Anti-blocking and anti-shunting constant flow blanking plug

Abstract

The invention relates to the technical field of oil production engineering, in particular to an anti-blocking and anti-shunting constant flow blanking plug. The anti-blocking and anti-shunting constant-current blanking plug comprises an upper main body, a lower main body and a screen plug which are connected end to end, a fishing rod is arranged at the top end of the upper main body, and a cam is arranged in the upper main body; a plunger main body capable of moving up and down is arranged in the lower main body, a plunger piston is arranged above the plunger main body, a multi-stage water nozzle structure is arranged at the lower part of the plunger main body, and the plunger main body and the lower main body are respectively provided with water outlets with corresponding positions; a screen plug water outlet is arranged below the screen plug, and a steel ball is arranged between the screen plug and the lower main body. According to the anti-blocking and anti-shunting constant flow blanking plug, the contact ratio of the water outlet holes is changed through the plunger body and the plunger spring along with pressure, the water injection amount is kept constant, and the area of the ceramic stress piece is changed to adjust the constant quantity of water injection; through a multi-stage nozzle structure, the flow area of the device is enlarged, and the anti-blocking capacity is improved; the blocking ball between the bottom end of the lower main body and the screen plug blocks the screen plug during well washing, and liquid flow division is prevented.

Description

Technical Field

[0001] The present invention relates to the technical field of oil production engineering, and particularly relates to a constant flow plugging device for preventing blockage and shunt flow. Background Art

[0002] In oilfield operations, it is necessary to inject water into injection wells in layers by placing plugging devices in the injection wells. In the prior art, common plugging devices include retrievable plugging devices and adjustable plugging devices, etc. In practical applications, both retrievable plugging devices and adjustable plugging devices have problems that the actual water injection volume changes with pressure fluctuations and the liquid flow will shunt into the tubing from the plugging device when washing the injection well. Especially in wells with small flow rate water injection, due to the small diameter of its water nozzle, it is extremely easy to be blocked by fine particles in the liquid during operation, resulting in device failure. Therefore, in view of the above deficiencies, a constant flow plugging device for preventing blockage and shunt flow is proposed. Summary of the Invention

[0003] (I) Technical Problems to be Solved In view of the deficiencies of the prior art, the present invention provides a constant flow plugging device for preventing blockage and shunt flow, which solves the problems that the water injection volume in the injection well changes with the pressure fluctuations in the well, the liquid flow will shunt into the tubing from the plugging device when washing the injection well, and it is easy to be blocked and malfunction in the small flow rate injection well.

[0004] (II) Technical Solutions To solve the above problems, the present invention provides a constant flow plugging device for preventing blockage and shunt flow, including: An upper main body, a lower main body and a screen plug. The lower part of the upper main body is connected to the lower main body, and the bottom end of the lower main body is connected to the screen plug; A fishing rod is provided at the top end of the upper main body, and the fishing rod is fixed on the upper main body through a compression cap; The lower main body is tubular and sealed at the top end. A centralizing rod is provided inside the lower main body, and a plunger main body is provided below the centralizing rod. A water outlet hole of the lower main body is provided on the side wall of the lower main body, and a water outlet hole of the plunger main body is provided on the side wall of the plunger main body. The positions of the water outlet hole of the plunger main body and the water outlet hole of the lower main body correspond to each other; The plunger main body and the centralizing rod can move up and down inside the lower main body. A multi-stage nozzle structure is provided at the bottom of the plunger main body. The multi-stage nozzle structure is composed of a plurality of horizontally arranged ceramic force-receiving pieces arranged at intervals from top to bottom. Each ceramic force-receiving piece is provided with an eccentric through hole, and the through holes of two adjacent ceramic force-receiving pieces are arranged staggeredly; A plunger spring is provided outside the upper part of the centralizing rod. One end of the plunger spring contacts the inner top end of the lower main body, and the other end contacts the centralizing rod. The constant flow water injection volume of the device can be adjusted by adjusting the area of the ceramic force-receiving pieces; The bottom of the lower body is a downward cone, and several flow-through holes are provided on the conical surface. The bottom end of the sieve plug is provided with a sieve plug water outlet, and a ball stopper is arranged between the lower body and the sieve plug. When the ball stopper moves downward, it can block the sieve plug water outlet, and the shape of the top end of the conical surface matches the shape of the ball stopper.

[0005] Preferably, a cam is provided at the lower part of the upper body. The cam is connected to the upper body through a pin shaft and a torsion spring. The convex side of the cam is horizontally arranged, and a concave structure matching the bottom end of the fishing rod is provided at the top end. When the fishing rod sinks, it cooperates with the concave platform to fix the position of the cam. When the fishing rod is lifted, the cam rotates upward and screws the convex part into the upper body.

[0006] Preferably, a compression spring is arranged outside the fishing rod. The top end of the compression spring contacts the upper surface inside the compression cap, and the bottom end contacts the fishing rod.

[0007] Preferably, the centralizer and the plunger body are provided with steel balls, and installation grooves matching the size of the steel balls are respectively provided at the central positions of the contact surfaces between the centralizer and the plunger body.

[0008] Preferably, a plunger cap is provided at the bottom end of the plunger body to fix the ceramic force-receiving piece on the plunger body.

[0009] Preferably, a plurality of sealing packing is provided on the lower body.

[0010] Preferably, a plurality of flow-through holes are provided at the top end of the plunger body. When the plunger body and the centralizer move up and down, liquid flows into or out of the space between the upper part of the plunger body and the lower body through the flow-through holes.

[0011] (III) Beneficial Effects The anti-blocking and anti-shunt constant flow plugging device provided by the present invention, through the cooperation of the vertically movable plunger body and the plunger spring, can change the coincidence degree of the water outlet holes of the plunger body and the water outlet holes of the lower body with the change of pressure when the underground pressure fluctuates, so that the water injection volume of the device is constant; by changing the area of the ceramic force-receiving piece, the force condition of the plunger body is adjusted, and the constant water injection amount of the device underground is changed; through the multi-stage nozzle structure composed of ceramic force-receiving pieces, while not affecting the flow rate, the through-hole area on the ceramic force-receiving piece is enlarged, and the occurrence of device blockage is reduced; by providing a ball stopper between the bottom end of the lower body and the sieve plug, the bottom end of the device is blocked during the well flushing operation, preventing the occurrence of liquid shunting. Brief Description of the Drawings

[0012] Figure 1 is the structural diagram of the anti-blocking and anti-shunt constant flow plugging device of the present invention; Figure 2 is the multi-stage water nozzle structural diagram of the anti-blocking and anti-shunt constant flow plugging device of the present invention.

[0013] Among them, 1. fishing rod; 2. pressure cap; 3. compression spring; 4. upper body; 5. cam; 6. small shaft; 7. plunger spring; 8. lower body; 9. straightening rod; 10. steel ball; 11. plunger body; 12. ceramic stress plate; 13. plunger cap; 14. screen plug; 15. sealing packing; 16. torsion spring; 17. flow hole; 18. plunger body water outlet hole; 19. lower body water outlet hole; 20. blocking ball; 21. screen plug water outlet. Implementation

[0014] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0015] In the description of the present invention, it is necessary to understand that the orientations or positional relationships indicated by “upper”, “lower”, “inside”, “outside”, “top”, “bottom”, etc. are all based on the orientations or positional relationships shown in the accompanying drawings. The purpose is only to facilitate the description of the present invention and simplify the description. It does not indicate or imply that the referred parts must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0016] like Figure 1-2 As shown, the present invention provides a constant flow plugger for preventing blockage and diversion, which specifically includes: an upper main body 4, a lower main body 8 and a screen plug 14, wherein the lower part of the upper main body 4 is connected to the lower main body 8, and the bottom end of the lower main body 8 is connected to the screen plug 14.

[0017] The upper body 4 can cooperate with the components in the water injection well to fix the device at the designed water injection position, ensuring the stability of the position of the device during the working process in the water injection well. A fishing rod 1 is provided at the top of the upper body 4, and the fishing rod 1 is fixed to the upper body 4 through a pressure cap 2. When the fishing rod 1 is lifted, the upper body 4 can be smoothly put into or fished out from the water injection well. When the fishing rod 1 sinks, the position of the upper body 4 in the water injection well is fixed.

[0018] Among them, a cam 5 is provided in the upper main body 4, and the raised side of the cam 5 is arranged horizontally and extends out of the upper main body 4. The cam 5 is fixed in the upper main body 4 by a horizontal pin 6. The cam 5 can rotate around the pin 6. A torsion spring 16 is provided on the cam 5. In the absence of external force interference, the torsion spring 16 will drive the cam 5 to rotate upward along the pin 6 and screw the protruding part into the upper main body 4. At this time, the device can be normally put into or fished out of the water injection well.

[0019] It should be noted that a concave platform is provided at the top of the cam 5, and the shape of the concave platform is matched with the bottom of the fishing rod 1. When the fishing rod 1 is lifted upward, the cam rotates upward under the action of the torsion spring 16. At this time, the protruding part of the cam 5 is screwed into the upper main body 4, and the device is in a non-locked state and can be normally inserted and retrieved; when the fishing rod 1 seats down, the bottom end of the fishing rod 1 pushes the concave platform downward to make the cam 5 rotate downward around the pin shaft 6 to screw the protruding part out of the upper main body 4. When the device is lowered into the injection well to reach the set injection position, the fishing rod 1 seats down to make the cam 5 rotate downward. At this time, after the protruding part of the cam 5 is screwed out of the upper main body 4, it cooperates with the installation equipment under the injection well to fix the position of the device.

[0020] In addition, a compression spring 3 is arranged outside the fishing rod 1. The top end of the compression spring 3 contacts the inner upper surface of the compression cap 2, and the bottom end contacts the fishing rod 1. When the fishing rod 1 is lifted upward by force, the compression spring 3 always pushes the fishing rod 1 downward under the action of its own elastic force. When the upward lifting force on the fishing rod 1 disappears, the fishing rod 1 returns to the seated state under the action of the compression spring 3, and at the same time the cam 5 is screwed out. In the relaxed state, the fishing rod 1 is always in the seated state, and the position of the device is always fixed during the operation in the well, improving the stability of the device. Generally, a circumferential annular protrusion is provided at the bottom end of the fishing rod 1 inside the compression cap 2. One end of the compression spring 3 abuts against the inner upper surface of the compression cap 2 upward and the other end is installed on the annular protrusion downward to ensure that its pressure always acts on the fishing rod 1 and prevent the compression spring 3 from disengaging from the fishing rod 1 during the operation, resulting in the device falling off.

[0021] In the present invention, the lower main body 8 is tubular and sealed at the top. A plunger main body 11 is arranged inside the lower main body 8. A plunger main body water outlet hole 18 is provided on the side wall of the plunger main body 11, and a lower main body water outlet hole 19 is provided on the side wall of the lower main body 8. The positions of the plunger main body water outlet hole 18 and the lower main body water outlet hole 19 correspond to each other. The plunger main body 11 can move up and down in the lower main body 8. During the normal water injection operation, water flows into the device from below the lower main body 8. When the plunger main body water outlet hole 18 and the lower main body water outlet hole 19 partially overlap, the liquid flows out from the plunger main body water outlet hole 18 and the lower main body water outlet hole 19 and is injected into the target formation.

[0022] Among them, a plunger spring 7 is provided above the plunger body 11. One end of the plunger spring 7 contacts the inner top end of the lower body 8 upward, and the other end pushes the plunger body 11 downward. During the water injection operation, when the downhole pressure fluctuates with a fixed value, under the action of the plunger spring 7, the distance that the plunger body 11 moves up and down changes according to the pressure received. When the downhole pressure increases, the upward movement distance of the plunger spring 7 increases, resulting in a decrease in the overlap degree between the water outlet hole 18 of the plunger body and the water outlet hole 19 of the lower body, so that the water injection volume of the device into the target formation remains unchanged. On the contrary, when the downhole pressure increases, the movement distance decreases and the overlap degree increases, keeping the water injection volume of the device unchanged.

[0023] It should be noted that a number of sealing packing 15 are provided on the outer side of the lower body 8. The sealing packing 15 seals the periphery of the device in the injection well to prevent the downhole liquid from leaking out and improve the sealing performance of the device. A number of flow holes 17 are provided above the plunger body 11. When the plunger body 11 moves up and down in the lower body 8, water can flow into or out of the space between the upper part of the plunger body 11 and the lower body 8 through the flow holes 17, ensuring the normal movement of the plunger body 11 in the lower body 8.

[0024] As Figure 1 shown, a centralizer rod 9 is provided above the plunger body 11 in the lower body 8. The bottom end of the centralizer rod 9 is provided with a circumferential boss whose diameter matches the inner diameter of the lower body 8. Due to its diameter matching the inner diameter of the lower body 8, the centralizer rod 9 can only move up and down vertically in the lower body 8. The plunger spring 7 is sleeved on the centralizer rod 9, and the lower end abuts against the boss of the centralizer rod 9. By pushing the centralizer rod 9 downward, the plunger body 11 is pushed downward. Under the action of the centralizer rod 9, it is ensured that the direction of the plunger body 11 moving up and down in the lower body 8 is always vertical, improving the working stability of the device.

[0025] Among them, a steel ball 10 is provided between the centralizer rod 9 and the plunger body 11. Installation grooves matching the size of the steel ball 10 are respectively provided in the middle of the contact surfaces of the plunger body 11 and the centralizer rod 9. The steel ball 10 is matched with the installation grooves to connect the centralizer rod 9 and the plunger body 11 without damaging the structures of the plunger body 11 and the centralizer rod 9, making the centralizing effect of the centralizer rod 9 on the plunger body 11 more stable.

[0026] As Figure 1-2As shown, a multi-stage nozzle structure is provided at the bottom of the plunger body 11. The multi-stage nozzle mechanism is composed of a plurality of horizontally arranged ceramic force-receiving sheets 12 arranged at intervals from top to bottom. Each ceramic force-receiving sheet 12 is provided with an eccentric through-hole, and the through-holes of two adjacent ceramic force-receiving sheets 12 are arranged staggeredly. During the water injection operation, water flows upward through the through-holes of the ceramic force-receiving sheets 12 from bottom to top. At this time, the force acting on the ceramic force-receiving sheet 12 is the upward thrust received by the plunger body 11. By adjusting the area of the ceramic force-receiving sheet 12, the upward thrust received by the plunger body 11 under the same downhole pressure can be changed, thereby changing the coincidence degree between the water outlet hole 18 of the plunger body and the water outlet hole 19 of the lower body. By changing the area of the ceramic force-receiving sheet 12, the constant flow rate of the device during downhole water injection can be adjusted.

[0027] Among them, when working in a water injection well with a small flow rate, due to the staggered arrangement of the through-holes of the adjacent ceramic force-receiving sheets 12 in the multi-stage nozzle structure, while maintaining the water injection flow rate of the device unchanged, the through-hole diameter of each ceramic force-receiving sheet 12 can be increased. Through experimental verification, the through-hole diameter can be increased by up to 60% compared with the through-hole diameter of the single-stage nozzle structure, greatly improving the passing rate of particulate matter during downhole water injection work, reducing the blockage probability of the device during operation, improving the working efficiency of the device, reducing the maintenance frequency caused by blockage, and saving working time and maintenance costs.

[0028] It should be noted that since the material of the ceramic force-receiving sheet 12 is ceramic, it cannot be fixed by means of threads or bolts. Therefore, the ceramic force-receiving sheet 12 is fixed at the bottom end of the plunger body 11 through a plunger cap 13. The bottom end of the plunger body 11 is provided with a plunger cap 13. The plunger cap 13 is below the ceramic force-receiving sheet 12 and is connected to the bottom end of the plunger body 11. The plunger cap 13 fixes the ceramic force-receiving sheet 12 at the bottom end of the plunger body 11 to maintain the normal operation of the device.

[0029] In the present invention, the screen plug 14 is used to filter the liquid injected into the well to prevent large-sized sundries from entering and causing blockage or damage to the device. A screen plug water outlet 21 is provided below the screen plug 14, and water flows into the screen plug water outlet 21 during the water injection operation.

[0030] Among them, the bottom of the lower body 8 is a downward cone, and several flow holes are provided on the conical surface. During the operation underground, water flows into or out of the lower body 8 through the flow holes. The bottom end of the screen plug 14 is provided with a screen plug water outlet 21. A ball stopper 20 is provided between the lower body 8 and the screen plug 14. When the ball stopper 20 moves downward, it can block the screen plug water outlet 21, and the shape of the top of the conical surface matches the shape of the ball stopper 20. During normal water injection work, water flows into the screen plug from below. At this time, the ball stopper 20 moves upward under the action of the water flow, and the device works normally. During the well washing process, the liquid flows into the lower body water outlet hole 18 and flows towards the screen plug water outlet 21. At this time, the ball stopper 20 moves downward under the action of the hydraulic force to block the screen plug water outlet 21, preventing the liquid flow from being diverted, so that all the well washing fluid can achieve the well washing effect.

[0031] The anti-blocking and anti-diversion constant flow plugging device provided by the present invention can keep the water injection volume constant in the water injection well and adjust the constant water injection volume; improve the anti-blocking ability of the device during small flow water injection; and prevent the occurrence of liquid diversion during well washing work. The specific working process of the device is as follows: Step 1: Adjust the area of the ceramic force-receiving piece according to the work plan, and then assemble the device and lift the fishing rod to lower the device to the working position in the injection well. During this process, after the fishing rod is lifted, the cam rotates upward under the action of the torsion spring, and the device smoothly enters the injection well. After releasing the fishing rod, the fishing rod moves downward under the action of the compression spring and pushes the cam to rotate downward. At this time, the cam cooperates with the internal structure of the injection well to fix the position of the device.

[0032] Step 2: Inject water into the injection well according to the work plan. At this time, water flows in from below through the screen plug water outlet and applies an upward thrust to the plunger body by pushing the ceramic force-receiving piece. Under the action of the thrust and the plunger spring, the plunger body moves upward, and the moving distance is proportional to the magnitude of the thrust received. During this process, as the plunger body moves, the overlap degree between the plunger body water outlet hole and the lower body water outlet hole continuously changes. When the underground pressure increases, the overlap degree decreases, and when the underground pressure decreases, the overlap degree increases, so that the water injection volume of the device for the target formation remains constant.

[0033] Step 3: Perform well washing operation as needed during the water injection work. During this process, the liquid enters from the plunger body water outlet hole and the lower body water outlet hole and flows towards the screen plug water outlet. The ball stopper moves downward under the action of the liquid flow to block the screen plug water outlet, and the well washing fluid cannot pass through the plugging device, preventing the diversion of the well washing fluid.

[0034] During the above working process, the multi-stage nozzle structure enables the device to maintain a constant flow rate while expanding the diameter of the nozzle during small flow water injection, improving the anti-blocking ability of the device.

[0035] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A constant flow plugging device for preventing blockage and shunt, characterized in that, it includes: an upper body (4), a lower body (8) and a screen plug (14). The lower part of the upper body (4) is connected to the lower body (8), and the bottom end of the lower body (8) is connected to the screen plug (14); a fishing rod (1) is provided at the top end of the upper body (4), and the fishing rod (1) is fixed on the upper body (4) through a compression cap (2); the lower body (8) is tubular and its top end is sealed. A centralizing rod (9) is provided inside the lower body (8), and a plunger body (11) is provided below the centralizing rod (9). A lower body water outlet hole (19) is provided on the side wall of the lower body (8), and a plunger body water outlet hole (18) is provided on the side wall of the plunger body (11). The positions of the plunger body water outlet hole (18) and the lower body water outlet hole (19) correspond to each other; the plunger body (11) and the centralizing rod (9) can move up and down inside the lower body (8). A multi-stage nozzle structure is provided at the bottom of the plunger body (11). The multi-stage nozzle structure is composed of a plurality of horizontally arranged ceramic stress-bearing pieces (12) arranged at intervals from top to bottom. Each ceramic stress-bearing piece (12) is provided with an eccentric through hole, and the through holes of two adjacent ceramic stress-bearing pieces (12) are arranged staggeredly; a plunger spring (7) is provided outside the upper part of the centralizing rod (9). One end of the plunger spring (7) contacts the inner top end of the lower body (8), and the other end contacts the centralizing rod (9). The constant flow water injection volume of the device can be adjusted by adjusting the area of the ceramic stress-bearing piece (12); the bottom of the lower body (8) is a downward cone. A plurality of flow holes are provided on the conical curved surface. A screen plug water outlet (21) is provided at the bottom end of the screen plug (14). A ball stopper (20) is provided between the lower body (8) and the screen plug (14). When the ball stopper (20) moves downward, it can block the screen plug water outlet (21). The shape of the top end of the conical surface matches the shape of the ball stopper (20).

2. The constant flow plugging device for preventing blockage and shunt according to claim 1, characterized in that, a cam (5) is provided at the lower part of the upper body (4). The cam (5) is connected to the upper body (4) through a pin shaft (6) and a torsion spring (16). The convex side of the cam is horizontally arranged, and a concave structure matching the bottom end of the fishing rod (1) is provided at the top end. When the fishing rod (1) sinks, it cooperates with the concave structure to fix the position of the cam (5). When the fishing rod (1) is lifted, the cam (5) rotates upward to screw the convex part into the upper body (4).

3. The constant flow plugging device for preventing blockage and shunt according to claim 1, characterized in that, a compression spring (3) is provided outside the fishing rod (1). The top end of the compression spring (3) contacts the upper surface inside the compression cap (2), and the bottom end contacts the fishing rod (1).

4. The constant flow plugging device for preventing blockage and shunt according to claim 1, characterized in that, steel balls (10) are provided on the centralizing rod (9) and the plunger body (11). Installation grooves matching the size of the steel balls (10) are respectively provided at the central positions of the contact surfaces between the centralizing rod (9) and the plunger body (11).

5. The constant flow plugging device for preventing blockage and shunt according to claim 1, characterized in that, A plunger cap (13) is provided at the bottom end of the plunger body (11) to fix the ceramic force-receiving piece (12) on the plunger body (11).

6. The anti-blocking and anti-shunt constant flow plugging device according to claim 1, characterized in that, a plurality of sealing packing (15) are provided on the lower body (8).

7. The anti-blocking and anti-shunt constant flow plugging device according to claim 1, characterized in that, a plurality of flow holes (17) are provided at the top end of the plunger body (11). When the plunger body (11) and the centralizer rod (9) move up and down, liquid flows into or out of the space between the upper part of the plunger body (11) and the lower body (8) through the flow holes (17).

Images