An expansion pipe tool for repairing damaged wells

Abstract

The present invention relates to a tool for repairing damaged casing wells with an expandable pipe, which comprises a vertically arranged expandable pipe. The upper part of the expandable pipe is a launching cavity, in which a soluble expansion cone is hermetically arranged. A soluble bottom pipe is hermetically fixed at the lower end of the expandable pipe through shear pins. The tool for repairing damaged casing wells with an expandable pipe according to the present invention can achieve expansion from top to bottom. After the expansion construction is completed, there is no need to mill or fish the bottom plug of the expandable pipe, which is safe to use and saves the construction period.

Description

Technical Field

[0001] The present invention relates to the field of drilling and repairing well equipment and tools in the petroleum industry, and in particular to an expandable tube tool for repairing casing damaged wells, which is mainly used for repairing casing damaged wells. Background Art

[0002] Expandable tubing is a metal circular tube with good ductility and strength. Once placed in the well, a special expansion head (expansion cone) pre-installed inside it is hydraulically driven to move axially, expanding both the inner and outer diameters by 15-30%. This technology can be used to repair damaged casing or seal complex open-hole sections.

[0003] Casing damage is a common problem in the middle and late stages of oilfield development. It manifests in a variety of ways, including casing corrosion, deformation, and faults, which can severely impact the normal production of oil and gas wells and cause significant economic losses to the oilfield. The expansion tube repair technology for casing-damaged wells refers to the use of expansion tubes to repair damaged casing during the well repair process, thereby restoring normal production. Currently, there are a large number of casing-damaged wells in various oilfields across my country, and the main technologies for repairing casing-damaged wells include expansion tube technology, casing replacement technology, and reinforced tube reinforcement technology. Compared with other sealing and reinforcement repair technologies, the expansion tube repair technology for casing-damaged wells not only achieves excellent sealing and fixing effects, but the diameter of the repaired wellbore is only reduced by approximately two expansion tube wall thicknesses. Therefore, this technology has been widely used in oilfield well repair operations.

[0004] Currently, the expandable tubing tools used in various oilfields to repair casing damage utilize an expansion cone that expands upward from the bottom. After the expansion is complete, the bottom plug of the expansion tubing must be milled or salvaged to connect the wellbore. However, this process presents the following challenges: 1. If the expansion process encounters an unexpected obstruction, it can easily cause a stuck drill, making it impossible to remove the expansion cone from the surface, making subsequent incident management extremely difficult. 2. After the expansion is complete, the bottom plug of the expansion tubing must be milled or salvaged to connect the wellbore, increasing the construction time.

[0005] Therefore, the inventors, relying on their many years of experience and practice in related industries, have proposed a tool for repairing casing damage in wells using an expandable tubing to overcome the defects of the prior art. Summary of the Invention

[0006] The purpose of the present invention is to provide an expansion tube repair casing damage well tool, which can realize top-down expansion and does not require milling or fishing of the bottom plug of the expansion tube after the expansion construction is completed. It is safe to use and saves construction time.

[0007] The object of the present invention is achieved as follows. A tool for repairing damaged wells with an expandable tube includes a vertically arranged expandable tube. The upper part of the expandable tube is a launching cavity, in which a soluble expansion cone is hermetically arranged. A soluble bottom tube is fixedly sealed at the lower end of the expandable tube by shear pins.

[0008] In a preferred embodiment of the present invention, the soluble expansion cone includes a soluble expansion cone body in the shape of a cylinder. An annular groove is formed on the side wall of the soluble expansion cone body, and an expansion cone ring is sleeved in the annular groove. The expansion cone ring is in sealing contact with the inner wall of the expandable tube.

[0009] In a preferred embodiment of the present invention, the soluble expansion cone body includes a soluble expansion cone seat and a soluble locking ring. The soluble expansion cone seat is composed of a base and an extended columnar body extending upward from the center of the base. The expansion cone ring and the soluble locking ring are sequentially sleeved on the extended columnar body from bottom to top. The inner wall of the soluble locking ring is fixedly threaded with the outer wall of the extended columnar body. An annular groove is formed between the bottom surface of the soluble locking ring, the outer wall of the extended columnar body, and the top surface of the base.

[0010] In a preferred embodiment of the present invention, the outer wall of the lower end of the base is a tapered surface that tapers downward.

[0011] In a preferred embodiment of the present invention, an axial groove extending axially downward is formed on the top surface of the extended columnar body.

[0012] In a preferred embodiment of the present invention, both the soluble expansion cone body and the soluble bottom tube are made of soluble metal.

[0013] In a preferred embodiment of the present invention, the soluble metal is soluble magnesium alloy.

[0014] In a preferred embodiment of the present invention, the inner diameter of the soluble bottom tube is smaller than the inner diameter of the expandable tube. The upper end of the soluble bottom tube is inserted from the bottom end of the expandable tube and fixed to the lower end wall of the expandable tube by shear pins.

[0015] In a preferred embodiment of the present invention, the outer wall of the lower end of the soluble bottom tube is a tapered surface that tapers downward.

[0016] In a preferred embodiment of the present invention, the tool for repairing damaged wells with an expandable tube further includes a feeding connecting pipe connected to the top end of the expandable tube. The outer wall of the lower end of the feeding connecting pipe is fixedly threaded with the inner wall of the expandable tube.

[0017] In a preferred embodiment of the present invention, a plurality of rubber rings are sleeved on the outer wall of the expandable tube.

[0018] As described above, the expansion tube tool for repairing casing damaged wells in the present invention sets the launch chamber at the upper part of the expansion tube. After pressure expansion through the cooperation of the soluble expansion cone and the soluble bottom pipe, the soluble expansion cone and the soluble bottom pipe will all fall to the bottom of the well, and the entire expansion tube tool for repairing casing damaged wells is connected from top to bottom. Therefore, the tool of the present invention can realize the expansion construction of the expansion tube from top to bottom. Once an unexpected obstruction is encountered during the expansion process, the soluble expansion cone and other related tools can be directly pulled out without causing a drill stuck accident, making it safer to use. At the same time, the soluble bottom pipe is used at the lower end of the tool to replace the lower bottom plug of the conventional expansion tube. After the expansion is completed, there is no need to grind or salvage the lower bottom plug. The operation is simple, which greatly improves the safety of the construction and saves the construction period. It can realize efficient and safe casing damaged well repair, and the soluble expansion cone and the soluble bottom pipe that fall to the bottom of the well can be dissolved and will not affect the bottom of the well. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The following drawings are intended only to illustrate and explain the present invention, and are not intended to limit the scope of the present invention.

[0020] Figure 1 : A schematic structural diagram of the expandable tubular tool for repairing casing damage wells provided by the present invention.

[0021] Figure 2 : A schematic structural diagram of the delivery connector provided by the present invention.

[0022] Figure 3 : A schematic structural diagram of the expansion tube provided by the present invention.

[0023] Figure 4 : A schematic structural diagram of the soluble expansion cone provided by the present invention.

[0024] Figure 5 : A schematic structural diagram of the soluble bottom tube provided by the present invention.

[0025] Figure 6 : A state diagram of the expansion tube provided by the present invention after repairing the damaged casing.

[0026] Description of Figure Numbers:

[0027] 1. Send to take over;

[0028] 2. Expansion tube; 21. Launch chamber;

[0029] 3. Dissolvable expansion cone; 31. Dissolvable expansion cone seat; 311. Base; 312. Extended column; 3121. Axial groove; 32. Expansion cone ring; 33. Dissolvable locking ring;

[0030] 4. Soluble bottom tube;

[0031] 5. Shear pins;

[0032] 6. Rubber ring;

[0033] 7. Casing; 71. Perforation damage of the casing. Detailed implementation manner

[0034] For a clearer understanding of the technical features, objectives, and effects of the present invention, the specific implementation manner of the present invention will now be described with reference to the accompanying drawings.

[0035] As Figures 1 to 6 shown, this embodiment provides a tool for repairing damaged casing wells with an expandable tube, including a vertically arranged expandable tube 2. The upper part of the expandable tube 2 is a launching cavity 21. A soluble expansion cone 3 is hermetically arranged in the launching cavity 21. A soluble bottom tube 4 is hermetically fixed at the lower end of the expandable tube 2 through a shear pin 5.

[0036] Among them, the inner diameter of the launching cavity 21 is larger than the inner diameter of the lower part of the expandable tube 2, and the lower hole wall of the launching cavity 21 is a tapered surface that tapers downward. The part of the expandable tube 2 corresponding to the launching cavity 21 is specifically pre-expanded by mechanical means (such as applying thrust with a hydraulic cylinder) to the upper part of the expandable tube 2 on the ground. Generally, an expansion cone is used during pre-expansion. The outer diameter after pre-expansion (that is, the outer diameter of the part of the expandable tube 2 corresponding to the launching cavity 21) is approximately equal to (or slightly smaller than) the inner diameter of the casing 7 to be patched, so as to ensure that the pre-expanded expandable tube 2 can smoothly reach the predetermined well section. The specific pre-expansion process is prior art and will not be elaborated here.

[0037] During use, after the expandable tube 2 is lowered to the predetermined position in the wellbore, pressure is applied to the expandable tube 2. The hydraulic pressure will push the soluble expansion cone 3 downward, causing the expandable tube 2 to expand radially. When the soluble expansion cone 3 moves downward to contact the soluble bottom tube 4, it will push the soluble bottom tube 4 downward, causing the shear pin 5 to be cut off. The soluble expansion cone 3 and the soluble bottom tube 4 will jointly fall to the bottom of the well. After a certain period of time, the soluble expansion cone 3 and the soluble bottom tube 4 will dissolve.

[0038] Therefore, for the tool for repairing damaged casing wells with an expandable tube in this embodiment, the launch cavity 21 is arranged at the upper part of the expandable tube 2. After pressure expansion through the cooperation of the soluble expansion cone 3 and the soluble bottom tube 4, the soluble expansion cone 3 and the soluble bottom tube 4 will all fall to the bottom of the well, and the entire tool for repairing damaged casing wells with an expandable tube is unobstructed from top to bottom. Therefore, the tool in this embodiment can realize the expansion construction of the expandable tube 2 from top to bottom. Once encountering an unexpected blockage during the expansion process, relevant tools such as the soluble expansion cone 3 can be directly lifted out, without causing a sticking accident, and it is safer to use. At the same time, a soluble bottom tube 4 is used at the lower end of the tool to replace the lower bottom plug of the conventional expandable tube. After the expansion is completed, there is no need to mill or fish for the lower bottom plug, which is simple to operate, greatly improves the construction safety, saves the construction period, can realize the efficient and safe repair of damaged casing wells, and the soluble expansion cone 3 and the soluble bottom tube 4 falling to the bottom of the well can dissolve without affecting the bottom of the well.

[0039] In a specific implementation manner, to ensure the mechanical strength, as Figure 1 and Figure 4 shown, the soluble expansion cone 3 includes a soluble expansion cone body in the shape of a cylinder. An annular groove is formed on the side wall of the soluble expansion cone body, and an expansion cone ring 32 is sleeved in the annular groove. The expansion cone ring 32 is in sealed contact with the inner wall of the expandable tube 2. Among them, the expansion cone ring 32 is made of hard alloy to ensure the strength requirements of the soluble expansion cone 3.

[0040] Specifically, for the convenience of processing and installation, the soluble expansion cone body includes a soluble expansion cone seat 31 and a soluble locking ring 33. The soluble expansion cone seat 31 is composed of a base 311 and an extended column 312 extending upward from the center of the base 311. The expansion cone ring 32 and the soluble locking ring 33 are sleeved on the extended column 312 from bottom to top in sequence, and the inner wall of the soluble locking ring 33 is fixedly threaded with the outer wall of the extended column 312. The bottom surface of the soluble locking ring 33, the outer wall of the extended column 312, and the top surface of the base 311 form the above-mentioned annular groove. When the soluble expansion cone 3 falls to the bottom of the well, the soluble expansion cone seat 31 and the soluble locking ring 33 will all dissolve.

[0041] In addition, the lower outer wall of the base 311 is a downwardly tapered surface, which is then fitted with the tapered surface at the lower end of the launch cavity 21 to facilitate the expansion of the expandable tube 2 when the soluble expansion cone 3 moves downward.

[0042] In practical applications, an axial groove 3121 extending axially downward is formed on the top surface of the extended column 312 to ensure the smoother downward movement of the soluble expansion cone 3.

[0043] Furthermore, the above-mentioned soluble expansion cone and soluble bottom pipe 4 are both made of soluble metal, that is, the material of the above-mentioned soluble expansion cone seat 31 and soluble locking ring 33 are both soluble metal, so that they can begin to dissolve 48 hours after entering the well and can be completely dissolved after 72 to 120 hours, without affecting the production of oil and gas wells.

[0044] Specifically, the soluble metal is a soluble magnesium alloy, which begins to dissolve upon contact with the drilling fluid in the well. Therefore, the specific type of soluble metal can be selected based on the specific composition of the drilling fluid. The soluble magnesium alloy material is composed of a magnesium matrix and other alloying elements. Its technical parameters, such as pressure resistance, temperature resistance, tensile strength, and dissolution rate, can be customized based on demand. It can dissolve spontaneously in aqueous solutions containing electrolytes and in various liquid environments, with varying compositions and mechanical properties. The aforementioned soluble magnesium alloy materials are existing and will not be described in detail here.

[0045] Typically, a control film is applied to the surface of the soluble metal. By controlling the thickness of the film, the dissolution rate of the soluble metal can be controlled, thereby prolonging or shortening the dissolution period. Specifically, high-pressure hydrogen is used to reduce metal ions in the metal salt solution and deposit them onto the surface of the suspended particles, controlling the corrosion rate and, in turn, the dissolution rate. The coating technology is well-known and will not be elaborated on here.

[0046] Furthermore, in order to facilitate the soluble expansion cone 3 to push the soluble bottom tube 4 downward when it descends, as shown in FIG. Figure 1 As shown, the inner diameter of the soluble bottom tube 4 is smaller than that of the expandable tube 2. The upper end of the soluble bottom tube 4 is inserted from the bottom end of the expandable tube 2 and fixed to the lower end wall of the expandable tube 2 via a shear pin 5. Generally, the lower end outer wall of the soluble bottom tube 4 is a tapered surface that tapers downward to guide the lowering of the tool.

[0047] In the specific use process, in order to facilitate the insertion of tools, such as Figure 1 and Figure 2 As shown, the expandable tube casing damage repair tool further comprises a delivery pipe 1 connected to the top of the expansion pipe 2 , and the outer wall of the lower end of the delivery pipe 1 is threadedly fixed to the inner wall of the expansion pipe 2 .

[0048] Typically, the upper inner wall of the delivery pipe 1 is machined with oil pipe threads to facilitate connection with a delivery string such as oil pipe or drill pipe to facilitate the delivery of tools. The lower outer wall of the delivery pipe 1 is machined with left-hand coarse threads, and the upper inner wall of the expansion pipe 2 is machined with left-hand coarse threads. The two are connected by the left-hand threads. After construction is completed, the delivery string can be rotated forward to achieve reverse threading and release.

[0049] To ensure the sealing performance during pressure testing, sealing grooves are provided on the lower outer wall of the feeding pipe 1, the side wall of the expansion cone ring 32, and the upper outer wall of the soluble bottom pipe 4, and sealing rings are sleeved in the sealing grooves to achieve sealing between components.

[0050] To ensure the sealing performance of the expansion pipe 2 after expansion, multiple rubber rings 6 are sleeved on the outer wall of the expansion pipe 2. Generally, the rubber rings 6 are bonded to the outer wall of the expansion pipe 2 through a vulcanization process. In this embodiment, a set of rubber rings 6 is provided at each end of the expansion pipe 2, and each set of rubber rings 6 includes multiple rubber rings 6 arranged at equal intervals vertically. For example, each set of rubber rings 6 includes 3 to 5 rubber rings 6, and the specific number is determined according to needs.

[0051] More specifically, during use, the upper end of the feeding pipe 1 is connected to an oil pipe or a drill pipe, and the tool is lowered to a predetermined position in the wellbore, so that the upper and lower sets of rubber rings 6 are respectively located at both ends of the casing damage perforation 71. Then, the pressure testing and expansion pipeline is connected on the ground, and drilling fluid is pumped in by a high-pressure pump truck or a mud pump for pressure testing and expansion. The pressure is transmitted through the oil pipe or the drill pipe to the pressure chamber composed of the feeding pipe 1, the expansion pipe 2, and the soluble expansion cone 3. The soluble expansion cone 3 moves downward under the drive of hydraulic pressure, causing the expansion pipe 2 to expand radially. The soluble expansion cone 3 moves downward under the drive of hydraulic pressure until it contacts the soluble bottom pipe 4.

[0052] At this time, the expansion pressure increases; continue to apply pressure, and the shear pin 5 is cut off under the push of the soluble expansion cone 3; the soluble expansion cone 3 and the soluble bottom pipe 4 jointly fall to the bottom of the well. After 72 to 120 hours, except for the expansion cone ring 32, the sealing ring on the expansion cone ring 32, and the shear pin 5, the soluble expansion cone seat 31, the soluble locking ring 33, and the soluble bottom pipe 4 can be completely dissolved in the drilling fluid in the well. Since there is a reserved depth at the bottom of the well during drilling, the expansion cone ring 32, the sealing ring, and the shear pin 5 are all small components and will not affect the bottom of the well.

[0053] After the construction of the expansion pipe 2 is completed, each rubber ring 6 is closely attached to the inner wall of the casing 7, forming a firm suspension and sealing for the damaged casing 7, thereby restoring the integrity of the wellbore of the oil and gas well and ensuring normal production. In addition, after the construction is completed, the expansion pressure will suddenly drop from 20 to 30 MPa to 0; at this time, rotating the feeding string forward can achieve reverse buckling and releasing, and the feeding pipe 1 will be lifted out of the ground with the feeding string.

[0054] The above is only a schematic specific embodiment of the present invention and is not intended to limit the scope of the present invention. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principles of the present invention shall fall within the scope of protection of the present invention.

Claims

1. An expansion tube tool for repairing damaged wells, characterized in that It includes a vertically arranged expansion tube; The upper part of the expansion tube is a launch cavity, in which a soluble expansion cone is hermetically arranged. A soluble bottom tube is hermetically fixed at the lower end of the expansion tube through a shear pin. The soluble expansion cone includes a soluble expansion cone body in the shape of a cylinder. An annular groove is formed on the side wall of the soluble expansion cone body. An expansion cone ring is sleeved in the annular groove, and the expansion cone ring is in sealing contact with the inner wall of the expansion tube; The soluble expansion cone body includes a soluble expansion cone seat and a soluble locking ring. The soluble expansion cone seat is composed of a base and a lengthened cylinder extending upward from the center of the base. The expansion cone ring and the soluble locking ring are sequentially sleeved on the lengthened cylinder from bottom to top, and the inner wall of the soluble locking ring is fixedly threaded with the outer wall of the lengthened cylinder. The bottom surface of the soluble locking ring, the outer wall of the lengthened cylinder, and the top surface of the base form the annular groove. The outer wall of the lower end of the base is a tapered surface that gradually shrinks downward. The inner diameter of the soluble bottom tube is smaller than the inner diameter of the expansion tube. The upper end of the soluble bottom tube is inserted from the bottom end of the expansion tube and is fixed to the lower end pipe wall of the expansion tube through the shear pin.

2. The tool for repairing damaged casing wells with an expansion tube according to claim 1, wherein, An axial groove extending axially downward is formed by the top surface of the lengthened cylinder.

3. The tool for repairing damaged casing wells with an expansion tube according to claim 1, wherein, Both the soluble expansion cone and the soluble bottom tube are made of soluble metal.

4. The tool for repairing damaged casing wells with an expansion tube according to claim 3, wherein, The soluble metal is soluble magnesium alloy.

5. The tool for repairing damaged casing wells with an expansion tube according to claim 1, wherein, The outer wall of the lower end of the soluble bottom tube is a tapered surface that gradually shrinks downward.

6. The tool for repairing damaged casing wells with an expansion tube according to claim 1, wherein, The tool for repairing damaged casing wells with an expansion tube further includes a feeding connection pipe connected to the top end of the expansion tube. The outer wall of the lower end of the feeding connection pipe is fixedly threaded with the inner wall of the expansion tube.

7. The tool for repairing damaged casing wells with an expansion tube according to claim 1, wherein, A plurality of rubber rings are sleeved on the outer wall of the expansion tube.

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