retaining screen sleeve is formed by winding stainless steel wire, and forms a liquid flow channel with a small outside and a large inside in the radial direction.

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