Deblocable frac packer, tool string, methods of packing and deblocking

Abstract

The application provides a fracturing acidizing packer, a tool pipe string, and a packing and unpacking method, wherein the packer comprises a center pipe, a setting driving mechanism, a first setting mechanism and a second setting mechanism, the setting driving mechanism comprises a piston, a cylinder sleeve and a joint, the joint is fixedly connected with the center pipe, the piston is located above the joint, and the cylinder sleeve is fixedly connected with the piston; the first setting mechanism and the second setting mechanism are both sleeved on the center pipe, the second setting mechanism is located above the setting driving mechanism, and the first setting mechanism is located above the second setting mechanism; the first setting mechanism comprises slips, and the second setting mechanism comprises a rubber sleeve; the liquid pressure in the inner cavity of the center pipe can act on the lower end of the first piston, push the piston and the cylinder sleeve to move upward in the axial direction, and sequentially compress the second setting mechanism and the first setting mechanism, so that the rubber sleeve and the slips are expanded and set. The application is provided with an unpacking system, can realize unpacking by ball pressure holding, has high unpacking reliability, and can effectively recover the packer after the operation is completed.

Description

Technical Field

[0001] This invention relates to the field of downhole tools technology for oil and gas drilling and production, and more specifically, to a resealable fracturing and acidizing packer, tool string, packer and resealable method. Background Technology

[0002] Currently, my country's oil and gas development is gradually shifting towards deeper formations, which are characterized by high temperature and high pressure, making them more complex than conventional reservoirs. Horizontal well staged fracturing and acidizing is a commonly used reservoir stimulation method. This method requires installing multiple packers within the reservoir to isolate it in stages, and then fracturing and acidizing each stage separately to increase production. The packer is a crucial tool for reservoir stimulation, primarily used for fracturing and acidizing individual reservoirs within the casing of ultra-deep, high-temperature wells. The performance of the packer directly determines the effectiveness of the fracturing and acidizing process.

[0003] For example, Chinese patent CN113882831A discloses a novel packer, comprising an upper central tube, with an upper rubber sleeve drive ring and an upper rubber sleeve sequentially fitted on the outer side of the upper central tube from top to bottom. The lower central tube has a connecting thread on its bottom outer side, through which a lower central tube is connected. The lower central tube also has a lower rubber sleeve drive ring and a lower rubber sleeve sequentially fitted on its outer side from top to bottom. The lower central tube has a connecting thread on its bottom outer side, through which a lower connector is connected. The lower connector also has a connecting thread on its bottom outer side, through which a lower plug is connected. This novel packer, by employing two or more sets of independent working rubber sleeves, where each set no longer shares a single power source but instead has its own dedicated power assembly, forms two sets of rubber sleeve setting groups with targeted and differentiated performance under power coordination. This enables setting requirements in deep wells under higher pressures.

[0004] For example, Chinese Patent CN108060906A discloses a non-throttling fracturing packer for high-pressure oil and gas wells, comprising an upper connector with at least two rubber sleeves outside the upper connector, adjacent rubber sleeves separated by spacer rings; a spring center tube connected to the lower end of the upper connector, with a pre-tightened spring and a spring preload ring for adjusting the spring preload outside the spring center tube, and a rubber sleeve drive sleeve outside the spring preload ring; a power chamber center tube connected to the lower end of the spring center tube, with a lower connector connected to the end of the power chamber center tube, and a power slider outside the power chamber center tube, the power slider and the power chamber center tube forming an air chamber, and the power slider, the power chamber center tube, and the lower connector forming a hydraulic chamber; a soluble plunger is provided on the power slider corresponding to the air chamber; and a waterproof cover is provided outside the soluble plunger. This invention solves the problems of low sand removal and low working efficiency caused by the need for throttling when using traditional packers in high-pressure oil and gas wells; it can solve the problem of stuck well phenomenon, and is conducive to reducing construction costs and safety risks.

[0005] The first type of packer described above can effectively seal the annulus after setting, but it cannot fulfill the requirement for unsealing. The second type of packer achieves unsealing through the dissolution of a soluble metal, with a waterproof cover covering the outside of the soluble metal column. Under complex downhole conditions, this unsealing method has lower reliability compared to mechanical methods. Summary of the Invention

[0006] The purpose of this invention is to address at least one of the aforementioned deficiencies in the prior art. For example, one objective of this invention is to provide a resealable fracturing acidizing packer, tool string, packer, and resealable method to solve the technical problems in the prior art where the packer cannot be resealed after setting, or where the resealable method has low reliability.

[0007] To achieve the above objectives, the present invention provides a resealable fracturing acidizing packer. The packer may include a central tube, a first setting drive mechanism, a first setting mechanism, and a second setting mechanism. The first setting drive mechanism includes a first piston, a first cylinder liner, and a first connector. The upper end of the first connector is fitted onto the lower end of the central tube and fixedly connected to the central tube. The first piston is fitted onto the central tube and axially positioned above the first connector. The first cylinder liner is fitted onto the first connector and the first piston and fixedly connected to the first piston. Both the first and second setting mechanisms are fitted onto the central tube, with the second setting mechanism axially positioned above the first setting drive mechanism. A first setting mechanism is located axially above a second setting mechanism; the first setting mechanism includes a slip sleeved on a central tube, and the second setting mechanism includes a rubber sleeve sleeved on a central tube; a first gap is formed between the lower end of the first piston, the upper end of the first connector, the inner wall of the first cylinder liner, and the outer wall of the central tube; a radially penetrating first pressure transmission hole is opened on the side wall of the central tube, and the first pressure transmission hole communicates with the first gap; the liquid pressure in the inner cavity of the central tube can act on the lower end of the first piston along the first pressure transmission hole and the first gap, pushing the first piston and the first cylinder liner to move axially upward and sequentially compress the second setting mechanism and the first setting mechanism, so that the rubber sleeve and the slip sleeve expand radially to perform setting.

[0008] Optionally, the packer may further include a thrust sleeve and a locking mechanism, both of which are fitted onto the central tube. The upper end of the thrust sleeve is fixedly connected to the lower end of the locking mechanism, and the lower end of the thrust sleeve abuts against the first piston. The thrust sleeve and the central tube are connected by an actuating shear pin. The locking mechanism includes a locking ring and a locking sleeve. The locking ring is installed between the outer wall of the central tube and the inner wall of the locking sleeve, and the locking ring is fixedly connected to the inner wall of the locking sleeve. The upper end of the locking sleeve abuts against the lower end of the rubber sleeve, and the lower end of the locking sleeve is fixedly connected to the thrust sleeve. A matching ratchet structure is formed between the inner wall of the locking sleeve and the outer wall of the central tube. The thrust sleeve can shear the actuating shear pin and push the locking mechanism upward to compress the rubber sleeve under the thrust of the first piston. The ratchet structure can prevent the locking mechanism from moving downward relative to the central tube.

[0009] Optionally, the packer may further include a second setting drive mechanism connected to the lower end of the first setting drive mechanism. The second setting drive mechanism includes a second piston, a second cylinder liner, a second connector, and a centering sleeve. The upper end of the second connector is fitted onto the lower end of the first connector and is fixedly connected to the first connector. The second piston is fitted onto the first connector and is located axially above the second connector. The second cylinder liner is fitted onto the second connector and the second piston and is fixedly connected to the second piston. The centering sleeve is fitted onto the second connector and connected to the lower end of the second cylinder liner. A second gap is formed between the lower end of the second piston, the upper end of the second connector, the inner wall of the second cylinder liner, and the outer wall of the first connector. A radially penetrating second pressure transmission hole is provided on the side wall of the first connector. The second pressure transmission hole communicates with the second gap. The liquid pressure in the inner cavity of the first connector can act on the lower end of the second piston along the second pressure transmission hole and the second gap, pushing the second piston and the second cylinder liner to move axially upward and sequentially compress the second setting mechanism and the first setting mechanism, causing the rubber sleeve and the slip to expand radially to perform setting.

[0010] Optionally, the first setting mechanism may further include an upper cone, a lower cone, a slip support, a cone pressure cap, and a wave spring. The upper cone is sleeved on the central tube and located at the upper end of the slip, and the lower end of the upper cone can be inserted between the slip and the central tube. The lower cone is sleeved on the central tube and connected to the central tube via a cone shear pin. The lower cone is located at the lower end of the slip and can shear the cone shear pin under axial thrust, inserting its upper end between the slip and the central tube, causing the slip to open radially and set. The slip support is sleeved on the upper and lower cones and is used to limit the upper and lower cones. The cone pressure cap is installed between the slip support and the upper cone and is used to position the upper cone. The wave spring is embedded in the slip and is used to limit the slip.

[0011] Optionally, an anti-rotation key is provided between the lower cone and the central tube, the anti-rotation key being used to keep the lower cone and the central tube circumferentially relatively fixed.

[0012] Alternatively, the second setting mechanism may further include a rubber sleeve seat, the upper end of which is sleeved on the lower end of the first setting mechanism and fixedly connected to the first setting mechanism, and the lower end of the rubber sleeve seat abutting against the upper end of the rubber sleeve.

[0013] Optionally, the packer may further include a release mechanism, which includes an upper connector, a release ball seat, a release shear pin, a release spring claw, and a connecting sleeve. The lower end of the release spring claw is fitted onto the upper end of the central tube and is fixedly connected to the central tube. The connecting sleeve is fitted onto the release spring claw, and the upper end of the connecting sleeve is fixedly connected to the lower end of the upper connector. The release ball seat passes through the release spring claw and is fixedly connected to the release spring claw via the release shear pin. The release ball seat can shear the release shear pin and push the central tube downward after being subjected to axial downward pressure, and drive the first setting drive mechanism downward, so that the rubber sleeve and the slip retract radially to release the seal.

[0014] Alternatively, an outer step may be formed on the outer wall of the central tube, and an inner step may be provided on the inner wall of the thrust sleeve. When the central tube is pushed down by the unsealing ball seat, the outer step may abut against the inner step, thereby driving the thrust sleeve and the locking mechanism down together to achieve unsealing.

[0015] Another aspect of the present invention provides a tool string, which may include the resealable fracturing acid packer as described above.

[0016] In another aspect, the present invention provides a method for sealing and unsealing a resealable fracturing and acidizing packer. The sealing and unsealing method can employ the resealable fracturing and acidizing packer as described above, or the tool string as described above. The sealing and unsealing method includes a sealing stage and an unsealing stage. The sealing stage includes inserting a setting ball into an opening ball seat located below the packer to seal the lower end of the packer, pressurizing the central tube, and allowing high-pressure liquid to enter the first gap along the first pressure transmission hole, pressurizing the lower end of the first piston, pushing the first piston upwards and sequentially squeezing the second and first setting mechanisms, causing the rubber sleeve and slips to expand radially and complete the setting. The unsealing stage includes subjecting the central tube to an axially downward force, causing it to descend, and driving the first setting drive mechanism downwards together, releasing the extrusion force acting on the second and first setting mechanisms, causing the rubber sleeve and slips to contract radially and return to their initial position, thus completing the unsealing.

[0017] Compared with the prior art, the beneficial effects of the present invention include at least one of the following:

[0018] 1. After the hydraulic cylinder power system in the packer of the present invention is started, the packer sleeve and the packer's dual-support anchoring system (slips) are sequentially set and engaged. The dual-support anchoring system provides support and protection for the sleeve setting, thereby improving the packer's pressure-bearing capacity.

[0019] 2. In this invention, multiple sets of high-temperature and high-pressure resistant sealing rings are respectively provided between the piston and the central tube, the cylinder liner, between the release pawl and the central tube, the release ball seat, the connecting sleeve, and between the upper connector and the release ball seat. The rubber sleeve is made of high-temperature resistant material, so that the packer can effectively adapt to high-temperature and high-pressure conditions.

[0020] 3. The present invention provides an unsealing system on the upper part of the packer, which can unseal the packer at any time by throwing a ball to pressurize it. The unsealing system has high reliability, which enables the packer to be effectively recovered after fracturing and acidizing operations are completed. Attached Figure Description

[0021] The above and other objects and / or features of the present invention will become clearer from the following description taken in conjunction with the accompanying drawings, in which:

[0022] Figure 1 An overall structural diagram of a resealable fracturing acid packer according to an exemplary embodiment of the present invention is shown.

[0023] Figure 2 It shows Figure 1 A partial structural diagram at point A in the middle.

[0024] Figure 3 It shows Figure 1 A partial structural diagram at point B in the middle.

[0025] Figure 4 It shows Figure 1 A partial structural diagram at point C.

[0026] Figure 5 It shows Figure 1 A partial structural diagram at point D.

[0027] Figure 6 It shows Figure 3 Cross-sectional view at "EE".

[0028] Explanation of reference numerals in the attached figures:

[0029] 1. Central tube; 11. First pressure transmission hole; 12. Outer step; 2. First setting drive mechanism; 21. First piston; 22. First cylinder liner; 23. First connector; 231. Second pressure transmission hole; 24. First clearance; 3. First setting mechanism; 31. Slip; 32. Upper cone; 33. Lower cone; 34. Slip support; 35. Cone pressure cap; 36. Wave spring; 37. Cone shear pin; 38. Anti-rotation key; 4. Second setting mechanism; 41. 42. Glue tube, 5. Thrust sleeve, 51. Inner step, 52. Starting shear pin, 6. Locking mechanism, 61. Locking ring, 62. Locking sleeve, 621. Ratchet structure, 7. Second setting drive mechanism, 71. Second piston, 72. Second cylinder liner, 73. Second connector, 74. Straightening sleeve, 75. Second clearance, 8. Unsealing mechanism, 81. Upper connector, 82. Unsealing ball seat, 83. Unsealing shear pin, 84. Unsealing spring claw, 85. Connecting sleeve. Detailed Implementation

[0030] In the following sections, the resealable fracturing acid packer, tool string, packer, and unpacking method of the present invention will be described in detail with reference to exemplary embodiments.

[0031] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, 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 this application.

[0032] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0033] In the description of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" 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 direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication 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.

[0034] In related technologies, on the one hand, while packers can effectively seal the annulus after setting, they cannot meet the unsealing requirements; on the other hand, packers can be unsealed by dissolving soluble metals. The soluble metal column is covered with a waterproof cover, but under complex downhole conditions, this unsealing method is less reliable than mechanical methods.

[0035] Based on this, the present invention provides a resealable fracturing acidizing packer, a tool string, a packer, and a method for packing and unpacking. The packer includes a central tube, a first setting drive mechanism, a first setting mechanism, and a second setting mechanism. The first setting drive mechanism includes a first piston, a first cylinder liner, and a first connector. The upper end of the first connector is fitted onto the lower end of the central tube and fixedly connected to the central tube. The first piston is fitted onto the central tube and axially positioned above the first connector. The first cylinder liner is fitted onto the first connector and the first piston and fixedly connected to the first piston. Both the first and second setting mechanisms are fitted onto the central tube, with the second setting mechanism axially positioned above the first setting drive mechanism. The first setting mechanism is located axially above the second setting mechanism. The first setting mechanism includes a slip sleeved on the central tube, and the second setting mechanism includes a rubber sleeve sleeved on the central tube. A first gap is formed between the lower end of the first piston, the upper end of the first connector, the inner wall of the first cylinder liner, and the outer wall of the central tube. A radially penetrating first pressure transmission hole is opened on the side wall of the central tube. The first pressure transmission hole communicates with the first gap. The liquid pressure in the inner cavity of the central tube can act on the lower end of the first piston along the first pressure transmission hole and the first gap, pushing the first piston and the first cylinder liner to move axially upward and sequentially compress the second setting mechanism and the first setting mechanism, so that the rubber sleeve and the slip sleeve expand radially to perform setting.

[0036] After the hydraulic cylinder power system in the packer of this invention is started, the packer sleeve and the packer's dual-support anchoring system (slips) are sequentially set and engaged. The dual-support anchoring system provides support and protection for the sleeve setting, improving the packer's pressure-bearing capacity. This invention provides multiple sets of high-temperature and high-pressure resistant sealing rings between the piston and the central tube / cylinder liner, between the release pawl and the central tube, the release ball seat, and the connecting sleeve, and between the upper connector and the release ball seat. The sleeve is made of high-temperature resistant material, enabling the packer to effectively adapt to high-temperature and high-pressure conditions. This invention also includes a release system on the upper part of the packer, allowing for release at any time by throwing a ball to pressurize the packer. The release system has high reliability, enabling effective recovery of the packer after fracturing and acidizing operations.

[0037] Exemplary Example 1

[0038] This exemplary embodiment provides a resealable fracturing acid packer.

[0039] Figure 1An overall structural diagram of a resealable fracturing acid packer according to an exemplary embodiment of the present invention is shown; Figure 2 It shows Figure 1 A partial structural diagram at point A in the middle; Figure 3 It shows Figure 1 Local structural diagram at point B; Figure 4 It shows Figure 1 Local structural diagram at point C; Figure 5 It shows Figure 1 Local structural diagram at point D; Figure 6 It shows Figure 3 Cross-sectional view at "EE".

[0040] like Figures 1 to 6 As shown in the exemplary embodiment, the resealable fracturing acid packer may include a central tube 1, a first setting drive mechanism 2, a first setting mechanism 3, and a second setting mechanism 4. The first setting drive mechanism 2 may include a first piston 21, a first cylinder liner 22, and a first connector 23. The upper end of the first connector 23 may be sleeved on the lower end of the central tube 1 and fixedly connected to the central tube 1 by threaded connections. The first piston 21 may be sleeved on the central tube 1 and located axially above the first connector 23. The first cylinder liner 22 may be sleeved outside the first connector 23 and the first piston 21 and fixedly connected to the first piston 21 by threaded connections.

[0041] The first setting mechanism 3 and the second setting mechanism 4 can both be sleeved on the central tube 1. The second setting mechanism 4 can be located above the first setting drive mechanism 2 in the axial direction, and the first setting mechanism 3 can be located at the upper end of the second setting mechanism 4 in the axial direction. The first setting mechanism 3 may include a slip 31 sleeved on the central tube 1, and the second setting mechanism 4 may include a rubber sleeve 41 sleeved on the central tube 1.

[0042] A first gap 24 can be formed between the lower end of the first piston 21, the upper end of the first connector 23, the inner wall of the first cylinder liner 22, and the outer wall of the central tube 1. A radially penetrating first pressure-transmitting hole 11 is provided on the side wall of the central tube 1. Here, the number of first pressure-transmitting holes 11 can be 4, and the 4 first pressure-transmitting holes 11 can be evenly distributed along the circumference of the side wall of the central tube 1. The first gap 24 can communicate with the first pressure-transmitting holes 11. When liquid is introduced into the inner cavity of the central tube 1 for pressurization, the liquid in the central tube 1 can enter the first gap 24 through the first pressure-transmitting holes 11 and apply pressure to the lower end of the first piston 21, which can push the first piston 21. Together with the first cylinder liner 22, it moves upward along the axial direction, which can compress the second setting mechanism 4 and the first setting mechanism 3 above. At the same time, it can cause the rubber sleeve 41 and the slip 31 to expand radially and set the sleeve outside the packer. However, the present invention is not limited to this. The first pressure transmission hole 11 opened on the side wall of the central tube 1 can also be other numbers, which can be arbitrarily selected according to actual needs. The connection method between the first connector 23 and the central tube 1 and the connection method between the first cylinder liner 22 and the first piston 21 are not limited to threaded connection. They can also be arbitrarily selected according to actual needs. The present invention does not make specific limitations on this.

[0043] In this embodiment, the resealable fracturing acid packer described in this exemplary embodiment may further include a thrust sleeve 5 and a locking mechanism 6. Both the thrust sleeve 5 and the locking mechanism 6 can be sleeved on the central tube 1 and located axially between the first setting drive mechanism 2 and the second setting mechanism 4. The upper end of the thrust sleeve 5 can be sleeved on the lower end of the locking mechanism 6 and fixedly connected to the locking mechanism 6 through a threaded connection. The lower end of the thrust sleeve 5 can abut against the upper end of the first piston 21. The thrust sleeve 5 can be fixedly connected to the central tube 1 by activating the shear pin 52.

[0044] The locking mechanism 6 may include a locking ring 61 and a locking sleeve 62. The locking sleeve 62 may be fitted onto the central tube 1. The inner wall of the upper section of the locking sleeve 62 may have a ratchet structure 621. The ratchet structure 621 may engage with the ratchet structure on the outer wall of the central tube 1, thereby allowing the locking sleeve 62 to move upward and preventing the locking sleeve 62 from moving downward in the axial direction. The locking ring 61 may be installed between the inner wall of the lower section of the locking sleeve 62 and the outer wall of the central tube 1. The upper end of the locking ring 61 may abut against the step on the inner wall of the locking sleeve 62. The inner wall of the locking ring 61 may also have a ratchet structure, which may also engage with the ratchet on the outer wall of the central tube 1, thereby also preventing the locking ring 61 from moving downward.

[0045] When the first piston 21 applies an upward thrust to the thrust sleeve 5, and the magnitude of the thrust exceeds a certain critical value, the starting shear pin 52 connecting the thrust sleeve 5 and the central tube 1 can be cut off, thereby freeing the thrust sleeve 5 from the constraint of the central tube 1. The thrust sleeve 5 can then transmit the thrust applied by the first piston 21 to the locking mechanism 6, causing the thrust sleeve 5 and the locking mechanism 6 to move upward along the axial direction together, compressing the second setting mechanism 4 and the first setting mechanism 3, causing the rubber sleeve 41 and the slip 31 to expand radially for setting. In addition, after the locking mechanism 6 moves upward along the axial direction, the ratchet structure 621 on its inner wall can cooperate with the ratchet structure on the outer wall of the central tube to prevent the locking mechanism 6 from moving downward, thereby maintaining the compression force on the second setting mechanism 4 and the first setting mechanism 3, ensuring that the rubber sleeve 41 and the slip 31 always maintain the setting of the outer sleeve, and avoiding setting failure.

[0046] In this embodiment, the resealable fracturing acid packer described in this exemplary embodiment may further include a second setting drive mechanism 7. The second setting drive mechanism 7 may be connected below the first setting drive mechanism 2. The second setting drive mechanism 7 may include a second piston 71, a second cylinder liner 72, a second connector 73, and a centralizing sleeve 74. The upper end of the second connector 73 may be fitted onto the lower end of the first connector 23 and fixedly connected to the first connector 23 by threaded connections. The second piston 71 may be fitted onto the first connector 23 and located axially above the second connector 73. The second cylinder liner 72 may be fitted onto the second connector 73 and the second piston 71 and fixedly connected to the second piston 71 by threaded connections. The centralizing sleeve 74 may be fitted onto the second connector 73 and abut against the lower end of the second cylinder liner 72.

[0047] A second gap 75 can be formed between the lower end of the second piston 71, the upper end of the second connector 73, the inner wall of the second cylinder liner 72, and the outer wall of the first connector 23. A radially penetrating second pressure-transmitting hole 231 is provided on the side wall of the first connector 23. Here, the number of second pressure-transmitting holes 231 can be four, and the four second pressure-transmitting holes 231 can be evenly distributed along the circumference of the side wall of the first connector 23. The second gap 75 can communicate with the second pressure-transmitting holes 231. When liquid is introduced into the inner cavity of the first connector 23 for pressurization, the liquid in the first connector 23 can enter the second gap 75 along the second pressure-transmitting holes 231 and apply pressure to the lower end of the second piston 71, which can push the second piston 71 continuously. Together with the second cylinder liner 72, the first cylinder liner 22, and the first piston 21, they move upward along the axial direction, compressing the second setting mechanism 4 and the first setting mechanism 3 above. At the same time, the rubber sleeve 41 and the slip 31 expand radially to set the sleeve outside the packer. However, the present invention is not limited to this. The number of second pressure transmission holes 231 opened on the side wall of the first connector 23 can also be other, and can be arbitrarily selected according to actual needs. The connection method between the second connector 73 and the first connector 23, as well as the connection method between the second cylinder liner 72 and the second piston 71, is not limited to threaded connection, and can be arbitrarily selected according to actual needs. The present invention does not make specific limitations in this regard.

[0048] In this embodiment, the first setting mechanism 3 may further include an upper cone 32, a lower cone 33, a slip support 34, a cone pressure cap 35, and a wave spring 36. The upper cone 32 can be sleeved on the central tube 1 and located at the upper end of the slip 31. The lower end of the upper cone 32 can be formed into a cone shape and can be inserted into the gap between the slip 31 and the central tube 1. The lower cone 33 can be sleeved on the central tube 1 and located at the lower end of the slip 31. The lower cone 33 and the central tube 1 can be connected by cone shear pins 37. Here, the number of cone shear pins 37 can be 4. Each conical shear pin 37 can be evenly distributed circumferentially in the side wall of the lower cone 33; the upper end of the lower cone 33 can be formed into a cone shape, and the lower cone 33 can be subjected to an upward axial force. When the magnitude of the axial force exceeds a certain critical value, the lower cone 33 can cut off the conical shear pin 37 and insert it upward into the gap between the slip 31 and the central tube 1, so that the slip 31 can be radially opened and hung on the inner wall of the outer sleeve; however, the present invention is not limited to this, and the number of conical shear pins 37 can be selected according to actual needs. The present invention does not specifically limit this.

[0049] The slip support 34 can be simultaneously fitted over the upper cone 32 and the lower cone 33. The cone pressure cap 35 is installed between the slip support 34 and the upper cone 32. The slip support 34 and the cone pressure cap 35 work together to limit the upper cone 32 and the lower cone 33. The wave spring 36 is embedded in the slip 31 to limit the slip 31. The wave spring 36 can provide the slip 31 with a rebound force. After unsealing, the cone returns to its original position, and the slip 31 can naturally shrink radially under the action of the wave spring 36.

[0050] Optionally, an anti-rotation key 38 is also provided between the lower cone 33 and the central tube 1. Here, the number of anti-rotation keys 38 can be two. The two anti-rotation keys 38 can be evenly distributed along the circumference of the side wall of the lower cone 33. The anti-rotation keys 38 can be used to keep the lower cone 33 and the central tube 1 relatively fixed in the circumference, and prevent relative rotation between the lower cone 33 and the central tube 1. However, the present invention is not limited to this. The number of anti-rotation keys 38 can be selected according to actual needs. The present invention does not make a specific limitation on this.

[0051] In this embodiment, the second sealing mechanism 4 may further include a rubber sleeve seat 42. The upper end of the rubber sleeve seat 42 may be sleeved on the lower end of the lower cone 33 and fixedly connected to the lower cone 33 by a threaded connection. An anti-loosening pin (not shown in the figure) is also provided between the rubber sleeve seat 42 and the lower cone 33 to prevent the threaded connection between the rubber sleeve seat 42 and the lower cone 33 from loosening and disengaging. The lower end of the rubber sleeve seat 42 may abut against the upper end of the rubber sleeve 41. When the rubber sleeve 41 is compressed and expanded by axial force, it can also transmit the axial force through the rubber sleeve seat 42 to the lower cone 33 and above it, so that the slip 31 opens and sits. However, the present invention is not limited to this. The rubber sleeve seat 42 and the lower cone 33 may also be connected in other ways as needed. The present invention does not specifically limit this.

[0052] In this embodiment, the resealable fracturing acid packer described in this exemplary embodiment may further include a resealable mechanism 8. The resealable mechanism 8 may include an upper connector 81, a resealable ball seat 82, a resealable shear pin 83, a resealable spring claw 84, and a connecting sleeve 85. The lower end of the resealable spring claw 84 may be fitted onto the upper end of the central tube 1 and fixedly connected to the central tube via threads. The connecting sleeve 85 may be fitted outside the resealable spring claw 84, and its lower end may be fitted onto the upper end of the upper cone 32 and fixedly connected to the upper cone 32 via threads. The upper end of the connecting sleeve 85 may pass through the lower end of the upper connector 81 and fixedly connected to the upper connector 81 via threads. The resealable ball seat 82 passes through the resealable spring claw 84, releasing… The sealing ball seat 82 can be fixedly connected to the unsealing claw 84 via the unsealing shear pin 83; the inner wall of the upper end of the unsealing claw 84 can be tightly attached to the outer wall of the unsealing ball seat 82, and the protrusion of the upper outer wall of the unsealing claw 84 is tightly fastened in the groove between the upper end of the connecting sleeve 85 and the inner wall step of the upper connector 81, and is limited by the unsealing ball seat 82, and the outer wall of the unsealing claw 84 can be attached to the inner wall of the connecting sleeve 85 under the action of the unsealing ball seat 82; however, the present invention is not limited to this, and the unsealing claw 84 and the central tube 1, and the connecting sleeve 85 and the upper cone 32 and the upper connector 81 can also be connected by other means other than threaded connection, and the present invention does not specifically limit this.

[0053] The unsealing ball seat 82 can be subjected to a downward axial force. When the magnitude of this axial force exceeds a certain critical value, the unsealing ball seat 82 can cut the unsealing shear pin 83, and the unsealing ball seat 82 can lose the constraint of the unsealing spring claw 84 and descend until it is fully inserted into the unsealing spring claw 84. When the unsealing ball seat 82 descends until it leaves the upper end of the unsealing spring claw 84, the upper end of the unsealing spring claw 84 can contract radially due to the downward thrust exerted by the unsealing ball seat 82 on the central tube 1, causing the protrusion of the outer wall of the upper end of the unsealing spring claw 84 to leave the groove between the connecting sleeve 85 and the upper connector 81. The unsealing ball seat 82 can continue to descend until it abuts the upper end of the central tube 1, and pushes the central tube 1 downward together under the action of axial force. During the descent, the central tube 1 can drive the first sealing drive mechanism 2 to descend together, which can cause the rubber sleeve 41 and the slip 31 to contract radially and complete the unsealing.

[0054] Optionally, an outer step 12 is provided on the outer wall of the central tube 1, and an inner step 51 is provided on the inner wall of the thrust sleeve 5. When the central tube 1 descends during the unsealing process, the outer step 12 can abut against the inner step 51, which can drive the thrust sleeve 5, the locking mechanism 6 and the first sealing drive mechanism 2 to descend together, thereby relieving the axial force on the first sealing mechanism 3 and the second sealing mechanism 4 and restoring them to their initial positions, thus realizing the unsealing process.

[0055] The setting and unsealing process of the resealable fracturing acidizing packer described in this exemplary embodiment is described in detail below.

[0056] When the resealable fracturing acidizing packer is connected to the tool string and lowered into the outer casing for setting, a setting ball is first inserted into the central tube. The setting ball falls from the middle of the packer onto the opening ball seat below the packer, sealing the upper end of the opening ball seat. Liquid is then introduced into the central tube and pressurized. The liquid pressure in the central tube enters the first and second gaps through the first and second pressure transmission holes, respectively, applying axial force to the lower ends of the first and second pistons. When the axial force exceeds... Exceeding the critical value can cut off the starting shear pin and the cone shear pin, and push the first piston, the second piston, together with the first cylinder liner, the second cylinder liner, the thrust sleeve and the locking mechanism upward, compressing the rubber sleeve so that the rubber sleeve expands radially and sits on the inner wall of the outer sleeve; at the same time, the axial force can continue to be transmitted upward to push the rubber sleeve seat and the lower cone to continue to rise, so that the upper end of the lower cone and the lower end of the upper cone are inserted into the gap between the slip and the central tube, so that the slip opens radially and sits on the inner wall of the outer sleeve, realizing the setting operation.

[0057] When the unsealing operation of the unsealed fracturing acid packer is required, an unsealing ball is inserted into the upward connector, sealing the upper end of the unsealing ball seat. Liquid is then introduced into the upward connector and pressurized. When the pressure exceeds a critical value, the unsealing shear pin is cut off, and the unsealing ball seat loses its constraint from the unsealing claw, descending until it is fully inserted into the unsealing claw. As the unsealing ball seat descends until it leaves the upper end of the unsealing claw, the upper end of the unsealing claw contracts radially due to the downward thrust exerted by the unsealing ball seat 82 on the central tube 1, thus releasing the unsealing ball. The protrusion on the outer wall of the upper end of the sealing claw leaves the groove between the connecting sleeve and the upper connector; the unsealing ball seat can continue to descend until it abuts against the upper end of the central tube, and under the action of axial force, it pushes the central tube down together. During the descent, the outer step on the outer wall of the central tube can abut against the inner step on the inner wall of the thrust sleeve, which can drive the first setting drive mechanism down together, and at the same time, the axial force on the first setting mechanism and the second setting mechanism is relieved and returned to the initial position, which can cause the rubber sleeve and the slip to shrink radially and complete the unsealing.

[0058] Exemplary Example 2

[0059] This exemplary embodiment provides a tool string.

[0060] The tool string described in this exemplary embodiment may include a resealable fracturing acid packer as described in Exemplary Embodiment 1.

[0061] The resealable fracturing and acidizing packer described in this exemplary embodiment has the same structure and function as the resealable fracturing and acidizing packer described in Exemplary Embodiment 1, and will not be described in detail here.

[0062] Exemplary Example 3

[0063] This exemplary embodiment provides a method for sealing and unsealing a resealable fracturing acidizing packer.

[0064] The sealing and unsealing method of the resealable fracturing and acidizing packer described in this exemplary embodiment can use the resealable fracturing and acidizing packer as described in Exemplary Embodiment 1 or the tool string as described in Exemplary Embodiment 2.

[0065] The sealing and unsealing method for the resealable fracturing acidizing packer described in this exemplary embodiment may include a sealing step and an unsealing step, wherein:

[0066] The isolation process may include the following steps:

[0067] First, a setting ball is inserted into the central tube. The setting ball falls from the middle of the packer onto the opening ball seat below the packer, sealing the upper end of the opening ball seat. Liquid is then introduced into the central tube and pressurized. The high-pressure liquid in the central tube enters the first and second gaps through the first and second pressure transmission holes, respectively, applying axial force to the lower ends of the first and second pistons. When the axial force exceeds the critical value, it can cut off the starting shear pin and the cone shear pin, and push the first and second pistons, along with the first and second cylinder liners, the thrust sleeve, and the locking mechanism, upward. This compresses the rubber sleeve, causing it to expand radially and set on the inner wall of the outer sleeve. Simultaneously, the axial force continues to be transmitted upward, pushing the rubber sleeve seat and the lower cone to continue moving upward, so that the upper end of the lower cone and the lower end of the upper cone are inserted into the gap between the slip and the central tube. This causes the slip to open radially and sit on the inner wall of the outer sleeve, thus achieving the setting operation.

[0068] The reopening process may include the following steps:

[0069] Insert the unsealing ball into the upper connector, causing it to seal the upper end of the unsealing ball seat. Liquid is then introduced into the upper connector and pressurized. When the pressure exceeds a critical value, the unsealing shear pin is cut off, and the unsealing ball seat loses its constraint from the unsealing spring claw, descending until it is fully inserted into the unsealing spring claw. As the unsealing ball seat descends until it leaves the upper end of the unsealing spring claw, the upper end of the unsealing spring claw contracts radially due to the downward thrust exerted by the unsealing ball seat on the central tube. This causes the protrusion on the outer wall of the upper end of the unsealing spring claw to leave the groove between the connecting sleeve and the upper connector. The unsealing ball seat continues to descend until it abuts against the upper end of the central tube, pushing the central tube downwards under axial force. During this descent, the outer step on the outer wall of the central tube abuts against the inner step on the inner wall of the thrust sleeve, driving the first setting drive mechanism downwards. Simultaneously, the axial compressive force on the first and second setting mechanisms is relieved, and they return to their initial positions, allowing the rubber sleeve and slip to contract radially and complete the unsealing process.

[0070] In summary, after the hydraulic cylinder power system in the packer of this invention is started, the packer sleeve and the packer's dual-support anchoring system (slips) are sequentially set and engaged. The dual-support anchoring system provides support and protection for the sleeve setting, thereby improving the packer's pressure-bearing capacity. This invention provides multiple sets of high-temperature and high-pressure resistant sealing rings between the piston and the central tube, between the release pawl and the central tube, the release ball seat, and the connecting sleeve, and between the upper connector and the release ball seat. The sleeve is made of high-temperature resistant material, enabling the packer to effectively adapt to high-temperature and high-pressure conditions. This invention also includes a release system on the upper part of the packer, which can be used to release the packer at any time by throwing a ball to pressurize it. The release system has high reliability, allowing the packer to be effectively recovered after fracturing and acidizing operations.

[0071] Although the present invention has been described above in conjunction with exemplary embodiments and accompanying drawings, those skilled in the art should understand that various modifications can be made to the above embodiments without departing from the spirit and scope of the claims.

Claims

1. A resealable fracturing acidizing packer, characterized in that, The packer includes a central tube, a first setting drive mechanism, a first setting mechanism, and a second setting mechanism, wherein... The first setting drive mechanism includes a first piston, a first cylinder liner and a first connector. The upper end of the first connector is sleeved on the lower end of the central tube and fixedly connected to the central tube. The first piston is sleeved on the central tube and is located axially above the first connector. The first cylinder liner is sleeved on the first connector and the first piston and fixedly connected to the first piston. The first and second setting mechanisms are both sleeved on the central tube. The second setting mechanism is located axially above the first setting drive mechanism, and the first setting mechanism is located axially above the second setting mechanism. The first setting mechanism includes a slip sleeved on the central tube, and the second setting mechanism includes a rubber sleeved on the central tube. A first gap is formed between the lower end of the first piston, the upper end of the first connector, the inner wall of the first cylinder liner, and the outer wall of the central tube. A first pressure-transmitting hole is provided on the side wall of the central tube in a radial direction. The first pressure-transmitting hole communicates with the first gap. The liquid pressure in the inner cavity of the central tube can act on the lower end of the first piston along the first pressure-transmitting hole and the first gap, pushing the first piston and the first cylinder liner to move upward along the axial direction and compress the second setting mechanism and the first setting mechanism in sequence, so that the rubber sleeve and the slip expand and open radially to perform setting. The packer also includes a thrust sleeve and a locking mechanism, both of which are sleeved on the central tube. The upper end of the thrust sleeve is fixedly connected to the lower end of the locking mechanism, and the lower end of the thrust sleeve abuts against the first piston. The thrust sleeve and the central tube are connected by an actuation shear pin. The locking mechanism includes a locking ring and a locking sleeve. The locking ring is installed between the outer wall of the central tube and the inner wall of the locking sleeve, and the locking ring is fixedly connected to the inner wall of the locking sleeve. The upper end of the locking sleeve abuts against the lower end of the rubber tube, and the lower end of the locking sleeve is fixedly connected to the thrust sleeve. A matching ratchet structure is formed between the inner wall of the locking sleeve and the outer wall of the central tube. The thrust sleeve can shear off the starting pin and push the locking mechanism upward to compress the rubber tube under the thrust of the first piston; the ratchet structure can prevent the locking mechanism from moving downward relative to the central tube. The packer also includes a release mechanism, which includes an upper connector, a release ball seat, a release shear pin, a release spring claw, and a connecting sleeve. The lower end of the release spring claw is sleeved on the upper end of the central tube and fixedly connected to the central tube. The connecting sleeve is sleeved on the outside of the release spring claw, and the upper end of the connecting sleeve is fixedly connected to the lower end of the upper connector. The release ball seat passes through the release spring claw and is fixedly connected to the release spring claw by the release shear pin. The unsealing ball seat can shear off the unsealing pins and push the central tube downward after being subjected to axial downward pressure, and drive the first setting drive mechanism downward, so that the rubber tube and the slip retract radially to unseal; An outer step is formed on the outer wall of the central tube, and an inner step is provided on the inner wall of the thrust sleeve. When the central tube is pushed down by the unsealing ball seat, the outer step is abutted against the inner step, so as to drive the thrust sleeve and the locking mechanism down together to achieve unsealing.

2. The resealable fracturing acid packer according to claim 1, characterized in that, The packer further includes a second setting drive mechanism, which is connected to the lower end of the first setting drive mechanism. The second setting drive mechanism includes a second piston, a second cylinder liner, a second connector, and a centering sleeve. The upper end of the second connector is sleeved on the lower end of the first connector and is fixedly connected to the first connector. The second piston is sleeved on the first connector and is located axially above the second connector. The second cylinder liner is sleeved on the second connector and the second piston and is fixedly connected to the second piston. The centering sleeve is sleeved on the second connector and connected to the lower end of the second cylinder liner. A second gap is formed between the lower end of the second piston, the upper end of the second connector, the inner wall of the second cylinder liner, and the outer wall of the first connector. A radially penetrating second pressure transmission hole is provided on the side wall of the first connector. The second pressure transmission hole communicates with the second gap. The liquid pressure in the inner cavity of the first connector can act on the lower end of the second piston along the second pressure transmission hole and the second gap, pushing the second piston and the second cylinder liner to move upward along the axial direction and sequentially compress the second setting mechanism and the first setting mechanism, so that the rubber sleeve and the slip expand radially to perform setting.

3. The resealable fracturing acidizing packer according to claim 1, characterized in that, The first setting mechanism also includes an upper cone, a lower cone, a slip support, a cone pressure cap, and a wave spring. The upper cone is sleeved on the central tube and located at the upper end of the slip. The lower end of the upper cone can be inserted between the slip and the central tube. The lower cone is fitted onto the central tube and connected to the central tube via a cone shear pin. The lower cone is located at the lower end of the slip. Under the action of axial thrust, the lower cone can shear the cone shear pin and insert its upper end between the slip and the central tube, so that the slip opens and hangs radially. The slip support is fitted onto the upper and lower cones to limit their movement; the cone pressure cap is installed between the slip support and the upper cone to position the upper cone; the wave spring is embedded in the slip to limit its movement.

4. The resealable fracturing acidizing packer according to claim 3, characterized in that, An anti-rotation key is also provided between the lower cone and the central tube. The anti-rotation key is used to keep the lower cone and the central tube circumferentially relatively fixed.

5. The resealable fracturing acidizing packer according to claim 1, characterized in that, The second setting mechanism also includes a rubber sleeve seat, the upper end of which is sleeved on the lower end of the first setting mechanism and fixedly connected to the first setting mechanism, and the lower end of the rubber sleeve seat abuts against the upper end of the rubber sleeve.

6. A tool string, characterized in that, The tool string includes a resealable fracturing acid packer as described in any one of claims 1 to 5.

7. A method for sealing and unsealing a resealable fracturing acidizing packer, characterized in that, The sealing and unsealing method employs a resealable fracturing acidizing packer as described in any one of claims 1 to 5, or a tool string as described in claim 6; the sealing and unsealing method includes a sealing stage and an unsealing stage, wherein... The sealing process includes inserting a setting ball into the opening ball seat located below the packer to seal the lower end of the packer, pressurizing the central tube, and allowing high-pressure liquid to enter the first gap along the first pressure transmission hole, pressurizing the lower end of the first piston, pushing the first piston upward and sequentially squeezing the second setting mechanism and the first setting mechanism, causing the rubber sleeve and the slip to expand radially to complete the setting process. The unsealing process involves subjecting the central tube to an axial downward force, causing it to descend and driving the first setting mechanism downward as well. This releases the compressive force acting on the second and first setting mechanisms, allowing the rubber sleeve and slips to contract radially and return to their initial positions, thus completing the unsealing process.

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