A gradual expansion packer for oil fields

Abstract

The present invention belongs to the technical field of oilfield isolation, and relates to a gradually expanding packer for oilfields. It comprises: a central tube, wherein the central tube is fixedly connected with a connecting sleeve, a lower joint, and an upper joint, a rubber tube is fixedly connected between the central tube and the upper joint, the central tube is provided with a through hole, and a cavity is formed between the central tube, the upper joint, and the rubber tube; a sliding sleeve, slidably connected to the central tube; a protective tube, rotatably connected to the sliding sleeve, and the protective tube wraps the rubber tube; a transmission mechanism, provided between the connecting sleeve and the upper joint, for causing the protective tube and the rubber tube to slide relative to each other. The present invention uses the protective tube to cover the rubber tube during the lowering process, so that the rubber tube is prevented from being rubbed by the well wall during the lowering process, ensuring the normal shape of the outer side of the rubber tube, thereby improving the sealing effect after the rubber tube contacts the well wall.

Description

Technical Field

[0001] The present invention relates to the technical field of oilfield isolation, in particular to a gradually expanding packer for oilfields. Background Art

[0002] Expandable packers are key tools for downhole isolation in the oil and gas industry. They are mainly used to isolate different layers of the wellbore, prevent fluid crossflow or control injection and production pressure. The core principle is to use external drive to expand the rubber tube and adhere to the well wall to form a sealing barrier, thereby isolating the upper and lower layers, and subsequently ensuring the stability of the injection pressure, ensuring the sealing effect of the rubber tube on the well wall under high temperature, high pressure and vibration environment underground.

[0003] Most of the existing expandable packers simply lower a straight rubber tube directly into the isolation layer section downhole. However, during the lowering process, the rubber tube and the well wall rub against each other, causing damage to the rubber tube. Even in horizontal wells or highly deviated wells, gravity causes the packer to deviate to one side of the well wall, aggravating the friction and seriously affecting the subsequent sealing quality of the rubber tube on the well wall after expansion. To address the above problems, a gradually expandable packer for oil fields is proposed. Summary of the Invention

[0004] In order to overcome the shortcomings mentioned in the above technical background, the present invention provides a gradual expansion packer for oil fields.

[0005] The technical solution of the present invention is: a gradual expansion packer for oil fields, comprising:

[0006] A central tube, wherein the central tube is fixedly connected to a connecting sleeve, a lower joint, and an upper joint, the connecting sleeve and the lower joint are fixedly connected, a rubber tube is fixedly connected between the central tube and the upper joint, the central tube is provided with a through hole, a cavity is formed between the central tube, the upper joint, and the rubber tube, and the cavity is communicated with the through hole on the central tube;

[0007] a sliding sleeve, slidably connected to the central tube;

[0008] A protective tube is rotatably connected to the sliding sleeve, the protective tube wraps the rubber tube, and the protective tube is in contact with the rubber tube;

[0009] The transmission mechanism is arranged between the connecting sleeve and the upper joint, and is used to make the protective tube and the rubber tube slide relative to each other.

[0010] Preferably, the through hole on the central tube is located at the lower part of the cavity between the central tube and the rubber tube, and is used for discharging liquid medium.

[0011] Preferably, the upper side surface of the protective tube is an inclined surface, and the distance between the upper side surface of the protective tube and the horizontal plane gradually decreases from the inside to the outside.

[0012] Preferably, the protective cylinder is fixedly connected to a scraper shell, and a limiting component is provided between the central tube and the protective cylinder, and the limiting component is used to limit the sliding sleeve and the protective cylinder respectively, so that the sliding sleeve and the protective cylinder rotate relative to each other.

[0013] Preferably, the transmission mechanism includes:

[0014] a first magnetic ring, slidably connected to the upper joint, the upper joint being provided with a first cavity, the first magnetic ring being located in the first cavity, the upper joint being provided with a connecting hole, the connecting hole being in communication with the first cavity;

[0015] The second magnetic ring is fixedly connected to the protective tube. The magnetic poles of the adjacent sides of the first magnetic ring and the second magnetic ring are the same. A first elastic element is fixedly connected between the connecting sleeve and the sliding sleeve.

[0016] Preferably, there is an angle between the connecting hole and the horizontal plane, and the distance between the connecting hole and the horizontal plane gradually increases from one side close to the central axis of the upper joint to the other side.

[0017] Preferably, the limiting component includes:

[0018] A limiting column, fixedly connected to the protective tube;

[0019] A limiting protrusion is provided on the sliding sleeve, the central tube is provided with a first groove and a second groove, the first groove and the second groove respectively limit the limiting column and the limiting protrusion, the first groove is spiral, the length of the limiting protrusion is greater than the pitch of the first groove, and the scraper shell is made of an elastic and deformable material;

[0020] An extrusion structure is provided on the protective tube and is used to expand the scraper shell.

[0021] Preferably, the first groove separates the second groove, and the depth of the first groove is greater than the depth of the second groove.

[0022] Preferably, the extrusion structure includes:

[0023] a sliding member, slidably connected to the protective tube, wherein a second elastic element is fixedly connected between the sliding member and the protective tube;

[0024] A sphere is provided on a side of the sliding member close to the sliding sleeve, the sphere is in contact with the sliding sleeve, the protective tube is provided with a second cavity, and the second cavity is communicated with the scraper shell;

[0025] a sliding ring, sealingly and slidingly connected in the second cavity, the sliding ring being fixedly connected to the sliding member;

[0026] A limiting member is fixedly connected to the sliding sleeve, the limiting member is rotatably connected to the protective tube, and the limiting member is provided with an inclined surface arranged in a mirror image, and the inclined surface is used to squeeze the sphere.

[0027] Preferably, the sphere is not in contact with the limiting member in an initial state, ensuring that the scraper shell is in an undeformed state.

[0028] Compared with the prior art, the present invention has at least the following beneficial effects: the present invention covers the rubber tube with a protective tube during the lowering process, so that the rubber tube is prevented from being rubbed by the well wall during the lowering process, thereby ensuring the normal shape of the outer side of the rubber tube, and thus improving the sealing effect after the subsequent rubber tube contacts the well wall; the rotating scraping shell is used to perform a rotational downward scraping "grinding" on the well wall, thereby applying multi-directional forces to the protrusions on the well wall, increasing the degree of removal of the protrusions on the well wall, and reducing the degree of squeezing of the protrusions on the well wall on the rubber tube, thereby improving the uniformity of the rubber tube in the subsequent expansion process, and thus improving the fitting effect between the rubber tube and the well wall after expansion, improving the sealing effect, and at the same time making the well wall A continuous annular sealing belt (similar to a labyrinth seal) is formed between the scraper shell, which greatly extends the leakage path and improves the sealing effect. At the same time, the periodic structure of the thread on the well wall can disperse the overall expansion stress of the rubber tube to multiple contact points, avoiding the traditional straight rubber tube due to the limitation of the uneven protrusions on the well wall, which causes local excessive stretching and crack expansion, thereby affecting the normal sealing; the sphere is limited by the mirror-image arrangement of the inclined surface on the limiter, so that the scraper shell applies different forces to the well wall during the scraping process, so that spiral "grooves" with different scraping depths are formed on the well wall, thereby increasing the contact area between the rubber tube and the well wall after expansion, thereby improving the sealing effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the overall three-dimensional structure of the present invention;

[0030] Figure 2 This is a sectional view of the three-dimensional structure of the connecting sleeve, the upper joint and the protective tube of the present invention;

[0031] Figure 3 It is a three-dimensional structural cross-sectional view of the connecting sleeve, lower joint and upper joint of the present invention;

[0032] Figure 4 This is a sectional view of the three-dimensional structure of the upper joint, protective tube and scraping shell of the present invention;

[0033] Figure 5It is a three-dimensional structural cross-sectional view of the rubber tube, sliding sleeve and protective tube of the present invention;

[0034] Figure 6 A three-dimensional structural cross-sectional view of the sliding member and the sliding ring of the present invention;

[0035] Figure 7 This is an exploded view of the three-dimensional structure of the central tube and the parts thereon of the present invention.

[0036] Markings in the accompanying drawings: 1: center tube, 2: connecting sleeve, 3: lower joint, 4: upper joint, 5: rubber tube, 6: sliding sleeve, 7: protective tube, 8: scraper shell, 901: first magnetic ring, 902: first cavity, 903: connecting hole, 904: second magnetic ring, 905: first elastic element, 1001: limiting column, 1002: limiting protrusion, 1003: first groove, 1004: second groove, 1101: sliding part, 1102: second elastic element, 1103: sphere, 1104: second cavity, 1105: sliding ring, 1106: limiting part. DETAILED DESCRIPTION

[0037] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0038] like Figure 1-Figure 3 、 Figure 5 and Figure 7As shown, a gradually expanding packer for oil fields is used to solve the problem that during the lowering process of the existing packer, the rubber tube on the packer directly contacts the well wall, thereby generating friction and damaging the rubber tube. Even in horizontal wells or highly deviated wells, gravity causes the packer to deviate to one side of the well wall, aggravating friction and affecting normal use. The packer comprises: a central pipe 1, the central pipe 1 is fixedly connected with a connecting sleeve 2, a lower joint 3, and an upper joint 4, the connecting sleeve 2 and the lower joint 3 are fixedly connected, a rubber tube 5 is fixedly connected between the central pipe 1 and the upper joint 4, the central pipe 1 is provided with a through hole, a cavity is formed between the central pipe 1, the upper joint 4 and the rubber tube 5, the cavity is communicated with the through hole on the central pipe 1, and the through hole on the central pipe 1 is located between the central pipe 1 and the rubber tube 5. The lower part of the cavity is used to discharge the liquid medium; the sliding sleeve 6 is slidably connected to the central tube 1; the protective tube 7 is rotatably connected to the sliding sleeve 6, the upper side surface of the protective tube 7 is an inclined surface, and the distance between the upper side surface of the protective tube 7 and the horizontal plane gradually decreases from the inside to the outside, which is used to remove impurities adhering to the outer wall of the rubber tube 5. The protective tube 7 wraps the rubber tube 5, and the protective tube 7 is in contact with the rubber tube 5; the protective tube 7 is fixedly connected to the scraper shell 8, and a limiting component is provided between the central tube 1 and the protective tube 7. The limiting component is used to limit the sliding sleeve 6 and the protective tube 7 respectively, so that the sliding sleeve 6 and the protective tube 7 rotate relative to each other; the transmission mechanism is provided between the connecting sleeve 2 and the upper joint 4, and is used to make the protective tube 7 and the rubber tube 5 slide relative to each other.

[0039] In the above scheme, the rubber tube 5 is made of fluororubber, and the central axes of the central tube 1, connecting sleeve 2, lower joint 3, upper joint 4, rubber tube 5, sliding sleeve 6, protective tube 7 and scraper shell 8 coincide with each other. A boss is provided in the lower joint 3 for placing a sealing ball. The through hole on the central tube 1 gradually tilts downward from the outside to the inside, and the outer side of the scraper shell 8 is wavy. When using this device, the staff lowers the device along the oil well to the target layer (the area that needs to be sealed) through the oil pipe. During the lowering process, the protective tube 7 covers the rubber tube 5, so that the rubber tube 5 is prevented from suffering friction from the well wall during the lowering process, ensuring the normal shape of the outer side of the rubber tube 5, thereby improving the sealing effect after the subsequent rubber tube 5 contacts the well wall.

[0040] After the device is lowered to the target layer, the staff puts a sealing ball into the oil pipe. The sealing ball moves downward under the action of its own gravity until it moves downward and contacts the boss on the lower joint 3. Then the staff injects high-pressure liquid (high-pressure water can be used) into the device. Under the action of high-pressure water and the transmission mechanism, the sliding sleeve 6 and the protective tube 7 begin to slide downward along the central tube 1. The protective tube 7 drives the scraper shell 8 to move downward together. The scraper shell 8 scrapes the well wall, thereby reducing the roughness of the well wall and reducing the influence of the protrusions on the well wall on the rubber tube 5 during the subsequent expansion process, thereby improving the sealing effect.

[0041] During the downward movement of the protection tube 7, the protection tube 7 rotates counterclockwise (eg Figure 5 Taking the top view as an example), the protective tube 7 drives the scraper shell 8 to rotate counterclockwise to further scrape the well wall. After the protective tube 7 moves downward to the limit position (the protective tube 7 loses the state of wrapping the rubber tube 5), as the high-pressure water continues to enter the central tube 1, the high-pressure water enters the cavity between the central tube 1 and the rubber tube 5 through the through hole on the central tube 1, and then the rubber tube 5 gradually expands under the action of the high-pressure water until the rubber tube 5 is tightly fitted to the well wall, thus completing the isolation of the oil well, and then maintain the high-pressure state of the high-pressure water. After the isolation work is completed, the staff removes the external high-pressure water, the rubber tube 5 gradually loses its extrusion and gradually resets, and then the sliding sleeve 6 and the protective tube 7 begin to move upward (reset) under the action of the transmission mechanism. After all parts are reset, the staff can take the device out of the oil well through the oil pipe.

[0042] like Figure 3-Figure 5 and Figure 7 As shown, the transmission mechanism includes: a first magnetic ring 901, which is slidably connected to the upper joint 4, and the upper joint 4 is provided with a first cavity 902. The first magnetic ring 901 is located in the first cavity 902, and the upper joint 4 is provided with a connecting hole 903. The connecting hole 903 is connected to the first cavity 902, and there is an angle between the connecting hole 903 and the horizontal plane, and the distance between the connecting hole 903 and the horizontal plane gradually increases from one side close to the central axis of the upper joint 4 to the other side; a second magnetic ring 904, which is fixedly connected to the protective tube 7, and the magnetic poles of the adjacent sides of the first magnetic ring 901 and the second magnetic ring 904 are the same, and a first elastic element 905 is fixedly connected between the connecting sleeve 2 and the sliding sleeve 6.

[0043] In the above scheme, the first elastic element 905 is a spring, which is used to reset the protective tube 7, and the elastic coefficient of the first elastic element 905 is smaller than the elastic coefficient of the rubber tube 5, so that the rubber tube 5 starts to expand only after the first elastic element 905 is fully compressed. After the high-pressure water enters the central tube 1, the high-pressure water enters the first cavity 902 through the connecting hole 903, and the first magnetic ring 901 is squeezed by the high-pressure water and begins to move downward in the first cavity 902. The first magnetic ring 901 drives the second magnetic ring 904 to move downward together through magnetic force, and the second magnetic ring 904 drives the protective tube 7 and the parts thereon to move downward together. The first elastic element 905 is compressed, and the protective tube 7 gradually loses its wrapping of the rubber tube 5 until the protective tube 7 stops moving after losing its wrapping of the rubber tube 5.

[0044] After completing the plugging of the oil well, the staff stops adding high-pressure water to the central pipe 1. The protective tube 7 begins to move upward under the action of the elastic force of the first elastic element 905. The protective tube 7 drives the first magnetic ring 901 to move upward together through the second magnetic ring 904. The first magnetic ring 901 squeezes out the high-pressure water in the first cavity 902.

[0045] like Figure 3 、 Figure 6 and Figure 7 As shown, the limiting assembly includes: a limiting column 1001, fixedly connected to the protective tube 7; a limiting protrusion 1002, arranged on the sliding sleeve 6, and the central tube 1 is provided with a first groove 1003 and a second groove 1004, the first groove 1003 and the second groove 1004 respectively limit the limiting column 1001 and the limiting protrusion 1002, the first groove 1003 is spiral, the length of the limiting protrusion 1002 is greater than the pitch of the first groove 1003, the first groove 1003 separates the second groove 1004, the depth of the first groove 1003 is greater than the depth of the second groove 1004, and the scraper shell 8 is made of an elastic deformable material; an extrusion structure is provided on the protective tube 7, for expanding the scraper shell 8.

[0046] In the above scheme, the central axis of the first groove 1003 coincides with the central axis of the central tube 1, the scraper shell 8 is made of soft wear-resistant rubber, the first groove 1003 is a left-handed spiral, and the second groove 1004 is a vertical groove. In the process of the protective cylinder 7 moving downward, the protective cylinder 7 drives the limiting column 1001 and the sliding sleeve 6 to move downward together, and the sliding sleeve 6 drives the limiting protrusion 1002 to move downward together, and the limiting protrusion 1002 slides downward along the second groove 1004, and the limiting column 1001 starts to slide along the first groove 1003. The limiting column 1001 starts to rotate counterclockwise under the action of the first groove 1003 (such as Figure 5 Taking the top view as an example), the limiting column 1001 drives the protective tube 7 to rotate counterclockwise, and the protective tube 7 and the sliding sleeve 6 rotate relative to each other, and the protective tube 7 drives the scraper shell 8 to rotate counterclockwise, so that the scraper shell 8 performs a rotational downward scraping and "grinding" on the well wall, thereby applying multi-directional force to the protrusions on the well wall, increasing the degree of removal of the protrusions on the well wall, and reducing the degree of squeezing of the rubber tube 5 by the protrusions on the well wall, thereby improving the uniformity of the rubber tube 5 in the subsequent expansion process, and then improving the fit between the rubber tube 5 and the well wall after expansion, and improving the sealing effect.

[0047] During the process of the scraper shell 8 rotating downward to scrape and "grind" the well wall, spiral marks are formed on the well wall after being scraped, so that multiple sealing belts (similar to labyrinth seals) are formed between the well wall and the scraper shell 8, which greatly extends the leakage path and improves the sealing effect. At the same time, the periodic structure of the thread on the well wall can disperse the overall expansion stress of the rubber tube 5 to multiple contact points, avoiding the traditional straight rubber tube due to the limitation of the uneven protrusions on the well wall, resulting in crack expansion caused by local excessive stretching, thereby affecting normal sealing.

[0048] like Figure 2 and Figure 5-Figure 7 As shown, the extrusion structure includes: a sliding member 1101, which is slidably connected to the protective tube 7, and a second elastic element 1102 is fixedly connected between the sliding member 1101 and the protective tube 7; a sphere 1103, which is arranged on the side of the sliding member 1101 close to the sliding sleeve 6, and the sphere 1103 is in contact with the sliding sleeve 6. The protective tube 7 is provided with a second cavity 1104, and the second cavity 1104 is connected to the scraper shell 8; a sliding ring 1105, which is sealingly slidably connected in the second cavity 1104, and the sliding ring 1105 is fixedly connected to the sliding member 1101; a limiting member 1106, which is fixedly connected to the sliding sleeve 6, and the limiting member 1106 is rotatably connected to the protective tube 7. The sphere 1103 is not in contact with the limiting member 1106 in its initial state, ensuring that the scraper shell 8 is in an undeformed state. The limiting member 1106 is provided with a mirror-image inclined surface, which is used to extrude the sphere 1103.

[0049] In the above scheme, the second elastic element 1102 is a spring, which is used to reset the sliding member 1101. The scraper shell 8 and the second cavity 1104 are filled with a transmission medium, and hydraulic oil can be selected. The scraper shell 8 is made of high-strength deformable rubber material, which is used to generate deformation to avoid hard protrusions in the oil well. The distance between the mirror-arranged inclined surfaces on the limiter 1106 gradually decreases from top to bottom. The mirror-arranged inclined surfaces on the limiter 1106 are horizontal planes, and the horizontal plane is located at the upper part of the limiter 1106. During the counterclockwise rotation of the protective cylinder 7, the protective cylinder 7 drives the sliding member 1101 to rotate counterclockwise together, and the sliding member 1101 drives the ball 1103 to rotate counterclockwise together. After the inclined surface on the rear side of 1106 contacts, as the ball 1103 continues to rotate counterclockwise, the ball 1103 begins to move upward under the support of the inclined surface on the rear side of the limiter 1106, the second elastic element 1102 is compressed, and the ball 1103 drives the sliding ring 1105 to move upward through the sliding member 1101, and the sliding ring 1105 begins to squeeze the hydraulic oil in the second cavity 1104. The squeezed hydraulic oil enters the scraper shell 8, and the scraper shell 8 begins to expand, thereby increasing the scraping force on the well wall, improving the smoothness of the well wall, and facilitating the subsequent sealing of the well wall, until the ball 1103 rotates counterclockwise to disengage from the inclined surface on the rear side of the limiter 1106 and the sliding member 1101 stops moving upward.

[0050] After the ball 1103 rotates counterclockwise to disengage from the inclined surface on the rear side of the limit piece 1106, as the ball 1103 rotates counterclockwise, the ball 1103 begins to roll on the horizontal surface on the limit piece 1106. At this time, the scraper shell 8 remains in an expanded state. After the ball 1103 rotates counterclockwise to the inclined surface on the front side of the limit piece 1106, the sliding member 1101 begins to move downward under the elastic force of the second elastic element 1102, and the sliding member 1101 drives the sliding ring 1105 to move downward together. The hydraulic oil gradually flows back into the second cavity 1104 under the squeezing action of the scraper shell 8. In this way, the scraper shell 8 rotates downward to scrape the well wall (equivalent to continuous spiral grinding of the well wall), so that spiral "grooves" with different scraping depths are formed on the well wall, thereby increasing the contact area between the rubber tube 5 and the well wall after expansion, thereby improving the sealing effect.

[0051] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A gradual expansion packer for oil fields, Its characteristics include: A central tube (1), wherein the central tube (1) is fixedly connected to a connecting sleeve (2), a lower joint (3), and an upper joint (4), wherein the connecting sleeve (2) and the lower joint (3) are fixedly connected, and a rubber tube (5) is fixedly connected between the central tube (1) and the upper joint (4), wherein the central tube (1) is provided with a through hole, and a cavity is formed between the central tube (1), the upper joint (4), and the rubber tube (5), and the cavity is communicated with the through hole on the central tube (1); A sliding sleeve (6) slidably connected to the central tube (1); A protective tube (7) is rotatably connected to the sliding sleeve (6), the protective tube (7) wraps the rubber tube (5), and the protective tube (7) is in contact with the rubber tube (5); A transmission mechanism is provided between the connecting sleeve (2) and the upper joint (4), and is used to enable the protective tube (7) and the rubber tube (5) to slide relative to each other; The protective tube (7) is fixedly connected to a scraper shell (8), and the scraper shell (8) is made of an elastic and deformable material; A limiting assembly is provided between the central tube (1) and the protective tube (7), and the limiting assembly is used to limit the sliding sleeve (6) and the protective tube (7) respectively, thereby causing the sliding sleeve (6) and the protective tube (7) to rotate relative to each other; The limiting assembly comprises an extrusion structure, which is arranged on the protective cylinder (7) and is used to expand the scraper shell (8).

2. The gradual expansion packer for oil fields according to claim 1, characterized in that: The through hole on the central tube (1) is located at the lower part of the cavity between the central tube (1) and the rubber tube (5) and is used for discharging liquid medium.

3. The gradual expansion packer for oil fields according to claim 1, characterized in that: The upper side surface of the protective tube (7) is an inclined surface, and the distance between the upper side surface of the protective tube (7) and the horizontal plane gradually decreases from the inside to the outside.

4. The gradual expansion packer for oil fields according to claim 3, characterized in that: The transmission mechanism includes: A first magnetic ring (901) is slidably connected to the upper joint (4), the upper joint (4) is provided with a first cavity (902), the first magnetic ring (901) is located in the first cavity (902), the upper joint (4) is provided with a connecting hole (903), and the connecting hole (903) is communicated with the first cavity (902); The second magnetic ring (904) is fixedly connected to the protective tube (7), the magnetic poles of the adjacent sides of the first magnetic ring (901) and the second magnetic ring (904) are the same, and a first elastic element (905) is fixedly connected between the connecting sleeve (2) and the sliding sleeve (6).

5. The gradual expansion packer for oil fields according to claim 4, characterized in that: There is an angle between the connecting hole (903) and the horizontal plane, and the distance between the connecting hole (903) and the horizontal plane gradually increases from one side close to the central axis of the upper joint (4) to the other side.

6. The gradual expansion packer for oil fields according to claim 5, characterized in that: The limiting component also includes: A limiting column (1001) is fixedly connected to the protective tube (7); A limiting protrusion (1002) is provided on the sliding sleeve (6); the central tube (1) is provided with a first groove (1003) and a second groove (1004); the first groove (1003) and the second groove (1004) respectively limit the limiting column (1001) and the limiting protrusion (1002); the first groove (1003) is spiral; the length of the limiting protrusion (1002) is greater than the pitch of the first groove (1003).

7. The gradual expansion packer for oil fields according to claim 6, characterized in that: The first groove (1003) separates the second groove (1004), and the depth of the first groove (1003) is greater than the depth of the second groove (1004).

8. The gradual expansion packer for oil fields according to claim 7, characterized in that: The extrusion structure includes: A sliding member (1101) is slidably connected to the protective tube (7), and a second elastic element (1102) is fixedly connected between the sliding member (1101) and the protective tube (7); A sphere (1103) is provided on a side of the sliding member (1101) close to the sliding sleeve (6), the sphere (1103) is in contact with the sliding sleeve (6), the protective tube (7) is provided with a second cavity (1104), and the second cavity (1104) is in communication with the scraper shell (8); A sliding ring (1105) is sealingly and slidingly connected in the second cavity (1104), and the sliding ring (1105) is fixedly connected to the sliding member (1101); A limiting member (1106) is fixedly connected to the sliding sleeve (6), the limiting member (1106) is rotatably connected to the protective tube (7), and the limiting member (1106) is provided with a mirror-image inclined surface, which is used to squeeze the sphere (1103).

9. The gradual expansion packer for oil fields according to claim 8, characterized in that: In its initial state, the sphere (1103) does not contact the limiting member (1106), ensuring that the scraper shell (8) is in an undeformed state.

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