Sliding sleeve of ball throwing switch

Abstract

The utility model relates to a ball throwing switch sliding sleeve which comprises an outer cylinder, an inner cylinder, an inner piston, an outer piston and a lower connector. An oil pipe buckle is arranged at the upper end of the outer cylinder, is in threaded connection with the blocking plug, is detachably connected with the outer piston and is in threaded connection with the lower connector. According to the utility model, the sliding sleeve can be closed by throwing a ball after the construction is finished; selective layer sealing is achieved, and the oil and gas well transformation effect is improved; the construction period is greatly shortened, and the construction cost is reduced; and coiled tubing tripping-in can be flexibly realized for small-specification oil tubes.

Description

Technical Field

[0001] The utility model relates to the technical field of downhole tools for oil development, in particular to a ball-dropping switch sliding sleeve. Background Art

[0002] In the field of old well reconstruction, the existing technology generally adopts the staged fracturing process. Specifically, its principle is:

[0003] After the ball is dropped to seal the packer, the ball is dropped again to pressurize and open the sliding sleeve for fracturing test. If there is no production during the test, the sliding sleeve needs to be closed.

[0004] The defect of the prior art is that the sliding sleeve designed according to the prior art cannot be closed after it is opened.

[0005] In addition, there is also an existing technology that uses a coiled tubing tool to open and close the sliding sleeve. This technology can solve the problems of the above-mentioned existing technologies, but it also brings other drawbacks:

[0006] 1. The construction period is long and the cost is high;

[0007] 2. It is difficult to run coiled tubing into small-sized tubing. Utility Model Content

[0008] In response to the above problems, the utility model provides a ball-drop switch sliding sleeve, the purpose of which is to enable the sliding sleeve to be closed by dropping a ball after the construction is completed; to achieve selective sealing and improve the oil and gas well transformation effect; to significantly shorten the construction period and reduce the construction cost; and to flexibly realize the continuous tubing running for small-sized oil pipes.

[0009] In order to solve the above problems, the technical solution provided by the present invention is as follows:

[0010] A ball-dropping switch sliding sleeve comprises an outer cylinder, an inner cylinder, an inner piston, an outer piston, and a lower joint, wherein:

[0011] An oil pipe buckle is provided at the upper end of the outer cylinder; the interior of the upper end of the outer cylinder is threadedly connected to the stopper through an internal thread, the middle part is detachably connected to the outer piston through a shear pin, and the lower end is threadedly connected to the lower joint through a thread.

[0012] Preferably, the outer cylinder is provided with a groove for placing the shear ring at the inner hole below the stopper;

[0013] The inner cylinder is provided with 8 evenly distributed waist-shaped grooves in the middle part; and 8 threaded holes are provided below the waist-shaped grooves.

[0014] Preferably, the outer portion of the inner cylinder is sleeved with an outer piston; the inner portion of the inner cylinder is sleeved on the inner piston; the middle portion of the inner cylinder is provided with 8 evenly distributed waist-shaped grooves, a rupture disk is provided at the largest outer circle of the lower portion of the inner cylinder; and a 45° boss is provided at the inner hole at the lower end of the inner cylinder.

[0015] Preferably, the rupture disk is threadably connected to the inner cylinder via a thread; an O-ring is installed on the rupture disk.

[0016] Preferably, a groove for placing a shear ring is provided on the outer circle of the upper end of the inner piston; a 20° conical surface is provided inside the upper end of the inner piston; and the soluble ball is placed on the conical surface.

[0017] Preferably, the shear ring is cut along the axial direction to form a slit with a width of 2 mm.

[0018] Preferably, a groove for placing a locking block therein is provided at the upper end of the outer piston; and a groove for placing the shear pin therein is provided at the middle of the outer circle of the outer piston.

[0019] Preferably, the upper end of the locking block is provided with a 30° conical surface, and a 2mm wide slit is cut along the axial direction.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] 1. The ball-drop switch sliding sleeve provided by the utility model can be opened by holding pressure to perform fracturing operations, thereby enabling the sliding sleeve to be closed by dropping a ball after the operation is completed;

[0022] 2. Since the utility model can close the sliding sleeve by throwing the ball after the construction is completed, it can achieve selective sealing and improve the oil and gas well transformation effect;

[0023] 3. Since the utility model does not require additional coiled tubing tools to open and close the sleeve, the construction period is greatly shortened and the construction cost is reduced;

[0024] 4. Since the utility model does not require an additional coiled tubing tool to open and close the sliding sleeve, the coiled tubing can be flexibly run even for small-sized tubing. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a structural diagram of a ball-dropping switch sliding sleeve according to a specific embodiment of the present utility model;

[0026] Figure 2 This is a schematic diagram of the switch sleeve opening structure of a specific embodiment of the utility model;

[0027] Figure 3 This is a schematic diagram of the switch sleeve closing structure of a specific embodiment of the utility model.

[0028] Among them: 1. Outer cylinder, 2. Stop plug, 3. Shear ring, 4. Inner cylinder, 5. Inner piston, 6. Locking block, 7. Outer piston, 8. Shear pin, 9. Rupture disk, 10. Set screw, 11. Lower connector. DETAILED DESCRIPTION

[0029] The present invention is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading the present invention, modifications of various equivalent forms of the present invention made by those skilled in the art all fall within the scope defined by the claims attached to this application.

[0030] like Figure 1 As shown, a ball-dropping switch sliding sleeve includes an outer tube 1, an inner tube 4, an inner piston 5, an outer piston 7, and a lower joint 11, wherein:

[0031] An oil pipe buckle is provided at the upper end of the outer cylinder 1; the interior of the upper end of the outer cylinder 1 is threadedly connected to the stopper 2 through an internal thread, the middle part is detachably connected to the outer piston 7 through a shear pin 8, and the lower end is threadedly connected to the lower joint 11 through a thread.

[0032] In this specific embodiment, a set screw 10 is further provided at the connection between the outer cylinder 1 and the lower joint 11 to prevent loosening.

[0033] In this specific embodiment, the outer cylinder 1 is provided with a groove for placing the shear ring 3 at the inner hole below the stopper 2 .

[0034] It should be noted that the principle of placing the shear ring 3 in the groove is that when the outer piston 7 is opened, the locking block 6 is opened and locked in the groove, thereby axially fixing the inner piston 5 .

[0035] In this specific embodiment, the inner cylinder 4 is provided with 8 evenly distributed waist-shaped grooves in the middle portion; and 8 threaded holes are provided below the waist-shaped grooves.

[0036] It should be noted that the inner tube 4 is provided with 8 evenly distributed waist-shaped grooves in the middle portion, which mainly serve as fracturing channels.

[0037] It should be further explained that there are 8 threaded holes below the waist-shaped groove, which are used to install shear pins 8 to prevent the sliding sleeve from opening prematurely.

[0038] In this specific embodiment, an outer piston 7 is sleeved on the outside of the inner cylinder 4; the inner cylinder 4 is sleeved on the inner piston 5; the middle part of the inner cylinder 4 is provided with 8 evenly distributed waist-shaped grooves, and a rupture disk 9 is provided at the largest outer circle of the lower part of the inner cylinder 4; there is a 45° boss at the inner hole of the lower end of the inner cylinder 4.

[0039] It should be noted that the outer piston 7 and the inner piston 5 that are sleeved on the inner tube 4 have the following functions: before the ball-dropping switch tool of the present invention is put into the well, the pressure inside and outside the sleeve is sealed by the outer piston 7; the inner part of the inner tube 4 is sleeved on the inner piston 5, and the middle part is provided with 8 evenly distributed waist-shaped grooves, which are mainly used to form a fracturing channel. A rupture disk 9 is provided at the largest outer circle of the lower part, and a 45° boss is provided at the inner hole of the lower end, which serves as an axial positioning step after the inner piston 5 is opened to prevent the inner piston 5 from falling into the well.

[0040] In this specific embodiment, the rupture disk 9 is threadedly connected to the inner cylinder 4 via a thread; an O-ring is installed on the rupture disk 9.

[0041] It should be noted that the rupture disk 9 used in this embodiment has an accuracy error of up to 2%, and can be set to a precise rupture force value. When the tubing pressure and the string hydrostatic pressure reach the rupture force value of the rupture disk 9, the disk ruptures.

[0042] In this specific embodiment, a groove for placing the shear ring 3 is provided on the outer circle of the upper end of the inner piston 5; a 20° conical surface is provided inside the upper end of the inner piston 5; and the soluble ball is placed on this conical surface.

[0043] It should be noted that the function of this conical surface is that the soluble ball can be placed there, and the ball is sealed with the conical surface after the soluble ball is thrown in. When the shear force of the shear ring 3 is reached, the inner piston 5 opens.

[0044] In this specific embodiment, the shear ring 3 is cut along the axial direction to form a slit with a width of 2 mm.

[0045] It should be noted that the purpose of such slits is to provide the shear ring 3 with a certain elasticity in the axial direction so that it can be fitted into the groove with interference fit, while maintaining a stable shear force value.

[0046] In this specific embodiment, a groove for placing the locking block 6 is provided at the upper end of the outer piston 7; and a groove for placing the shear pin 8 is provided in the middle of the outer circle of the outer piston 7.

[0047] It should be noted that the working principle of the above-mentioned groove and locking block 6 is that the locking block 6 is placed in the groove, and there is a groove in the middle of the outer circle, and the shear pin 8 is placed in the groove, so that the pressure inside and outside the sliding sleeve can be sealed before fracturing, and after fracturing, it can be locked in the outer tube 1 through the locking block 6.

[0048] In this specific embodiment, a 30° conical surface is provided on the upper end of the locking block 6, and a 2 mm wide slit is cut along the axial direction.

[0049] It should be further explained that the working principle of the above-mentioned slit and tapered surface is that the 30° tapered surface facilitates the installation of the outer piston 7, while the 2 mm wide slit in the axial direction has a certain elasticity in the axial direction, and can bounce up and lock the outer cylinder 1 and the outer piston 7 when it reaches the groove of the outer cylinder 1.

[0050] A method for using a ball-throwing switch sliding sleeve comprises the following steps:

[0051] S100. The tubing is connected to the first packer, the ball-drop switch sleeve, the second packer, and the pressure plug and lowered into the well. When the tubing reaches the preset layer, the ball is dropped to slowly pressure-seal the first and second packers until the setting process is complete. The first and second packers are then tested for sealing.

[0052] It should be noted that the purpose of testing the sealing of the first packer and the second packer is to detect the sealing effects of the first packer and the second packer.

[0053] It should be noted that the pressure seal should be applied slowly, not quickly or too violently.

[0054] S200. Calculate and obtain the hydrostatic pressure of the sliding sleeve and the rupture opening force of the rupture disk 9.

[0055] S300: Execute a pressure operation. When the tubing pressure and the tubing string hydrostatic pressure reach the rupture opening force value of the rupture disk 9, the rupture disk 9 is ruptured.

[0056] It should be noted that the suppression operation should be slow, not fast or too strong.

[0057] like Figure 2 As shown, S400. The hydraulic pressure enters the right end of the outer piston 7 through the channel of the rupture disk 9. When the pressure is greater than the shear force of the shear pin 8, the outer piston 7 is pushed to the left until the locking block 6 moves to the groove of the outer cylinder 1 and pops out and locks. The inner and outer structures of the sliding sleeve form a channel and the fracturing construction begins.

[0058] S500. After the fracturing operation is completed, a soluble ball is added.

[0059] It should be noted that the basis of S500 is that when the fracturing construction is completed, S500 and subsequent steps need to be executed when the sliding sleeve needs to be closed due to low production or severe water discharge.

[0060] S600. The soluble ball falls onto the upper conical surface of the inner piston 5 to form a seal.

[0061] S700: Perform a pressing operation. When the pressure exceeds the shear force of the shear ring 3, the shear ring 3 is cut off.

[0062] It should be noted that the suppression operation should be slow, not fast or too strong.

[0063] like Figure 3 As shown, S800. The soluble ball moves the inner piston 5 to the right until it stops at the 45° boss at the lower end of the inner tube 4; the inner piston 5 closes the 8 waist-shaped grooves of the inner tube 4, and the inner and outer channels of the sliding sleeve are completely closed; at this point, the sliding sleeve is closed.

[0064] It should be noted that the technical solution of the present invention is not only applicable to the method of use described in this specific embodiment, but is also applicable to multi-layer staged fracturing; specifically:

[0065] By adopting the complete technical solution of the present invention, different opening force values ​​of the rupture disk 9 can be set to achieve step-by-step fracturing from bottom to top; in this way, when water is found in a certain layer, soluble balls of appropriate size can be selected for selective closure, thereby ultimately improving oil and gas development efficiency and reducing construction costs.

[0066] In the foregoing detailed description, various features are grouped together in a single embodiment to simplify the disclosure. This method of disclosure should not be interpreted as reflecting an intention that embodiments of the claimed subject matter require more features than are expressly recited in each claim. On the contrary, as reflected in the appended claims, the invention comprises less than all features of any individual disclosed embodiment. The appended claims are hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate preferred embodiment of the invention.

[0067] The above description of the disclosed embodiments is intended to enable any person skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments without departing from the spirit and scope of the present disclosure. Therefore, the present disclosure is not limited to the embodiments presented herein but is intended to be consistent with the broadest scope of the principles and novel features disclosed herein.

[0068] The foregoing description includes examples of one or more embodiments. Of course, it is not possible to describe all possible combinations of components or methods for the purposes of describing the above embodiments, but one of ordinary skill in the art will recognize that the various embodiments may be further combined and arranged. Therefore, the embodiments described herein are intended to encompass all such changes, modifications and variations that fall within the scope of the appended claims. Furthermore, to the extent the term "comprising" is used in the specification or claims, the term is intended to be encompassed in a manner similar to the term "including," as explained in terms of "including," used as a transitional word in the claims. Furthermore, any use of the term "or" in the specification of the claims is intended to mean a "non-exclusive or."

[0069] The specific implementation methods described above further illustrate the purpose, technical solutions and beneficial effects of the utility model in detail. It should be understood that the above description is only a specific implementation method of the utility model and is not intended to limit the scope of protection of the utility model. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the utility model should be included in the scope of protection of the utility model.

Claims

1. A ball-casting switch sleeve, characterized in that: It includes an outer tube, an inner tube, an inner piston, an outer piston, and a lower joint, wherein: An oil pipe buckle is provided at the upper end of the outer cylinder; the interior of the upper end of the outer cylinder is threadedly connected to the stopper through an internal thread, the middle part is detachably connected to the outer piston through a shear pin, and the lower end is threadedly connected to the lower joint through a thread.

2. The ball-pitch switch sleeve according to claim 1, characterized in that: The outer cylinder is provided with a groove for placing the shear ring at the inner hole below the stopper; The inner cylinder is provided with 8 evenly distributed waist-shaped grooves in the middle part; and 8 threaded holes are provided below the waist-shaped grooves.

3. The ball-pitch switch sliding sleeve according to claim 2, characterized in that: The outer part of the inner cylinder is sleeved with the outer piston; the inner part of the inner cylinder is sleeved on the inner piston; the middle part of the inner cylinder is provided with 8 evenly distributed waist-shaped grooves, and a rupture disk is provided at the maximum outer circle of the lower part of the inner cylinder; and a 45° boss is provided at the inner hole at the lower end of the inner cylinder.

4. The ball pitching switch sliding sleeve according to claim 3, characterized in that: The rupture disk is threadably connected to the inner cylinder; an O-ring is installed on the rupture disk.

5. The ball pitching switch sliding sleeve according to claim 4, characterized in that: A groove for placing a shear ring therein is provided at the outer circle of the upper end of the inner piston; a 20° conical surface is provided inside the upper end of the inner piston; and a soluble ball is placed on the conical surface.

6. The ball-pitch switch sliding sleeve according to claim 5, characterized in that: The shear ring is cut along the axial direction to form a slit with a width of 2 mm.

7. The ball pitching switch sliding sleeve according to claim 6, characterized in that: A groove for placing the locking block is provided at the upper end of the outer piston; a groove for placing the shear pin is provided at the middle of the outer circle of the outer piston.

8. The ball-pitch switch sliding sleeve according to claim 7, characterized in that: The upper end of the locking block is provided with a 30° conical surface, and a slit with a width of 2 mm is cut along the axial direction.

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