Radial pipe expander and radial pipe expanding method

Abstract

The invention belongs to the technical field and discloses a radial pipe expander and a radial pipe expanding method. The radial pipe expander comprises a central pipe, an upper hydraulic cylinder, a lower hydraulic cylinder, a fixing sleeve, a connecting joint, a pushing joint, an expansion cone, a first elastic piece and a second elastic piece. An opening in the top end of the central pipe is used for injecting high-pressure liquid. A first driving cavity is formed between the upper hydraulic cylinder and the central pipe; a transmission cavity is formed between the lower hydraulic cylinder and the center pipe, a second driving cavity is formed between the pushing connector and the lower hydraulic cylinder, the fixing sleeve is fixedly connected to the center pipe, the top end of the connecting connector is connected with the upper hydraulic cylinder, the bottom end of the connecting connector is connected with the lower hydraulic cylinder, and the expansion cone is connected with the bottom end of the center pipe. The two ends of the first elastic piece abut against the upper hydraulic cylinder and the fixing sleeve respectively. The two ends of the second elastic piece abut against the pushing connector and the expansion cone respectively. The expansion pipe can be expanded in the radial direction again, so that the sealing effect of the well wall is improved, and the expansion pipe can be recycled and reused.

Description

Technical Field

[0001] This invention relates to the field of oil and gas drilling and well workover technology, and in particular to a radial expander and a radial expander method. Background Technology

[0002] During oil drilling, when encountering abnormal formations such as unusually high pressure, lost circulation, water production, or collapse, the conventional approach is to install a new layer of casing for isolation. However, when encountering multiple complex formations, this involves multiple casing layers, high costs, long construction periods, and small wellbore dimensions, making it difficult to reach the target formation. Using open-hole sealing technology with expandable tubing involves running expandable tubing with excellent properties into the well, expanding and tightly fitting it to the wellbore. This effectively isolates complex formations prone to collapse, leakage, mudstone, and unusually high pressure, minimizing wellbore size loss while ensuring smooth drilling and facilitating the installation of subsequent tools. However, in practice, the presence of complex formations can cause the wellbore size to either increase or decrease. A small wellbore size can be restored by enlargement; however, during expandable tubing installation, if the sealing section of the expandable tubing is located within the enlarged section, it cannot fit snugly against the wellbore, leading to incomplete sealing and affecting the drilling results.

[0003] For enlarged diameter sections, expansion tubes can be used to patch the casing, repairing damaged casing and restoring its seal and integrity. However, in shale gas and shale oil fields requiring large-scale fracturing operations, the casing is often severely damaged and deformed after fracturing. When the inner diameter of the casing increases at one or more points, or even becomes excessively large, expansion tube patching technology still cannot achieve a tight fit with the outer casing wall, and the sealing and pressure-bearing performance cannot meet the requirements. When the wellbore size is uneven or the well diameter is irregular, existing casing patching methods cannot meet the needs of all sizes of expansion tubes at once and cannot be applied to open-hole sealing operations with expansion tubes. Summary of the Invention

[0004] The purpose of this invention is to provide a radial expander and a radial expander method for radially expanding an expansion tube to improve the subsidy effect.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] A radial expander for radially expanding an expansion tube; the radial expander comprises:

[0007] A central tube, wherein the tube wall is provided with a first through hole and a second through hole from top to bottom; the bottom end of the central tube is sealed and the top end of the central tube is open, the top end opening being used to inject high-pressure liquid into the central tube;

[0008] An upper liquid cylinder is sleeved on the outside of the central tube and forms a first driving cavity between it and the outer wall of the central tube. The first driving cavity is connected to the first through hole.

[0009] The lower liquid cylinder is sleeved on the outside of the central tube and located below the upper liquid cylinder. A transmission cavity is formed between the lower liquid cylinder and the outer wall of the central tube. The tube wall of the lower liquid cylinder has a third through hole. The transmission cavity is configured to connect the second through hole and the third through hole.

[0010] A fixing sleeve, the top end of which is located between the first through hole and the second through hole and is fixedly connected to the outer wall of the central tube, and the inner wall of the bottom end of the fixing sleeve is slidably sealed to the outer wall of the lower liquid cylinder;

[0011] A connecting joint, wherein the top end of the connecting joint is inserted upward through the fixing sleeve and fixedly connected to the upper liquid cylinder, and the bottom end of the connecting joint is fixedly connected to the lower liquid cylinder;

[0012] A push joint is provided, wherein a second driving cavity is formed between the inner wall of the push joint and the outer wall of the lower liquid cylinder, and the second driving cavity is connected to the third through hole;

[0013] An expansion cone, wherein the top end of the expansion cone has a segmented structure, and the bottom end of the expansion cone is sleeved on the central tube and fixedly connected to the central tube;

[0014] The first elastic element has two ends that abut against the upper liquid cylinder and the fixed sleeve, respectively.

[0015] The second elastic element has two ends that abut against the push joint and the expansion cone, respectively. Under the elastic force of the second elastic element, the push joint abuts against and is limited by the fixed sleeve.

[0016] The elastic force of the first elastic element is greater than that of the second elastic element.

[0017] In some embodiments, the radial expander further includes an upper connector, the bottom end of the upper liquid cylinder is threadedly connected to the upper connector, the bottom end face of the upper connector elastically abuts against the first elastic element, the inner wall of the upper connector is threadedly connected to the outer wall of the connecting connector, and the top end face of the upper connector, the outer wall of the central tube and the inner wall of the upper liquid cylinder enclose to form the first driving cavity.

[0018] In some embodiments, the outer wall of the fixed sleeve is provided with a first limiting step. In the initial state, under the action of the second elastic member, the top end of the push joint abuts against the first limiting step, and the transmission cavity and the second drive cavity are in a connected state.

[0019] In some embodiments, the outer wall of the lower liquid cylinder is provided with a groove, which is connected to the top end face of the lower liquid cylinder. When the lower liquid cylinder moves downward to the point where the second drive chamber is connected to the groove, the high-pressure liquid in the second drive chamber can flow out along the groove.

[0020] In some embodiments, the inner wall of the push joint is provided with a first stepped groove and a second stepped groove. In the initial state, the push joint is at its maximum height. Part of the groove wall of the first stepped groove is slidably and sealingly connected to the outer wall of the fixed sleeve. The bottom of the first stepped groove, another part of the groove wall of the stepped groove, the bottom end face of the fixed sleeve, and the groove wall of the second stepped groove are slidably and sealingly connected to the outer wall of the lower liquid cylinder. When the lower liquid cylinder moves downward to the second drive chamber communicating with the groove to release pressure, the push joint is reset.

[0021] In some embodiments, the top end of the connector is a segmented structure, and the fixing sleeve is a segmented structure.

[0022] In some embodiments, the outer diameter of the bottom outer wall of the push joint gradually increases from bottom to top, and the inner wall of the push joint is provided with a limiting groove, wherein the top end of the second elastic member abuts against the bottom of the limiting groove.

[0023] A radial tube expanding method, using the radial tube expander provided by the present invention, the radial tube expanding method comprising the following steps:

[0024] S1, after the open hole is sealed and solidified by the expansion tube, the expansion tube is attached to the well wall, and the well wall has one or more enlarged diameter sections;

[0025] S2, Based on the well logging data, the radial expander is lowered into the expansion tube so that the expansion cone is located below the expansion section;

[0026] S3, inject high-pressure liquid into the central tube and pressurize it to the first pressure. The first pressure is less than the elastic force of the first elastic element and greater than the elastic force of the second elastic element. Under the action of the high-pressure liquid, the joint is pushed to move downward against the elastic force of the second elastic element and support the expansion cone. The expansion cone expands the expansion tube and fits against the inner wall of the expansion section.

[0027] In some embodiments, the radial tube expansion method further includes step S4, lifting the central tube, and under the action of the expansion cone, the outer diameter of the expansion tube continues to expand along its axial direction until the lifting resistance suddenly increases, the lifting stops, and the tube expansion ends.

[0028] In some embodiments, during steps S3 and S4, when the first pressure of the high-pressure liquid instantly rises to the second pressure, under the action of the high-pressure liquid, the upper liquid cylinder overcomes the elastic force of the first elastic element and moves downward. At the same time, the upper liquid cylinder drives the lower liquid cylinder to move downward through the connecting joint until the high-pressure liquid in the second drive chamber flows out through the groove on the outer wall of the top of the lower liquid cylinder. The push joint releases pressure and retracts under the elastic force of the second elastic element, the expansion cone resets, and the expansion tube stops.

[0029] The beneficial effects of this invention are:

[0030] The radial expander provided by this invention is used when the expansion tube needs to be radially expanded after the wellbore has been sealed and solidified in the open hole. The radial expander is inserted into the expansion tube using a lowering tool, which allows for further radial expansion of the expansion tube. This ensures that the outer wall of the expansion tube is tightly fitted against the inner wall of the expanded section of the wellbore, improving the wellbore sealing effect. Furthermore, the expander can be recycled and reused. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the wellbore state after the expansion tube is sealed and solidified in the open hole, as described in this invention.

[0032] Figure 2 This is a schematic diagram of the wellbore state after radial expansion using the radial expander provided in this embodiment of the invention;

[0033] Figure 3 This is a schematic diagram of the initial state structure of the radial expander provided in an embodiment of the present invention;

[0034] Figure 4 This is a schematic diagram of the radial expansion tube expansion device provided in an embodiment of the present invention.

[0035] Figure 5 This is a schematic diagram of the radial expander provided in the embodiment of the present invention during the radial expansion process;

[0036] Figure 6 This is a schematic diagram of the radial expander provided in this embodiment of the invention, showing the push joint and expansion cone retracted after radial expansion is completed.

[0037] Figure 7 yes Figure 3 Enlarged structural diagram of region A in the middle;

[0038] Figure 8 yes Figure 3 Enlarged structural diagram of region B in the middle;

[0039] Figure 9 yes Figure 6 A magnified structural diagram of region C in the middle.

[0040] In the picture:

[0041] 100. Expansion pipe; 101. Sealing device; 200. Well wall; 201. Enlarged diameter section;

[0042] 1. Central tube; 2. Upper liquid cylinder; 3. Upper connector; 4. First elastic element; 5. Fixing sleeve; 6. Connecting connector; 7. Lower liquid cylinder; 8. Push connector; 9. Second elastic element; 10. Expansion cone; 11. First through hole; 12. Second through hole; 13. First driving cavity; 14. Transmission cavity; 15. Third through hole; 16. Second driving cavity; 17. First limiting step; 18. Groove; 19. V-shaped sealing ring; 20. Limiting groove. Detailed Implementation

[0043] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0044] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0045] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0046] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0047] This invention provides a radial expander, such as... Figure 1 After the implementation of the open-hole sealing and wall-fixing technology and the expansion tube 100 supplementary sleeve repair technology, when there is one or more enlarged diameter sections 201 on the well wall 200, if the sealing section of the expansion tube 100 is located in the enlarged diameter section 201 of the well wall 200, there will be a problem of incomplete sealing. At this time, the radial expander provided in the embodiment of the present invention can be used to perform secondary expansion of the expansion tube 100, so that the outer wall of the expansion tube 100 in the enlarged diameter section 201 fits the outer well wall 200 to the maximum extent, ensuring the construction effect of the open-hole sealing and wall-fixing of the expansion tube 100.

[0048] Combination Figures 1-9The radial expander provided in this embodiment of the invention performs radial expansion of the expansion tube 100; the radial expander includes a central tube 1, an upper liquid cylinder 2, a lower liquid cylinder 7, a fixing sleeve 5, a connecting joint 6, a pushing joint 8, an expansion cone 10, a first elastic element 4, and a second elastic element 9. The central tube 1 is fitted with an upper liquid cylinder 2, a first elastic element 4, a fixing sleeve 5, a lower liquid cylinder 7, a push joint 8, and an expansion cone 10 from top to bottom on its outer side. The central tube 1 has a first through hole 11 and a second through hole 12 from top to bottom on its wall. The bottom end of the central tube 1 is sealed, and the top end of the central tube 1 is open for injecting high-pressure liquid into the central tube 1. The upper liquid cylinder 2 is fitted on the outer side of the central tube 1 and forms a first driving cavity 13 with the outer wall of the central tube 1. The first driving cavity 13 is connected to the first through hole 11. When high-pressure liquid is injected into the central tube 1, the high-pressure liquid can enter the first driving cavity 13 through the first through hole 11 to drive the upper liquid cylinder 2 to move downward. It can be understood that the top wall of the first driving cavity 13 is the outer wall of the central tube 1 so that the upper liquid cylinder 2 can move downward relative to the central tube 1 under the action of high-pressure liquid. The lower liquid cylinder 7 is sleeved on the outside of the central tube 1 and located below the upper liquid cylinder 2. A transmission cavity 14 is formed between the lower liquid cylinder 7 and the outer wall of the central tube 1. The tube wall of the lower liquid cylinder 7 has a third through hole 15. The transmission cavity 14 is configured to connect the second through hole 12 and the third through hole 15. The top end of the fixing sleeve 5 is located between the first through hole 11 and the second through hole 12 and is fixedly connected to the outer wall of the central tube 1. The inner wall of the bottom end of the fixing sleeve 5 slides and seals against the outer wall of the lower liquid cylinder 7. The top end of the connecting joint 6 passes through the fixing sleeve 5 and is fixedly connected to the upper liquid cylinder 2. The bottom end of the connecting joint 6 is fixedly connected to the lower liquid cylinder 7. A second driving cavity 16 is formed between the inner wall of the push connector 8 and the outer wall of the lower liquid cylinder 7. In the initial state, the second driving cavity 16 is connected to the third through hole 15. The top of the expansion cone 10 has a split structure, and the bottom of the expansion cone 10 is sleeved on the central tube 1 and fixedly connected to the central tube 1. The two ends of the first elastic member 4 abut against the upper liquid cylinder 2 and the fixed sleeve 5, respectively. The two ends of the second elastic member 9 abut against the push connector 8 and the expansion cone 10, respectively. The push connector 8 abuts against the fixed sleeve 5 and is limited under the elastic force of the second elastic member 9. The elastic force of the first elastic member 4 is greater than the elastic force of the second elastic member 9.

[0049] In this embodiment of the invention, the initial state refers to the state at the time of insertion. Unless otherwise specified, the fixed connection method is threaded connection. The top end of the center pipe is used to connect to the drill string and a high-pressure pump to inject high-pressure liquid into the center pipe 1; the bottom end of the center pipe 1 is provided with a bottom plug or other tool connection to achieve sealing during pressurization. The fixing sleeve 5 is fixedly connected to the center pipe 1. The upper liquid cylinder 2 and the lower liquid cylinder 7 are respectively located on the upper and lower sides of the fixing sleeve 5 and are fixedly connected by the connecting joint 6. The fixing sleeve 5 has a segmented structure, and the top end of the connecting joint 6 has a segmented structure, with the top end of the connecting joint 6 passing through the fixing sleeve 5. The expansion cone 10 has a segmented structure, and the outer diameter of the expansion cone 10 can be enlarged or reduced. In this embodiment of the invention, the push joint 8 can be inserted into the top end of the expansion cone 10 to expand the expansion cone 10 and achieve radial compensation of the enlarged diameter section 201 on the well wall 200.

[0050] The radial expander provided by this invention is used after the expansion tube 100 has undergone open-hole sealing and wall consolidation, such as... Figure 1 As shown, since the wellbore 200 has an enlarged section 201, the expansion tube 100 needs to be radially expanded to improve the sealing effect. By using a lowering tool, the radial expander provided by this invention is inserted into the expansion tube 100, allowing for further radial expansion of the expansion tube 100. This ensures that the outer wall of the expansion tube 100 is tightly fitted against the inner wall of the enlarged section 201 of the wellbore 200. Figure 2 As shown, the sealing pressure-bearing capacity is effectively improved, providing technical support for the application of high-pressure expansion tube 100-layer technology in shale gas wells and shale oil and gas fields; the radial expander of this invention can be recycled and reused, which is green, clean and saves a lot of costs.

[0051] In some embodiments, the radial expander further includes an upper connector 3, the bottom end of the upper liquid cylinder 2 is threadedly connected to the upper connector 3, the bottom end face of the upper connector 3 elastically abuts against the first elastic member 4, the inner wall of the upper connector 3 is threadedly connected to the outer wall of the connecting connector 6, and the top end face of the upper connector 3, the outer wall of the central tube 1 and the inner wall of the upper liquid cylinder 2 enclose to form a first driving cavity 13.

[0052] like Figure 1As shown, the top outer wall of the upper connector 3 is threadedly connected to the bottom inner wall of the upper cylinder 2, and the bottom inner wall of the upper connector 3 is threadedly connected to the top outer wall of the connecting connector 6, thereby enabling the upper cylinder 2 to drive the lower cylinder 7 to move synchronously. The first elastic element 4 is a spring, sleeved on the outside of the connecting connector 6. In the initial state, under the elastic force of the first elastic element 4, the upper cylinder 2 and the lower cylinder 7 are at their highest positions, the first driving cavity 13 is connected to the first through hole 11, the second through hole 12 is connected to the transmission cavity 14, and the two ends of the third through hole 15 are connected to the transmission cavity 14 and the second driving cavity 16, respectively. The first pressure of the high-pressure liquid is controlled to be greater than the elastic force of the second elastic element 9 and less than the elastic force of the first elastic element 4, thereby pushing the connector 8 to move downward under the action of the first pressure to insert into the expansion cone 10, causing the expansion cone 10 to expand, and thus the expansion tube 100 expands radially to achieve tube expansion. When the pressure of the high-pressure liquid increases to the second pressure, the first pressure is greater than the elastic force of the first elastic element 4. At this time, the second pressure in the first drive chamber 13 overcomes the elastic force of the first elastic element 4 and pushes the upper liquid cylinder 2 to move downward. Then, through the connecting joint 6, it drives the lower liquid cylinder 7 to move downward. When the lower liquid cylinder 7 moves downward, the second through hole 12 is misaligned with the transmission chamber 14, and the third through hole 15 is misaligned with the second drive chamber 16, until the high-pressure liquid in the second drive chamber 16 flows out, pushing the joint 8 to release pressure. The joint 8 is pushed to reset under the elastic force of the second elastic element 9, pushing the joint 8 away from the expansion cone 10. The expansion cone 10 is reset, thereby stopping the radial expansion or protecting the radial expander in case of an emergency.

[0053] In some embodiments, the outer wall of the fixed sleeve 5 is provided with a first limiting step 17. In the initial state, under the action of the second elastic member 9, the top end of the push connector 8 is stopped on the first limiting step 17, and the transmission cavity 14 and the second drive cavity 16 are in a connected state.

[0054] like Figure 3 and Figure 4 As shown, in the initial state, the fixed sleeve 5 limits the upper limit position of the push joint 8; when the push joint 8 is subjected to high-pressure liquid with a first pressure, the push joint 8 moves downward relative to the fixed sleeve 5, and the expansion tube 100 begins to expand; since the relative positions of the lower cylinder 7 and the fixed sleeve 5 remain unchanged, the high-pressure liquid continuously passes through the second through hole 12, the transmission cavity 14 and the third through hole 15, providing a continuous force to the push joint 8, and continuously expanding the tube wall of the expansion tube 100 during the upward movement of the central tube 1, thus obtaining... Figure 5 The state shown.

[0055] In some embodiments, the outer wall of the lower cylinder 7 is provided with a groove 18, which is connected to the top end face of the lower cylinder 7. When the lower cylinder 7 moves downward to the second drive chamber 16 and the groove 18, the high-pressure liquid in the second drive chamber 16 can flow out along the groove 18.

[0056] like Figure 3 As shown, since both the fixing sleeve 5 and the connecting joint 6 are segmented structures, and the first elastic element 4 is a spring, in the initial state, the groove 18 connects to the space between the upper liquid cylinder 2 and the expansion tube 100 through the top end face of the lower liquid cylinder 7. When the pressure of the high-pressure liquid reaches the second pressure, it causes the lower liquid cylinder 7 to move downwards, as shown. Figure 6 As shown, when the hydraulic cylinder 7 moves downward to the point where the second drive chamber 16 connects with the groove 18, the high-pressure liquid in the second drive chamber 16 flows out through the groove 18, pushing the connector 8 to release pressure. Under the elastic force of the second elastic element 9, the connector 8 will return to its initial position, thereby depressurizing the expansion cone 10. The expansion cone 10 will also return to its initial state, which is conducive to the recycling operation.

[0057] In some embodiments, the inner wall of the push connector 8 is provided with a first stepped groove and a second stepped groove. In the initial state, the push connector 8 is at its maximum height and abuts against the first limiting step 17 of the fixed sleeve 5. Part of the groove wall of the first stepped groove is slidably sealed to the outer wall of the fixed sleeve 5. A second driving cavity 16 is formed between the bottom of the first stepped groove, another part of the groove wall, the bottom end face of the fixed sleeve 5 and the outer wall of the lower liquid cylinder 7. In the initial state, the second driving cavity 16 is connected to the third through hole 15. The groove wall of the second stepped groove is slidably sealed to the outer wall of the lower liquid cylinder 7. The high-pressure liquid in the central tube 1 can enter the transmission cavity 14 through the second through hole 12 and enter the second driving cavity 16 through the third through hole 15, forming a force on the push connector 8.

[0058] like Figure 8 In the initial state, a second driving cavity 16 is formed between the bottom of the first stepped groove and the bottom end face of the fixed sleeve 5. The bottom part of the groove wall of the first stepped groove is directly opposite the third through hole 15. During expansion, high-pressure liquid can pass through the second through hole 12, the transmission cavity 14, and the third through hole 15 and enter the second driving cavity 16 to form pressure on the bottom of the first stepped groove to drive the movement of the push joint 8. The space of the second driving cavity 16 also increases continuously until the push joint 8 and the expansion cone 10 are tightly tightened. When the lower cylinder 7 moves downward, as... Figure 9 As shown, the lower liquid cylinder 7 moves downward relative to the central tube 1, the second through hole 12 is offset from the transmission cavity 14, and the second drive cavity 16 is offset from the third through hole 15, until the second drive cavity 16 is connected to the groove 18, and the second through hole 12 is directly opposite the V-shaped sealing ring 19 set on the inner wall of the lower liquid cylinder 7. The high pressure liquid in the second drive cavity 16 flows out through the groove 18, pushing the connector 8 to release pressure and reset. The expansion cone 10 is then reset to the initial state, the radial expansion ends and the radial expander is lifted.

[0059] In some embodiments, the outer diameter of the bottom outer wall of the push connector 8 gradually increases from bottom to top, and the inner wall of the push connector 8 is provided with a limiting groove 20, and the top end of the second elastic member 9 abuts against the bottom of the limiting groove 20.

[0060] Combination Figure 3 The bottom outer wall of the push connector 8 forms a conical structure, which facilitates smooth insertion of the push connector 8 into the expansion cone 10 to achieve expansion. A limiting groove 20 is provided on the inner wall of the push connector 8 to limit the second elastic element 9 and improve the elasticity of the bottom of the push connector 8, facilitating elastic deformation to fit the expansion cone 10 for expansion. Preferably, the outer wall of the push connector 8 has a rounded transition structure, and the inner wall of the top of the expansion cone 10 matches the outer wall of the bottom of the push connector 8 to reduce friction. Furthermore, the outer wall of the top of the expansion cone 10 has a rounded transition protrusion to facilitate sliding contact with the inner wall of the expansion tube 100 for expansion, reducing friction and wear, and minimizing jamming damage. The second elastic element 9 is sleeved on the central tube 1, with both ends respectively limited between the push connector 8 and the expansion cone 10. The initial state of the second elastic element 9 is elastic compression, and the push connector 8 separates from the expansion cone 10 under the elastic force of the second elastic element 9.

[0061] Using the radial expander provided by this invention, embodiments of this invention also provide a radial expander method comprising the following steps:

[0062] S1, after the open-hole sealing and wall consolidation is performed using the expansion tube 100, the expansion tube 100 adheres to the well wall 200, and the well wall 200 has one or more enlarged diameter sections 201; such as Figure 1 As shown, the outer wall of the expansion pipe 100 and the well wall 200 are sealed by a sealing device 101. When there is more than one enlarged diameter section 201 on the well wall 200, there is a large gap between the expansion pipe 100 and the enlarged diameter section 201 on the well wall 200, which affects the sealing performance. It is necessary to further enlarge the diameter of the expansion pipe 100 to make it fit the well wall 200.

[0063] S2, based on well logging data, the radial expander is lowered into the expansion tube 100, ensuring the expansion cone 10 is positioned below the enlarged section 201; as Figure 3 The state shown.

[0064] S3, inject high-pressure liquid (such as clean water) into the central tube 1 and pressurize it to the first pressure (generally 25-28 MPa). The first pressure is less than the elastic force of the first elastic element 4 and greater than the elastic force of the second elastic element 9. Under the action of the high-pressure liquid, the connector 8 is pushed downward against the elastic force of the second elastic element 9 and the expansion cone 10 is supported. The expansion cone 10 expands the expansion tube 100 and fits it against the inner wall of the expansion section 201. Figure 4 As shown, the expansion tube 100 undergoes secondary expansion under the action of the expansion cone 10, as... Figure 2The outer wall of the expansion tube 100 fits against the inner wall of the enlarged section 201 of the well wall 200, thus achieving a seal on the well wall 200.

[0065] The radial expansion method provided by the present invention further seals the expanded diameter section 201 on the well wall 200 by expanding the expansion pipe 100 a second time, thereby improving the sealing effect and facilitating subsequent construction.

[0066] In some embodiments, the radial tube expansion method further includes step S4, lifting the central tube 1, and under the action of the expansion cone 10, the outer diameter of the expansion tube 100 continues to expand along its axial direction until the lifting resistance suddenly increases, the lifting stops, and the tube expansion ends.

[0067] like Figure 5 As shown, when the enlarged section 201 on the well wall 200 has a certain length along the axial direction of the well wall 200, the expansion tube 100 can be continuously radially enlarged in the axial direction by pulling the radial expander upward, so that the expansion tube 100 and the enlarged section 201 are completely sealed together. During the process of pulling the radial expander, the resistance to increase needs to be monitored in real time. Once the upward pull is blocked, it means that the enlarged section 201 has been fully expanded, and at this time, the pressure can be released and recovered. If there are other enlarged sections 201 on the well wall 200, the radial expander can be moved to the lower end of the corresponding enlarged section 201, and the above steps S2-S4 can be repeated until the expansion tube 100 and the well wall 200 are completely sealed together.

[0068] In some embodiments, in steps S3 and S4, when the first pressure of the high-pressure liquid instantly rises to the second pressure, under the action of the high-pressure liquid, the upper liquid cylinder 2 will overcome the elastic force of the first elastic element 4 and move downward. At the same time, the upper liquid cylinder 2 drives the lower liquid cylinder 7 to move downward through the connecting joint 6 until the high-pressure liquid in the second drive chamber 16 flows out through the groove 18 on the outer wall of the top of the lower liquid cylinder 7, pushing the joint 8 to release pressure and retract under the action of the elastic force of the second elastic element 9, the expansion cone 10 resets, and the expansion tube stops.

[0069] When the radial dimension of the expanding section 201 varies along the axial direction, the radial expander may encounter a shrinkage in the size of the expanding section 201 during lifting, or other situations that may cause a sudden increase in pressure during pressurization. In this invention, the second pressure is set to 30 MPa. When the first pressure of the high-pressure liquid instantly rises to the second pressure, to avoid damage to the expansion tube 100 and the radial expander, measures to stop the expansion are needed. In this invention, when the pressure of the high-pressure liquid reaches the second pressure, the high-pressure liquid in the first drive chamber 13 causes the upper cylinder 2 to overcome the elastic force of the first elastic element 4 and move downwards. The lower cylinder 7 moves downwards through the connecting joint 6. When the second drive chamber 16 communicates with the groove 18, the pressure received by the push joint 8 decreases. Under the elastic force of the second elastic element 9, the push joint 8 moves upwards away from the expansion cone 10, thus stopping the expansion process. Figure 6 The push joint 8 and expansion cone 10 shown are both reset and retracted to facilitate lifting and retraction and reoperation.

[0070] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A radial expander for radially expanding an expansion tube (100); characterized in that, The radial expander includes: A central tube (1) is provided with a first through hole (11) and a second through hole (12) from top to bottom on the tube wall; the bottom end of the central tube (1) is sealed and the top end of the central tube (1) is open, and the top end opening is used to inject high pressure liquid into the central tube (1); Upper liquid cylinder (2), the upper liquid cylinder (2) is sleeved on the outside of the central tube (1) and forms a first driving cavity (13) between it and the outer wall of the central tube (1), the first driving cavity (13) is connected to the first through hole (11); The lower liquid cylinder (7) is sleeved on the outside of the central tube (1) and located below the upper liquid cylinder (2). A transmission cavity (14) is formed between the lower liquid cylinder (7) and the outer wall of the central tube (1). The tube wall of the lower liquid cylinder (7) has a third through hole (15). The transmission cavity (14) is connected to the second through hole (12) and the third through hole (15). The top end of the fixed sleeve (5) is located between the first through hole (11) and the second through hole (12) and is fixedly connected to the outer wall of the central tube (1). The inner wall of the bottom end of the fixed sleeve (5) is slidably sealed to the outer wall of the lower liquid cylinder (7). Connecting joint (6), the top end of the connecting joint (6) is inserted upward through the fixing sleeve (5) and fixedly connected to the upper liquid cylinder (2), and the bottom end of the connecting joint (6) is fixedly connected to the lower liquid cylinder (7); A push joint (8) is provided, and a second drive cavity (16) is formed between the inner wall of the push joint (8) and the outer wall of the lower liquid cylinder (7). The second drive cavity (16) is connected to the third through hole (15). An expansion cone (10) has a split top end and a bottom end that is fitted onto the central tube (1) and fixedly connected to the central tube (1). The first elastic element (4) has two ends that abut against the upper liquid cylinder (2) and the fixed sleeve (5), respectively. The second elastic element (9) has two ends that abut against the push joint (8) and the expansion cone (10) respectively. The push joint (8) is abutted against and limited by the fixed sleeve (5) under the elastic force of the second elastic element (9). The elastic force of the first elastic element (4) is greater than the elastic force of the second elastic element (9).

2. The radial expander according to claim 1, characterized in that, It also includes an upper connector (3), the bottom end of the upper liquid cylinder (2) is threadedly connected to the upper connector (3), the bottom end face of the upper connector (3) elastically abuts against the first elastic element (4), the inner wall of the upper connector (3) is threadedly connected to the outer wall of the connecting connector (6), and the top end face of the upper connector (3), the outer wall of the central tube (1) and the inner wall of the upper liquid cylinder (2) enclose to form the first driving cavity (13).

3. The radial expander according to claim 1, characterized in that, The outer wall of the fixed sleeve (5) is provided with a first limiting step (17). In the initial state, under the action of the second elastic member (9), the top end of the push joint (8) abuts against the first limiting step (17), and the transmission cavity (14) and the second drive cavity (16) are in a connected state.

4. The radial expander according to claim 1, characterized in that, The outer wall of the lower liquid cylinder (7) is provided with a groove (18), which is connected to the top end face of the lower liquid cylinder (7). When the lower liquid cylinder (7) moves downward to the second drive chamber (16) and the groove (18) are connected, the high pressure liquid in the second drive chamber (16) can flow out along the groove (18).

5. The radial expander according to claim 4, characterized in that, The inner wall of the push joint (8) is provided with a first stepped groove and a second stepped groove. In the initial state, the push joint (8) is at its maximum height. Part of the groove wall of the first stepped groove is slidably and sealed to the outer wall of the fixed sleeve (5). The bottom of the first stepped groove, another part of the groove wall of the stepped groove, the bottom end face of the fixed sleeve (5) and the groove wall of the second stepped groove are slidably and sealed to the outer wall of the lower liquid cylinder (7). When the lower liquid cylinder (7) moves downward to the second drive chamber (16) and the groove (18) to communicate to release pressure, the push joint (8) is reset.

6. The radial expander according to claim 1, characterized in that, The top of the connecting joint (6) is a split structure, and the fixing sleeve (5) is a split structure.

7. The radial expander according to claim 1, characterized in that, The outer diameter of the bottom outer wall of the push joint (8) gradually increases from bottom to top. The inner wall of the push joint (8) is provided with a limiting groove (20). The top end of the second elastic member (9) abuts against the bottom of the limiting groove (20).

8. A radial tube expansion method, characterized in that, The radial expander according to any one of claims 1-7, the radial expander method comprising the following steps: S1, after the open hole is sealed and solidified by the expansion tube (100), the expansion tube (100) is attached to the well wall (200), and the well wall (200) has one or more enlarged diameter sections (201); S2, based on the logging data, the radial expander is lowered into the expansion tube (100) and the expansion cone (10) is positioned below the expansion section (201); S3, inject high-pressure liquid into the central tube (1) and pressurize it to the first pressure. The first pressure is less than the elastic force of the first elastic element (4) and greater than the elastic force of the second elastic element (9). Under the action of the high-pressure liquid, push the connector (8) to move downward against the elastic force of the second elastic element (9) and support the expansion cone (10). The expansion cone (10) expands the expansion tube (100) and fits against the inner wall of the expansion section (201).

9. The radial tube expansion method according to claim 8, characterized in that, It also includes step S4, lifting the central tube (1), under the action of the expansion cone (10), the outer diameter of the expansion tube (100) continues to expand along its axial direction until the lifting resistance suddenly increases, the lifting stops, and the tube expansion ends.

10. The radial tube expansion method according to claim 9, characterized in that, In steps S3 and S4, when the first pressure of the high-pressure liquid instantly rises to the second pressure, under the action of the high-pressure liquid, the upper liquid cylinder (2) will overcome the elastic force of the first elastic element (4) and move downward. At the same time, the upper liquid cylinder (2) drives the lower liquid cylinder (7) to move downward through the connecting joint (6) until the high-pressure liquid in the second driving chamber (16) flows out through the groove (18) on the outer wall of the top of the lower liquid cylinder (7). The push joint (8) releases pressure and retracts under the elastic force of the second elastic element (9). The expansion cone (10) resets and stops the expansion tube.

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