Ball seat type expanding packer activated by throwing steel ball

Abstract

The invention relates to the technical field of oil production engineering, in particular to a ball seat type expanding packer activated by throwing a steel ball. The ball seat type expanding packer activated by throwing the steel ball comprises a central pipe, an upper connector is arranged above the central pipe, a lower connector is arranged below the central pipe, a through-flow hole is formed in the side of the central pipe, a rubber sleeve is arranged on the outer side of the through-flow hole, a ball seat is arranged in the central pipe, a centralizing ring with a built-in spring is arranged on the upper connector, and an upper steel body and a lower steel body are arranged on the rubber sleeve. Shoulders at two ends of the rubber sleeve are of a metal and nylon interwoven vulcanized rubber structure. According to the ball seat type expanding packer activated by throwing the steel balls, after the balls are thrown, the packer can be activated to be matched with an existing tool string to complete packing of all fracturing layer sections, fracturing pipe columns are prevented from being lifted and lowered for multiple times, the construction efficiency is improved, the cost is saved, and the centralizing effect is achieved through the built-in spring type centralizing body when the well diameter changes; the rubber sleeve with the reinforced shoulder can improve the success rate of setting and unsetting of the device.

Description

Technical Field

[0001] The invention relates to the technical field of oil production engineering, in particular to a ball seat type expansion packer activated by throwing a steel ball. Background Art

[0002] With the continuous development of oil fields, the number of casing damaged wells increases year by year, and the diameter of the casing of such wells becomes smaller after repair. In the prior art, conventional packers and their supporting tools are prone to problems such as being unable to be smoothly lowered or lifted out of such wells, or the packers are not tightly sealed, especially when the fracturing object is a reservoir with many small vertical layers and large differences in interlayer distances. The existing drag-type fracturing string cannot complete the isolation of all fracturing layers due to the fixed distance between the two packers. It can only choose to abandon the layer, pressurize multiple layers together, or lift and lower the fracturing string multiple times, which increases the workload, low construction efficiency, and increased operating costs. Therefore, in view of the above shortcomings, a ball seat type expandable packer activated by throwing a steel ball is proposed. Summary of the invention

[0003] 1. Technical issues to be resolved In view of the deficiencies in the prior art, the present invention provides a ball-seat-type expandable packer activated by throwing a steel ball, which solves the problems that the prior packer cannot be smoothly lowered and pulled out in a casing damaged well after the diameter becomes smaller, and that the fracturing transformation of a reservoir with a large interlayer distance difference cannot be completed at one time due to the fixed spacing of the fracturing string, resulting in abandoned layers, multi-layer combined fracturing or multiple fracturing string lifting and lowering operations, resulting in low construction efficiency and increased construction costs.

[0004] (II) Technical solution In order to solve the above problems, the present invention provides a ball-seat type expandable packer activated by throwing a steel ball, comprising: an upper joint, a lower joint and a center tube; the upper end of the center tube is connected to the upper joint, and the lower end of the center tube is connected to the lower joint; a flow hole is provided in the middle of the center tube, and a wear-resistant ball seat is provided inside the center tube, the position of the wear-resistant ball seat coincides with the position of the flow hole and is connected to the center tube through a shear pin; a rubber sleeve is provided outside the center tube, the position of the rubber sleeve corresponds to the flow hole, and the liquid in the center tube causes the rubber sleeve to act and seal through the flow hole; both ends of the rubber sleeve adopt a metal and nylon interwoven vulcanized rubber structure to provide shoulder protection for the rubber sleeve; annular straightening bodies are circumferentially provided outside the upper joint and the lower joint, and the straightening bodies adopt an internal spring design and can shrink and expand with the change of wellbore diameter.

[0005] Preferably, an upper steel body is provided above the rubber cylinder, and a lower steel body is provided below the rubber cylinder.

[0006] Preferably, the upper steel body is annular and is in contact with the upper joint, the center tube and the rubber cylinder.

[0007] Preferably, the lower steel body is annular and is in contact with the lower joint, the center tube and the rubber cylinder at the same time.

[0008] Preferably, a limiting ring is provided below the lower steel body, and the limiting ring is fixed to the lower joint by a fixing pin.

[0009] Preferably, a retaining ring is provided on the outer side of the lower joint below the limiting ring.

[0010] Preferably, an anti-rotation pin is provided between the upper joint and the central pipe.

[0011] Preferably, a first sealing ring is provided between the upper steel body and the upper joint; a second sealing ring is provided between the upper steel body and the center tube; a third sealing ring is provided on both sides of the flow hole and on both sides of the shear pin on the contact surface between the center tube and the ball seat; a fourth sealing ring is provided between the lower steel body and the lower joint; and a fifth sealing ring is provided between the center tube and the lower joint.

[0012] (III) Beneficial effects The ball seat type expandable packer activated by throwing a steel ball provided by the present invention has the same function as a normal oil pipe short-circuit when not activated, and does not have the function of a packer. When it is necessary to add a set of card distances for isolation and fracturing, the device can be activated by throwing a ball. After being activated by throwing a ball, the device becomes a packer, which can cooperate with other packers on the existing tool string to change the card distance of the fracturing layer section, complete the isolation of all fracturing layer sections, avoid the occurrence of abandoned layers and multi-layer compression, save the work of lifting and lowering the fracturing pipe string many times, and can improve construction efficiency and save construction costs; at the same time, by providing a built-in spring-type straightening body, the outer diameter of the device can change with the change of the wellbore diameter when the inner diameter of the wellbore changes, thereby ensuring the passability of the device in the wellbore; by adopting a metal and nylon interwoven vulcanized rubber structure at both ends of the rubber tube, the probability of the device being worn during the lowering and lifting process is reduced, and the success rate of the device sealing and unsealing is improved. The device can be sealed by throwing a ball and can be unsealed by reducing the pressure in the oil pipe, and the operation is simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A structural diagram of a ball seat type expandable packer activated by throwing a steel ball according to the present invention; Figure 2 The figure is a schematic diagram of the rubber cylinder structure of the ball seat type expandable packer activated by throwing a steel ball according to the present invention.

[0014] Among them, 1. upper joint; 2. straightening body; 3. first sealing ring; 4. anti-rotation pin; 5. second sealing ring; 6. center tube; 7. upper steel body; 8. shear pin; 9. end reinforcement rubber sleeve; 10. wear-resistant ball seat; 11. third sealing ring; 12. lower steel body; 13. fourth sealing ring; 14. lower joint; 15. fifth sealing ring; 16. limit ring; 17. fixing pin; 18. stop ring. Implementation

[0015] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0016] In the description of the present invention, it is necessary to understand that the orientations or positional relationships indicated by “upper”, “lower”, “inside”, “outside”, “top”, “bottom”, etc. are all based on the orientations or positional relationships shown in the accompanying drawings. The purpose is only to facilitate the description of the present invention and simplify the description. It does not indicate or imply that the referred parts must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0017] like Figure 1-2 As shown, the present invention provides a ball-seat type expandable packer activated by throwing a steel ball, which specifically comprises: an upper joint 1, a central pipe 6 and a lower joint 14; the upper joint 1 is connected to the upper end of the central pipe 6, and the lower joint 14 is connected to the lower end of the central pipe 6. After the device is connected to the tool string, oil flows from the upper joint 1 through the central pipe 6 and flows out from the lower joint 14. A fifth sealing ring 15 is provided between the central pipe 6 and the lower joint 14 to maintain the sealing of the device.

[0018] The central tube 6 has a through-flow hole on its side wall. When the through-flow hole is opened, the liquid in the central tube 6 flows out through the through-flow hole. A rubber sleeve 9 is provided outside the central tube 6. The position of the rubber sleeve corresponds to the position of the through-flow hole. The liquid in the central tube 6 flows into the rubber sleeve 9 through the through-flow hole. When the liquid pressure in the central tube 6 increases, the high-pressure liquid fills the rubber sleeve 9, causing the rubber sleeve 9 to expand and seal.

[0019] Among them, an upper steel body 7 is provided above the rubber cylinder 9, and a lower steel body 12 is provided below the rubber cylinder; the upper steel body 7 is annularly sleeved above the central tube 6, and is in contact with the central tube 6, the upper joint 1 and the upper end of the rubber cylinder 9. When high liquid is injected into the rubber cylinder 9 to expand, the upper steel body 7 fixes the position of the rubber cylinder 9 to prevent the rubber cylinder 9 from moving upward during expansion, causing the rubber cylinder 9 to separate from the flow hole, thereby improving the working efficiency of the device. During the working process, the upper end of the upper steel body 7 abuts against the upper joint 1, and cooperates with the upper joint 1 to limit the upper end of the rubber cylinder 9.

[0020] Among them, in the present invention, a first sealing ring 3 is provided between the top of the upper steel body 7 and the upper joint 1 to prevent liquid from flowing out from the gap between the upper steel body 7 and the upper joint 1 to damage the straightening body 2; a second sealing ring 5 is provided between the upper steel body 7 and the center pipe 6 to improve the sealing performance of the device.

[0021] Similarly, the lower steel body 12 is annularly sleeved under the central tube 6, and is in contact with the central tube 6, the lower joint 14 and the lower end of the rubber cylinder 9. During the expansion of the rubber cylinder 9, the lower steel body 12 fixes the position of the rubber cylinder 9 to prevent the rubber cylinder 9 from separating from the flow hole, thereby improving the working efficiency of the device; a limiting ring 16 is provided at the bottom end of the lower steel body 12, and the limiting ring 16 abuts against the bottom end of the lower steel body 12. The limiting ring 16 is fixed on the lower joint 14 and cooperates with the lower joint 14 to limit the lower end of the rubber cylinder 9 and the lower steel body 12.

[0022] A fourth sealing ring 13 is provided between the lower steel body 12 and the lower joint 14 to improve the sealing performance of the device.

[0023] like Figure 2 As shown, both ends of the rubber cylinder 9 adopt a metal and nylon interwoven vulcanized rubber structure to provide shoulder protection for the rubber cylinder 9 to prevent the shoulder of the rubber cylinder 9 from rubbing against the upper steel body 7 and the lower steel body 12 during operation, causing the rubber cylinder 9 to deform and be damaged. The shoulder of the rubber cylinder 9 adopting the metal and nylon interwoven vulcanized rubber structure has good elasticity, which makes the device more smooth when unsealing and recovering, making the sealing and unsealing of the sealer more stable.

[0024] In the present invention, the upper joint 1 and the lower joint 14 are respectively sleeved with an annular straightening body 2. The straightening body 2 is designed with an internal spring to evenly divide the straightening body 2 into a plurality of straightening blocks, and a straightening spring is respectively provided under each straightening block. Under the action of the straightening spring, the straightening block will extend outward, and the outer diameter is slightly larger than the device. When the well wall below shrinks and the straightening block contacts the well wall, the straightening spring under the straightening block is compressed and the elastic force is applied to the upper joint 1 to push the device away from the well wall to a suitable position in the well, so that the device can smoothly pass through the wellbore with a changed inner diameter, especially when the well diameter of the casing repair well has a small well diameter of the casing compensation section with a normal inner diameter change value, the straightening body 2 will play a straightening role on both ends of the device, and can effectively prevent the rubber tube 9 or the upper and lower steel bodies from being scratched by the friction of the well wall and the perforation blast hole when working in the well. The straightening body 2 can improve the functional stability and safety of the device and ensure the normal operation of the device.

[0025] A ball seat 10 is provided inside the central tube 6. The ball seat 10 is tubular and has a small slope wedge-shaped top. In the early stage of downhole fracturing, the liquid in the central tube 6 can pass through the ball seat 10 normally without affecting other devices such as packers on the tool string. The position of the ball seat 10 corresponds to the position of the flow hole on the central tube 6. The ball seat 10 is connected to the central tube 6 through the shear pin 8. When the ball throwing operation is not performed, the shear pin 8 fixes the position of the ball seat 10, blocks the flow hole, and the rubber cylinder 9 does not move.

[0026] Among them, third sealing rings 11 are respectively provided between the center tube 6 and the ball seat 10, and at both ends of the flow hole and the shear pin 8 to ensure the sealing of the device and prevent liquid from entering the rubber cylinder before the steel ball is lowered, causing the rubber cylinder to be sealed prematurely and affecting the normal operation of the device.

[0027] During operation, a steel ball is thrown into the oil pipe, and the steel ball moves downward under the pressure in the pipe and its own gravity. When the steel ball contacts the ball seat 10, the channel in the middle of the ball seat 10 is sealed, and the oil pipe begins to be pressurized. When the pressure on the ball seat 10 is greater than the maximum shear force that the shear pin 8 can withstand, the shear pin 8 is disconnected, and the ball seat 10 moves downward. At this time, the flow hole opens, and the liquid in the pipe enters the rubber cylinder 10 to drive the rubber cylinder 10 to seal. When it needs to be unsealed, it is only necessary to reduce the pressure in the pipe. The operation is simple and the controllability is strong. The small slope wedge design at the top of the inner diameter of the ball seat is conducive to the combination of the steel ball and the ball seat after it is lowered, and the sealing between the steel ball and the ball seat 10 is improved, which is conducive to the normal operation of the device to hold the pressure and ensure the realization of the tool sealing function.

[0028] In order to ensure that the ball seat 10 is not corroded by the sand-carrying fluid in the pipe during the early stage of fracturing, the ball seat 10 is generally made of alloy material and is treated with a wear-resistant process to reduce the failure rate of the device and improve the practicality of the device.

[0029] like Figure 1 As shown, the lower joint 14 is provided with a retaining ring 18, which is threadedly connected to the lower joint 14. During the process of lowering the device into the well, the retaining ring 18 is used to protect the components on the upper device body and prevent friction or collision between the protrusions on the well wall and the rubber cylinder 9 or the upper and lower steel bodies.

[0030] Among them, the retaining ring 18 is provided with a fixing pin 17 to further connect and fix the retaining ring 18 to the lower joint 14, so as to prevent the retaining ring 18 from falling off due to loosening of the thread during underground work, thereby improving the stability of the device.

[0031] The ball seat type expandable packer activated by throwing a steel ball provided by the present invention has the same function as a conventional oil pipe short-circuit before the device is activated, and can be transformed into a packer after activation. The packers on the tool string cooperate to realize the isolation of all fracturing layers, avoiding the occurrence of abandoned layers and multi-layer compression. The device can be activated at any time by throwing a steel ball, and has strong controllability, so that a new set of card distances can be added to the fracturing string, thereby completing the fracturing transformation of reservoirs with large interlayer differences, with small workload and high efficiency. Secondly, when lowering into the wellbore, the device can be straightened according to the change of the wellbore diameter, and the composite materials innovatively designed at both ends of the rubber tube can provide protection for the device rubber tube in the well, ensuring good sealing effect and high sealing success rate. The specific operation process of the device is as follows: First, the device is installed on the upper packer of the matching small-diameter double-seal single-card tool string, and lowered into the well together for the initial fracturing work. During the initial fracturing work, the device does not participate in the fracturing work, and the liquid in the central tube can flow normally, which has no impact on the initial fracturing work.

[0032] Then, when the distance of the fracturing layer needs to be changed, a steel ball is put into the central pipe. At this time, the steel ball moves downward under the pressure in the pipe and its own gravity. When the steel ball reaches the ball seat, the steel ball and the top of the ball seat are tightly combined to block the channel in the middle of the ball seat, preventing the flow of liquid in the pipe and causing the pressure in the pipe to be blocked. When the pressure is greater than the maximum shear force that the shear pin can withstand, the shear pin breaks, the steel ball pushes the ball seat downward, the flow hole opens, and the liquid enters the rubber cylinder to expand and seal it. At this time, the device cooperates with other packers on the tool string to change the distance of the fracturing layer.

[0033] Finally, after the fracturing of the device is completed, the liquid in the pipe is depressurized. At this time, since the pressure in the pipe is not enough to support the rubber cartridge to seal, the rubber cartridge is unsealed after the device is lifted up, and the device is lifted up again to be taken out of the well.

[0034] During operation, when the device moves on the inner wall of the casing with irregular diameter, the straightening ring always plays a straightening role to ensure the passability of the pipe string in the wellbore.

[0035] The ball seat type expandable packer activated by throwing a steel ball provided by the present invention can cooperate with the packer on the existing tool string to change the card distance of the fracturing layer section, complete the isolation of all fracturing layer sections, avoid the occurrence of abandoned layers and multi-layer compression, and do not need to carry out the fracturing pipe string lifting and lowering work multiple times, thereby improving construction efficiency and saving construction costs.

[0036] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A ball seat type expandable packer activated by throwing a steel ball, characterized in that: include: An upper joint (1), a lower joint (14) and a center tube (6); the upper end of the center tube (6) is connected to the upper joint (1), and the lower end of the center tube (6) is connected to the lower joint (14); a flow hole is provided in the middle of the center tube (6), and a wear-resistant ball seat (10) is provided inside the center tube (6); the position of the wear-resistant ball seat (10) coincides with the position of the flow hole and is connected to the center tube (6) through a shear pin (8); a rubber sleeve (9) is provided outside the center tube (6), and the position of the rubber sleeve (9) corresponds to the flow hole, and the liquid in the center tube (6) passes through the flow hole to cause the rubber sleeve (9) to act as a seal; the two ends of the rubber sleeve (9) adopt a metal and nylon interwoven vulcanized rubber structure to provide shoulder protection for the rubber sleeve; an annular centralizing body (2) is circumferentially provided outside the upper joint (1) and the lower joint (14), and the centralizing body (2) adopts a built-in spring design and can shrink and expand with the change of the wellbore diameter.

2. The ball seat type expandable packer activated by throwing a steel ball according to claim 1, characterized in that: An upper steel body (7) is provided above the rubber cylinder (9), and a lower steel body (12) is provided below the rubber cylinder (9).

3. The ball seat type expandable packer activated by throwing a steel ball according to claim 2, characterized in that: The upper steel body (7) is annular and is in contact with the upper joint (1), the central tube (6) and the rubber cylinder (9).

4. The ball seat type expandable packer activated by throwing a steel ball according to claim 2, characterized in that: The lower steel body (12) is annular and is in contact with the lower joint (14), the central tube (6) and the rubber cylinder (9).

5. The ball seat type expandable packer activated by throwing a steel ball according to claim 1, characterized in that: A limiting ring (16) is provided below the lower steel body (12), and the limiting ring (16) is fixed to the lower joint (14) via a fixing pin (17).

6. The ball seat type expandable packer activated by throwing a steel ball according to claim 1, characterized in that: A retaining ring (18) is provided on the outer side of the lower joint (14) below the limiting ring (16).

7. The ball seat type expandable packer activated by throwing a steel ball according to claim 1, characterized in that: An anti-rotation pin (4) is provided between the upper joint (1) and the central tube (6).

8. The ball seat type expandable packer activated by throwing a steel ball according to claim 1, characterized in that: A first sealing ring (3) is provided between the upper steel body (7) and the upper joint (1); a second sealing ring (5) is provided between the upper steel body (7) and the center tube; a third sealing ring (11) is provided on both sides of the flow hole and on both sides of the shear pin (8) on the contact surface between the center tube (6) and the ball seat (10); a fourth sealing ring (13) is provided between the lower steel body (12) and the lower joint (14); and a fifth sealing ring (15) is provided between the center tube (6) and the lower joint (14).

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