Anti-backflow waterproof oil extraction well completion pipe string

Abstract

The utility model provides an anti-backflow waterproof oil extraction well completion pipe string which comprises a well pipe and a packer, the packer comprises a plugging pipe installed in the well pipe, the inner wall of the plugging pipe is fixedly connected with a fixing piece, the inner wall of the plugging pipe on the lower side of the fixing piece is fixedly connected with a socket, a plugging block is inserted into the socket, and the plugging block is connected with a plug. The socket is also fixedly connected with an electric push rod for driving the plugging block to lift; the top surface inclination of the plugging block is the same as that of the inner side surface of the fixing sheet; an electric screw rod is embedded in the plugging block, and the electric screw rod is rotationally connected with the telescopic end of the electric push rod; the electric screw is in threaded connection with a threaded pipe, waterproof cloth is fixedly connected to the bottom edge of the outer wall of the threaded pipe, and the end, away from the bottom edge of the outer wall of the threaded pipe, of the waterproof cloth is connected with the edge of the bottom end of the plugging block. According to the utility model, the plugging block is attached to or separated from the fixing sheet, so that the plugging pipe is closed or opened, the well casing is closed or opened, and the plugging pipe can be recycled.

Description

Technical Field

[0001] The utility model relates to the technical field of underwater oil well mining, in particular to an anti-backflow water-insulating oil production completion pipe column. Background Art

[0002] Subsea oil is one of the mineral resources buried in sedimentary rocks and bedrock below the bottom of the ocean. Because it is underwater, unlike oil extraction on land, when extracting oil underwater, it is necessary to consider the water isolation of pipe piles and prevention of backflow.

[0003] Therefore, the prior art discloses a backflow prevention and water-insulating oil production completion string and device, with the publication number: CN201013300Y, using a φ73.03mm outer diameter oil pipe to lower the Y541 packer into a φ139.7mm casing. When the wellhead applies liquid pressure from the oil pipe, the liquid pushes the upper cylinder, and at the same time, the lower cylinder breaks the limit screw and pushes the upper cylinder, and the upper cylinder pushes the retaining spring groove cylinder upward and compresses the rubber cylinder, and at the same time, the sealing rubber cylinder leather cup is opened to achieve the packer to isolate the oil and casing annular space. At this time, the retaining spring is engaged with the retaining spring groove cylinder, and the locking mechanism enters a locking state to prevent the rubber cylinder and the rubber cylinder leather cup from loosening after being sealed. When the packer is unsealed, it is only necessary to lift the pipe column and pull off the unsealing pin connecting the lower center pipe of the packer and the retaining spring. The locking mechanism becomes invalid, and under the action of the elastic restoring force of the rubber cylinder, the retaining spring groove cylinder and the retaining spring move downward relative to the lower center pipe of the packer, and the packer is unsealed.

[0004] Although the above patent improves the water isolation and backflow prevention of pipe piles to a certain extent, the limit screws and unsealing rivets that are pulled off in the above patent cannot be reused, so the device involved in the above patent needs to be replaced and repaired after each use. Utility Model Content

[0005] In view of the above-mentioned shortcomings of the prior art, the technical problem to be solved by the utility model is to provide an anti-backflow and water-insulating oil production completion string, which is used to ensure the anti-backflow and water-insulating oil production function of the completion string during offshore oil production.

[0006] To achieve the above-mentioned purpose, the utility model provides an anti-backflow water-proof oil production completion string, including a well pipe and a packer, the packer including a plugging tube installed in the well pipe, the inner wall of the plugging tube is fixedly connected to a fixing plate, the inner wall of the plugging tube below the fixing plate is fixedly connected to a socket, a plugging block is plugged into the socket, and an electric push rod for driving the plugging block to rise and fall is also fixedly connected to the socket, the top surface inclination of the plugging block is the same as the inner surface inclination of the fixing plate; an electric screw is embedded in the plugging block, and the electric screw is rotatably connected to the telescopic end of the electric push rod; a threaded pipe is threadedly connected to the electric screw, a waterproof cloth is fixedly connected to the bottom edge of the outer wall of the threaded pipe, and the end of the waterproof cloth away from the bottom edge of the outer wall of the threaded pipe is connected to the bottom edge of the plugging block.

[0007] Preferably, an elastic member is fixedly connected between the inner side surface of the waterproof cloth and the bottom end of the blocking block.

[0008] Preferably, a telescopic rod is fixedly connected to the bottom end of the threaded tube, and the telescopic rod is inserted into the bottom end of the blocking block.

[0009] Preferably, a sealing ring that fits with the bottom end of the blocking tube is fixedly connected to the inner wall of the well pipe, and a fixing frame is provided on the inner wall of the blocking tube near the top; the fixing frame includes a center rod, and a plurality of screw rods distributed in a circular array are rotatably connected to the outer circumference of the center rod, a plug block is threadedly connected to the screw rod, a slot that is engaged with the plug block is provided on the inner wall of the well pipe, and the plug-in parts of the plug block and the slot are both configured as triangles.

[0010] Preferably, a plurality of guide rods are also provided on the central rod, and the guide rods pass through the plug block; a plug plate connected with the inclined surface of the slot is passed through the plug block, and a plug plate telescopic rod is also provided between the side of the plug plate and the guide rods.

[0011] Preferably, the end of the screw rod away from the center rod is rotatably connected to the inner wall of the sealing tube, and the outer peripheral surface of the end of the screw rod close to the center rod is also provided with a bevel gear block; a bevel gear ring is rotatably provided on the center rod, and the bevel gear ring is meshed with the bevel gear block; a bevel gear ring drive assembly is also provided on the fixed frame, which is used to drive the bevel gear ring to rotate.

[0012] Preferably, the bevel gear ring drive assembly includes a bevel gear ring drive source and a bevel gear ring transmission gear, the bevel gear ring transmission gear is transmission-connected to the bevel gear ring drive source via a gear transmission shaft, and the bevel gear ring transmission gear is meshingly connected to the bevel gear ring.

[0013] Preferably, a roller is embedded in the outer wall of the plugging tube, and the roller is rollingly connected to the inner wall of the well pipe.

[0014] Preferably, a roller driving source is also provided in the blocking tube, and the roller driving source is used to drive the roller to rotate.

[0015] As described above, the anti-backflow water-insulating oil production completion string involved in the utility model has the following beneficial effects:

[0016] 1. In the utility model, the plugging block is lifted and lowered by utilizing the extension and retraction of the electric push rod, and the plugging pipe is closed or opened by utilizing the sealing block and the fixing plate to fit or separate, thereby realizing the closing or opening of the well pipe; a waterproof cloth is provided, and when the plugging pipe is in the process of opening, the waterproof cloth is stretched into a cone, which effectively reduces the pressure exerted by the oil on the bottom end of the plugging block, reduces the working pressure of the electric push rod, ensures the effective use of the electric push rod for a long time, and thus ensures that the plugging pipe can be recycled.

[0017] 2. The utility model is provided with a roller, through which the blocking tube can move along the inner wall of the well pipe. Under the action of friction, the blocking tube can be lowered to the sealing ring position in the well pipe, and the sealing ring can ensure the sealing and waterproofing of the bottom end of the blocking tube. Correspondingly, the reverse rotation of the roller can be used to make the blocking tube rise in the well pipe, thereby enabling the blocking tube to enter and exit the well pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the spatial structure of the anti-backflow water-proof oil production completion pipe string involved in the utility model;

[0019] Figure 2 It is a partial cross-sectional view of the anti-backflow water-proof oil production completion pipe string involved in the utility model;

[0020] Figure 3 yes Figure 2 A schematic cross-sectional structure diagram of ;

[0021] Figure 4 yes Figure 3 The enlarged view of point A in the middle;

[0022] Figure 5 yes Figure 3 Enlarged view of point B in the middle.

[0023] Description of reference numerals:

[0024] 1. Well pipe; 2. Sealing pipe; 3. Roller; 4. Center rod; 5. Insert block; 6. Screw rod; 7. Insert plate; 8. Bevel gear ring; 9. Fixing plate; 10. Electric push rod; 11. Socket; 12. Sealing ring; 13. Sealing block; 14. Waterproof cloth; 15. Threaded pipe; 16. Electric screw; 17. Slot; 18. Bevel gear block; 19. Insert plate telescopic rod; 20. Gear transmission shaft; 21. Elastic part; 22. Guide rod; 23. Telescopic rod. DETAILED DESCRIPTION

[0025] The following is a description of the implementation of the present invention by means of specific embodiments. People familiar with the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0026] It should be noted that the structures, proportions, sizes, etc. drawn in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the utility model, so they have no substantial technical significance. Any modification of the structure, change of the proportional relationship or adjustment of the size, without affecting the effects and purposes that can be achieved by the utility model, should still fall within the scope of the technical content disclosed by the utility model. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and so on quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the utility model. The change or adjustment of their relative relationship should also be regarded as the scope of the implementation of the utility model without substantial change of the technical content.

[0027] like Figure 1-Figure 5 As shown, the utility model provides an anti-backflow and water-proof oil production completion string, including a well pipe 1 and a packer, the packer includes a plugging pipe 2 installed in the well pipe 1, the inner wall of the plugging pipe 2 is fixedly connected to a fixing plate 9, a socket 11 is fixedly connected to the inner wall of the plugging pipe 2 below the fixing plate 9, a plugging block 13 is plugged into the socket 11, and an electric push rod 10 for driving the plugging block 13 to rise and fall is also fixedly connected to the socket 11, the top surface inclination of the plugging block 13 is the same as the inner surface inclination of the fixing plate 9; an electric screw 16 is embedded in the plugging block 13, and the electric screw 16 is rotatably connected to the telescopic end of the electric push rod 10; a threaded pipe 15 is threadedly connected to the electric screw 16, a waterproof cloth 14 is fixedly connected to the bottom edge of the outer wall of the threaded pipe 15, and the end of the waterproof cloth 14 away from the bottom edge of the outer wall of the threaded pipe 15 is connected to the bottom edge of the plugging block 13.

[0028] The utility model relates to an anti-backflow water-proof oil production completion string, in which a fixing plate 9 is provided inside the plugging pipe 2, a plugging block 13 is provided below the fixing plate 9, and an electric push rod 10 is provided below the plugging block 13. The plugging block 13 is moved upward by the electric push rod 10 until the plugging block 13 fits with the inner wall of the fixing plate 9, thereby realizing the internal partition of the plugging pipe 2 and sealing the well pipe 1. In addition, an electric screw 16 is provided inside the plugging block 13, and a threaded tube 15 is connected to the electric screw 16 by threads. When the electric screw 16 rotates, the threaded tube 15 will rise and fall along the electric screw 16, thereby driving the waterproof cloth 14 at the bottom edge of the outer wall of the threaded tube 15 to stretch, so that the surface of the waterproof cloth 14 becomes conical, effectively reducing the pressure of the oil on the bottom end of the plugging block 13.

[0029] In this embodiment, the well pipe 1 is an oil pipe extending into an oil field.

[0030] Preferably, Figure 5As shown, an elastic member 21 is fixedly connected between the inner side of the waterproof cloth 14 and the bottom end of the blocking block 13. In this embodiment, the elastic member 21 is an elastic rope, and the elastic rope is stretched during the stretching and unfolding process of the waterproof cloth 14, so the elastic rope provides a pulling force during the storage process of the waterproof cloth 14 to ensure that the waterproof cloth 14 is in contact with the bottom end of the blocking block 13 after the storage is completed.

[0031] Preferably, Figure 5 As shown, the bottom end of the threaded tube 15 is fixedly connected with a telescopic rod 23, and the telescopic rod 23 is plugged into the bottom end of the blocking block 13. In this embodiment, a plug hole is provided on the bottom end of the blocking block 13, and the telescopic rod 23 is plugged into the plug hole of the blocking block 13 from bottom to top in the vertical direction. The bottom end of the telescopic rod 23 is fixedly connected to the outer wall of the bottom end of the threaded tube 15, so as to ensure that the threaded tube 15 will not rotate with the electric screw 16. When the electric screw 16 rotates, the threaded tube 15 will move up and down along the electric screw 16, and the corresponding telescopic rod 23 will move up and down in the plug hole. The telescopic rod 23 adopts a sleeve rod. In addition, the lower end of the threaded tube 15 can also be sleeved with the cylinder body part of the electric push rod 10, so that it can be located on the periphery of the electric push rod 10 when descending, so that the conical slope formed by the waterproof cloth 14 meets the pressure reduction requirements.

[0032] Furthermore, the electric screw 16 is connected to an electric screw driving source, and the electric screw driving source adopts a waterproof motor to drive the electric screw 16 to rotate; the electric screw driving source can be set on the top surface of the blocking block 13.

[0033] Preferably, Figure 3 , Figure 4 As shown, a sealing ring 12 which fits with the bottom end of the plugging tube 2 is fixedly connected to the inner wall of the well pipe 1, and a fixing frame is arranged near the top of the inner wall of the plugging tube 2; the fixing frame comprises a central rod 4, and a plurality of screw rods 6 distributed in a circular array are rotatably connected to the outer peripheral surface of the central rod 4, and a plug block 5 is threadedly connected to the screw rod 6, and a slot 17 which is engaged with the plug block 5 is provided on the inner wall of the well pipe 1, and the plug-in parts of the plug block 5 and the slot 17 are both arranged in a triangle.

[0034] Preferably, Figure 4As shown, the center rod 4 is also provided with a plurality of guide rods 22, which penetrate the plug block 5, and one end of the guide rod 22 away from the center rod 4 is fixed on the inner wall of the plugging tube 2; the plug block 5 is provided with a plug plate 7 inserted into the inclined surface of the slot 17, and a plug plate telescopic rod 19 is also provided between the side of the plug plate 7 and the guide rod 22. In this embodiment, the extension direction of the guide rod 22 is parallel to the extension direction of the screw rod 6, and the guide rod 22 is used to guide the plug block 5 when it moves on the screw rod 6. One screw rod 6 is equipped with two guide rods 22, and the two guide rods 22 are respectively arranged on the upper side and the lower side of the screw rod 6, and the side of the plug plate 7 is connected to the guide rod 22 on the upper side through the plug plate telescopic rod 19. In this embodiment, the plug plate telescopic rod 19 adopts a spring rod, and the elasticity of the spring rod is used to connect the plug plate 7 to the plug block 5 and the slot 17 to prevent the plug block 5 from rising in the slot 17.

[0035] Preferably, Figure 4 As shown, the end of the screw rod 6 away from the center rod 4 is rotatably connected to the inner wall of the plugging tube 2, and the outer peripheral surface of the end of the screw rod 6 close to the center rod 4 is also provided with a bevel gear block 18; the center rod 4 is rotatably provided with a bevel gear ring 8, and the bevel gear ring 8 is meshed with the bevel gear block 18; the fixed frame is also provided with a bevel gear ring driving assembly for driving the bevel gear ring 8 to rotate. In this embodiment, the screw rod 6 is rotatably connected to the inner wall of the plugging tube 2 through a bearing, and the screw rod 6 is rotatably connected to the center rod 4 through a bearing, and the bevel gear block 18 is arranged on the screw rod 6, and the bevel gear block 18 is meshed with the bevel gear ring 8. When the bevel gear ring driving assembly drives the bevel gear ring 8 to rotate, the bevel gear ring 8 drives the bevel gear block 18 to rotate, and then the screw rod 6 moves synchronously, and under the action of the guide rod 22, the plug block 5 moves along the screw rod 6 until the plug block 5 is plugged into the slot 17 on the inner wall of the well pipe 1.

[0036] Preferably, Figure 4 As shown, the bevel gear ring drive assembly includes a bevel gear ring drive source and a bevel gear ring transmission gear, the bevel gear ring transmission gear is transmission-connected to the bevel gear ring drive source through a gear transmission shaft 20, and the bevel gear ring transmission gear is meshed with the bevel gear ring 8. In this embodiment, the bevel gear ring drive source adopts a waterproof motor, the bevel gear ring drive source is fixed on the guide rod 22 on the lower side, the gear transmission shaft 20 penetrates the guide rod 22 on the lower side from bottom to top, and the gear transmission shaft 20 is transmission-connected to the bevel gear ring drive source, and the bevel gear ring transmission gear is meshed with the bevel gear ring 8.

[0037] Preferably, Figure 2-Figure 4 As shown, a roller 3 is embedded in the outer wall of the plugging pipe 2, and the roller 3 is rollingly connected to the inner wall of the well pipe 1. Furthermore, a roller driving source is also provided in the plugging pipe 2, and the roller driving source is used to drive the roller 3 to rotate. In this embodiment, the roller driving source adopts a waterproof motor, and the roller driving source is provided on the inner wall of the plugging pipe 2.

[0038] The utility model relates to an anti-backflow water-proof oil production completion string, and the working steps are as follows:

[0039] S1: The operator shall Figure 1-Figure 5 , and the descriptions of the above components to install each component;

[0040] S2: placing the packer into the well pipe 1;

[0041] S2.1: The operator inserts the blocking tube 2 into the well pipe 1, and the roller 3 embedded in the blocking tube 2 is connected to the inner wall of the well pipe 1 by rolling; the roller driving source arranged in the blocking tube 2 is started, and the roller driving source drives the roller 3 to rotate, and the blocking tube 2 moves downward along the inner wall of the well pipe 1; when the bottom end surface of the blocking tube 2 abuts against the sealing ring 12 arranged on the inner wall of the well pipe 1, the bevel gear ring driving source is started, and the bevel gear ring driving source drives the bevel gear ring 8 to rotate through the gear transmission shaft 20, and the bevel gear ring 8 drives the screw 6 to rotate through the bevel gear block 18, so that the plug block 5 moves along the screw 6 under the action of the guide rod 22 until the plug block 5 is engaged in the slot 17 opened on the inner wall of the well pipe 1. Since the plug-in block 5 and the slot 17 are both in a triangular shape, there is contact and sliding between the plug-in block 5 and the slot 17 during the process of the plug-in block 5 being clamped in the slot 17, forcing the plug-in block 5 to move downward together with the fixing frame and the plugging pipe 2 until the bottom end surface of the plugging pipe 2 is tightly fitted with the sealing ring 12 provided on the inner wall of the well pipe 1, thereby ensuring the sealing of the bottom end surface of the plugging pipe 2. When the plug-in block 5 is inserted into the slot 17, the plug-in plate 7 penetrating the plug-in block 5 abuts against the inclined surface of the slot 17 under the action of the plug-in plate telescopic rod 19, thereby realizing the limit of the plug-in block 5 and preventing the plug-in block 5 from rising in the slot 17.

[0042] S3: After the packer in step S2 is placed into the well pipe 1, and the bottom end surface of the plugging pipe 2 is tightly fitted with the sealing ring 12 provided on the inner wall of the well pipe 1; the process of closing and opening the well pipe 1 by the packer is as follows:

[0043] S3.1: When the well pipe 1 needs to be closed, the operator starts the electric push rod 10, the telescopic end of the electric push rod 10 extends, and the blocking block 13 moves upward under the guidance of the socket 11 until the blocking block 13 rises to fit the inner wall of the fixing plate 9. At this time, the blocking block 13 and the fixing plate 9 are sealed and connected, so that the blocking pipe 2 is closed, and then the well pipe 1 is closed.

[0044] S3.2: When the well pipe 1 needs to be opened, the operator starts the electric push rod 10, the telescopic end of the electric push rod 10 contracts, and the blocking block 13 moves downward under the guidance of the socket 11. The blocking block 13 descends and separates from the inner wall of the fixing plate 9. At this time, the blocking pipe 2 is opened, and then the well pipe 1 is opened.

[0045] S4: taking the packer out of the well pipe 1;

[0046] S4.1: The operator starts the bevel gear ring drive source in reverse, and the bevel gear ring drive source drives the bevel gear ring 8 to rotate through the gear transmission shaft 20, and the bevel gear ring 8 drives the screw 6 to rotate through the bevel gear block 18, so that the plug block 5 moves along the screw 6 under the action of the guide rod 22, and the plug block 5 is pulled out from the slot 17 opened on the inner wall of the well pipe 1. The plug block 5 moves away from the inner wall of the well pipe 1 along the screw 6. In the process of moving away, the plug block 5 squeezes the plug plate telescopic rod 19, overcomes the elasticity of the plug plate telescopic rod 19, and pulls the plug plate 7 out from the inclined surface of the slot 17, so that the plug block 5 is separated from the slot 17 set on the inner wall of the well pipe 1. Then the operator starts the roller drive source in reverse, and the roller drive source drives the roller 3 to rotate, and the plugging pipe 2 moves upward along the inner wall of the well pipe 1, so that the plugging pipe 2 is separated from the well pipe 1.

[0047] Preferably, in step S3.1, when the operator starts the electric push rod 10, the electric screw driving source can be turned on at the same time. The electric screw driving source drives the electric screw 16 to rotate. Under the action of the telescopic rod 23, the threaded tube 15 connected to the electric screw 16 will move upward along the electric screw 16. At this time, the waterproof cloth 14 fixed at the bottom end of the threaded tube 15 will be stretched upward to present a cone shape, so that the liquid flowing in the blocking tube 2 slides along the conical waterproof cloth 14, effectively reducing the pressure generated on the bottom end of the blocking block 13.

[0048] Preferably, in step S3.2, when the operator starts the electric push rod 10, the electric screw driving source can be turned on at the same time. The electric push rod 10 driving source drives the electric screw 16 to rotate. Under the action of the telescopic rod 23, the threaded tube 15 connected to the electric screw 16 will move downward along the electric screw 16. At this time, the waterproof cloth 14 fixed at the bottom end of the threaded tube 15 will be stretched downward to present a cone shape, so that the liquid flowing in the blocking tube 2 slides along the conical waterproof cloth 14, effectively reducing the pressure generated on the bottom end of the blocking block 13.

[0049] Preferably, in step S3.1 and step S3.2, when the waterproof cloth 14 is stretched to present a cone shape, the elastic member 21 is also stretched accordingly. When the waterproof cloth 14 is reset, the elastic force of the elastic member 21 ensures that the waterproof cloth 14 fits the bottom end of the blocking block 13.

[0050] Preferably, the wiring diagram of the electric push rod 10 and the waterproof motor involved in the utility model belongs to the common knowledge in the field, and its working principle is a well-known technology. The model is selected according to the actual use. Therefore, the control method and wiring arrangement of the electric push rod 10 and the waterproof motor are no longer explained in detail. When in use, the power supply of the electrical equipment in the blocking pipe 2 can be achieved by adding electric wires.

[0051] The utility model relates to an anti-backflow water-proof oil production completion string, which utilizes the extension and retraction of an electric push rod 10 to realize the lifting and lowering of a blocking block 13, and utilizes the sealing block 13 to fit or separate from a fixing plate 9 to realize the closing or opening of a blocking pipe 2, thereby realizing the closing or opening of a well pipe 1; a waterproof cloth 14 is provided, and when the blocking pipe 2 is in the process of opening, the waterproof cloth 14 is stretched into a cone, which effectively reduces the pressure exerted by the oil on the bottom end of the blocking block 13, reduces the working pressure of the electric push rod 10, and ensures that the electric push rod 10 can be effectively used for a long time, thereby ensuring that the blocking pipe 2 can be recycled, thereby solving the problem in the prior art that maintenance is required after each use.

[0052] In summary, the utility model effectively overcomes various shortcomings of the prior art and has high industrial utilization value.

[0053] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the technology may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed in the present invention shall still be covered by the claims of the present invention.

Claims

1. A backflow prevention and water-insulating oil production completion string, comprising a well pipe (1) and a packer, characterized in that: The packer comprises a plugging pipe (2) installed in a well pipe (1), the inner wall of the plugging pipe (2) being fixedly connected to a fixing plate (9), a socket (11) being fixedly connected to the inner wall of the plugging pipe (2) below the fixing plate (9), a plugging block (13) being plugged into the socket (11), an electric push rod (10) for driving the plugging block (13) to rise and fall being also fixedly connected to the socket (11), the top surface of the plugging block (13) having an inclination which is in line with the fixed plate (9). The inner side surfaces of the plates (9) have the same inclination; the blocking block (13) is embedded with an electric screw (16), and the electric screw (16) is rotatably connected to the telescopic end of the electric push rod (10); a threaded tube (15) is threadedly connected to the electric screw (16), and a waterproof cloth (14) is fixedly connected to the bottom edge of the outer wall of the threaded tube (15); and one end of the waterproof cloth (14) away from the bottom edge of the outer wall of the threaded tube (15) is connected to the bottom edge of the blocking block (13).

2. The anti-backflow water-proof oil production completion string according to claim 1, characterized in that: An elastic member (21) is fixedly connected between the inner side of the waterproof cloth (14) and the bottom end of the blocking block (13).

3. The anti-backflow water-proof oil production completion string according to claim 1, characterized in that: The bottom end of the threaded tube (15) is fixedly connected to a telescopic rod (23), and the telescopic rod (23) is plugged into the bottom end of the blocking block (13).

4. The anti-backflow water-proof oil production completion string according to claim 1, characterized in that: The inner wall of the well pipe (1) is fixedly connected with a sealing ring (12) which is in contact with the bottom end of the plugging pipe (2); a fixing frame is arranged near the top end of the inner wall of the plugging pipe (2); the fixing frame comprises a central rod (4); a plurality of screw rods (6) arranged in a circular array are rotatably connected to the outer peripheral surface of the central rod (4); a plug block (5) is threadedly connected to the screw rod (6); a slot (17) which is engaged with the plug block (5) is provided on the inner wall of the well pipe (1); and the plugging parts of the plug block (5) and the slot (17) are both arranged in a triangular shape.

5. The anti-backflow water-proof oil production completion string according to claim 4, characterized in that: The central rod (4) is also provided with a plurality of guide rods (22), and the guide rods (22) penetrate the plug block (5); a plug plate (7) is provided inside the plug block (5) and is plugged into the inclined surface portion of the slot (17); and a plug plate telescopic rod (19) is also provided between the side of the plug plate (7) and the guide rods (22).

6. The anti-backflow water-proof oil production completion string according to claim 4, characterized in that: The end of the screw rod (6) away from the center rod (4) is rotatably connected to the inner wall of the plugging tube (2), and the outer peripheral surface of the end of the screw rod (6) close to the center rod (4) is also provided with a bevel gear block (18); a bevel gear ring (8) is rotatably provided on the center rod (4), and the bevel gear ring (8) is meshed with the bevel gear block (18); and a bevel gear ring driving assembly is also provided on the fixing frame for driving the bevel gear ring (8) to rotate.

7. The anti-backflow water-proof oil production completion string according to claim 6, characterized in that: The bevel gear ring drive assembly comprises a bevel gear ring drive source and a bevel gear ring transmission gear, wherein the bevel gear ring transmission gear is transmission-connected to the bevel gear ring drive source via a gear transmission shaft (20), and the bevel gear ring transmission gear is meshingly connected to the bevel gear ring (8).

8. The anti-backflow water-proof oil production completion string according to claim 1, characterized in that: A roller (3) is embedded in the outer wall of the plugging pipe (2), and the roller (3) is rollingly connected to the inner wall of the well pipe (1).

9. The anti-backflow water-proof oil production completion string according to claim 8, characterized in that: A roller driving source is also provided in the plugging tube (2), and the roller driving source is used to drive the roller (3) to rotate.

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