Anchoring and sealing back-inserting connector for fracturing and using method of anchoring and sealing back-inserting connector
By employing multiple sealing methods and metal friction structures in the fracturing re-entry joint, the problems of poor sealing effect under dynamic friction and difficulty in anchoring under narrow wall thickness were solved, achieving stable sealing during the fracturing process and improving sealing performance and construction reliability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA NAT PETROLEUM CORP
- Filing Date
- 2024-11-11
- Publication Date
- 2026-05-12
AI Technical Summary
Existing fracturing re-insertion joints have poor sealing performance under dynamic friction, O-ring wear leads to seal leakage, and they cannot be effectively anchored in narrow wall thickness conditions, affecting the stability and sealing of fracturing operations.
It employs multiple sealing methods and metal friction structures, including anchoring sealing parts and insertion sealing parts. Through the cooperation of metal mesh cylinder and limiting ring, and the use of toothed block support and vulcanized rubber ring compression, a multi-layer seal is formed, which reduces the movement of the tubing at the insertion sealing end and improves sealing performance.
During fracturing, the combination of the metal mesh cylinder and the limiting ring effectively supports and compresses the rubber ring, enhancing sealing performance, preventing O-ring wear and seal leakage, and ensuring the stability and sealing of the fracturing process.
Smart Images
Figure CN122014122A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of downhole tools used for sealing during drilling and completion in the petroleum industry, specifically relating to an anchoring and sealing fracturing back-fit connector and its usage method. Background Technology
[0002] The fracturing back-joint is a key component for sealing the connection between the fracturing tubing and the tailpipe. With the development of oil drilling technology, back-joint fracturing can reduce tubing material loss, reduce original wellbore seal loss, and reduce leakage between the fracturing tubing and the original wellbore. This technology is mainly used in complex well conditions such as harsh borehole conditions and water-bearing reservoirs, avoiding the risks of running prefabricated fracturing tubing and improving reservoir stimulation effects. Since no cementing operations are carried out above the hanger, the structural safety of the upper casing back-joint is crucial, directly affecting the smooth progress of the operation. Severe casing failure may lead to the abandonment of the entire well. Therefore, the existing fracturing back-joint technology still has shortcomings.
[0003] (1) Generally, the re-insertion tool used for fracturing requires a stabilizing and reinforcing device at the fracturing plug. However, in some cases where the diameter requirement is high and the available wall thickness of the fracturing string is extremely narrow, it is impossible to design an anchoring device, posing a risk of the plug detaching under stress during fracturing. For example, the utility model "A Re-insertion Joint for Fracturing String and its Tailpipe Hanger" with authorization announcement number (CN 211924112 U) requires the re-insertion joint to be fixed by a hydraulic anchor under the existing technical conditions. The invention patent with authorization announcement number (CN 109267943 B) uses a naked-eye packer and an anchor to fix the string. Therefore, the fixation of the tools all require external structural stabilization.
[0004] (2) Existing fracturing return plugs all use static O-ring seals. When the insertion tube is inside the return sleeve, the O-ring rubs against the inner wall of the return sleeve, causing O-ring wear. During long-term fracturing, this wear can lead to O-ring seal failure and leakage from the high-pressure side to the low-pressure side. Similar patents have improved sealing performance by adding O-ring sets or using wider O-rings, but the O-rings still experience frictional wear under dynamic friction. Therefore, existing technologies only consider the sealing effect under static conditions. There are no relevant technical solutions for dynamic conditions.
[0005] In existing fracturing string technologies, anchoring is required to improve the relative position stability of the return pipe and the return joint. However, later stages of fracturing place high demands on the pipe string diameter. For example, when inserting a φ114.3mm casing with a wall thickness of 8.65mm into a φ139.7mm casing with a wall thickness of 6.35mm, the inner diameter of the 139.7mm casing is 124.3mm. Therefore, the outer diameter of the return string can only be between 94-118mm. Anchoring tools cannot be designed for a wall thickness of only 12mm. Thus, anchoring cannot be achieved in such conditions. In cases where anchoring is not feasible, the only solution is to lower the return fracturing string further down, placing a weight at the return pipe to stabilize the relative position of the string under pressure. Sealing is still achieved using O-rings. As the scale, intensity, and duration of fracturing increase, the reinjection fracturing head and reinjection pipe undergo creep under the influence of high-frequency fluid flow, causing the reinjection fracturing head and reinjection pipe to reciprocate in a piston-like manner. After the O-rings wear, sealing leaks occur. Summary of the Invention
[0006] To overcome the problem of existing tubing creep causing piston-like reciprocating motion of the reinsertion fracturing head and reinsertion pipe, and O-ring wear leading to seal leakage, this invention provides an anchored sealing reinsertion joint for fracturing and its usage method. This invention improves the sealing performance of the tubing by employing multiple sealing methods and metal friction to reduce the movement of the tubing at the reinsertion sealing end.
[0007] The technical solution adopted in this invention is as follows: An anchored sealing re-insertion joint for fracturing includes an anchoring sealing portion and an insertion sealing portion, both of which are assembled on a single tube body; the outer diameter of the upper end of the tube body is larger than the outer diameter of the lower end.
[0008] The tube is a metal tube, and the whole is T-shaped. The outer diameter of the horizontal end of the T-shape is larger than the outer diameter of the vertical end, and a threaded coupling is provided at the horizontal end.
[0009] The anchoring and sealing part includes a metal mesh cylinder and a limiting ring. The outer wall of the metal mesh cylinder has a mesh groove, and vulcanized rubber blocks are vulcanized in the mesh groove. Each mesh point of the mesh groove has a downwardly inclined toothed block. The metal mesh cylinder is sleeved on the tube body, and the upper end of the metal mesh cylinder is located at the lower surface of the tube body's maximum outer diameter. The limiting ring is sleeved on the tube body and located below the metal mesh cylinder.
[0010] The tooth block is an alloy tooth or a ceramic tooth.
[0011] The height of the assembled tooth block is lower than the maximum outer diameter of the tube.
[0012] The limiting ring is a metal limiting ring with a notch, and the height of the limiting ring after assembly is the same as the maximum outer diameter of the tube. The insertion sealing part includes a vulcanized rubber ring, a rubber ring, and a limiting ring. The limiting ring is located between two rubber rings to form a limiting sealing assembly. The vulcanized rubber ring and the limiting sealing assembly are sequentially sleeved on the tube body from top to bottom. There are multiple sets of vulcanized rubber rings and limiting sealing assemblies. The vulcanized rubber ring is vulcanized and sleeved on the tube body below the limiting ring in the anchoring sealing part.
[0013] The maximum outer diameter of the vulcanized rubber ring is more than 2 mm larger than the inner diameter of the return tube into which the sealing part is inserted; the outer diameter of the rubber ring after assembly is more than 2 mm larger than the inner diameter of the return tube into which the sealing part is inserted, and the outer diameter of the limiting ring is more than 1 mm smaller than the inner diameter of the return tube into which the sealing part is inserted.
[0014] The limiting ring is an open metal limiting ring. A method for using an anchored sealing fracturing re-insertion joint, the specific steps of which are as follows: After the fracturing re-joint of the anchor seal is inserted into the re-joint tube, the upper edge of the re-joint tube will contact the limiting ring of the anchor seal section by pressing down. The limiting ring is compressed and moves upward to squeeze the metal mesh tube. When squeezing the metal mesh tube, the obliquely placed teeth on the mesh will open in an umbrella-like shape, supporting between the tube body and the outer sleeve and rivet the entire tube body; at the same time, it will squeeze the vulcanized rubber block to form a seal between the entire tube body and the outer sleeve. After the anchored seal fracturing re-entry connector is inserted into the re-entry cylinder, the vulcanized rubber ring of the inserted sealing part forms a seal with the inside of the re-entry cylinder. During the fracturing process, if upward pressure leakage occurs, the lower limiting ring will squeeze the rubber ring upward due to the pressure. As the pressure increases, the limiting ring is squeezed, and the rubber ring becomes stronger under pressure, thus improving the sealing performance.
[0015] The beneficial effects of this invention are: Compared to existing technologies, when the re-insertion sealing head is inserted into the re-insertion tube, it is not anchored. Under pressure, because the relative position is not constrained, reciprocating piston movement occurs between the re-insertion sealing head and the re-insertion tube. This leads to seal leakage when the tubing is fracturing. In this invention, after the re-insertion tube is inserted, by pressing down, the upper edge of the re-insertion tube will contact the limiting ring of the anchoring sealing part. The limiting ring is compressed and moves upward to squeeze the metal mesh tube. When the metal mesh tube is squeezed, the obliquely placed teeth on the mesh will open in an umbrella-like shape, supporting the entire metal tube body and the outer sleeve, and rivet the entire metal tube body; at the same time, it will squeeze the vulcanized rubber block to form a seal between the entire metal tube body and the outer sleeve.
[0016] After the reconnector is inserted, the vulcanized rubber ring forms a seal with the inside of the reconnector. During the fracturing process, if upward pressure leakage occurs, the lower limiting ring will squeeze the rubber ring upward due to the pressure. As the pressure increases, the squeezing of the limiting ring becomes more obvious, and the rubber ring is subjected to stronger pressure, resulting in a more obvious sealing performance. Attached Figure Description
[0017] Figure 1 This is a schematic diagram of the structure of the present invention.
[0018] Figure 2 This is a schematic diagram of the metal tube structure of the present invention.
[0019] Figure 3 This is a schematic diagram of the metal mesh cylinder structure of the present invention.
[0020] Figure 4 This is a schematic diagram of the notched limiting ring structure of the present invention.
[0021] The present invention will now be described in further detail with reference to the accompanying drawings.
[0022] In the figure, the attached reference numerals are: 1. Vulcanized rubber block; 2. Tooth block; 3. Metal mesh cylinder; 4. Limiting ring; 5. Vulcanized rubber ring; 6. Rubber ring; 7. Limiting ring; 8. Coupling; 9. Pipe body. Detailed Implementation
[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0024] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.
[0025] Example 1: To overcome the problem of existing tubing string exhibiting creep leading to piston-like reciprocating motion of the re-insertion fracturing head and re-insertion pipe, and O-ring wear causing seal leakage, this invention provides... Figure 1-4The present invention discloses an anchored sealing fracturing re-insertion joint and its usage method. By employing multiple sealing methods and metal friction, the present invention reduces the movement of the tubing string at the re-insertion sealing end, thereby improving the sealing characteristics of the tubing string.
[0026] An anchored sealing re-insertion joint for fracturing includes an anchoring sealing portion and an insertion sealing portion, both of which are mounted on a tube body 9; the outer diameter of the upper end of the tube body 9 is larger than the outer diameter of the lower end.
[0027] This invention improves the sealing performance of the tubing by employing multiple sealing methods in the anchoring and insertion sealing parts and reducing metal friction to decrease the movement of the tubing at the insertion sealing end.
[0028] In this invention, the tube body 9 has an outer stepped hole in the lower middle part, forming a T-shape overall.
[0029] In this invention, after the reconnecting sleeve is inserted, downward pressure causes the upper edge of the reconnecting sleeve to be positioned, anchored, and sealed with the anchoring and sealing part. The insertion sealing part also seals the reconnecting sleeve. During fracturing, if upward pressure leakage occurs, the limiting ring 7 at the bottom of the insertion sealing part will press upward against the rubber ring 6 due to the pressure. As the pressure increases, the compression of the limiting ring 7 becomes more pronounced, resulting in stronger pressure on the rubber ring 6 and a more effective sealing performance.
[0030] Example 2: Based on Embodiment 1, in this embodiment, preferably, the tube 9 is a metal tube, which is T-shaped, with the outer diameter of the horizontal end of the T-shape being larger than the outer diameter of the vertical end, and a threaded coupling 8 is provided at the horizontal end.
[0031] like Figure 2 As shown, tube 9 is a metal tube with the maximum outer diameter at the top.
[0032] Preferably, the anchoring and sealing part includes a metal mesh cylinder 3 and a limiting ring 4. The outer wall of the metal mesh cylinder 3 has a mesh groove, and vulcanized rubber blocks 1 are vulcanized in the mesh groove. Each mesh point of the mesh groove has a downwardly inclined tooth block 2. The metal mesh cylinder 3 is sleeved on the tube body 9, and the upper end of the metal mesh cylinder 3 is located at the lower surface of the maximum outer diameter of the tube body 9. The limiting ring 4 is sleeved on the tube body 9 and located below the metal mesh cylinder 3.
[0033] In this invention, the mesh groove can be in the shape of a rhomboid mesh, a honeycomb mesh, a circular mesh, etc. For example... Figure 3As shown, the mesh groove in this invention is preferably rhomboid in shape. The upper end of the mesh groove is limited by a right-angle diameter-changing limit on the T-shaped tube 9. The outer diameter of the metal mesh cylinder 3 after assembly is the same as the maximum outer diameter of the overall metal tube 9. The rubber filling the mesh groove structure is filled by vulcanization, and the outer diameter formed by the overall thickness of the vulcanized rubber after filling is 2mm larger than the maximum outer diameter of the tube 9.
[0034] Preferably, the tooth block 2 is an alloy tooth or a ceramic tooth.
[0035] Preferably, the height of the assembled tooth block 2 is lower than the maximum outer diameter of the tube body 9.
[0036] In this invention, the height of the downwardly inclined tooth block 2 is lower than the maximum outer diameter of the tube body 9. After being squeezed into a shape perpendicular to the tube body, the maximum outer diameter is greater than the inner diameter of the outer sleeve.
[0037] Preferably, the limiting ring 4 is a metal limiting ring with a notch, and the height of the limiting ring 4 after assembly is the same as the maximum outer diameter of the tube body 9. like Figure 4 In this invention, the limiting ring 4 can tightly wrap around the tube body 9 through the notch. The limiting ring 4 is made of tough materials such as copper, iron, and nickel. The notch on the metal limiting ring facilitates assembly. The height of the limiting ring 4 after assembly is the same as the maximum outer diameter of the entire metal tube body 9 and is greater than the outer diameter of the return tube to be inserted, while also tightly wrapping around the entire metal tube body 9.
[0038] Preferably, the insertion sealing part includes a vulcanized rubber ring 5, a rubber ring 6, and a limiting ring 7. The limiting ring 7 is disposed between two rubber rings 6 to form a limiting sealing assembly. The vulcanized rubber ring 5 and the limiting sealing assembly are sequentially sleeved on the tube body 9 from top to bottom. There are multiple sets of vulcanized rubber rings 5 and limiting sealing assemblies. The vulcanized rubber ring 5 is vulcanized and sleeved on the tube body 9 below the limiting ring 4 in the anchoring sealing part.
[0039] Preferably, the maximum outer diameter of the vulcanized rubber ring 5 is more than 2 mm larger than the inner diameter of the return tube into which the sealing part is inserted; the outer diameter of the rubber ring 6 after assembly is more than 2 mm larger than the inner diameter of the return tube into which the sealing part is inserted; and the outer diameter of the limiting ring 7 is more than 1 mm smaller than the inner diameter of the return tube into which the sealing part is inserted.
[0040] In this invention, the vulcanized rubber ring 5 is vulcanized at the lower part of the limiting ring 4, and the maximum outer diameter of the vulcanized rubber ring 5 is more than 2 mm larger than the inner diameter of the return cylinder. Multiple sets of vulcanized rubber rings 5 are used, and the configuration is determined according to requirements.
[0041] Preferably, the limiting ring 7 is an open metal limiting ring. In this invention, the limiting ring 7 is open to better install on the tube body 9, and the outer diameter of the limiting ring 7 is smaller than the outer diameter of the limiting ring 4. In this invention, the limiting ring 7 and the limiting ring 4 are the same in structure, material and function except for size, and will not be further described in this invention.
[0042] In this invention, the rubber ring 6, in conjunction with the limiting ring 7, tightly wraps around the entire metal tube 9. Multiple rubber rings can be combined. After assembly, the outer diameter of the rubber ring 6 is at least 2mm larger than the inner diameter of the reconnecting sleeve. The outer diameter of the limiting ring 7 is at least 1mm smaller than the inner diameter of the reconnecting sleeve. This ensures a better seal on the reconnecting sleeve during use of the reconnecting connector provided by this invention, preventing leakage during cracking.
[0043] In this invention, the metal mesh cylinder 3, the limiting ring 4, the vulcanized rubber ring 5, the rubber ring 6, and the limiting ring 7 are connected to the tube body 9 from top to bottom; the upper end of the metal mesh cylinder 3 is limited by the horizontal end of the T-shaped tube body 9.
[0044] The assembly sequence of this invention is as follows: The first step is to install the metal mesh tube 3 on the tube body 9; The second step is to vulcanize and fill the vulcanized rubber block 1 on the mesh groove structure of the metal mesh cylinder 3, and vulcanize the vulcanized rubber ring 5 at the corresponding position of the tube body 9. The third step is to inlay high-hardness alloy teeth or ceramic teeth at the mesh connection points of the mesh grooves of the metal mesh tube 3. Step 4: Install the notched limiting ring 4; Step 5: Insert the rubber ring 6; Step 7: Install the limit ring 7.
[0045] This invention provides a method for using an anchored sealing re-insertion joint for fracturing, the specific steps of which are as follows: After the fracturing re-joint of the anchoring seal is inserted into the re-joint tube, the upper edge of the re-joint tube will contact the limiting ring 4 of the anchoring seal part by pressing down. The limiting ring 4 is compressed and moves upward to squeeze the metal mesh tube 5. When squeezing the metal mesh tube 5, the oblique teeth 2 on the mesh will open in an umbrella-like shape, supporting the tube body 9 and the outer sleeve, and rivet the entire tube body 9; at the same time, it will squeeze the vulcanized rubber block to form a seal between the entire tube body and the outer sleeve. After the anchored seal fracturing re-insertion connector is inserted into the re-insertion cylinder, the vulcanized rubber ring 5 of the inserted sealing part forms a seal with the inside of the re-insertion cylinder. During the fracturing process, if upward pressure leakage occurs, the lower limiting ring 7 will press the rubber ring 6 upward due to the pressure. As the pressure increases, the limiting ring 7 will be squeezed, and the rubber ring 6 will be under stronger pressure, thus improving the sealing performance.
[0046] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.
[0047] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.
[0048] The examples above are merely illustrative of the present invention and do not constitute a limitation on the scope of protection of the present invention. All designs that are the same as or similar to the present invention fall within the scope of protection of the present invention. Device structures and method steps not described in detail in this invention are prior art and will not be further described in this invention.
Claims
1. A re-insertion joint for fracturing with anchored sealing, characterized in that: It includes an anchoring seal and an insertion seal, both of which are mounted on a tube (9); the outer diameter of the upper end of the tube (9) is larger than the outer diameter of the lower end.
2. The anchored sealing fracturing re-insertion joint according to claim 1, characterized in that: The tube body (9) is a metal tube body, and the whole is T-shaped. The outer diameter of the horizontal end of the T-shape is larger than the outer diameter of the vertical end, and a threaded coupling (8) is provided at the horizontal end.
3. The anchored sealing fracturing re-insertion joint according to claim 1, characterized in that: The anchoring and sealing part includes a metal mesh cylinder (3) and a limiting ring (4). The outer wall of the metal mesh cylinder (3) has a mesh groove, and vulcanized rubber blocks (1) are vulcanized in the mesh groove. Each mesh point of the mesh groove has a downwardly inclined tooth block (2). The metal mesh cylinder (3) is sleeved on the tube body (9), and the upper end of the metal mesh cylinder (3) is located at the lower surface of the maximum outer diameter of the tube body (9). The limiting ring (4) is sleeved on the tube body (9) and located below the metal mesh cylinder (3).
4. The anchored sealing fracturing re-entry joint according to claim 3, characterized in that: The tooth block (2) is an alloy tooth or a ceramic tooth.
5. A re-insertion joint for fracturing with anchored sealing according to claim 4, characterized in that: The height of the assembled tooth block (2) is lower than the maximum outer diameter of the tube body (9).
6. The anchored sealing fracturing re-entry joint according to claim 3, characterized in that: The limiting ring (4) is a metal limiting ring with a notch. The height of the limiting ring (4) after assembly is the same as the maximum outer diameter of the tube body (9).
7. The anchored sealing fracturing re-insertion joint according to claim 1, characterized in that: The insertion sealing part includes a vulcanized rubber ring (5), a rubber ring (6) and a limiting ring (7). The limiting ring (7) is located between two rubber rings (6) to form a set of limiting sealing components. The vulcanized rubber ring (5) and the limiting sealing components are sequentially sleeved on the tube body (9) from top to bottom. There are multiple sets of vulcanized rubber rings (5) and limiting sealing components. The vulcanized rubber ring (5) is vulcanized and sleeved on the tube body (9) below the limiting ring (4) in the anchoring sealing part.
8. A re-insertion joint for fracturing with anchored sealing according to claim 7, characterized in that: The maximum outer diameter of the vulcanized rubber ring (5) is more than 2 mm larger than the inner diameter of the return tube into which the sealing part is inserted; the outer diameter of the rubber ring (6) after assembly is more than 2 mm larger than the inner diameter of the return tube into which the sealing part is inserted; and the outer diameter of the limiting ring (7) is more than 1 mm smaller than the inner diameter of the return tube into which the sealing part is inserted.
9. A re-insertion joint for fracturing with anchored sealing according to claim 7, characterized in that: The limiting ring (7) is an open metal limiting ring.
10. The method of using any one of the anchored sealing fracturing re-insertion joints according to claims 1-9, characterized in that: The specific steps are as follows: After the anchor seal fracturing re-insertion joint is inserted into the re-insertion tube, the upper edge of the re-insertion tube will contact the limiting ring (4) of the anchor seal part by pressing down. The limiting ring (4) is pressed and moves upward to squeeze the metal mesh tube (5). When squeezing the metal mesh tube (5), the oblique teeth (2) on the mesh will open in an umbrella-like shape, supporting the tube body (9) and the outer sleeve, and rivet the entire tube body (9); at the same time, it will squeeze the vulcanized rubber block to form a seal between the entire tube body and the outer sleeve. After the anchored seal fracturing re-insertion joint is inserted into the re-insertion cylinder, the vulcanized rubber ring (5) of the inserted sealing part forms a seal with the inside of the re-insertion cylinder. During the fracturing process, if upward pressure leakage occurs, the lower limiting ring (7) will squeeze the rubber ring (6) upward due to the pressure. As the pressure increases, the limiting ring (7) will be squeezed, and the rubber ring (6) will be compressed and strengthened, thus improving the sealing performance.