An external casing packer for oil fields

Abstract

The present application relates to the technical fields of packer, especially to a casing external packer for oil field. The casing external packer comprises a casing, the casing is provided with an oil conveying channel and symmetrically distributed liquid inlet channels which are communicated with each other, the casing is slidably connected with a rubber tube, a piston is slidably connected in the liquid inlet channel, the casing is provided with an annular cavity, the piston is fixedly connected with a slide rod which is slidably connected with the casing, symmetrically distributed slide rods are fixedly connected with a slide ring which slides in the annular cavity, the slide ring is provided with a blind hole, the casing is slidably connected with symmetrically distributed pins which are respectively inserted into adjacent blind holes. The casing external packer quantifies the volume expansion of the rubber tube, determines whether the packer is completed setting by whether the vertical rod is inserted into the adjacent blind hole, thereby reducing the determination of whether the packer is completed setting by whether the downhole pressure reaches the setting value, effectively avoiding the influence of the well wall protrusion on the sealing effect of the rubber tube, and assisting the setting of the packer.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of packer, in particular to a casing external packer for oil field. BACKGROUND

[0002] In the process of oil field drilling and well completion, casing external packer is a key tool for sealing the annular space between casing string and well wall, realizing layer isolation, preventing fluid channeling and protecting casing from corrosion. The casing external packer in the prior art usually relies on hydraulic or mechanical drive to expand the rubber sleeve to make it adhere to the well wall and form a seal. However, due to the complex environment of the wellbore and the inability to directly observe, especially the irregular geometry (such as local protrusions, depressions or cracks) of the well wall in open hole section, the existing packer faces significant problems in actual application. When the packer is positioned, if the rubber sleeve is aligned with the inward protruding part of the well wall, the protruding part will hinder the uniform deformation of the rubber sleeve during the expansion process, resulting in the local rubber sleeve unable to fully expand. This uneven expansion will cause the rubber sleeve to bear abnormal stress at the protruding part, not only reducing the sealing reliability, but also causing local damage or early failure of the rubber sleeve.

[0003] In addition, the prior art usually monitors whether the downhole pressure reaches the preset setting value to determine whether the packer is successfully set, but in the case of protrusions on the well wall, the system pressure can still reach the setting threshold when the rubber sleeve is not fully expanded, thus incorrectly indicating that the setting is complete. This misjudgment can lead to sealing failure in subsequent operations (such as cementing, fracturing or production), causing downhole accidents or reducing production efficiency. SUMMARY

[0004] In order to overcome the shortcomings of the existing packer that cannot determine whether there is a well wall protrusion at the sealing position, the present application provides a feedback type casing external packer for oil field.

[0005] The technical scheme of the present application is as follows: a casing external packer for oil field, comprising a shell, the shell is provided with an oil conveying channel and symmetrically distributed liquid inlet channels which are in communication with each other, the shell is provided with a rubber sleeve, a piston is sealingly and slidingly connected in the liquid inlet channel, the rubber sleeve and the shell cooperate to form a sealing cavity which is in communication with the symmetrically distributed liquid inlet channels, the sealing cavity and the liquid inlet channel are both filled with liquid, the shell is provided with an annular cavity below the sealing cavity, the piston is fixedly connected with a slide rod which is sealingly and slidingly connected with the shell, the symmetrically distributed slide rods are jointly fixedly connected with a sliding ring which slides in the annular cavity on the upper side, the sliding ring is provided with symmetrically distributed blind holes, the shell is slidingly connected with symmetrically distributed pins which are respectively inserted into adjacent blind holes, the end of the pin away from the sliding ring penetrates into the oil conveying channel, and the symmetrically distributed pins are jointly used to intercept the balls in the oil conveying channel. The upper side diameter of the oil conveying channel is larger than the lower side diameter.

[0006] As a preferred technical solution of the present application, the sliding range of the piston is greater than the height difference between the blind hole and the pin.

[0007] As a preferred technical solution of the present application, the length of the pin inserted into the oil delivery channel is not greater than the depth of the blind hole.

[0008] As a preferred technical solution of the present application, the outer side of the sliding ring is fixed with first slips distributed equidistantly in the circumference, and the shell is provided with a rotating ring located at the lower side in the annular cavity, and the rotating ring is provided with second slips distributed equidistantly in the circumference and mutually extruded with the corresponding first slips.

[0009] As a preferred technical solution of the present application, the rotating ring is provided with guide grooves distributed centrally symmetrically, the pin is fixed with vertical rods sliding in adjacent guide grooves, the shell is fixed with U-shaped frames distributed symmetrically and respectively used for guiding adjacent vertical rods, and the rotating ring and the shell are limitingly connected in rotation, and the first slips distributed equidistantly in the circumference and the second slips distributed equidistantly in the circumference are staggered.

[0010] As a preferred technical solution of the present application, the distance of the guide grooves to the axis of the rotating ring gradually increases from one end to the other end, and the included angle between the line connecting one end of the guide groove with the axis of the rotating ring and the line connecting the other end of the guide groove with the axis of the rotating ring is equal to the angle of the second slip relative to the corresponding first slip.

[0011] As a preferred technical solution of the present application, the sliding ring is fixed with L-shaped plates distributed equidistantly in the circumference, the L-shaped plates distributed equidistantly in the circumference and the first slips distributed equidistantly in the circumference are staggered, the L-shaped plates are fixed with arc-shaped plates used for limiting adjacent second slips, and the rotating ring is hinged with the second slips.

[0012] As a preferred technical solution of the present application, the second slips are provided with limiters distributed symmetrically, and the arc-shaped plates are used for limiting adjacent limiters.

[0013] As a preferred technical solution of the present application, the distance between adjacent limiters on different second slips is less than the distance between two ends of the arc-shaped plate, and the arc length between lower sides of adjacent second slips is greater than the arc length of the arc-shaped plate.

[0014] As a preferred technical solution of the present application, the longitudinal length of the limiter is greater than the height difference between the blind hole and the pin.

[0015] In summary, the present application includes at least one of the following beneficial technical effects: the present application quantifies the volume expansion of the rubber sleeve, determines whether the packer has completed setting by whether the vertical rod is inserted into the adjacent blind hole, thereby reducing the determination of whether the packer has completed setting by whether the downhole pressure reaches the setting value, effectively avoiding the influence of the well wall protrusion on the sealing effect of the rubber sleeve, assisting the setting of the packer, the present packer can switch between the releasable and unreleasable modes, increasing the application range of the present packer, using the mutual locking of the first and second slips to increase the connection strength, thereby realizing the unreleasable effect, and after the second slip moves away from the sliding ring, the adjacent first slip is released, realizing the releasable effect. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a schematic diagram of the three-dimensional structure of the present application;

[0017] Figure 2 is a schematic diagram of the three-dimensional structure of the present application;

[0018] Figure 3 is a schematic diagram of the three-dimensional structure of the present application;

[0019] Figure 4 is a schematic diagram of the three-dimensional structure of the present application Figure 3 is an enlarged view of position A in the present application;

[0020] Figure 5 is a schematic diagram of the three-dimensional structure of the present application;

[0021] Figure 6 is a schematic diagram of the three-dimensional structure of the present application;

[0022] Figure 7 is a schematic diagram of the three-dimensional structure of the present application;

[0023] Figure 8 is a schematic diagram of the three-dimensional structure of the present application;

[0024] In the figure, 1 is the shell, 111 is the oil delivery channel, 112 is the U-shaped frame, 110 is the ball, 101 is the liquid inlet channel, 102 is the sealing cavity, 103 is the annular cavity, 2 is the rubber sleeve, 3 is the piston, 4 is the sliding rod, 5 is the sliding ring, 501 is the blind hole, 6 is the pin, 601 is the vertical rod, 7 is the first slip, 8 is the rotating ring, 801 is the guide groove, 9 is the second slip, 901 is the limiting part, 10 is the L-shaped plate, and 11 is the arc-shaped plate. DETAILED DESCRIPTION

[0025] The present application is further described in detail below in conjunction with the drawings and specific embodiments, but does not limit the protection scope and application scope of the present application, and the present packer only shows the rubber sleeve part, and the locking mechanism below is not shown. Embodiment 1

[0026] The existing casing packer is used to seal the annular space between the casing and the inner wall of the oil well. Since the well wall environment cannot be observed, and the inner wall of the oil well is irregular and has an inward protrusion, if the rubber sleeve on the packer is flush with the protrusion of the well wall after positioning is completed, after the rubber sleeve of the packer is expanded, the outer side of the rubber sleeve cannot be completely expanded due to the existence of the protrusion of the well wall, so that the part of the rubber sleeve located at the protrusion of the well wall is unevenly stressed, affecting the sealing effect. And under the condition of pressure, whether the downhole pressure reaches the setting value is judged to determine whether the packer is set. However, the protrusion of the well wall will also cause the downhole pressure to reach the setting value, so the existing packer cannot guarantee whether the rubber sleeve thereon is completely expanded.

[0027] A casing packer for oil field, as shown in Figures 1-7 The casing packer for oil field, as shown in The casing packer for oil field, as shown in

[0028] The casing packer for oil field, as shown in Figure 3As shown, the piston 3 is located on the upper side of the adjacent liquid inlet channel 101, and the pin 6 is inserted into the oil delivery channel 111 away from the end of the sliding ring 5. The end of the pin 6 close to the sliding ring 5 is in close contact with the inner wall of the sliding ring 5 and cannot move. When the packer is needed to seal the annular space between the casing and the well wall, the operator first puts the packer into the designated position in the well with the casing. Then the operator puts a ball 110 with a diameter equal to the diameter of the lower side of the oil delivery channel 111 into the casing from the wellhead (the ball 110 is made of degradable material and will degrade by itself after a period of time in the well). The ball 110 moves downward through the casing into the oil delivery channel 111. After contacting the two pins 6, the ball 110 is intercepted by the two pins 6 and cannot continue to move downward (as shown in FIG. 6). Figure 3 At this time, the ball 110 blocks the lower side of the oil delivery channel 111. Then the operator pressurizes the well. The pressure in the oil delivery channel 111 increases, and the pressure above the adjacent piston 3 in the liquid inlet channel 101 also increases. Taking the right piston 3 as an example, the pressure above the piston 3 pushes it to move downward. The piston 3 drives the slide rod 4 to move downward, and the slide rod 4 drives the sliding ring 5 to move downward, so that the blind hole 501 on the sliding ring 5 gradually approaches the pin 6. The piston 3 pushes the hydraulic oil below it in the liquid inlet channel 101 downward into the sealing cavity 102. The increase in the volume of the sealing cavity 102 causes the rubber sleeve 2 to expand and expand outward.

[0029] When the blind hole 501 is aligned with the adjacent pin 6, the downhole pressure reaches the setting value. Then the high pressure in the oil delivery channel 111 pushes the ball 110 to move downward. The ball 110 causes the two pins 6 to move away from each other. The two pins 6 are inserted into the adjacent blind holes 501, respectively. The sliding ring 5 is limited by the two pins 6 and cannot move longitudinally. When the blind hole 501 is occupied by the adjacent pin 6, the end of the pin 6 away from the sliding ring 5 no longer probes into the oil delivery channel 111. The ball 110 is no longer limited and continues to move downward along the oil delivery channel 111. The downhole pressure instantaneously decreases. The operator determines that the setting is complete. At this time, the outer side of the rubber sleeve 2 is in close contact with the well wall. The setting process of the packer is completed.

[0030] If there is a protrusion on the well wall, the rubber sleeve 2 cannot expand completely, the volume change of the sealing cavity 102 is less than the above-mentioned change, and the blind hole 501 will be located above the pin 6 and cannot be aligned with the pin 6. Then the ball 110 will be limited by the two pins 6 and will always block the lower side of the oil delivery channel 111. The operator will continue to pressurize. When the downhole pressure exceeds the setting value, it will not instantaneously decrease. It is determined that the rubber sleeve 2 has not expanded completely. The operator no longer continues to pressurize the well. The downhole pressure decreases, and the rubber sleeve 2 contracts. Then the operator cleans the protrusion of the well wall at this position or reselects the setting position and continues to repeat the above steps until the rubber sleeve 2 expands completely to achieve setting.

[0031] When the unsealing operation is needed, the operator throws a ball 110 into the casing from the wellhead, the ball 110 has the same diameter as the upper side of the oil delivery channel 111, and the ball 110 cannot move downward when it moves to the upper side of the oil delivery channel 111 (as shown in Figure 2 When the unsealing operation is needed, the operator throws a ball 110 into the casing from the wellhead, the ball 110 has the same diameter as the upper side of the oil delivery channel 111, and the ball 110 cannot move downward when it moves to the upper side of the oil delivery channel 111 (as shown in Example 2

[0032] On the basis of example 1, an oilfield casing external packer, as shown in Figures 2-6 The outer side of the sliding ring 5 is fixedly connected with six first slips 7 distributed at equal intervals in the circumferential direction, and the housing 1 is provided with a rotating ring 8 located at the lower side in the annular cavity 103 (in this embodiment, the rotating ring 8 is considered to be fixedly connected with the housing 1), and the rotating ring 8 is provided with six second slips 9 distributed at equal intervals in the circumferential direction and in contact with the corresponding first slips 7 (in this embodiment, the second slips 9 are considered to be fixedly connected with the rotating ring 8).

[0033] The existing packers are divided into two types: unsealable and sealable. The packer in example 1 is sealable, and the strength of this type of packer is lower than that of the unsealable packer because it relies on the pin 6 for fixation. In this embodiment, the one-way locking of the slips makes the packer unsealable, thereby improving the strength of the packer. The specific operation is as follows: in the initial state, the second slip 9 is aligned with the adjacent first slip 7, and in this embodiment, the teeth of the first slip 7 and the second slip 9 can be deformed. During the downward movement of the sliding ring 5 in example 1, the first slip 7 on the sliding ring 5 moves downward, and for example, the right side of the first slip 7 moves downward and is in contact with and pressed by the second slip 9, and both the first slip 7 and the second slip 9 are deformed. When the pin 6 is inserted into the adjacent blind hole 501, the state is as shown in Figure 6 and Figure 7 The first slip 7 and the adjacent second slip 9 are locked, and the sliding ring 5 cannot move upward. When the downhole pipeline vibrates, the connection strength between the first slip 7 and the second slip 9 is greater than the fixation strength of the pin 6, thereby improving the stability of the packer and ensuring the normal operation of the packer. This packer is used in downhole environments where the setting is not needed to be released. Example 3

[0034] On the basis of embodiment 2, an oilfield casing external packer, such as Figures 2-7 As shown in the figure, the swivel 8 is provided with two guide grooves 801 which are centrally symmetrically distributed, the pin 6 is fixedly connected with a vertical rod 601 which slides in the adjacent guide groove 801, the shell 1 is fixedly connected with a U-shaped frame 112 which is symmetrically distributed and is respectively used for guiding the adjacent vertical rod 601, the U-shaped frame 112 ensures that the adjacent vertical rod 601 can only move horizontally, and in the embodiment, the swivel 8 and the shell 1 are limitingly and rotatably connected, the circumferentially equidistantly distributed first slips 7 and the circumferentially equidistantly distributed second slips 9 are staggeredly distributed, the distance from the guide groove 801 to the axis of the swivel 8 gradually increases from one end to the other end, the angle between the line connecting the one end of the guide groove 801 with the axis of the swivel 8 and the line connecting the other end of the guide groove 801 with the axis of the swivel 8 is 30°, and taking the right vertical rod 601 as an example, when the vertical rod 601 is located at the right side of the guide groove 801, the states of the first slip 7 and the second slip 9 are as shown in the figure. Figure 6

[0035] In embodiment 2, the first slip 7 and the second slip 9 will deform at the same time when they are pressed against each other, and the premise of the deformation of the two is that they are both deformable materials, but the fixing effect of the deformable material is poor relative to the non-deformable material, and the second slip 9 will provide resistance to the downward movement of the first slip 7, and the operator needs to observe the change of the downhole pressure to know whether the packer has completed setting, if the resistance to the downward movement of the first slip 7 increases, the downhole pressure will increase, which affects the judgment of the operator on the change of the downhole pressure, therefore, in the embodiment, the first slip 7 and the second slip 9 are both set to be non-deformable materials, and the first slip 7 will not be affected by the second slip 9 when it moves downward, and the specific operation is as follows: in the initial state, as shown in the figure, the circumferentially equidistantly distributed first slips 7 and the circumferentially equidistantly distributed second slips 9 are staggeredly distributed, and the first slip 7 is located at the upper side of the second slip 9, in embodiment 1, in the process of the downward movement of the sliding ring 5, the sliding ring 5 drives the first slip 7 thereon to move downward, the first slip 7 is located between the adjacent two second slips 9 and moves downward without contacting the adjacent two second slips 9, therefore, the second slip 9 will not provide resistance to the first slip 7, which ensures the accuracy of the judgment of the operator on the downhole pressure. Figure 2

[0036] When the blind hole 501 and the adjacent pin 6 are aligned, the tooth on the second slip 9 is aligned with the gap between the adjacent two teeth on the first slip 7, which facilitates the subsequent insertion of the tooth on the second slip 9 into the gap between the two teeth on the adjacent first slip 7, and in the process of the insertion of the pin 6 into the adjacent blind hole 501, taking the right pin 6 as an example, in the process of the right movement of the pin 6, the pin 6 drives the vertical rod 601 to move rightward, the vertical rod 601 extrudes the swivel 8 through the guide groove 801 to make the swivel 8 rotate clockwise (counterclockwise rotation is the same as clockwise rotation) Figure 2 ​​Figure 2 (top view direction), the second slips 9 on the swivel 8 clockwise rotation, the second slips 9 on the card teeth between the adjacent two card teeth between the gap of the first slip 7, while the first slip 7 on the card teeth between the adjacent two card teeth between the gap of the second slip 9, when the pin 6 will occupy the blind hole 501, the right vertical rod 601 located in the adjacent guide groove 801 right side, left vertical rod 601 located in the adjacent guide groove 801 left side, the first slip 7 and the second slip 9 each other, as shown in Figure 3 (top view direction) state, the fixed mode in example 2 is the same as the existing unsealable fixed mode, and the packer in example 2 is optimized in this example. In order to adapt to the judgment of whether the packer is set in this example 1, the resistance generated by the mutual extrusion of the first slip 7 and the second slip 9 is eliminated, and the mutual locking of the first slip 7 and the second slip 9 is ensured. Figure 7 The fixed mode in example 2 is the same as the existing unsealable fixed mode, and the packer in example 2 is optimized in this example. In order to adapt to the judgment of whether the packer is set in this example 1, the resistance generated by the mutual extrusion of the first slip 7 and the second slip 9 is eliminated, and the mutual locking of the first slip 7 and the second slip 9 is ensured. Example 4

[0037] On the basis of example 3, an oilfield casing external packer, as shown in Figure 2 and Figures 4-7 The sliding ring 5 is fixed with six L-shaped plates 10 distributed equidistantly in the circumferential direction, the six L-shaped plates 10 and the six first slips 7 are staggered, the L-shaped plate 10 is fixed with an arc plate 11 for limiting the adjacent second slip 9, and the swivel 8 is hinged with the second slip 9 in this example, as shown in Figure 7 The right side, the hinge between the second slip 9 and the swivel 8 limits the second slip 9, so that the upper side of the second slip 9 cannot approach the sliding ring 5 and can only move away from the sliding ring 5, the second slip 9 is provided with two limiting parts 901 distributed symmetrically, the arc plate 11 is used for limiting the adjacent limiting part 901, the distance between the adjacent limiting parts 901 on different second slips 9 is less than the distance between the two ends of the arc plate 11, the arc length between the lower sides of the adjacent second slips 9 is greater than the arc length of the arc plate 11, and the longitudinal length of the limiting part 901 is greater than the height difference between the blind hole 501 and the pin 6. When the pin 6 is inserted into the adjacent blind hole 501, the arc plate 11 is still in contact with the adjacent limiting part 901.

[0038] In this embodiment, the packer of embodiment 3 is optimized, and the packer is added with a deblocking function on the basis of embodiment 3 (ensuring that the function of the packer in embodiment 3 is unchanged). The packer has both high fixing strength of the slips and the deblocking function. The specific operation is as follows: in the initial state, the arc-shaped plate 11 is located on the side of the adjacent second slip 9 away from the sliding ring 5, and even if the second slip 9 and the rotating ring 8 are hinged, the second slip 9 can be ensured to be in a vertical state. When the pin 6 is aligned with the adjacent blind hole 501, the arc-shaped plate 11 is located on the outside of the adjacent second slip 9 and supports the second slip 9. During the process of inserting the pin 6 into the adjacent blind hole 501, the second slip 9 gradually turns to the adjacent two arc-shaped plates 11, but during the process, the arc-shaped plate 11 still supports the outside of the adjacent second slip 9. When the second slip 9 and the adjacent first slip 7 are clamped with each other, the arc-shaped plate 11 contacts the limiting part 901 of the adjacent two second slips 9, and the state is as shown in Figure 6 .

[0039] During the deblocking process in embodiment 1, the sliding ring 5 moves downward to cut off the two pins 6, the sliding ring 5 drives the first slip 7 and the L-shaped plate 10 on it to move downward, the L-shaped plate 10 drives the arc-shaped plate 11 to move downward, and the arc-shaped plate 11 gradually locates below the adjacent limiting part 901. During the process of moving the first slip 7 downward, the first slip 7 moves downward to extrude the second slip 9 so that the second slip 9 is deformed. When the arc-shaped plate 11 is located below the limiting part 901, the second slip 9 is extruded by the first slip 7 and cooperates with its own gravity, so that the upper side of the second slip 9 gradually moves away from the first slip 7. The final state is as shown in Figure 8 . The arc-shaped plate 11 is located between the adjacent limiting part 901 and the sliding ring 5. During the process of moving the sliding ring 5 upward, the sliding ring 5 drives the first slip 7 and the L-shaped plate 10 on it to move upward, the L-shaped plate 10 drives the arc-shaped plate 11 to move upward, and the first slip 7 and the arc-shaped plate 11 are both free to move upward and are not intercepted by the second slip 9, so as to realize the deblocking process.

[0040] The embodiments of the application are described in detail above in combination with the drawings, but the application is not limited to the above-described embodiments. Various changes can be made within the knowledge of those skilled in the art without departing from the purpose of the application.

Claims

1. An external packer for oilfield casing, comprising a housing (1), wherein the housing (1) is provided with interconnected oil delivery channels (111) and symmetrically distributed fluid inlet channels (101), and the housing (1) is provided with a rubber sleeve (2), characterized in that: A piston (3) is slidably connected to the liquid inlet channel (101). The rubber sleeve (2) and the housing (1) cooperate to form a sealed cavity (102) that communicates with the symmetrically distributed liquid inlet channels (101). Both the sealed cavity (102) and the liquid inlet channel (101) are filled with liquid. The housing (1) is provided with an annular cavity (103) located below the sealed cavity (102). The piston (3) is fixedly connected to a slide rod (4) that is slidably connected to the housing (1). The symmetrically distributed slide rods (4) are jointly fixedly connected to... A sliding ring (5) slides on the upper side of the annular cavity (103). The sliding ring (5) is provided with symmetrically distributed blind holes (501). The housing (1) is slidably connected with symmetrically distributed pins (6) that are respectively used to insert into adjacent blind holes (501). The end of the pin (6) away from the sliding ring (5) is inserted into the oil delivery channel (111). The symmetrically distributed pins (6) are used together to intercept the ball (110) in the oil delivery channel (111). The upper diameter of the oil delivery channel (111) is larger than the lower diameter.

2. The oilfield casing external packer according to claim 1, characterized in that: The sliding range of the piston (3) is greater than the height difference between the blind hole (501) and the pin (6).

3. The oilfield casing external packer according to claim 2, characterized in that: The length by which the pin (6) penetrates the oil channel (111) is no greater than the depth of the blind hole (501).

4. The oilfield casing external packer according to claim 1, characterized in that: The outer side of the sliding ring (5) is fixed with a first slip (7) that is circumferentially evenly distributed. The housing (1) is provided with a rotating ring (8) located on the lower side of the annular cavity (103). The rotating ring (8) is provided with a second slip (9) that is circumferentially evenly distributed and presses against the corresponding first slip (7).

5. The oilfield casing external packer according to claim 4, characterized in that: The rotating ring (8) is provided with guide grooves (801) that are centrally symmetrically distributed. The pin (6) is fixedly connected to a vertical rod (601) that slides in the adjacent guide grooves (801). The housing (1) is fixedly connected to a U-shaped frame (112) that is symmetrically distributed and used to guide the adjacent vertical rods (601). The rotating ring (8) and the housing (1) are connected in a limited rotational manner. The first slip (7) and the second slip (9) that are circumferentially equally spaced are staggered.

6. The oilfield casing external packer according to claim 5, characterized in that: The distance from the guide groove (801) to the axis of the rotating ring (8) gradually increases from one end to the other. The angle between the line connecting one end of the guide groove (801) to the axis of the rotating ring (8) and the line connecting the other end of the guide groove (801) to the axis of the rotating ring (8) is equal to the angle at which the second slip (9) deflects relative to the corresponding first slip (7).

7. The oilfield casing external packer according to claim 6, characterized in that: The sliding ring (5) is fixedly connected to an L-shaped plate (10) with equal circumferential spacing. The L-shaped plate (10) and the first slip (7) with equal circumferential spacing are staggered. The L-shaped plate (10) is fixedly connected to an arc plate (11) for limiting the adjacent second slip (9). The rotating ring (8) is hinged to the second slip (9).

8. An external packer for oilfield casing according to claim 7, characterized in that: The second slip (9) is provided with symmetrically distributed limiting parts (901), and the arc plate (11) is used to limit the adjacent limiting parts (901).

9. An external packer for oilfield casing according to claim 8, characterized in that: The distance between adjacent limiting portions (901) on the second slip (9) is less than the distance between the two ends of the arc plate (11), and the arc length between the lower sides of adjacent second slips (9) is greater than the arc length of the arc plate (11).

10. An external packer for oilfield casing according to claim 9, characterized in that: The longitudinal length of the limiting part (901) is greater than the height difference between the blind hole (501) and the pin (6).

Images