Automatic pressure balancing device for casing liquid column

Abstract

The invention relates to the technical field of oil exploration, and discloses a casing liquid column pressure automatic balancing device which comprises an upper connector, a lower connector and a pressure balancing device. The outer sleeve is arranged outside the upper joint; the first shear pin is arranged on the inner side of the upper connector. When the whole device is tripped into a well, the internal and external pressure difference can be balanced, so that the whole device can be prevented from being extruded and damaged by the liquid column pressure difference generated due to untimely grouting, the labor intensity of workers can be reduced, a large amount of energy consumption for casing running pump starting grouting is saved, and the problem that the grouting pipeline is not firmly fixed and cannot be damaged is solved. And manual grouting at a well mouth is not needed, the potential safety hazard in the grouting process is reduced, the casing running speed is improved by more than 30%, the time is saved, the time efficiency is improved, air is prevented from being pressed into a well in the grouting process, and the well wall instability and well control risk caused by the pressure of a liquid column 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 fluid 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 string, the casing internal and external fluid 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 fluid 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, and even causes injury to people.

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

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

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

[0007] In view of the above problems, the present application provides a casing fluid 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 fluid column pressure automatic balancing device, comprising: an upper joint for connecting a string; an outer sleeve arranged outside the upper joint; a first shear pin arranged inside the upper joint; a sealing ring arranged inside the upper joint; a sliding sleeve arranged inside the upper joint, the sealing ring being equidistantly connected outside the sliding sleeve, and the sliding sleeve and the upper joint being connected through the first shear pin; A lower joint connected with the upper joint, a grouting hole 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. The sealing enhancement assembly can improve the sealing effect of the sealing ring.

[0009] Further, the sealing enhancement assembly comprises: A first cavity arranged on one side of the inside of the sliding sleeve, the inside of the sealing ring being provided with a cavity, and the first cavity being in communication with the cavity; A liquid injection channel arranged inside the sliding sleeve, the liquid injection channel being in communication with the first cavity, and the end of the liquid injection channel being provided with a valve; A pressurizing assembly arranged on the sliding sleeve and used for injecting hydraulic oil into the inside of the first cavity to pressurize; The inside of the first cavity, the cavity, and the liquid injection channel is filled with hydraulic oil.

[0010] Further, the pressurizing assembly comprises: A cylinder arranged inside and below the sliding sleeve; An oil inlet pipe in communication with the cylinder and the first cavity; An oil inlet arranged inside and below the cylinder; A first one-way valve arranged inside the oil inlet and the oil inlet pipe, respectively; A first piston arranged inside the cylinder; A first spring arranged inside the cylinder; 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.

[0011] Further, the outside of the sliding sleeve is provided with a protection assembly capable of protecting the sliding sleeve; The protection assembly comprises: A ring pipe, the number of the ring pipes corresponding to the number of the sealing rings, the ring pipes being sleeved outside the sliding sleeve and being arranged in abutment with the sealing rings; A spray hole arranged outside the ring pipe; A lubricating assembly used for injecting lubricating grease into the ring pipe.

[0012] Further, the lubricating assembly comprises: A squeezing cavity arranged inside the sliding sleeve; A second piston arranged inside the squeezing cavity; A contact is connected to the second piston near the inside of the sliding sleeve, and one end of the contact extends to the inside of the sliding sleeve. A second spring is connected to the second piston away from the contact. An oil injection channel is arranged on the sliding sleeve, and the oil injection channel is communicated with the extrusion cavity. A plunger is arranged at the end of the oil injection channel. A second cavity is arranged in the inside of the sliding sleeve, and the second cavity is communicated with the inside of the ring pipe and the extrusion cavity. A second one-way valve is arranged in the inside of the second cavity.

[0013] Further, the contact is specifically arranged as a cylindrical member with a round end extending to the inside of the sliding sleeve.

[0014] Further, the spray hole is arranged as a plurality of holes and is equidistantly distributed on the outside of the ring pipe, and one end of the spray hole is directed to the sealing ring.

[0015] Further, the lubricating grease is specifically extreme pressure lubricating grease.

[0016] Technical effects and advantages of the present application: 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 due to 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 due to the insecure fixation, the accidents of hurting people are avoided, manual grouting at the wellhead is not needed, the safety hidden danger in the grouting process is reduced, the casing lowering speed is improved by more than 30%, the time is saved, the time efficiency is improved, the air is prevented from being pressed into the well during the grouting process, the wellbore instability and well control risk caused by the liquid column pressure in the well are reduced, the reverse mud spouting phenomenon caused by the air in the casing is avoided, the drilling platform hygiene is maintained, the frozen pipeline failure of the low-pressure grouting pipeline in winter is avoided, the casing lowering process is prevented from being delayed for grouting, the back pressure valve is prevented from being tipped over, and the downhole safety is improved. 2. The present application can pressurize the sealing ring, so that the sealing ring is expanded to be embedded into the inside of the recessed part, and the sealing ring can be more tightly abutted against the inner wall of the lower joint, so that the sealing effect is further improved. 3. The present application can lubricate the sealing ring, reduce the friction of the sealing ring, avoid the excessive wear of the sealing ring by the mud particles, protect the sealing ring, and ensure the sealing effect. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The structure schematic diagram of the casing liquid column pressure automatic balancing device is shown. Figure 2 A schematic diagram of the structure of the sliding sleeve according to an embodiment of the present invention is shown; Figure 3 A cross-sectional view of the sliding sleeve according to an embodiment of the present invention is shown; Figure 4 An embodiment of the present invention is shown. Figure 3 Enlarged structural diagram at point A in the middle; Figure 5 An embodiment of the present invention is shown. Figure 3 Enlarged structural diagram at point B; 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

[0018] 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.

[0019] 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; 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.

[0020] 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. After the grouting is completed, the ball is thrown into the upper joint 1, the ball falls on the ball seat 9, and then the casing pressure is raised, when the casing pressure is raised to 5MPa, the first shear pin 3 is sheared, the sliding sleeve 5 is lowered to cooperate with the sealing ring 4, the grouting hole 6 is closed, the pressure is continuously raised to 10MPa, the second shear pin 7 is sheared, the ball and the ball seat 9 are lowered and fall on the mesh plate 10, and the closure of the grouting hole 6 is completed; Through the sealing enhancement assembly, the sealing effect of the sealing ring 4 can be improved. When the present application is used, the labor intensity of workers can be reduced, a large amount of energy consumption of the open-pump grouting of the casing can be saved, accidents of splashing and dancing of the grouting pipeline caused by the insecure grouting pipeline are avoided, manual grouting at the wellhead is not needed, the safety hidden danger in the grouting process is reduced, the running speed of the casing 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 spouting phenomenon caused by the air in the casing is avoided, the drilling floor hygiene is maintained, the frozen pipeline failure of the low-pressure grouting pipeline in winter is avoided, the situation that the back pressure valve is tipped over due to the delayed grouting during the casing running process is avoided, and the safety of the well is beneficial.

[0021] As shown in Figures 2 to 5 The sealing enhancement assembly comprises a first cavity 12, a liquid injection channel and a pressurizing assembly. The first cavity 12 is arranged at the inner side of the sliding sleeve 5, the inner side of the sealing ring 4 is provided with a cavity, the first cavity 12 is communicated with the cavity, the liquid injection channel is arranged in the sliding sleeve 5, the liquid injection channel is communicated with the first cavity 12, the end of the liquid injection channel is provided with a valve 19, hydraulic oil is injected into the first cavity 12 and the cavity through the liquid injection channel, the sealing ring 4 is expanded with the continuous injection of the hydraulic oil, so that the sealing ring 4 can abut against the inner wall of the upper joint 1, then the injection is stopped, the liquid injection channel is closed through the valve 19, the pressurizing assembly is arranged on the sliding sleeve 5, and is used for injecting hydraulic oil into the inner side of the first cavity 12 to pressurize, the inner sides of the first cavity 12, the cavity and the liquid injection channel are filled with hydraulic oil.

[0022] When the sliding sleeve 5 is lowered to stop moving and the ball seat 9 leaves, the pressurizing assembly injects hydraulic oil into the inner side of the first cavity 12 to pressurize, if there is a recess or the like defect in the inner wall of the lower joint 8 at this time, the sealing ring 4 is expanded with the pressurizing, so as to be embedded into the inner side of the recess part, and then the sealing ring 4 can more closely abut against the inner wall of the lower joint 8, so that the sealing effect can be further improved.

[0023] As shown in Figures 3 to 5 The pressurizing assembly comprises a cylinder body 13, an oil inlet pipe 14, an oil inlet port, a first one-way valve 15, a first piston 16, a first spring 17 and a support 18. 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.

[0024] 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.

[0025] like Figures 3 to 5 As shown, the outer side of the sliding sleeve 5 is provided with a protective component to protect it; The protective components include: ring tube 20, nozzle, and lubrication assembly; 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.

[0026] 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.

[0027] 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; The extrusion cavity is arranged inside the sliding sleeve 5, the second piston 21 is arranged inside the extrusion cavity, the contact head 22 is fixedly connected to one side of the second piston 21 close to the inside of the sliding sleeve 5, one end of the contact head 22 extends to 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 head 22, the oil injection channel 26 is arranged on the sliding sleeve 5, the oil injection channel 26 is communicated with the extrusion cavity, the plunger is arranged at the end of the oil injection channel 26, the second cavity 24 is arranged inside the sliding sleeve 5, the second cavity 24 is communicated with the inside of the annular pipe 20 and the extrusion cavity, the second one-way valve 25 is arranged inside the second cavity 24, and the contact head 22 is specifically a columnar member with a round end extending to the inside of the sliding sleeve 5.

[0028] The contact head 22 is pressed to move along the extrusion cavity with the second piston 21, so that the air in the extrusion cavity is extruded through the oil injection channel 26, at the same time, the second spring 23 is compressed to deform by the second piston 21, then the straw connected with the lubricating grease outside is connected with the oil injection channel 26, the contact head 22 is loosened, the second spring 23 is reset, so that the second piston 21 and the contact head 22 are reset, the lubricating grease is sucked into the extrusion cavity, at this time, the second one-way valve 25 is closed, the lubricating grease is finally sucked into the extrusion cavity, the oil injection channel 26 is closed by the plunger, after the ball is put into, the ball enters into the sliding sleeve 5 and abuts against the contact head 22, so that the contact head 22 is pressed to move along the extrusion cavity with the second piston 21, so that the second spring 23 is compressed to deform, at the same time, the lubricating grease in the extrusion cavity is extruded outwards, at this time, the second one-way valve 25 is opened, the lubricating grease enters into the second cavity 24, then fills the second cavity 24 and enters into each annular pipe 20, finally fills the annular pipe 20 and is sprayed to the surface of the sealing ring 4 through the spray hole, so as to realize lubrication.

[0029] As shown in Figure 3 and Figure 4 , the spray hole is arranged in multiple and equidistantly distributed outside the annular pipe 20, one end of the spray hole faces the sealing ring 4, and the lubricating grease is specifically extreme pressure lubricating grease.

[0030] So that the lubricating grease sprayed from the spray hole can cover the surface of the sealing ring 4.

[0031] Working principle: the whole device is lowered into the well, during the lowering process, the mud in the well can enter into the lower joint 8, the sliding sleeve 5 and the upper joint 1 through the grouting hole 6, so that the internal and external pressure difference can be balanced, so that the device as a whole can be prevented from being extruded and damaged due to the liquid column pressure difference caused by the untimely grouting; After the grouting is completed, the ball is put into the upper joint 1, the ball falls onto the ball seat 9, then the casing pressure is raised, when the casing pressure is raised to 5MPa, the first shear pin 3 is sheared, the sliding sleeve 5 is lowered to cooperate with the sealing ring 4, the grouting hole 6 is closed, the pressure is continuously raised to 10MPa, the second shear pin 7 is sheared, the ball and the ball seat 9 are lowered and fall onto the mesh plate 10, the closure of the grouting hole 6 is completed; When the sliding sleeve 5 is lowered to stop moving, with the ball seat 9 leaving, if there is a recess defect at the contact position between the sealing ring 4 and the inner wall of the lower joint 8, at this time, the first spring 17 in the tensile deformation state moves with the first piston 16, and the hydraulic oil in the cylinder 13 is extruded outwards, at this time, the first one-way valve 15 in the oil inlet is closed, the first one-way valve 15 in the oil inlet pipe 14 is opened, the hydraulic oil is extruded into the first cavity 12, and then into the sealing ring 4, so that the sealing ring 4 expands, so that the surface of the sealing ring 4 can enter the inside of the recess of the inner wall of the lower joint 8, so that it can be more fitted with the inner wall of the lower joint 8, and the sealing performance is improved, when the sealing ring 4 is in contact with the recess, the sealing ring 4 cannot continue to expand, at this time, the first piston 16 cannot continue to move; After the ball is put in, the ball enters the sliding sleeve 5 and will be in contact with the contact 22, so that the contact 22 is extruded to make the second piston 21 move along the extrusion cavity, so that the second spring 23 is compressed to deform, and at the same time, the lubricating grease in the extrusion cavity is extruded outwards, at this time, the second one-way valve 25 is opened, the lubricating grease enters the second cavity 24, and then fills the second cavity 24 and enters each annular pipe 20, and finally fills the annular pipe 20 and is sprayed to the surface of the sealing ring 4 through the spray hole, so as to realize lubrication, so that the subsequent sealing ring 4 can slide along the inner wall of the upper joint 1 and the lower joint 8, and the friction of the sealing ring 4 can be reduced, the mud particles can be prevented from excessively abrading the sealing ring 4, so that the sealing ring 4 can be protected, and the sealing effect is ensured.

[0032] The above examples are only used to illustrate the technical solutions of the present application, but not limit it.

Claims

1. An automatic pressure balancing device for casing fluid column, characterized in that, include: Upper connector (1) is used to connect the tubing string; Outer jacket (2), disposed outside the upper connector (1); The first shear pin (3) is located inside the upper connector (1); A sealing ring (4) is disposed inside the upper connector (1); The sliding sleeve (5) is disposed inside the upper connector (1), the sealing ring (4) is equidistantly connected to the outside of the sliding sleeve (5), and the sliding sleeve (5) and the upper connector (1) are connected by the first shear pin (3). The lower connector (8) is connected to the upper connector (1); grouting holes (6) are equidistantly arranged around the outside of the lower connector (8); ball seat (9) is arranged inside the sliding sleeve (5); second shear pin (7) connects the ball seat (9) to the sliding sleeve (5); mesh plate (10) is arranged inside the lower connector (8); floating hoop (11) is arranged inside the lower connector (8); The sealing enhancement component can improve the sealing effect of the sealing ring (4).

2. The automatic pressure balancing device for the casing fluid column according to claim 1, characterized in that: The sealing enhancement component includes: The first cavity (12) is disposed on one side inside the sliding sleeve (5), and the sealing ring (4) has a cavity inside, and the first cavity (12) communicates with the cavity; The liquid injection channel is located inside the sliding sleeve (5), and the liquid injection channel is connected to the first cavity (12). A valve (19) is provided at the end of the liquid injection channel. A pressurizing assembly, disposed on the sliding sleeve (5), is used to inject hydraulic oil into the interior of the first cavity (12) for pressurization; The first cavity (12), the cavity, and the injection channel are filled with hydraulic oil.

3. The automatic pressure balancing device for the casing fluid column according to claim 2, characterized in that: The pressurization component includes: The cylinder body (13) is located inside the lower part of the sliding sleeve (5); An oil inlet pipe (14) connects the cylinder body (13) to the first cavity (12); The oil filler port is located on the lower inner side of the cylinder body (13); The first one-way valve (15) is respectively installed inside the oil filling port and the oil inlet pipe (14); The first piston (16) is disposed inside the cylinder (13); The first spring (17) is disposed inside the cylinder (13); A bracket (18) is provided, one end of which extends into the interior of the cylinder (13) and is connected to the first piston (16). The bracket (18) abuts against the ball seat (9).

4. The automatic pressure balancing device for the casing fluid column according to claim 3, characterized in that: The outer side of the sliding sleeve (5) is provided with a protective component to protect it; The protection component includes: The number of ring tubes (20) corresponds to the number of sealing rings (4). The ring tubes (20) are sleeved on the outside of the sliding sleeve (5) and are fitted to the sealing rings (4). The nozzle is located on the outside of the annular tube (20); A lubrication assembly for injecting grease into the annular tube (20).

5. The automatic pressure balancing device for the casing fluid column according to claim 4, characterized in that: The lubrication assembly includes: The extrusion chamber is located inside the sliding sleeve (5); The second piston (21) is disposed inside the extrusion chamber; A contact (22) is connected to the side of the second piston (21) near the inside of the sliding sleeve (5), and one end of the contact (22) extends into the inside of the sliding sleeve (5); The second spring (23) is connected to the side of the second piston (21) away from the contact (22); An oil injection channel (26) is provided on the sliding sleeve (5), and the oil injection channel (26) is connected to the extrusion chamber; A plunger is disposed at the end of the oil injection channel (26); The second cavity (24) is disposed inside the sliding sleeve (5), and the second cavity (24) is in communication with the inside of the annular tube (20) and the extrusion cavity; The second check valve (25) is located inside the second cavity (24).

6. The automatic pressure balancing device for the casing fluid column according to claim 5, characterized in that: The contact (22) is specifically configured as a columnar member with one end rounded, extending into the interior of the sliding sleeve (5).

7. The automatic pressure balancing device for the casing fluid column according to claim 6, characterized in that: The nozzles are configured as multiple and equidistantly distributed outside the annular tube (20), with one end of each nozzle facing the sealing ring (4).

8. The automatic pressure balancing device for the casing fluid column according to claim 7, characterized in that: The grease is specifically an extreme pressure grease.

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