Efficient hole sealing and sand preventing device

Abstract

The efficient hole sealing and sand preventing device comprises a screen pipe, an oil outlet pipe, an elastic bag and a grouting pipe, an annular cavity is defined by the screen pipe and the oil outlet pipe, a port of the first end of the oil outlet pipe is plugged and located in the screen pipe, an oil inlet seam is formed in the side wall of the oil outlet pipe, a grate groove is formed in the side wall of the screen pipe, and the first end of the oil outlet pipe is communicated with the grate groove. The grate groove is used for filtering silt in petroleum so that the petroleum can enter the annular cavity through the grate groove, and the elastic bag spirally surrounds the top of the outer wall face of the screen pipe in the axial direction of the screen pipe. And the grouting pipe is connected with the elastic bag. During use, the sealing length between the screen pipe and the hole wall of the oil well is increased due to the spiral bag mounting mode, a liquid leakage channel can be prevented from being formed at the protrusion due to the long sealing length, the sealing performance of the oil well is effectively guaranteed, meanwhile, the fixing effect of the screen pipe is more reliable, and the mounting reliability is improved.

Description

Technical Field

[0001] This invention relates to the field of oil well sand control technology, specifically to a high-efficiency well sealing and sand control device. Background Technology

[0002] Sand production in oil wells is a long-standing problem during oil extraction. Sand production leads to wear and tear on oil well production equipment, reduced well productivity, and even forced shutdowns. Traditional sand control methods, such as screens and filters, while preventing sand particles from entering the production system to some extent, suffer from low filtration efficiency, clogging susceptibility, and frequent maintenance. Furthermore, screens in these technologies also suffer from low installation reliability. Therefore, to overcome the limitations of existing technologies, a high-efficiency well-sealing sand control device is proposed. Summary of the Invention

[0003] The present invention aims to at least partially solve one of the technical problems in the related art.

[0004] Therefore, embodiments of the present invention propose a high-efficiency sealing and sand-prevention device.

[0005] The high-efficiency sealing and sand-prevention device of this invention includes a screen pipe, an oil outlet pipe, an elastic bladder, and a grouting pipe. The screen pipe is sleeved on the oil outlet pipe and spaced apart from it. The screen pipe and the oil outlet pipe define an annular cavity. The first end of the oil outlet pipe is sealed and located inside the screen pipe, while the second end of the oil outlet pipe is located outside the screen pipe. The side wall of the oil outlet pipe has an oil inlet slit located within the annular cavity. Both ends of the screen pipe are sealed. The side wall of the screen pipe has a grate groove for filtering mud and sand in the oil, allowing the oil to enter the annular cavity through the grate groove.

[0006] The elastic bladder is spirally wrapped around the top of the outer wall of the screen pipe along the axial direction; the grouting pipe is connected to the elastic bladder and is used to inject grout into the elastic bladder so that the elastic bladder expands and abuts against the inner wall of the oil well.

[0007] In some embodiments, the elastic bladder is provided with a pressure relief valve. When the grouting pressure inside the elastic bladder exceeds a preset value, the pressure relief valve opens to discharge the grout inside the elastic bladder through the pressure relief valve.

[0008] In some embodiments, the high-efficiency sealing and sand-prevention device of the present invention further includes an air supply pipe, a one-way valve, and a shut-off valve. The inlet of the air supply pipe is connected to a compressed gas source, and the outlet of the air supply pipe is connected to the oil outlet pipe. The outlet of the air supply pipe is located above the oil inlet slit. The one-way valve is located at the outlet of the air supply pipe, and the outlet direction of the one-way valve is oriented towards the inner cavity of the oil outlet pipe. The shut-off valve is located on the oil outlet pipe and above the outlet of the air supply pipe. The shut-off valve is used to control the opening and closing of the oil outlet pipe.

[0009] In some embodiments, the high-efficiency sealing and sand-prevention device of the present invention further includes a filter layer, which is disposed in the annular cavity and surrounds the oil outlet pipe. The filter layer is attached to the outer wall surface of the oil outlet pipe. The oil entering the annular cavity through the grate is filtered by the filter layer and then enters the oil outlet pipe through the oil inlet slit.

[0010] In some embodiments, the filter layer includes a first filter layer and a second filter layer arranged in an inward and outward direction, wherein the first filter layer is located outside the second filter layer and the pore size of the first filter layer is larger than the pore size of the second filter layer.

[0011] In some embodiments, the two ends of the screen tube are respectively provided with a first sealing plate and a second sealing plate. The first sealing plate is located above the second sealing plate. The filter layer is arranged axially with the first sealing plate. An air inlet chamber is defined between the first sealing plate, the inner wall surface of the screen tube, the filter layer and the outer wall surface of the oil outlet pipe. The outlet end of the air supply pipe extends into the air inlet chamber and communicates with the oil outlet pipe. An air outlet hole is opened on a portion of the side wall of the air supply pipe located in the air inlet chamber.

[0012] In some embodiments, the gas supply pipe includes a vertical section and a horizontal section connected together. The vertical section is arranged parallel to the axis of the oil outlet pipe. One end of the vertical section extends out of the air intake chamber, and the other end of the vertical section extends into the air intake chamber and is connected to the horizontal section. The horizontal section is arranged perpendicular to the axis of the oil outlet pipe and communicates with the oil outlet pipe. The gas outlet is provided on the vertical section.

[0013] In some embodiments, the number of air outlets is multiple, the multiple air outlets are divided into multiple hole groups, the multiple hole groups are arranged at intervals along the axial direction of the vertical segment, and the hole group includes multiple air outlets arranged at intervals along the circumferential direction of the vertical segment.

[0014] In some embodiments, the screen tube includes a cylindrical body, a plurality of grate discs, and a plurality of washers. The cylindrical body is sleeved on the oil outlet pipe. The grate discs are annular structural components and are disposed below the cylindrical body and coaxially arranged with the cylindrical body. The plurality of grate discs and the plurality of washers are arranged alternately in sequence along the axial direction of the cylindrical body so that the grate groove is defined between two adjacent grate discs.

[0015] In some embodiments, a connecting rod is provided on the bottom end face of the cylinder, the connecting rod is arranged parallel to the axial direction of the oil outlet pipe, the grate and the second sealing plate are provided with connecting holes for the connecting rod to pass through, the grate and the second sealing plate are connected by the connecting rod, and the washer is sleeved on the connecting rod.

[0016] In use, the high-efficiency well sealing and sand prevention device of this invention consists of an elastic bladder spirally wrapped around the top of the outer wall of the screen pipe along its axial direction. The main function of the elastic bladder is to inject grout into it through the grouting pipe. After grouting, the bladder expands and abuts against the inner wall of the oil well, thereby sealing the well and preventing sand particles from entering the production system. The spiral bladder installation method increases the sealing length between the screen pipe and the well wall. This longer sealing length avoids the formation of leakage channels at protrusions, effectively ensuring the well's sealing performance. It also makes the screen pipe's fixation more reliable, improving installation reliability. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the high-efficiency sealing and sand-prevention device according to an embodiment of the present invention.

[0018] Figure 2 This is a schematic diagram of the installation of the high-efficiency sealing and sand-prevention device according to an embodiment of the present invention.

[0019] Figure 3 yes Figure 2 An enlarged schematic diagram of part A in the middle.

[0020] Figure 4 This is a cross-sectional view of the high-efficiency sealing and sand-prevention device according to an embodiment of the present invention.

[0021] Figure 5 yes Figure 4 Enlarged diagram of part B.

[0022] Figure 6 This is a partial structural schematic diagram of the sieve tube according to an embodiment of the present invention.

[0023] Figure label:

[0024] 100. A high-efficiency sealing and sand-prevention device; 1. Screen pipe; 101. Grate; 102. Cylinder; 103. Grate plate; 104. Washer; 2. Oil outlet pipe; 201. First end; 202. Second end; 203. Oil inlet slit; 3. Annular cavity; 4. Elastic bag; 5. Grouting pipe; 6. Air supply pipe; 601. Air outlet; 602. Vertical section; 603. Horizontal section; 7. One-way valve; 8. Shut-off valve; 9. Filter layer; 901. First filter layer; 902. Second filter layer; 10. First sealing plate; 11. Second sealing plate; 12. Air inlet chamber; 13. Connecting rod. Detailed Implementation

[0025] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0026] like Figures 1 to 6 As shown, the high-efficiency well sealing and sand control device 100 of this embodiment includes a screen pipe 1, an oil outlet pipe 2, an elastic bag 4, and a grouting pipe 5. The screen pipe 1 is sleeved on the oil outlet pipe 2 and spaced apart from it, with the screen pipe 1 and the oil outlet pipe 2 defining an annular cavity 3. The port of the first end 201 of the oil outlet pipe 2 is sealed and located inside the screen pipe 1, while the port of the second end 202 of the oil outlet pipe 2 is located outside the screen pipe 1. The side wall of the oil outlet pipe 2 has an oil inlet slot 203 located within the annular cavity 3. Both ends of the screen pipe 1 are sealed, and the side wall of the screen pipe 1 has a grate 101 for filtering mud and sand in the oil, allowing the oil to enter the annular cavity 3 through the grate 101. The elastic bag 4 is spirally wrapped around the top of the outer wall of the screen pipe 1 along its axial direction. The grouting pipe 5 is connected to the elastic bag 4 and is used to inject grout into the elastic bag 4, causing the elastic bag 4 to expand and abut against the inner wall of the oil well.

[0027] In use, the high-efficiency well sealing and sand prevention device of this invention consists of an elastic bag 4 spirally wrapped around the top of the outer wall of the screen pipe 1 along its axial direction. The main function of the elastic bag 4 is to inject grout into it through the grouting pipe 5. After grouting, the bag expands and abuts against the inner wall of the oil well, thereby sealing the well and preventing sand particles from entering the production system. The spiral bag installation method increases the sealing length between the screen pipe 1 and the well wall. This longer sealing length avoids the formation of leakage channels at protrusions, effectively ensuring the well's sealing performance. It also makes the fixing effect of the screen pipe 1 more reliable, improving the reliability of the installation.

[0028] In some embodiments, the elastic bag 4 is equipped with a pressure relief valve. When the grouting pressure inside the elastic bag 4 exceeds a preset value, the pressure relief valve opens to discharge the grout inside the elastic bag 4. When the grouting pressure is greater than the preset value, the pressure relief valve plays a pressure relief role, ensuring the safety and reliability of the elastic bag 4 in use and avoiding the risk of bursting and failure due to excessive grouting pressure during grouting.

[0029] In some embodiments, the high-efficiency sealing and sand-prevention device 100 of the present invention further includes an air supply pipe 4, a one-way valve 5, and a shut-off valve 6. The inlet of the air supply pipe 4 is connected to a compressed gas source, and the outlet of the air supply pipe 4 is connected to the oil outlet pipe 2. The outlet of the air supply pipe 4 is located above the oil inlet slit 203. The one-way valve 5 is located at the outlet of the air supply pipe 4, with its outlet direction facing the inner cavity of the oil outlet pipe 2. The shut-off valve 6 is located on the oil outlet pipe 2 and above the outlet of the air supply pipe 4, and is used to control the opening and closing of the oil outlet pipe 2.

[0030] In use, the high-efficiency sealing and sand-prevention device 100 of this invention allows oil carrying sand particles in the oil layer to rise to the screen pipe 1. The grate 101 of the screen pipe 1 acts as a filter, allowing oil to pass through while intercepting sand particles. The annular cavity 3 between the screen pipe 1 and the oil outlet pipe 2 serves as a transition space, allowing the pre-filtered oil to flow within this space, further reducing the chance of sand particles entering the oil outlet pipe 2. The oil entering the annular cavity 3 passes through the inlet slot 203 and enters the oil outlet pipe 2 for oil extraction. A one-way valve 5 is located at the outlet of the gas pipeline 4, causing the oil in the oil outlet pipe 2 to flow back, ensuring that the compressed gas can only flow unidirectionally to the oil outlet pipe 2. The shut-off valve 6 is used to control the opening and closing of the oil outlet pipe 2, facilitating sand removal operations.

[0031] Specifically, when the grate 101 and the inlet slot 203 are blocked by mud and sand, the outlet pipe 2 is closed by the shut-off valve 6, and then compressed gas is introduced into the outlet pipe 2 through the gas supply pipe 4. The compressed gas enters the annular cavity 3 through the inlet slot 203 and pushes the sand particles through the grate 101 to be discharged, thereby clearing the mud and sand blocking the inlet slot 203 and the grate 101, and improving the oil production efficiency.

[0032] The high-efficiency well sealing and sand control device 100 of this invention, through the design of the grate 101 and annular cavity 3 of the screen pipe 1, effectively filters mud and sand in oil, reduces sand particles entering the production system, and improves sand control efficiency. Reducing sand particle entry significantly reduces wear on production equipment and extends its service life. By using compressed gas for sand removal, the cumbersome steps of traditional mechanical sand removal, which requires well shutdown, are avoided, simplifying the sand removal process and improving the production efficiency of oil wells. The simplified sand removal operation means a significant reduction in maintenance costs and also reduces production losses caused by maintenance.

[0033] In some embodiments, the high-efficiency sealing and sand-prevention device 100 of the present invention further includes a filter layer 7, which is disposed in the annular cavity 3 and surrounds the oil outlet pipe 2. The filter layer 7 is attached to the outer wall surface of the oil outlet pipe 2. Oil entering the annular cavity 3 through the grate 101 is filtered by the filter layer 7 and then enters the oil outlet pipe 2 through the oil inlet slit 203.

[0034] like Figure 3 As shown, the filter layer 7 is located within the annular cavity 3, surrounding the oil outlet pipe 2. It adheres tightly to the outer wall of the oil outlet pipe 2, ensuring that after oil enters the annular cavity 3 through the grate 101, it must pass through the filter layer 7 before passing through the inlet slot 203 into the oil outlet pipe 2. The filter layer 7 can be made of various filter materials. When oil enters the annular cavity 3 through the grate 101, it first comes into contact with the filter layer 7. The filter layer 7 can intercept finer sand and solid particles, allowing only clean oil to pass through. Because the filter layer 7 adheres tightly to the outer wall of the oil outlet pipe 2, dead zones are reduced, filtration efficiency is improved, and damage to the filter layer 7 due to fluid impact is also reduced.

[0035] In some embodiments, the filter layer 7 includes a first filter layer 701 and a second filter layer 702 arranged in the inward and outward directions, the first filter layer 701 being located outside the second filter layer 702, and the pore size of the first filter layer 701 being larger than the pore size of the second filter layer 702.

[0036] like Figure 3 As shown, the first filter layer 701, located on the outer side, has a larger pore size and is mainly used to intercept larger sand and solid particles. It acts as a pre-filter, reducing the workload on the second filter layer 702. The second filter layer 702, located on the inner side, has a smaller pore size and is used to intercept finer particles. It provides finer filtration based on the first filter layer 701.

[0037] When oil enters the annular cavity 3 from the grate 101, it first passes through the first filter layer 701, where larger particles are intercepted. Then, the fluid filtered by the first filter layer 701 passes through the second filter layer 702, where finer particles are further removed. The difference in pore size between the first filter layer 701 and the second filter layer 702 ensures the effectiveness of the two-stage filtration. The larger pore size in the first filter layer 701 reduces clogging, while the smaller pore size in the second filter layer 702 provides finer protection.

[0038] The dual-layer filtration structure can more effectively remove solid particles from fluids, improving overall filtration efficiency. Because the first filter layer 701 can intercept larger particles, the workload on the second filter layer 702 is reduced, thereby extending the service life of the filter layer 7. The dual-layer filtration design helps reduce the frequency of maintenance due to clogging of the filter layer 7, lowering maintenance costs.

[0039] In some embodiments, the oil inlet slit 203 is spirally arranged around the oil outlet pipe 2 along its axial direction.

[0040] The oil inlet slit 203 is not a simple straight line or annular slit, but rather a spiral slit that surrounds the oil outlet pipe 2, thus creating multiple oil inlet points around the oil outlet pipe 2. The spiral oil inlet slit 203 promotes the swirling flow of fluid within the annular cavity 3. This flow helps to suspend and carry sand particles in the fluid, reducing the deposition of sand particles on the grate 101 and the filter layer 7.

[0041] Optionally, the highest point of the filter layer 7 is higher than the highest point of the oil inlet slit 203, and the lowest point of the filter layer 7 is lower than the lowest point of the oil inlet slit 203.

[0042] In some embodiments, the two ends of the screen tube 1 are respectively provided with a first sealing plate 8 and a second sealing plate 9, with the first sealing plate 8 located above the second sealing plate 9. The filter layer 7 is arranged axially with the first sealing plate 8 in the oil outlet pipe 2. The first sealing plate 8, the inner wall surface of the screen tube 1, the filter layer 7 and the outer wall surface of the oil outlet pipe 2 define an air inlet chamber 12. The outlet end of the air supply pipe 4 extends into the air inlet chamber 12 and communicates with the oil outlet pipe 2. An air outlet hole 401 is opened on the part of the side wall of the air supply pipe 4 located in the air inlet chamber 12.

[0043] When sand removal is required, compressed gas enters the oil outlet pipe 2 through the outlet of the gas supply pipe 4. The compressed gas is then sprayed radially outward through the oil inlet slit 203 on the oil outlet pipe 2 to remove the silt and sand clogging the oil inlet slit 203, grate 101, and filter layer 7 in the radial direction of the oil outlet pipe 2. Simultaneously, the silt and sand clogging the oil inlet slit 203, grate 101, and filter layer 7 is removed axially from the oil outlet pipe 2, thus improving the sand removal efficiency.

[0044] In some embodiments, the gas supply pipe 4 includes a vertical section 402 and a horizontal section 403 connected to each other. The vertical section 402 is arranged parallel to the axis of the oil outlet pipe 2. One end of the vertical section 402 extends out of the air intake chamber 12, and the other end of the vertical section 402 extends into the air intake chamber 12 and is connected to the horizontal section 403. The horizontal section 403 is arranged perpendicular to the axis of the oil outlet pipe 2 and communicates with the oil outlet pipe 2. An air outlet 401 is provided on the vertical section 402.

[0045] One end of the vertical section 402 extends out of the intake chamber 12 for easy connection to an external compressed gas source; the other end extends into the intake chamber 12 and connects to the horizontal section 403 to distribute gas into the intake chamber 12. The outlet 401 is located on the vertical section 402, allowing the wall surface to directly blow on the filter layer 7 after the compressed gas enters the intake chamber 12, thus disrupting the overall structure of the filter layer 7 and improving its operational reliability.

[0046] In some embodiments, there are multiple air outlets 401, which are divided into multiple hole groups. The multiple hole groups are arranged at intervals along the axial direction of the vertical section 402, and each hole group includes multiple air outlets 401 arranged at intervals along the circumferential direction of the vertical section 402.

[0047] like Figure 5 As shown, the air outlet 401 is divided into multiple hole groups. The air outlet 401 in each hole group is arranged at intervals along the circumference of the vertical section 402. This ensures that the compressed gas is evenly distributed in the air inlet chamber 12, so that the gas can be evenly distributed in different positions and directions, thereby improving the sand cleaning efficiency.

[0048] In some embodiments, the screen tube 1 includes a cylinder 102, a plurality of grate plates 103, and a plurality of washers 104. The cylinder 102 is sleeved on the oil outlet pipe 2. The grate plates 103 are annular structural members, located below the cylinder 102 and coaxially arranged with the cylinder 102. The plurality of grate plates 103 and the plurality of washers 104 are arranged alternately in sequence along the axial direction of the cylinder 102, so that a grate groove 101 is defined between two adjacent grate plates 103.

[0049] like Figure 3 and Figure 6 As shown, the main body of the screen tube 1 is a cylinder 102, which is fitted onto the oil outlet pipe 2, providing a supporting structure for the screen tube 1. The grate 103 is an annular structural component, located below the cylinder 102 and coaxially arranged with it. Multiple grate 103s and multiple washers 104 are arranged alternately along the axial direction of the cylinder 102, thus forming a grate groove 101 between adjacent grate 103s for accommodating and filtering sand particles.

[0050] The high-efficiency sealing and sand-prevention device 100 of the present invention, through the alternating arrangement of multiple grate plates 103 and gaskets 104, can achieve grate troughs 101 with different filter gap sizes by replacing the gaskets 104. In addition, it makes the structure of the screen tube 1 simple and easy to process and manufacture.

[0051] In some embodiments, a connecting rod 13 is provided on the bottom end face of the cylinder 102, and the connecting rod 13 is arranged parallel to the axial direction of the oil outlet pipe 2. The grate 103 and the second sealing plate 9 are provided with connecting holes for the connecting rod 13 to pass through. The grate 103 and the second sealing plate 9 are connected by the connecting rod 13, and the washer 104 is sleeved on the connecting rod 13.

[0052] like Figure 6 As shown, the high-efficiency sealing and sand-prevention device 100 of this embodiment of the invention has a connecting rod 13 on the bottom end face of the cylinder 102, which is arranged parallel to the axis of the oil outlet pipe 2. The function of the connecting rod 13 is to connect the various components of the screen pipe 1 together, providing structural stability. The grate 103 and the second sealing plate 9 have connecting holes for the connecting rod 13 to pass through, thereby firmly connecting them together. Through the connecting rod 13, the grate 103, the second sealing plate 9, and possibly other components are connected to form an integral structure.

[0053] The design of the connecting rod 13 ensures the stability between the screen tube 1 components, preventing component displacement due to vibration or pressure changes during production. During installation, the connecting rod 13 can first pass through the connecting holes of the grate 103 and the second sealing plate 9, and then be fixed together using threads or other connection methods on the connecting rod 13. The design of the connecting rod 13 allows for quick disassembly and assembly of the screen tube 1 as needed, enhancing the adaptability of the device.

[0054] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0055] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0056] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0057] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0058] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0059] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A high-efficiency sealing and sand-prevention device, characterized in that, include: A screen pipe (1) and an oil outlet pipe (2) are provided. The screen pipe (1) is sleeved on the oil outlet pipe (2) and spaced apart from the screen pipe (1). The screen pipe (1) and the oil outlet pipe (2) define an annular cavity (3). The port of the first end (201) of the oil outlet pipe (2) is blocked and located inside the screen pipe (1). The port of the second end (202) of the oil outlet pipe (2) is located outside the screen pipe (1). The side wall of the oil outlet pipe (2) has an oil inlet slit (203) located inside the annular cavity (3). The two ends of the screen pipe (1) are blocked. The side wall of the screen pipe (1) has a grate (101). The grate (101) is used to filter mud and sand in the oil so that the oil enters the annular cavity (3) through the grate (101). An elastic bag (4) is spirally wrapped around the top of the outer wall of the sieve tube (1) along the axial direction; Grouting pipe (5), which is connected to the elastic bag (4), is used to inject grout into the elastic bag (4) so ​​that the elastic bag (4) expands and abuts against the inner wall of the oil well.

2. The high-efficiency sealing and sand-prevention device according to claim 1, characterized in that, The elastic bladder (4) is equipped with a pressure relief valve. When the grouting pressure inside the elastic bladder (4) exceeds a preset value, the pressure relief valve opens to discharge the grout inside the elastic bladder (4) through the pressure relief valve.

3. The high-efficiency sealing and sand-prevention device according to claim 1, characterized in that, Also includes: Gas delivery pipe (6), the inlet of the gas delivery pipe (6) is used to connect to a compressed gas source, the outlet of the gas delivery pipe (6) is connected to the oil outlet pipe (2), and the outlet of the gas delivery pipe (6) is located above the oil inlet slit (203); One-way valve (7), the one-way valve (7) is located at the outlet of the gas pipeline (6) and the outlet direction of the one-way valve (7) is directed toward the inner cavity of the oil outlet pipe (2); A shut-off valve (8) is provided on the oil outlet pipe (2) and located above the outlet of the gas transmission pipe (6). The shut-off valve (8) is used to control the opening and closing of the oil outlet pipe (2).

4. The high-efficiency sealing and sand-prevention device according to claim 3, characterized in that, It also includes a filter layer (9), which is disposed in the annular cavity (3) and surrounds the oil outlet pipe (2). The filter layer (9) is attached to the outer wall surface of the oil outlet pipe (2). The oil entering the annular cavity (3) through the grate (101) is filtered by the filter layer (9) and then enters the oil outlet pipe (2) through the oil inlet slit (203).

5. The high-efficiency sealing and sand-prevention device according to claim 4, characterized in that, The filter layer (9) includes a first filter layer (901) and a second filter layer (902) arranged in the inward and outward directions. The first filter layer (901) is located outside the second filter layer (902), and the pore size of the first filter layer (901) is larger than that of the second filter layer (902).

6. The high-efficiency sealing and sand-prevention device according to claim 3, characterized in that, The screen tube (1) has a first sealing plate (10) and a second sealing plate (11) at its two ends respectively. The first sealing plate (10) is located above the second sealing plate (11). The filter layer (9) is arranged axially with the first sealing plate (10) in the oil outlet pipe (2). An air inlet chamber (12) is defined between the first sealing plate (10), the inner wall of the screen tube (1), the filter layer (9), and the outer wall of the oil outlet pipe (2). The outlet end of the air supply pipe (6) extends into the air inlet chamber (12) and communicates with the oil outlet pipe (2). An air outlet hole (601) is opened on the side wall of the air supply pipe (6) located in the air inlet chamber (12).

7. The high-efficiency sealing and sand-prevention device according to claim 6, characterized in that, The gas supply pipe (6) includes a vertical section (602) and a horizontal section (603) connected together. The vertical section (602) is arranged parallel to the axis of the oil outlet pipe (2). One end of the vertical section (602) extends out of the air inlet chamber (12), and the other end of the vertical section (602) extends into the air inlet chamber (12) and is connected to the horizontal section (603). The horizontal section (603) is arranged perpendicular to the axis of the oil outlet pipe (2) and communicates with the oil outlet pipe (2). The gas outlet (601) is provided on the vertical section (602).

8. The high-efficiency sealing and sand-prevention device according to claim 7, characterized in that, The number of air outlets (601) is multiple, and the multiple air outlets (601) are divided into multiple hole groups. The multiple hole groups are arranged at intervals along the axial direction of the vertical section (602). The hole group includes multiple air outlets (601) arranged at intervals along the circumferential direction of the vertical section (602).

9. A high-efficiency sealing and sand-prevention device according to claim 6, characterized in that, The screen tube (1) includes a cylinder (102), multiple grate plates (103) and multiple washers (104). The cylinder (102) is sleeved on the oil outlet pipe (2). The grate plate (103) is a circular structure. The grate plate (103) is located below the cylinder (102) and is coaxially arranged with the cylinder (102). The multiple grate plates (103) and the multiple washers (104) are arranged alternately in sequence along the axial direction of the cylinder (102) so that the grate groove (101) is defined between two adjacent grate plates (103).

10. A high-efficiency sealing and sand-prevention device according to claim 9, characterized in that, A connecting rod (13) is provided on the bottom end face of the cylinder (102). The connecting rod (13) is arranged parallel to the axial direction of the oil outlet pipe (2). The grate (103) and the second sealing plate (11) are provided with connecting holes for the connecting rod (13) to pass through. The grate (103) and the second sealing plate (11) are connected by the connecting rod (13). The washer (104) is sleeved on the connecting rod (13).

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