A hanger fracturing back-off tool

Abstract

This invention relates to a suspension fracturing reconnection tool, which mainly consists of a suspension unit and a sealing plug unit for fracturing operations. The suspension unit comprises a lifting sub, a pressure cap, a suspension cylinder, sealing rubber, an anti-falling object mechanism, an expansion cone base, an expansion cone, a connecting rod, a fracturing reconnection device, a casing sub, a rubber plug shearing mechanism, and a cementing rubber plug. The fracturing sealing plug unit is an integrated structure, mainly composed of a lifting sub, an upper sealing device surface, a snap-fit ​​structure, and a lower sealing surface. After the suspension unit is mounted inside the upper casing, the fracturing sealing plug is lowered, and the fracturing reconnection device is reconnected, allowing fracturing operations to commence. This invention combines a suspension unit with a fracturing sealing plug, offering advantages such as large diameter, excellent sealing performance, high load-bearing capacity, and the ability to meet various fracturing operation requirements. It can be widely applied to fracturing operations in various oil and water wells.

Description

Technical Field

[0001] This invention relates to the field of drilling and completion technology in the oil and gas industry, providing a suspended fracturing reconnection tool for subsequent fracturing operations. Background Technology

[0002] An expandable casing hanger is a tailpipe cementing tool that utilizes the expansion of a steel pipe for mounting and combines multiple seals. Through mechanical or hydraulic force, the steel pipe expands radially, and high-strength rubber materials are used for suspension and sealing. This provides a high-strength tailpipe head seal and a larger completion inner diameter, preventing water channeling. It can suspend casing of larger dimensions than conventional hangers, accommodating the insertion of large-diameter tools. Given these technological advantages, expandable casing hanger technology is now widely used in oilfield new well development, sidetracking of old wells, and well workover. It has become an effective means of optimizing wellbore structure in new wells, increasing the inner diameter of completion casing, suspending large-diameter casing for completion in sidetracked wells, and managing casing damage in long-term shutdown wells, providing effective technical support for improving oilfield efficiency.

[0003] However, the unique design principle of the expandable sleeve also limits its application and restricts its development. Because the expandable sleeve requires radial expansion of the suspension cylinder to achieve a sealing effect, the manufacturing material of the suspension cylinder is limited to a low-strength, high-ductility steel pipe. The high ductility of the material ensures that the expansion cylinder retains its original compressive and tensile mechanical properties, while the low strength keeps the construction pressure within a range easily implemented in the field. The material strength still meets the performance indicators of commonly used API casing in oilfields and satisfies the conventional development needs of most oil and water wells. Since the fracturing pressure in the later stages of development wells in low-permeability reservoirs often exceeds 70 MPa, the compressive strength of expandable sleeves developed by domestic companies is generally too low to handle such operations, limiting the application of expandable sleeve well completion technology in low-permeability reservoirs. To address this, this invention designs a suspension sleeve fracturing reconnection tool. Through improved structural design, the suspension sleeve, after being mounted, can meet the fracturing requirements of most oil and water wells. Summary of the Invention

[0004] The purpose of this invention is to address the issue that existing expansion hangers cannot meet the needs of fracturing in the later stages of low-permeability reservoirs. The invention designs a hanger fracturing reconnection tool that retains the advantages of existing expansion hangers while meeting the requirements of oil and water well fracturing operations. This hanger can be mounted using hydraulic, mechanical, or a combination of both methods and has advantages such as large diameter, strong sealing performance, and the ability to perform fracturing operations.

[0005] This invention is implemented as follows:

[0006] A suspension fracturing reconnection tool, comprising:

[0007] The components connected sequentially from top to bottom are: the first lifting section, the anti-falling object mechanism, the base, the connecting rod, the rubber plug shearing mechanism, and the cementing rubber plug.

[0008] The components connected sequentially from top to bottom outside the first lifting section are: pressure cap, suspension cylinder, fracturing reconnection device, coupling, and sleeve section.

[0009] The suspension cylinder has a variable diameter section machined in the middle, and the expansion cone is placed between the upper variable diameter section and the base.

[0010] Furthermore, the outer surface of the suspension cylinder is fixed with sealing rubber by vulcanization or mechanical means.

[0011] Furthermore, the pressure cap is fixed to the outer surface of the first lifting section by a pin and is sealed to the upper end of the suspension cylinder.

[0012] Furthermore, the rubber plug shearing mechanism is fixed to the cementing rubber plug by a pin.

[0013] Furthermore, an O-ring is installed between the rubber plug shearing mechanism and the cementing rubber plug.

[0014] Furthermore, the fracturing sealing plug is machined with upper and lower double sealing surfaces and fracturing reconnection threads, which are used to carry out fracturing operations in conjunction with the hanger tube and fracturing reconnection device after well completion.

[0015] Furthermore, the suspension cylinder is made of low-strength, high-plasticity steel pipe material, which can undergo radial cold expansion plastic deformation under hydraulic pressure or mechanical force.

[0016] Furthermore, the expansion cone is made of high-hardness steel such as tungsten steel, which can cause the suspension cylinder to undergo radial plastic deformation under the action of hydraulic pressure or mechanical force.

[0017] Furthermore, a V-shaped rubber cylinder is installed on the outer surface of the anti-falling object mechanism, and the rubber cylinder forms an interference fit with the inner wall of the suspension cylinder.

[0018] Furthermore, the fracturing reconnection device is made of high-strength steel, and the inner wall is machined with an upper sealing surface, a reconnection female thread, and a lower sealing surface. The reconnection female thread is a large-pitch, low-torque, left-hand flat thread.

[0019] The advantages of this invention are:

[0020] (1) The suspension cylinder body of the suspension device is made of low-strength steel. However, in the fracturing operation, the fracturing sealing plug is connected to the fracturing reconnection device at the bottom of the suspension cylinder, which can allow the high-pressure fluid to avoid the weak suspension cylinder body, thus reducing the processing cost and manufacturing difficulty of the expansion suspension device.

[0021] (2) The hanger of the present invention can hang casing with a larger diameter than conventional hangers, which facilitates the implementation of various operations such as fracturing construction, injection and production, and sand control in the later stage.

[0022] (3) All the internal tube mechanisms and fracturing sealing plugs involved in the structure of this invention can be recycled and reused, which greatly reduces the construction cost. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the main structure of the suspension device of the present invention.

[0024] Figure 2 This is a schematic diagram of the structure of the suspension device after expansion and sealing.

[0025] Figure 3 : This is a schematic diagram of the structure of the fracturing sealing plug of the present invention.

[0026] Figure 4 This is a schematic diagram of the fracturing process of the present invention.

[0027] In the diagram: 1. Suspension cylinder, 2. Sealing rubber, 3. Fracturing reconnection device, 4. Reconnection female thread, 5. Upper sealing surface, 6. Lower sealing surface, 7. Expansion cone, 8. Base, 9. Anti-falling object mechanism, 10. First lifting sub, 11. Pressure cap, 12. Connecting rod, 13. Rubber plug shearing mechanism, 14. Coupling, 15. Cementing rubber plug, 16. Casing sub, 17. Fracturing sealing plug, 18. Second lifting sub, 19. Upper sealing ring, 20. Reconnection male thread, 21. Lower sealing ring. Detailed Implementation

[0028] To provide a clearer explanation of the technical features, objectives, and effects of the present invention, specific embodiments of the invention will now be further described with reference to the accompanying drawings.

[0029] Example 1:

[0030] like Figures 1-4 As shown, this invention provides a suspension fracturing reconnection tool, including a suspension cylinder 1, sealing rubber 2, fracturing reconnection device 3, expansion cone 7, base 8, anti-falling object mechanism 9, first lifting sub 10, pressure cap 11, connecting rod 12, rubber plug shearing mechanism 13, coupling 14, cementing rubber plug 15, and casing sub 16 (as shown). Figure 1 (as shown) and fracturing seal plug 17 (as shown) Figure 3The device consists of components such as (as shown). The suspension cylinder 1 is made of low-strength, high-plasticity steel, with a variable diameter structure in the middle section processed by cold expansion. The outer surface of the suspension cylinder 1 is vulcanized or mechanically fixed with sealing rubber 2. The amount of sealing rubber can be adjusted according to actual needs. The lower end of the suspension cylinder 1 is connected to the fracturing reconnection device 3 via a thread. This device is made of high-strength steel, with an upper sealing surface 5, a reconnection female thread 4, and a lower sealing surface 6 machined on the inner wall. The reconnection female thread 4 is a large-pitch, low-torque, left-hand flat thread female thread. The lower end of the fracturing reconnection device 3 is connected to the sleeve short section 16 via a coupling 14. The expansion cone 7 is placed on the base 8 and forms a sealing fit. The expansion cone can be made of high-hardness alloy steel such as tungsten steel and is a key mechanism for the expansion seal mounting of the suspension device. The upper end of the base 8 is connected in sequence to the anti-falling object mechanism 9 and the first lifting section 10. The basic structure of the anti-falling object mechanism 9 is a metal body with a "V"-shaped ring rubber component installed on the outside, which forms an interference fit with the inner wall of the suspension cylinder body. Its function is to provide protection for the hanger during the lowering of the wellbore and prevent solid impurities in the wellbore from entering the suspension cylinder. The first lifting section 10 is mainly used for the hanger to cooperate with the drill pipe hanger for lowering. A pressure cap 11 is installed between the first lifting section 10 and the suspension cylinder 1. The pressure cap 11 is fixed to the outer surface of the first lifting section 10 by a pin and forms a seal with the upper end of the suspension cylinder 1. Its main function is to provide secondary protection for the hanger and prevent solid foreign objects from entering the suspension cylinder 1. The lower end of the base 8 is sequentially fixed with a connecting rod 12, a rubber plug shearing mechanism 13, and a cementing rubber plug 15. The rubber plug shearing mechanism 13 and the cementing rubber plug 15 are cemented by a pin and are equipped with sealing components such as "O" rings. The function of the cementing rubber plug is to completely push the cement slurry in the casing into the annulus between the casing and the wellbore during cementing. The shearing working pressure of the rubber plug shearing mechanism 13 and the cementing rubber plug 15 can be adjusted by adjusting the number of pins. The fracturing sealing plug 17 is an integral structure. The upper end is the second lifting section 18, and the lower outer surface is successively equipped with an upper sealing ring 19, a return male thread 20, and a lower sealing ring 21. The return thread is a large pitch, low torque, left-hand flat thread male thread, which is used to reconnect with the return female thread 4 of the fracturing return device 3 during the later fracturing operation, while meeting the high pressure sealing requirements.

[0031] When implementing the suspension device fracturing reconnection tool of this invention in the field, the assembled suspension device is first connected to the casing string, such as... Figure 1As shown, the drill pipe is delivered to the designed well section. After cementing is completed, a drill pipe plug is inserted at the wellhead, and water or mud is injected to continue the replacement operation. When the drill pipe plug reaches the cement plug 15, the fixing pin is sheared under pressure. The cement plug descends to the bottom of the casing and touches it. As the pressure increases, the hydraulic pressure acting on the expansion cone 7 increases continuously, eventually pushing the inner tube upward. At this time, the suspension cylinder 1 undergoes radial deformation under the action of the expansion cone 7. Since the deformation of the steel pipe is designed within the plastic deformation range, the suspension cylinder 1 will not rebound. After the expansion cone 7 completes the expansion operation of the entire suspension cylinder, the sealing rubber 2 is tightly squeezed between the suspension cylinder 1 and the outer casing, providing huge suspension force and sealing force at the same time.

[0032] like Figure 2 As shown, after the inner tube tool is pulled out, the hanger retains only the hanger cylinder 1, sealing rubber 2, fracturing reconnection device 3, and bottom casing short section in the wellbore. Compared with the mechanical hanger, it does not have hydraulic cylinder, slips, or other mechanisms, providing a larger diameter in the wellbore.

[0033] like Figure 3-4 As shown, after completing the casing perforation operation and establishing the passage between the casing and the formation to be fractured, a sealing ring is installed on the fracturing sealing plug 17. Then, the fracturing sealing plug 17 is lowered using drill pipe. When the fracturing sealing plug 17 is lowered to the vicinity of the expansion hanger, the lowering speed is controlled. When the fracturing sealing plug 17 is inserted into the suspension cylinder 1, the lowering continues until it encounters resistance of 2 tons. Then, the drill pipe is reversed mechanically or manually, with the torque controlled within 25% of the drill pipe backlash torque to prevent the drill pipe from backlashing. After reversing the drill pipe 5 times, lift it up. If the suspended weight increases by 3 tons compared to the original drill pipe weight, it indicates that the male thread 20 of the fracturing sealing plug 17 has successfully engaged with the female thread 4 of the fracturing return device 3. At this point, adjust the suspended weight back to the value before engagement, and continue reversing the drill pipe 5 times to ensure complete engagement between the male thread 20 and the female thread 4. Under the action of the upper sealing surface 5, lower sealing surface 6, upper sealing ring 19, and lower sealing ring 21, a high-pressure hydraulic seal is generated between the fracturing sealing plug 17 and the fracturing return device 3. Then, using surface fracturing equipment, the fracturing fluid is pumped sequentially through the drill pipe, fracturing sealing plug 17, and casing into the formation to be fractured. Using this fracturing method, the fracturing fluid can completely avoid the relatively weak suspension cylinder 1. After the fracturing operation is completed, turn the drill pipe 12 turns forward, disconnect the fracturing sealing plug 17 from the fracturing reconnection device 3, lift the drill pipe, restore the suspended weight to the original suspended weight of the drill pipe, continue to lift the drill pipe, and bring the fracturing tool out of the wellhead to end the fracturing operation.

[0034] Example 2:

[0035] A fracturing reconnection tool for a suspension device comprises a suspension cylinder 1, sealing rubber 2, a fracturing reconnection device 3, an expansion cone 7, a base 8, an anti-falling object mechanism 9, a first lifting sub 10, a pressure cap 11, a connecting rod 12, a rubber plug shearing mechanism 13, a coupling 14, a cementing rubber plug 15, a casing sub 16, and a fracturing sealing plug 17. The suspension cylinder 1 is made of low-strength, high-ductility steel. The sealing rubber 2 is fixed to the body of the suspension cylinder 1 by vulcanization or embedding. The number of sealing rubbers 2 can be adjusted according to specific requirements, and the rubber material can also be made of different rubber materials according to actual usage requirements. The lower part of the suspension cylinder 1 is sequentially connected to the fracturing reconnection device 3 and the casing sub 16. The fracturing reconnection device 3 is made of high-strength steel to meet the requirements of fracturing operations. The internal structure of the fracturing reconnection device 3, from top to bottom, consists of an upper sealing surface 5, a reconnection female thread 4, and a lower sealing surface 6. The reconnection female thread 4 uses a large-pitch left-hand flat thread to facilitate the reconnection operation during later implementation. The inner tube of the suspended fracturing reconnection tool, from top to bottom, comprises a first lifting section 10, an anti-falling object mechanism 9, a base 8, an expansion cone 7, a connecting rod 12, a rubber plug shearing mechanism 13, and a cementing rubber plug 15. The anti-falling object mechanism 9 has a V-shaped annular rubber component externally mounted, forming an interference fit with the inner wall of the suspended cylinder 1. The expansion cone 7 is made of special materials such as tungsten steel, with a hardness higher than that of the suspended cylinder 1. Its inner wall is machined with one or more sealing ring grooves, forming a hydraulic seal with the base 8 by installing sealing rings. The rubber plug shearing mechanism 13 and the cementing rubber plug 15 are fixedly connected by pins. The number of pins can be adjusted according to construction requirements. Sealing is achieved by installing a sealing ring. The fracturing sealing plug 17 is a one-piece structure made of high-strength steel. The upper part is machined with a second lifting section 18. The lower structure consists of an upper sealing groove, a large-pitch, low-torque left-hand flat thread, and a lower sealing groove. A matching sealing ring is installed inside the sealing groove.

[0036] The aforementioned suspension fracturing reconnection tool first uses a suspension device to connect the completion casing to the wellbore. After cementing is completed and the cement slurry is applied, the expansion cone 7 moves upward from the suspension cylinder 1 under hydraulic or mechanical force, causing plastic deformation of the suspension cylinder 1. After the cylinder is fully expanded, the suspension device sits on the inner wall of the upper casing, simultaneously achieving the functions of suspension and isolation. The drill string is then lifted to retrieve the expansion cone 7. The second drill string is then lowered, with a fracturing sealing plug 17 connected to the bottom. After the sealing plug reaches the inner cavity of the expansion suspension device, the sealing plug is engaged with the fracturing reconnection device 3 by reversing the drill string. The engagement process requires strict torque control to prevent drill pipe backlash; the engagement torque is controlled within 25% of the drill pipe unengagement torque. After the engagement process is completed, a sealing structure is machined between the sealing plug and the fracturing reconnection device 3, forming a complete hydraulic seal between the fracturing string and the casing, allowing for the next fracturing operation. The fracturing sealing plug 17 can be repeatedly recycled after the fracturing operation. The aforementioned suspension device fracturing reconnection tool has a simple and reliable structural design, a high success rate in construction, and the inner tube tool and fracturing sealing plug 17 can be recycled and reused, which greatly reduces the operating cost and has broad market application prospects.

[0037] The above description is merely an illustrative embodiment of the present invention and is not intended to limit the scope of the invention. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principles of the present invention should fall within the scope of protection of the present invention.

Claims

1. A suspension device fracturing reconnection tool, characterized in that, include: The components connected sequentially from top to bottom are: a first lifting sub, an anti-falling object mechanism, a base, a connecting rod, a rubber plug shearing mechanism, and a cementing rubber plug. From the outside of the first lifting sub, the components connected sequentially from top to bottom are: a pressure cap, a suspension cylinder, a fracturing reconnection device, a coupling, and a casing sub. The suspension cylinder has a diameter-changing section machined in the middle, with an expansion cone placed between the upper diameter-changing section and the base. The fracturing reconnection device has an upper sealing surface, a reconnection female thread, and a lower sealing surface machined on its inner wall. It also includes a fracturing sealing plug, which is an integral structure. The upper end is the second lifting sub, and the lower outer surface has an upper sealing ring, a reconnection male thread, and a lower sealing ring, arranged sequentially. After completing the casing perforation operation and establishing a channel between the casing and the formation to be fractured, the upper and lower sealing rings are installed on the fracturing sealing plug. Then, the fracturing sealing plug is lowered using drill pipe. When the fracturing sealing plug is lowered to the vicinity of the expansion hanger, the lowering speed is controlled. Once the fracturing sealing plug is inserted... When the suspension tube is in operation, continue descending until you encounter resistance of 2 tons. Then, reverse the drill pipe mechanically or manually, keeping the torque below 25% of the drill pipe's backlash torque to prevent backlash. After reversing 5 times, lift the drill pipe. If the suspended weight increases by 3 tons compared to the original suspended weight, it indicates that the male thread of the fracturing sealing plug has successfully engaged with the female thread of the fracturing back connection device. At this point, adjust the suspended weight to the value before engagement and continue reversing the drill pipe 5 times to ensure complete engagement between the male and female threads. Under the action of the upper and lower sealing surfaces and the upper and lower sealing rings, a high-pressure hydraulic seal is generated between the fracturing sealing plug and the fracturing back connection device. Then, use surface fracturing equipment to pump the fracturing fluid sequentially through the drill pipe, fracturing sealing plug, and casing into the formation to be fractured, ensuring that the fracturing fluid completely avoids the weaker suspension tube. After the fracturing operation is completed, rotate the drill pipe 12 times forward to disengage the fracturing sealing plug from the fracturing back connection device.

2. The suspension fracturing reconnection tool according to claim 1, characterized in that, The outer surface of the suspension cylinder is fixed with sealing rubber by vulcanization or mechanical means.

3. The suspension device fracturing reconnection tool according to claim 1, characterized in that, The pressure cap is fixed to the outer surface of the first lifting section by a pin and is sealed to the upper end of the suspension cylinder.

4. The suspension device fracturing reconnection tool according to claim 1, characterized in that, The rubber plug shearing mechanism is fixed to the cementing rubber plug by a pin.

5. A suspension fracturing reconnection tool according to claim 1, characterized in that, An O-ring is installed between the rubber plug shearing mechanism and the cementing rubber plug.

6. A suspension fracturing reconnection tool according to any one of claims 1-5, characterized in that, The suspension cylinder is made of low-strength, high-plasticity steel pipe material, which can undergo radial cold expansion plastic deformation under hydraulic or mechanical force.

7. A suspension fracturing reconnection tool according to any one of claims 1-5, characterized in that, The expansion cone is made of tungsten steel and can cause radial plastic deformation of the suspension cylinder under hydraulic or mechanical force.

8. A suspension fracturing reconnection tool according to any one of claims 1-5, characterized in that, The outer surface of the anti-falling object mechanism is fitted with a V-shaped rubber cylinder, which forms an interference fit with the inner wall of the suspension cylinder.

9. A suspension fracturing reconnection tool according to any one of claims 1-5, characterized in that, The fracturing reconnection device is made of high-strength steel, and the reconnection female thread is a large-pitch, low-torque left-hand flat thread.

Images