Casing fluid column pressure automatic balancing device

Abstract

The present application relates to the technical field of oil exploration, and discloses a casing liquid column pressure automatic balancing device, which comprises an upper joint for connecting a pipe column, an outer sleeve arranged outside the upper joint, and a first shear pin arranged inside the upper joint. When the device is lowered into a well, the device can balance the internal and external pressure difference, so that the device can be prevented from being squeezed and damaged by the liquid column pressure difference caused by untimely grouting, the labor intensity of workers can be reduced, a large amount of energy consumption for casing lowering and pump grouting can be saved, accidents caused by the unfirm fixing of grouting pipelines, such as splashing and dancing of the grouting pipelines, can be avoided, manual grouting at the wellhead is not needed, the safety hidden danger in the grouting process is reduced, the casing lowering speed is increased by more than 30%, time is saved, time efficiency is improved, air is prevented from being pressed into the well during the grouting process, wellbore instability and well control risks caused by the liquid column pressure in the well are reduced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of oil exploration, and particularly relates to a casing liquid column pressure automatic balancing device. BACKGROUND

[0002] Whether surface casing cementing, or technical casing and reservoir casing cementing, during the process of running in the pipe string, the casing internal and external liquid column pressure must be kept in a relatively balanced state, so as to ensure that the casing is not damaged or deformed by the external liquid column pressure.

[0003] The method adopted is usually wellhead manual grouting, which increases the labor intensity of workers, affects the work efficiency, and consumes a large amount of energy of the mud pump grouting. Meanwhile, the wellhead manual grouting also causes frequent accidents of splashing and dancing of the grouting pipeline, which may hurt people.

[0004] Because there is air in the casing, wellhead mud spewing may occur during grouting, and the grouting pipeline may be frozen in cold regions or seasons, which seriously affects the casing running speed.

[0005] If grouting is not timely, the back pressure valve may be tipped over, and even the casing may be deformed due to a large pressure difference, which may expand the stress cracks on the casing body, speed up the casing damage, and cause other events. If the grouting speed is fast, the displacement is large, or the mud is not fully grouted before connecting the drill pipe to circulate the mud, a large amount of air may be pressed into the well, which may reduce the liquid column pressure of the well barrel, cause well wall instability and well control risk, and affect the cementing quality.

[0006] Therefore, it is necessary to invent the casing liquid column pressure automatic balancing device to solve the above problems. SUMMARY

[0007] In view of the above problems, the present application provides a casing liquid column pressure automatic balancing device to solve the problems in the background art.

[0008] To achieve the above purpose, the present application provides the following technical scheme: a casing liquid column pressure automatic balancing device, comprising:

[0009] an upper joint for connecting a pipe string;

[0010] an outer sleeve arranged outside the upper joint;

[0011] a first shear pin arranged inside the upper joint;

[0012] a sealing ring arranged inside the upper joint;

[0013] a sliding sleeve arranged inside the upper joint, the sealing ring being equidistantly connected outside the sliding sleeve, and the sliding sleeve being connected with the upper joint through the first shear pin;

[0014] A lower joint connected with the upper joint; grouting holes equidistantly arranged outside the lower joint; a ball seat arranged inside the sliding sleeve; a second shear pin connecting the ball seat with the sliding sleeve; a mesh plate arranged inside the lower joint; and a float collar arranged inside the lower joint.

[0015] The sealing enhancement assembly can improve the sealing effect of the sealing ring.

[0016] Further, the sealing enhancement assembly comprises:

[0017] A first cavity arranged on one side of the inside of the sliding sleeve, wherein the inside of the sealing ring is provided with a cavity, and the first cavity is in communication with the cavity;

[0018] A liquid injection channel arranged inside the sliding sleeve, wherein the liquid injection channel is in communication with the first cavity, and an end of the liquid injection channel is provided with a valve;

[0019] A pressurizing assembly arranged on the sliding sleeve, for injecting hydraulic oil into the inside of the first cavity to pressurize;

[0020] The inside of the first cavity, the cavity and the liquid injection channel is filled with hydraulic oil.

[0021] Further, the pressurizing assembly comprises:

[0022] A cylinder arranged below the inside of the sliding sleeve;

[0023] An oil inlet pipe in communication with the first cavity;

[0024] An oil inlet arranged below the inside of the cylinder;

[0025] A first one-way valve arranged inside the oil inlet and the oil inlet pipe, respectively;

[0026] A first piston arranged inside the cylinder;

[0027] A first spring arranged inside the cylinder;

[0028] A bracket, one end of the bracket extending to the inside of the cylinder and connected with the first piston, and the bracket abutting against the ball seat.

[0029] Further, the outside of the sliding sleeve is provided with a protection assembly capable of protecting the sliding sleeve;

[0030] The protection assembly comprises:

[0031] A ring pipe, the number of the ring pipes corresponding to the number of the sealing rings, the ring pipes being sleeved on the outside of the sliding sleeve and being arranged in abutment with the sealing rings;

[0032] A spray hole is arranged outside the ring pipe.

[0033] A lubricating assembly is arranged for injecting lubricating grease into the ring pipe.

[0034] Further, the lubricating assembly comprises:

[0035] An extrusion cavity is arranged inside the sliding sleeve.

[0036] A second piston is arranged inside the extrusion cavity.

[0037] A contact is connected to one side of the second piston close to the inside of the sliding sleeve, and one end of the contact extends into the inside of the sliding sleeve.

[0038] A second spring is connected to one side of the second piston away from the contact.

[0039] An oil injection channel is arranged on the sliding sleeve, and the oil injection channel is in communication with the extrusion cavity.

[0040] A plunger is arranged at the end of the oil injection channel.

[0041] A second cavity is arranged inside the sliding sleeve, and the second cavity is in communication with the inside of the ring pipe and the extrusion cavity.

[0042] A second one-way valve is arranged inside the second cavity.

[0043] Further, the contact is specifically arranged as a cylindrical member with a round end extending into the inside of the sliding sleeve.

[0044] Further, the spray hole is arranged as a plurality of holes and is equidistantly distributed outside the ring pipe, and one end of the spray hole is directed towards the sealing ring.

[0045] Further, the lubricating grease is specifically extreme pressure lubricating grease.

[0046] Technical effects and advantages of the present application:

[0047] 1、The present application can balance the internal and external pressure difference when the device is lowered into the well as a whole, so that the device as a whole can be prevented from being squeezed and damaged by the liquid column pressure difference caused by the delayed grouting, the labor intensity of workers can be reduced, a large amount of energy consumption for casing lowering and pump grouting can be saved, the grouting pipeline is prevented from splashing and dancing to cause accidents, manual grouting at the wellhead is not needed, the safety hidden danger in the grouting process is reduced, the casing lowering speed is increased by more than 30%, time is saved, time efficiency is improved, air is prevented from being pressed into the well during the grouting process, wellbore instability and well control risk caused by the liquid column pressure in the well are reduced, the reverse mud kick phenomenon caused by the air in the casing is eliminated, the rig hygiene is maintained, the frozen pipeline failure of the low-pressure grouting pipeline in winter is eliminated, the casing lowering process is prevented from causing the back pressure valve to be tipped over due to the delayed grouting, and the downhole safety is beneficial;

[0048] 2、The present application can realize pressurization of the sealing ring, so that the sealing ring expands and is embedded into the recessed part, and the sealing ring can be more tightly abutted against the inner wall of the lower joint, and the sealing effect can be further improved;

[0049] 3、The present application can lubricate the sealing ring, reduce the friction of the sealing ring, avoid excessive wear of the sealing ring by mud particles, protect the sealing ring, and ensure the sealing effect. BRIEF DESCRIPTION OF DRAWINGS

[0050] Figure 1 The structure schematic view of the casing liquid column pressure automatic balancing device of the embodiment of the present application is shown;

[0051] Figure 2 The structure schematic view of the sliding sleeve of the embodiment of the present application is shown;

[0052] Figure 3 The cross-sectional structure schematic view of the sliding sleeve of the embodiment of the present application is shown;

[0053] Figure 4 The structure schematic view of the sliding sleeve of the embodiment of the present application is shown; Figure 3 The enlarged structure schematic view of position A in the sliding sleeve of the embodiment of the present application is shown;

[0054] Figure 5 The enlarged structure schematic view of position B in the sliding sleeve of the embodiment of the present application is shown; Figure 3 The enlarged structure schematic view of position B in the sliding sleeve of the embodiment of the present application is shown;

[0055] In the diagram: 1. Upper connector; 2. Outer sleeve; 3. First shear pin; 4. Sealing ring; 5. Sliding sleeve; 6. Grouting hole; 7. Second shear pin; 8. Lower connector; 9. Ball seat; 10. Mesh plate; 11. Floating hoop; 12. First cavity; 13. Cylinder body; 14. Oil inlet pipe; 15. First check valve; 16. First piston; 17. First spring; 18. Bracket; 19. Valve; 20. Ring pipe; 21. Second piston; 22. Contact; 23. Second spring; 24. Second cavity; 25. Second check valve; 26. Oil injection channel. Detailed Implementation

[0056] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments.

[0057] This invention provides an automatic pressure balancing device for the casing fluid column, such as... Figures 1 to 5 As shown, it includes: upper connector 1, outer sleeve 2, first shear pin 3, sealing ring 4, sliding sleeve 5, grouting hole 6, second shear pin 7, lower connector 8, ball seat 9, mesh plate 10, and floating hoop 11;

[0058] The upper connector 1 is used to connect the tubing column. The outer sleeve 2 is set outside the upper connector 1. The first shear pin 3 is set inside the upper connector 1. The sealing ring 4 is set inside the upper connector 1. The sliding sleeve 5 is set inside the upper connector 1. The sealing ring 4 is fixedly connected to the outside of the sliding sleeve 5 at equal intervals. The sliding sleeve 5 and the upper connector 1 are fixedly connected by the first shear pin 3. The lower connector 8 is connected to the upper connector 1. The grouting holes 6 are set around the outside of the lower connector 8 at equal intervals. The ball seat 9 is set inside the sliding sleeve 5. The second shear pin 7 connects and fixes the ball seat 9 to the sliding sleeve 5. The mesh plate 10 is set inside the lower connector 8. The floating hoop 11 is set inside the lower connector 8. The sealing enhancement component can improve the sealing effect of the sealing ring 4.

[0059] The entire device is lowered into the well. During the lowering process, the mud in the well can enter the lower joint 8, the sliding sleeve 5, and the upper joint 1 through the grouting hole 6, so as to balance the internal and external pressure difference and avoid the liquid column pressure difference caused by untimely grouting, which will squeeze and destroy the entire device.

[0060] After grouting is completed, the ball is thrown into the upper joint 1 and falls into the ball seat 9. Then the sleeve pressure is increased. When the sleeve pressure reaches 5MPa, the first shear pin 3 is cut off. The sliding sleeve 5 moves down to cooperate with the sealing ring 4 and closes the grouting hole 6. When the pressure continues to increase to 10MPa, the second shear pin 7 is cut off. The ball and the ball seat 9 move down and fall into the mesh plate 10, completing the sealing of the grouting hole 6.

[0061] The sealing effect of the sealing ring 4 can be improved by using the sealing enhancement component;

[0062] This invention reduces the labor intensity of workers, saves a large amount of energy consumption during casing pumping and grouting, avoids accidents caused by splashing and scattering of grout lines due to insecure fixing of the grouting pipeline, eliminates the need for manual grouting at the wellhead, reduces safety hazards during the grouting process, increases casing running speed by more than 30%, saves time, improves efficiency, prevents air from being forced into the well during the grouting process, reduces wellbore instability and well control risks caused by fluid column pressure in the well, eliminates backflow of mud caused by air in the casing, maintains drilling platform hygiene, prevents freezing of low-pressure grouting pipelines in winter, and avoids situations such as back pressure valve overturning due to untimely grouting during casing running, thus contributing to downhole safety.

[0063] like Figures 2 to 5 As shown, the sealing enhancement assembly includes: a first cavity 12, an injection channel, and a pressurization assembly;

[0064] The first cavity 12 is located inside the sliding sleeve 5. The sealing ring 4 has a cavity inside. The first cavity 12 communicates with the cavity. The injection channel is located inside the sliding sleeve 5 and communicates with the first cavity 12. A valve 19 is provided at the end of the injection channel. Hydraulic oil is injected into the first cavity 12 and the cavity through the injection channel. As the hydraulic oil is continuously injected, the sealing ring 4 expands, allowing the sealing ring 4 to abut against the inner wall of the upper connector 1. Then the injection stops, and the injection channel is closed by the valve 19. The pressurizing component is located on the sliding sleeve 5 and is used to inject hydraulic oil into the first cavity 12 for pressurization. The first cavity 12, the cavity, and the injection channel are filled with hydraulic oil.

[0065] When the sliding sleeve 5 moves downwards to a stop, as the ball seat 9 moves away, the pressurizing component injects hydraulic oil into the first cavity 12 to pressurize it. If there are defects such as dents on the inner wall of the lower connector 8, the sealing ring 4 will expand as the pressurization proceeds, thereby embedding itself into the dented part. This allows the sealing ring 4 to come into closer contact with the inner wall of the lower connector 8, further improving the sealing effect.

[0066] like Figures 3 to 5 As shown, the pressurization assembly includes: cylinder 13, oil inlet pipe 14, oil filler port, first check valve 15, first piston 16, first spring 17, and bracket 18;

[0067] The cylinder body 13 is filled with hydraulic oil. The cylinder body 13 is fixedly installed inside the lower part of the sliding sleeve 5. The oil inlet pipe 14 connects the cylinder body 13 with the first cavity 12. The oil filling port is located on the lower inner side of the cylinder body 13. The first one-way valve 15 is respectively located inside the oil filling port and the oil inlet pipe 14. The first piston 16 is located inside the cylinder body 13. Multiple first springs 17 are provided and located inside the cylinder body 13. The first springs 17 fix the first piston 16 to the inner wall of the cylinder body 13. One end of the bracket 18 extends into the inside of the cylinder body 13 and is fixedly connected to the first piston 16. The bracket 18 abuts against the ball seat 9.

[0068] When the ball seat 9 leaves the sliding sleeve 5, if there is a dent at the contact point between the sealing ring 4 and the inner wall of the lower connector 8, the first spring 17 in a stretched state moves with the first piston 16, squeezing the hydraulic oil in the cylinder 13 outward. At this time, the first check valve 15 in the oil filling port closes, and the first check valve 15 in the oil inlet pipe 14 opens, squeezing the hydraulic oil into the first cavity 12 and then into the sealing ring 4, causing the sealing ring 4 to expand. This allows the surface of the sealing ring 4 to enter the recessed area of ​​the inner wall of the lower connector 8, making it fit more closely to the inner wall of the lower connector 8 and improving the sealing performance. When the sealing ring 4 comes into contact with the recessed area, the sealing ring 4 can no longer expand, and the first piston 16 can no longer move.

[0069] like Figures 3 to 5 As shown, the outer side of the sliding sleeve 5 is provided with a protective component to protect it;

[0070] The protective components include: ring tube 20, nozzle, and lubrication assembly;

[0071] The number of annular tubes 20 corresponds to the number of sealing rings 4. The annular tubes 20 are sleeved on the outside of the sliding sleeve 5 and fit snugly with the sealing rings 4. The spray holes are located on the outside of the annular tubes 20. The lubrication assembly is used to inject grease into the annular tubes 20.

[0072] When the ball is thrown, it falls into the sliding sleeve 5. The lubrication component is used to inject grease into the ring tube 20. The grease is sprayed out through the nozzle to the surface of the sealing ring 4. This reduces the friction on the sealing ring 4 when it slides along the inner wall of the upper connector 1 and the lower connector 8, and prevents the mud particles from excessively wearing the sealing ring 4, thus protecting the sealing ring 4 and ensuring its sealing effect.

[0073] like Figures 3 to 5 As shown, the lubrication assembly includes: a compression chamber, a second piston 21, a contact 22, a second spring 23, a second cavity 24, a second check valve 25, an oil injection channel 26, and a plunger;

[0074] The extrusion chamber is located inside the sliding sleeve 5. The second piston 21 is located inside the extrusion chamber. The contact 22 is fixedly connected to the side of the second piston 21 near the inside of the sliding sleeve 5. One end of the contact 22 extends into the inside of the sliding sleeve 5. The second spring 23 is fixedly connected to the side of the second piston 21 away from the contact 22. The oil injection channel 26 is located on the sliding sleeve 5 and communicates with the extrusion chamber. The plunger is located at the end of the oil injection channel 26. The second cavity 24 is located inside the sliding sleeve 5 and communicates with the ring pipe 20 and the inside of the extrusion chamber. The second one-way valve 25 is located inside the second cavity 24. The contact 22 is specifically configured as a cylindrical member with a round end extending into the inside of the sliding sleeve 5.

[0075] Pressing the contact 22 causes the second piston 21 to move along the extrusion chamber, squeezing out the air in the extrusion chamber through the oil injection channel 26. At the same time, the second piston 21 compresses the second spring 23, deforming it. Then, the suction tube for connecting the external lubricant is connected to the oil injection channel 26. Releasing the contact 22 causes the second spring 23 to return to its original position, causing the second piston 21 and contact 22 to return to their original positions, drawing the lubricant into the extrusion chamber. At this time, the second one-way valve 25 closes, and the lubricant is finally drawn into the extrusion chamber. The oil injection channel 26 is then closed by the plunger. After the ball is inserted, it enters the sliding sleeve 5 and comes into contact with the contact 22, causing the contact 22 to compress the second piston 21 along the extrusion chamber, compressing the second spring 23 and deforming it. At the same time, the lubricant in the extrusion chamber is squeezed outward. At this time, the second one-way valve 25 opens, and the lubricant enters the second cavity 24, then fills the second cavity 24 and enters each ring tube 20. Finally, it fills the ring tube 20 and is sprayed out through the spray hole onto the surface of the sealing ring 4, achieving lubrication.

[0076] like Figure 3 and Figure 4 As shown, the nozzles are set to be multiple and equidistantly distributed on the outside of the ring tube 20, with one end of the nozzle facing the sealing ring 4, and the grease is specifically extreme pressure grease.

[0077] This allows the grease sprayed from the nozzle to cover the surface of the sealing ring 4.

[0078] Working principle: The entire device is lowered into the well. During the lowering process, the mud in the well can enter the lower joint 8, the sliding sleeve 5, and the upper joint 1 through the grouting hole 6, so as to balance the internal and external pressure difference and avoid the liquid column pressure difference caused by untimely grouting, which will squeeze and destroy the entire device.

[0079] After grouting is completed, the ball is thrown into the upper joint 1 and falls into the ball seat 9. Then the sleeve pressure is increased. When the sleeve pressure reaches 5MPa, the first shear pin 3 is cut off. The sliding sleeve 5 moves down to cooperate with the sealing ring 4 and closes the grouting hole 6. When the pressure continues to increase to 10MPa, the second shear pin 7 is cut off. The ball and the ball seat 9 move down and fall into the mesh plate 10, completing the sealing of the grouting hole 6.

[0080] When the sliding sleeve 5 moves down to a stop, as the ball seat 9 leaves, if there is a dent at the contact point between the sealing ring 4 and the inner wall of the lower connector 8, the first spring 17 in a stretched state moves with the first piston 16, squeezing the hydraulic oil in the cylinder 13 outward. At this time, the first check valve 15 in the oil filling port closes, and the first check valve 15 in the oil inlet pipe 14 opens, squeezing the hydraulic oil into the first cavity 12 and then into the sealing ring 4, causing the sealing ring 4 to expand. This allows the surface of the sealing ring 4 to enter the recessed area of ​​the inner wall of the lower connector 8, making it fit more closely to the inner wall of the lower connector 8 and improving the sealing performance. When the sealing ring 4 comes into contact with the recessed area, the sealing ring 4 can no longer expand, and the first piston 16 can no longer move.

[0081] After the ball is inserted, it enters the sliding sleeve 5 and comes into contact with the contact 22, causing the contact 22 to be squeezed. This causes the second piston 21 to move along the squeezing chamber, compressing the second spring 23 and deforming it. At the same time, the grease in the squeezing chamber is squeezed outward. At this time, the second one-way valve 25 opens, and the grease enters the second chamber 24. Then, it fills the second chamber 24 and enters each ring tube 20. Finally, it fills the ring tube 20 and is sprayed out through the spray hole to the surface of the sealing ring 4, achieving lubrication. This reduces the friction on the sealing ring 4 when it slides along the inner wall of the upper connector 1 and the lower connector 8, preventing excessive wear of the sealing ring 4 by mud particles, thus protecting the sealing ring 4 and ensuring its sealing effect.

[0082] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it.

Claims

1. A casing fluid column pressure automatic balancing device, characterized by, The device comprises: an upper joint (1) for connecting a pipe column; an outer sleeve (2) arranged outside the upper joint (1); a first shear pin (3) arranged inside the upper joint (1); a sealing ring (4) arranged inside the upper joint (1); a sliding sleeve (5) arranged inside the upper joint (1), the sealing ring (4) being equidistantly connected to the outside of the sliding sleeve (5), and the sliding sleeve (5) being connected to the upper joint (1) through the first shear pin (3); a lower joint (8) connected to the upper joint (1); grouting holes (6) equidistantly arranged outside the lower joint (8); a ball seat (9) arranged inside the sliding sleeve (5); a second shear pin (7) connecting the ball seat (9) to the sliding sleeve (5); a mesh plate (10) arranged inside the lower joint (8); and a float collar (11) arranged inside the lower joint (8); a sealing enhancement assembly capable of improving the sealing effect of the sealing ring (4); the sealing enhancement assembly comprising: a first cavity (12) arranged on one side of the inside of the sliding sleeve (5), the inside of the sealing ring (4) being provided with a cavity, and the first cavity (12) being in communication with the cavity; a liquid injection channel arranged inside the sliding sleeve (5), the liquid injection channel being in communication with the first cavity (12), and the end of the liquid injection channel being provided with a valve (19); a pressurizing assembly arranged on the sliding sleeve (5) and used for injecting hydraulic oil into the inside of the first cavity (12) to pressurize; the inside of the first cavity (12), the cavity, and the liquid injection channel being filled with hydraulic oil; the pressurizing assembly comprising: a cylinder (13) arranged below the inside of the sliding sleeve (5); an oil inlet pipe (14) connecting the cylinder (13) to the first cavity (12); an oil inlet port arranged below the inside of the cylinder (13); a first one-way valve (15) arranged inside the oil inlet port and the oil inlet pipe (14), respectively; a first piston (16) arranged inside the cylinder (13); a first spring (17) arranged inside the cylinder (13); a bracket (18), one end of the bracket (18) extending into the inside of the cylinder (13) and being connected to the first piston (16), and the bracket (18) being in abutment with the ball seat (9).

2. The casing fluid column pressure automatic balancing device according to claim 1, wherein: the outside of the sliding sleeve (5) is provided with a protection assembly capable of protecting the sliding sleeve (5); the protection assembly comprising: a ring pipe (20), the number of the ring pipes (20) corresponding to the number of the sealing rings (4), the ring pipes (20) being sleeved on the outside of the sliding sleeve (5) and being arranged in abutment with the sealing rings (4); injection holes arranged on the outside of the ring pipes (20); a lubricating assembly used for injecting lubricating grease into the ring pipes (20).

3. The casing fluid column pressure automatic balancing device according to claim 2, wherein: the lubricating assembly comprising: an extrusion cavity arranged inside the sliding sleeve (5). A second piston (21) is arranged inside the extrusion cavity; A contact (22) is connected to one side of the second piston (21) close to the inside of the sliding sleeve (5), one end of the contact (22) extends to the inside of the sliding sleeve (5); A second spring (23) is connected to the side of the second piston (21) away from the contact (22); An oil injection channel (26) is arranged on the sliding sleeve (5), the oil injection channel (26) communicates with the extrusion cavity; A plunger is arranged at the end of the oil injection channel (26); A second cavity (24) is arranged inside the sliding sleeve (5), the second cavity (24) communicates with the annular tube (20) and the inside of the extrusion cavity; A second one-way valve (25) is arranged inside the second cavity (24).

4. The automatic casing fluid column pressure balancing device according to claim 3, characterized in that: The contact (22) is specifically arranged as a cylindrical member with a round end extending to the inside of the sliding sleeve (5).

5. The automatic casing fluid column pressure balancing device according to claim 4, characterized in that: The injection holes are arranged as multiple and equidistantly distributed on the outside of the annular tube (20), one end of the injection holes faces the sealing ring (4).

6. The automatic casing fluid column pressure balancing device according to claim 5, characterized in that: The lubricating grease is specifically extreme pressure lubricating grease.

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