Differential circulating valve

Abstract

The utility model discloses a kind of differential circulation valves, it includes upper connector, circulating outer tube and lower connector connected in turn, the circulating hole is opened on the circulating outer tube, it further includes ball seat outer tube, spring claw type ball seat and sliding sleeve assembly, the ball seat outer tube is connected the upper connector with the circulating outer tube, the ball seat outer tube lower part is opened with limiting slot, the spring claw type ball seat is arranged in the ball seat outer tube interior, and its bottom is connected with the ball seat outer tube by first shear pin, the spring claw type ball seat top is adapted with the limiting slot, the sliding assembly is arranged in the circulating outer tube interior, for opening and closing the circulating hole. The utility model is by being provided with ball seat outer tube and spring claw type ball seat, so that first shear pin is sheared on spring claw type ball seat, only steel ball enters well, spring claw type ball seat does not fall into well, and there is no extra component falling into well, reduce the risk of jamming in the descending process of spring claw type ball seat.

Description

Technical Field

[0001] This utility model relates to the field of oilfield downhole tools technology, specifically to a differential circulation valve. Background Technology

[0002] Differential circulation valves are one of the important pieces of equipment in oil and gas production. They are installed downhole and connected to the tubing. Differential circulation valves have circulation holes for circulation operations and ball seats for receiving steel balls to seal the oil passage.

[0003] During the circulation operation, the circulation hole remains open under the action of the shear pin to create circulation between the inside and outside of the tubing. After the circulation operation is completed, a steel ball is dropped into the tubing from the wellhead. Under gravity, the steel ball automatically falls onto the ball seat inside the differential circulation valve to block the oil passage within the valve. Then, a pump truck continuously injects liquid from the wellhead into the tubing. When the flow resistance pressure at the top of the ball seat reaches the shearing pressure of the shear pin, the shear pin is cut off, the ball seat falls into the well, and the circulation hole closes. Utility Model Content

[0004] The purpose of this invention is to provide a differential circulation valve to solve the problems mentioned in the background art.

[0005] To solve the above-mentioned technical problems, this utility model provides a differential circulation valve, which includes an upper connector, a circulation outer cylinder, and a lower connector connected in sequence. The circulation outer cylinder has a circulation hole. It also includes a ball seat outer cylinder, a spring-claw ball seat, and a sliding sleeve assembly. The ball seat outer cylinder connects the upper connector and the circulation outer cylinder. A limit groove is formed at the lower part of the ball seat outer cylinder. The spring-claw ball seat is disposed inside the ball seat outer cylinder, and its bottom is connected to the ball seat outer cylinder through a first shear pin. The top of the spring-claw ball seat is adapted to the limit groove. The sliding sleeve assembly is disposed inside the circulation outer cylinder and is used to open and close the circulation hole.

[0006] Furthermore, a limiting block is fixedly installed on the top outer wall of the spring-claw ball seat, and the limiting block is adapted to the limiting groove.

[0007] Furthermore, the sliding sleeve assembly includes an upper sliding sleeve disposed above the circulation hole. The top of the upper sliding sleeve is provided with a first annular groove that adapts to the bottom of the spring-claw ball seat. The top of the upper sliding sleeve and the bottom of the spring-claw ball seat are connected to the outer cylinder of the ball seat through the first shear pin. The top of the lower connector is provided with a second annular groove that adapts to the bottom of the upper sliding sleeve.

[0008] Furthermore, the sliding sleeve assembly also includes a lower sliding sleeve disposed below the circulation hole. The lower sliding sleeve is connected to the lower connector via a second shear pin. The upper end face of the lower sliding sleeve is adapted to the lower end face of the upper sliding sleeve, and the bottom of the lower sliding sleeve is adapted to the second annular groove.

[0009] Furthermore, a limiting ring is fixedly installed on the top outer wall of the sliding sleeve, the outer ring of the limiting ring is adapted to the inner ring of the circulating outer cylinder, and the lower end face of the limiting ring is adapted to the upper end face of the lower connector.

[0010] Furthermore, both ends of the ball seat outer cylinder are located inside the upper connector and the circulating outer cylinder, and a first O-ring is provided between both ends of the ball seat outer cylinder and the upper connector and the circulating outer cylinder.

[0011] Furthermore, a second O-ring is provided between the upper sliding sleeve and the circulating outer cylinder.

[0012] Furthermore, a third O-ring is provided between the sliding sleeve and the circulating outer cylinder.

[0013] The beneficial effects of this utility model are as follows: By setting the outer cylinder of the ball seat and the spring-claw ball seat, this utility model ensures that after the first shearing pin on the spring-claw ball seat shears, only the steel ball enters the well, and the spring-claw ball seat does not fall into the well, and no extra parts fall into the well, reducing the risk of the spring-claw ball seat getting stuck during its descent. At the same time, after the spring-claw ball seat descents and springs into the limiting groove, it can maintain the same flow diameter as other testing tools, making the flow diameter of this differential circulation valve large, ensuring that any subsequent operating tools can pass through the valve without obstruction, greatly enhancing the functionality and compatibility of the tubing string. Attached Figure Description

[0014] Figure 1 This is a structural schematic diagram of an embodiment of the present utility model.

[0015] The components are: 1. Upper connector; 2. Ball seat outer cylinder; 3. Fixing screw; 4. Spring claw ball seat; 5. Circulating outer cylinder; 6. First shear pin; 7. Upper sliding sleeve; 8. Lower sliding sleeve; 9. Second shear pin; 10. Lower connector; 11. First O-ring; 12. Second O-ring; 13. Third O-ring; 14. Steel ball; 15. Limiting groove; 16. Limiting block; 17. Limiting ring. Detailed Implementation

[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only one embodiment of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0017] To make the objectives, technical solutions and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and specific embodiments.

[0018] In the following description, references to "an embodiment," "an embodiment," "an example," "example," etc., indicate that the described embodiment or example may include a particular feature, structure, characteristic, property, element, or limitation, but not every embodiment or example necessarily includes that particular feature, structure, characteristic, property, element, or limitation. Furthermore, the repeated use of the phrase "an embodiment according to this application," while possibly referring to the same embodiment, does not necessarily refer to the same embodiment.

[0019] like Figure 1 As shown, this utility model discloses a differential circulation valve, including an upper connector 1, a circulation outer cylinder 5, and a lower connector 10 connected in sequence. The circulation outer cylinder 5 has a circulation hole. It also includes a ball seat outer cylinder 2, a spring-claw ball seat 4, and a sliding sleeve assembly. The ball seat outer cylinder 2 connects the upper connector 1 and the circulation outer cylinder 5. A limiting groove 15 is opened at the lower part of the ball seat outer cylinder 2. The spring-claw ball seat 4 is disposed inside the ball seat outer cylinder 2, and its bottom is connected to the ball seat outer cylinder 2 by a first shear pin 6. The top of the spring-claw ball seat 4 is adapted to the limiting groove 15. The sliding sleeve assembly is disposed inside the circulation outer cylinder 5 and is used to open and close the circulation hole. In this embodiment, the top and bottom of the ball seat outer cylinder 2 are connected to the upper connector 1 and the circulation outer cylinder 5 respectively by fixing screws 3. The lower connector 10 and the circulation outer cylinder 5 are also connected by fixing screws 3.

[0020] When the valve is lowered into the well, the spring-claw ball seat 4 is fixed to the outer cylinder 2 of the ball seat by the first shear pin 6, placing it in its initial high position. The sliding sleeve assembly is fixed by the corresponding shear pin, and the circulation hole on the outer circulation cylinder 5 remains open. At this time, the inside and outside of the tubing are connected through the circulation hole, allowing for normal circulation operations.

[0021] After the circulation operation is completed, a steel ball 14 is dropped into the tubing from the wellhead. The steel ball 14 descends under gravity or carried by the circulating fluid, eventually settling on the conical seat of the spring-claw ball seat 4. The steel ball 14 engages with the seat, essentially blocking the main flow channel in the center of the tubing string. However, a complete seal cannot be achieved between the spring-claw ball seat 4 and the steel ball 14. During forward circulation, the circulating fluid passes through the ball seat, creating flow resistance in the tubing above the ball seat. Pressure is generated above and below the ball; the greater the flow rate, the greater the pressure difference. When the pressure difference exceeds the shearing pressure of the first shear pin 6 of the spring-claw ball seat 4, the first shear pin 6 shears, causing the spring-claw ball seat 4 to descend, simultaneously pushing the sliding sleeve assembly downwards.

[0022] As the sliding sleeve assembly descends, its sidewalls gradually cover the circulation holes on the outer circulation cylinder 5, eventually closing them completely and cutting off the internal and external channels of the oil pipe. Simultaneously, the spring-loaded ball seat 4 continues to descend, and its elastic claw portion enters the limiting groove 15 area at the lower part of the outer cylinder 2. When the elastic claw moves to align with the limiting groove 15, due to the loss of radial constraint from the cylinder wall, the elastic claw rapidly opens radially outwards and engages in the limiting groove 15.

[0023] As steel ball 14 loses its support, it falls downwards under the influence of gravity, passing through the enlarged inner diameter of the ball seat. Finally, steel ball 14 reaches the bottom of the well. At this point, the obstruction in the internal passage of the differential circulation valve is completely cleared, forming a continuous, complete, and uniformly sized "full-bore" passage from the upper tubing string to the lower tubing string.

[0024] This invention, by setting up an outer cylinder 2 for the ball seat and a spring-claw ball seat 4, ensures that after the first shearing pin 6 on the spring-claw ball seat 4 shears, only the steel ball 14 enters the well, while the spring-claw ball seat 4 does not fall into the well, and no extra parts fall into the well, reducing the risk of the spring-claw ball seat 4 getting stuck during its descent. Simultaneously, after the spring-claw ball seat 4 springs into the limiting groove 15, it maintains the same flow diameter as other testing tools, resulting in a large flow diameter for this differential circulation valve. This ensures that any subsequent operating tools can pass through the valve without obstruction, greatly enhancing the functionality and compatibility of the tubing string.

[0025] In one embodiment, a limiting block 16 is fixedly installed on the top outer wall of the spring-loaded ball seat 4, and the limiting block 16 is adapted to the limiting groove 15. The limiting block 16 is integrally formed with the spring-loaded ball seat 4, that is, the presence of the limiting block 16 clearly defines the endpoint of the movement of the spring-loaded ball seat 4. This ensures that the ball seat can be locked in a unique and correct position each time, thereby ensuring that the inner diameter release mechanism can be fully triggered to form a perfect full bore. At the same time, the limiting block 16 slides along the inner wall of the outer cylinder 2 of the ball seat, playing a good guiding role and ensuring that the ball seat descends smoothly and is not prone to tilting or rotating.

[0026] In one embodiment, the sliding sleeve assembly includes an upper sliding sleeve 7, which is disposed above the circulation hole. The top of the upper sliding sleeve 7 is provided with a first annular groove that adapts to the bottom of the spring-claw ball seat 4. The top of the upper sliding sleeve 7 and the bottom of the spring-claw ball seat 4 are connected to the outer cylinder 2 of the ball seat through a first shear pin 6. The top of the lower connector 10 is provided with a second annular groove that adapts to the bottom of the upper sliding sleeve 7.

[0027] The spring-loaded ball seat 4 is fixed to the outer cylinder 2 of the ball seat by the first shear pin 6. The bottom of the spring-loaded ball seat 4 is inserted into the first annular groove at the top of the upper sliding sleeve 7. At the same time, the upper sliding sleeve 7 is also connected to the outer cylinder 2 of the ball seat by the same first shear pin 6. At this time, the upper sliding sleeve 7 is located above the circulation hole, and the circulation hole is in the open state.

[0028] When the first shear pin 6 is sheared, the spring-loaded ball seat 4 and the upper sliding sleeve 7 move downwards as a whole. The upper sliding sleeve 7 descends, covering and ultimately sealing the circulation hole on the outer circulation cylinder 5. At this point, the circulation channel is cut off.

[0029] After the circulation hole is closed, the inside of the tubing becomes a closed pressure vessel, and the pressure will rise sharply again. The spring-claw ball seat 4 and the upper sliding sleeve 7 continue to descend until the bottom of the upper sliding sleeve 7 is inserted into the second annular groove at the top of the lower connector 10, and the limiting block 16 on the spring-claw ball seat 4 is engaged in the limiting groove 15.

[0030] In one embodiment, the sliding sleeve assembly further includes a lower sliding sleeve 8, which is disposed below the circulation hole. The lower sliding sleeve 8 is connected to the lower connector 10 via a second shear pin 9. The upper end face of the lower sliding sleeve 8 is adapted to the lower end face of the upper sliding sleeve 7, and the bottom of the lower sliding sleeve 8 is adapted to the second annular groove.

[0031] After the circulation hole is closed, the inside of the tubing becomes a closed pressure vessel, and the pressure will rise sharply again. The spring-claw ball seat 4 and the upper sliding sleeve 7 continue to descend, pushing the lower sliding sleeve 8, causing its second shear pin 9 to be sheared, and the entire lower sliding sleeve 8 moves downward. Until the lower sliding sleeve 8 is inserted into the second annular groove at the top of the lower connector 10, the limiting block 16 on the spring-claw ball seat 4 is engaged in the limiting groove 15.

[0032] By using two independent shear pins 6 and 9 of different strengths, and a locked sliding sleeve 8, the logic of "the hole must be closed before the ball seat can be unlocked" is physically enforced. This is the most reliable sequence control mechanism.

[0033] In one embodiment, a limiting ring 17 is fixedly installed on the top outer wall of the sliding sleeve 8. The outer ring of the limiting ring 17 is adapted to the inner ring of the circulating outer cylinder 5, and the lower end face of the limiting ring 17 is adapted to the upper end face of the lower connector 10. The limiting ring 17 and the sliding sleeve 8 are integrally formed, and the limiting ring 17 plays a guiding role throughout the entire movement. It ensures the straightness of the movement of the sliding sleeve 8, prevents it from deviating, rotating, or jamming, and makes the operation more stable and reliable.

[0034] In one embodiment, both ends of the ball seat outer cylinder 2 are located inside the upper connector 1 and the circulation outer cylinder 5, and a first O-ring 11 is provided between both ends of the ball seat outer cylinder 2 and the upper connector 1 and the circulation outer cylinder 5. That is, a groove is made on the outer wall of the ball seat outer cylinder 2, and the first O-ring 11 is placed in the groove. This ensures the sealing of the connection between the ball seat outer cylinder 2 and the upper connector 1 and the circulation outer cylinder 5, and prevents liquid leakage.

[0035] In one embodiment, a second O-ring 12 is provided between the upper sliding sleeve 7 and the circulating outer cylinder 5. Specifically, a groove is cut into the outer wall of the upper sliding sleeve 7, and the second O-ring 12 is placed within the groove, ensuring close contact between the upper sliding sleeve 7 and the inner wall of the circulating outer cylinder 5 during its up-and-down sliding motion. This results in two independent pressure chambers formed above and below the upper sliding sleeve 7 inside the circulating outer cylinder 5.

[0036] In one embodiment, a third O-ring 13 is provided between the sliding sleeve 8 and the circulating outer cylinder 5. Specifically, a groove is cut into the inner wall of the circulating outer cylinder 5, and the third O-ring 13 is placed within the groove. In this embodiment, in the initial state, the third O-ring 13 adapts to the limiting ring 17, ensuring the integrity of the overall seal. After the circulation hole is closed, the third O-ring 13 engages with the outer wall of the upper sliding sleeve 7, further ensuring that there is no leakage after the circulation hole is closed.

[0037] This utility model is a full-bore pressure-controlled circulation valve designed to meet the specific needs of testing operations, and is suitable for circulation operations in high-pressure oil well testing. The workflow of this utility model embodiment is as follows: In the initial state, the spring-loaded ball seat 4 is fixed to the outer cylinder 2 of the ball seat by the first shear pin 6. The bottom of the spring-loaded ball seat 4 is inserted into the first annular groove at the top of the upper sliding sleeve 7. At the same time, the upper sliding sleeve 7 is also connected to the outer cylinder 2 of the ball seat by the same first shear pin 6. At this time, the upper sliding sleeve 7 is located above the circulation hole, and the lower sliding sleeve 8 is located below the circulation hole and fixed by the second shear pin 9. The circulation hole is in the open state, that is, the differential pressure circulation valve is in the open state.

[0038] After the circulation is completed, a steel ball 14 is inserted into the test column. The steel ball 14 is placed on the spring-claw ball seat 4 through positive circulation or free fall, blocking the column diameter. However, the ball seat and the ball cannot be completely sealed. During positive circulation, the circulating fluid passes through the ball seat and forms a flow obstruction in the column above the ball seat. Pressure is formed above and below the ball. The greater the flow rate, the greater the flow obstruction pressure difference. When the flow obstruction pressure difference is greater than the shearing pressure of the first shear pin 6, the first shear pin 6 shears, the spring-claw ball seat 4 moves downward, pushing the upper sliding sleeve 7 downward. The upper sliding sleeve 7 contacts the lower sliding sleeve 8 to close the circulation hole.

[0039] After the circulation hole is closed, the spring-claw ball seat 4 and the upper sliding sleeve 7 continue to descend, pushing the lower sliding sleeve 8, causing its second shear pin 9 to be sheared, and the lower sliding sleeve 8 to move downwards. Until the lower sliding sleeve 8 inserts into the second annular groove at the top of the lower connector 10, the limiting block 16 on the spring-claw ball seat 4 engages in the limiting groove 15 of the outer cylinder 2 of the ball seat. The circulation valve passage becomes a uniform passage. The inner diameter of the elastic seat increases, the steel ball 14 falls through the spring-claw ball seat 4, and the differential circulation valve changes from the open state to the closed state.

[0040] The above description of the disclosed embodiments enables those skilled in the art to implement or use this invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, this invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A differential circulating valve comprising an upper joint, a circulating outer cylinder and a lower joint connected in sequence, a circulating hole being formed in the circulating outer cylinder, characterized in that: It also includes a ball seat outer cylinder, a spring-claw ball seat, and a sliding sleeve assembly. The ball seat outer cylinder connects the upper connector and the circulation outer cylinder. A limiting groove is opened at the lower part of the ball seat outer cylinder. The spring-claw ball seat is disposed inside the ball seat outer cylinder, and its bottom is connected to the ball seat outer cylinder through a first shear pin. The top of the spring-claw ball seat is adapted to the limiting groove. The sliding sleeve assembly is disposed inside the circulation outer cylinder and is used to open and close the circulation hole.

2. A differential circulating valve according to claim 1, characterized in that: A limiting block is fixedly installed on the top outer wall of the spring-loaded ball seat, and the limiting block is adapted to the limiting groove.

3. A differential circulation valve according to claim 1, characterized in that: The sliding sleeve assembly includes an upper sliding sleeve disposed above the circulation hole. The top of the upper sliding sleeve is provided with a first annular groove that is adapted to the bottom of the spring-claw ball seat. The top of the upper sliding sleeve and the bottom of the spring-claw ball seat are connected to the outer cylinder of the ball seat through a first shear pin. The top of the lower connector is provided with a second annular groove that is adapted to the bottom of the upper sliding sleeve.

4. A differential circulating valve according to claim 3, wherein: The sliding sleeve assembly further includes a lower sliding sleeve disposed below the circulation hole. The lower sliding sleeve is connected to the lower connector via a second shear pin. The upper end face of the lower sliding sleeve is adapted to the lower end face of the upper sliding sleeve, and the bottom of the lower sliding sleeve is adapted to the second annular groove.

5. A differential circulation valve according to claim 4, characterized in that: A limiting ring is fixedly installed on the top outer wall of the sliding sleeve. The outer ring of the limiting ring is adapted to the inner ring of the circulating outer cylinder, and the lower end face of the limiting ring is adapted to the upper end face of the lower connector.

6. A differential circulation valve according to claim 1, characterized in that: Both ends of the ball seat outer cylinder are located inside the upper connector and the circulating outer cylinder, and a first O-ring is provided between both ends of the ball seat outer cylinder and the upper connector and the circulating outer cylinder.

7. A differential circulation valve according to claim 3, characterized in that: A second O-ring is provided between the upper sliding sleeve and the circulating outer cylinder.

8. A differential circulation valve according to claim 5, characterized in that: A third O-ring is provided between the sliding sleeve and the circulating outer cylinder.

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