A sand control centralizer for a casing

Abstract

The present application relates to the technical field of centralizer, especially relates to a sand-prevention centralizer for oil casing. The sand-prevention centralizer comprises a fixed pipe, the fixed pipe is fixedly connected to the casing, the fixed pipe is rotationally connected with a rotating sleeve, a sealing element is arranged between the rotating sleeve and the fixed pipe, the rotating sleeve is provided with a plurality of connecting plates which are uniformly distributed in the circumferential direction, the connecting plates are fixedly connected with a mounting shell and a connecting shell, the mounting shell and the connecting shell are both provided with sliding grooves which are uniformly distributed in the circumferential direction, the mounting shell and the connecting shell are both slidably connected with a plurality of spring plates, the mounting shell and the connecting shell are both slidably connected with a plurality of shielding blocks. After the casing enters into the horizontal well, the two sides of the spring plate are limited by the symmetrically distributed shielding blocks, so that the spring plate cannot be elastically deformed, and is converted into a rigid state to maintain the stability of the distance between the lower side of the casing and the well wall, thereby reducing the probability of eccentricity of the casing when moving in the horizontal well, and further improving the stability of the overall position of the casing.

Description

Technical Field

[0001] This invention relates to the field of centralizer technology, and more particularly to a sand-proof centralizer for oil casing. Background Technology

[0002] In oil and gas drilling and cementing engineering, casing centering is one of the key factors determining cementing quality. As an important downhole tool ensuring casing centering, the performance of the centralizer directly affects the displacement efficiency of the cement slurry and the uniform distribution of the cement sheath, thus impacting the effectiveness of interlayer sealing and the long-term integrity of the wellbore. Currently, casing centralizers commonly used in cementing engineering are mainly divided into two categories: elastic centralizers and rigid centralizers. Elastic centralizers primarily rely on circumferentially distributed spring plates to protect the casing, possessing good deformation adaptability and able to accommodate changes in well diameter to a certain extent. During the insertion process, when the well diameter decreases or increases, the elastic centralizer plates can retract or expand, demonstrating strong wellbore adaptability. For this reason, elastic centralizers are widely used in cementing of vertical wells and conventional deviated wells.

[0003] However, existing elastic centralizers still have the following problems in cementing operations of horizontal wells: After entering the horizontal section, the weight of the tubing string acts almost entirely radially, causing the casing to adhere to the lower well wall, resulting in overall eccentricity. At this time, the spring plates at the bottom of the centralizer bear the main pressure, with the lowest spring plate experiencing the greatest pressure. This causes the lowest spring plate to deform under pressure, resulting in uneven circumferential distribution of the centralizer's overall support force on the casing. This causes the casing to be placed eccentrically downwards under gravity, reducing the casing's centering accuracy. More seriously, during casing installation, the casing wall that is biased towards the lower well wall will directly contact and rub against the cuttings bed or broken pieces of the well wall. This not only increases the resistance to casing movement but also scratches the casing body, posing a hidden danger to subsequent operations and the long-term integrity of the wellbore. Summary of the Invention

[0004] In order to overcome the shortcomings mentioned in the background art, the present invention provides a sand-proof centralizer for oil casing.

[0005] The technical implementation scheme of the present invention is as follows: an oil casing sand-proof centralizer includes a fixed pipe, which is fixedly connected to the casing. A rotating sleeve is rotatably connected to the fixed pipe. A sealing element is provided between the rotating sleeve and the fixed pipe. The rotating sleeve is provided with a plurality of circumferentially evenly distributed connecting plates. The plurality of connecting plates are jointly fixedly connected to an mounting shell and a connecting shell. Both the mounting shell and the connecting shell are slidably connected to the casing. Both the mounting shell and the connecting shell are provided with circumferentially evenly distributed sliding grooves, and the sliding grooves of the two are one-to-one. The sliding grooves on the mounting shell and the corresponding sliding grooves on the connecting shell are jointly slidably connected to a spring plate. The spring plate is provided with an arc-shaped portion. Both the mounting shell and the connecting shell are slidably connected to a plurality of evenly distributed blocking blocks. The blocking blocks are used to limit the movement range of one of the spring plates. A weight is fixedly connected to the side of the rotating sleeve near the blocking block. The weight is used to drive the rotating sleeve to rotate relative to the fixed pipe.

[0006] More preferably, both the mounting shell and the connecting shell are fixedly connected to a guide member, and the guide member is provided with a compression ring. Both the mounting shell and the connecting shell are slidably connected to a movable plate. The compression ring is used to compress the corresponding movable plate. The mounting shell and the connecting shell are respectively fixedly connected to the corresponding movable plate with a return spring. The side of the blocking block near the central axis of the mounting shell is fixedly connected to a return spring. The return spring on the blocking block is fixedly connected to the corresponding movable plate.

[0007] More preferably, the guide is provided with an inclined annular surface, and the inclined annular surfaces on the two guides are inclined in the same direction.

[0008] More preferably, the inner diameter of the extrusion ring is larger than the inner diameter of the inclined ring surface on the guide, and the outer diameter of the extrusion ring is smaller than the outer diameter of the inclined ring surface on the guide.

[0009] More preferably, the weight of the compression ring is greater than the maximum tension of the reset spring on the moving plate.

[0010] More preferably, it also includes a fixing ring, which is located on the side of the mounting shell away from the rotating sleeve. A pressure spring is provided between the fixing ring and the mounting shell. The fixing ring is fixedly connected to the sleeve. A shielding shell is fixedly connected to the side of the mounting shell near the fixing ring. The fixing ring is located inside the shielding shell and rotates and slides with it, and a seal is provided between the two. The mounting shell is slidably connected to symmetrically distributed fixing posts. A rotating ring is rotatably connected to the side of the fixing ring near the mounting shell. The symmetrically distributed fixing posts and the pressure spring on the mounting shell are all fixedly connected to the rotating ring on the fixing ring. A movable ring is slidably connected inside the mounting shell. The fixing posts are fixedly connected to the movable ring. The compression ring inside the mounting shell is located on the movement path of the movable ring. The connecting plate is slidably connected to the rotating sleeve. The movable ring is provided with a notch for the corresponding movable plate to pass through.

[0011] More preferably, the rotating sleeve is fixedly connected to a symmetrically distributed extrusion rod on the side near the connecting shell, a drive ring is slidably connected inside the connecting shell, the extrusion rod is fixedly connected to the drive ring, the extrusion ring inside the connecting shell is located on the moving path of the drive ring, and the drive ring is provided with a notch for the corresponding moving plate to pass through.

[0012] More preferably, the spring constant of the pressure spring on the mounting housing is greater than the spring constant of the spring plate.

[0013] More preferably, a plurality of guide blocks are fixedly connected to the side of the arc-shaped portion of the spring plate away from the rotating sleeve, and the guide blocks are provided with a pointed tip on the side near the connecting shell.

[0014] More preferably, the tip of one of the guide blocks on the spring plate is located at a position away from the central axis of the rotating sleeve on the arcuate portion of the spring plate.

[0015] The beneficial effects of this invention are as follows: After the casing enters the horizontal well, the invention limits the two sides of the spring plate by symmetrically distributed blocking blocks, preventing the spring plate from undergoing elastic deformation and thus converting it into a rigid state. This maintains the stability of the distance between the lower side of the casing and the well wall, reduces the probability of eccentricity when the casing moves in the horizontal well, and thus improves the overall stability of the casing position. Furthermore, a sealing element is installed between the fixed pipe and the rotating sleeve to reduce the probability of impurities in the well entering between the fixed pipe and the rotating sleeve, ensuring that the fixed pipe and the rotating sleeve can rotate smoothly relative to each other.

[0016] When the spring plate encounters impurities fixed on the well wall, the reverse squeezing force of the impurities on the spring plate automatically releases the rigid lock of the blocking block on the spring plate, allowing the spring plate to regain its elastic deformation ability. This ensures that the casing can smoothly cross the obstacle and reduces the risk of the casing getting stuck when moving in a horizontal well. Attached Figure Description

[0017] Figure 1 This is a three-dimensional structural diagram of the present invention; Figure 2 This is a three-dimensional structural diagram of the rotating sleeve and connecting plate of the present invention; Figure 3 This is a three-dimensional structural cross-sectional view of the mounting shell of the present invention; Figure 4 This is a three-dimensional structural diagram of the guide and extrusion ring of the present invention; Figure 5 This is a three-dimensional structural diagram of the fixed column and the movable ring of the present invention; Figure 6 This is a three-dimensional structural diagram of the extrusion ring and the moving plate of the present invention; Figure 7 This is a three-dimensional structural diagram of the connecting shell and the extrusion rod of the present invention.

[0018] The markings in the attached diagram are as follows: 1: Sleeve, 2: Fixed tube, 3: Rotating sleeve, 4: Connecting plate, 5: Mounting shell, 51: Connecting shell, 6: Spring plate, 8: Blocking block, 9: Weight block, 10: Guide, 11: Extrusion ring, 12: Moving plate, 13: Fixed ring, 14: Blocking shell, 15: Fixed column, 16: Moving ring, 17: Extrusion rod, 18: Drive ring, 20: Guide block. Detailed Implementation

[0019] The embodiments of the present invention will be described below with reference to the accompanying drawings.

[0020] For ease of understanding, all parts of the present invention are shown in the figures with the casing 1 located in a horizontal well as an example.

[0021] Example 1 This embodiment discloses a casing sand control stabilizer, which aims to solve the problem that in existing elastic stabilizers, after entering the horizontal section, the lower spring plate of the stabilizer bears the main pressure, and the pressure on the bottommost spring plate is the greatest. This causes the bottommost spring plate to deform under pressure, resulting in uneven distribution of the overall support force of the stabilizer on the casing along the circumference. As a result, the casing is placed eccentrically downward under the action of gravity and comes into direct contact and friction with the cuttings bed or the falling blocks of the well wall. This increases the resistance to casing movement and can also cause damage to the casing body.

[0022] like Figures 1-6As shown, it includes a fixed pipe 2, which is fixedly connected to a sleeve 1. A rotating sleeve 3 is rotatably connected to the fixed pipe 2. A sealing element is provided between the rotating sleeve 3 and the fixed pipe 2. The rotating sleeve 3 is provided with several circumferentially evenly distributed connecting plates 4. The several connecting plates 4 are together fixedly connected to an installation shell 5 and a connecting shell 51. The installation shell 5 and the connecting shell 51 are both slidably connected to the sleeve 1. The installation shell 5 and the connecting shell 51 are both provided with circumferentially evenly distributed sliding grooves, and the sliding grooves of the two are one-to-one. The sliding grooves of the installation shell 5 and the corresponding sliding grooves on the connecting shell 51 are slidably connected to a spring plate 6. The spring plate 6 is provided with an arc-shaped part. The installation shell 5 and the connecting shell 51 are both slidably connected to several evenly distributed blocking blocks 8. The blocking blocks 8 are used to limit the movement range of one of the spring plates 6. A weight 9 is fixedly connected to the side of the rotating sleeve 3 near the blocking block 8. The weight 9 is used to drive the rotating sleeve 3 to rotate relative to the fixed pipe 2.

[0023] In the above scheme, the fixing method of the fixed pipe 2 and the casing 1 can be welding or other methods, which are selected by the staff and are not limited in detail in this article; the rotating sleeve 3 is located outside the fixed pipe 2, and the sealing element between the two is an existing device, which is used to improve the sealing performance between the two, reduce the probability of impurities in the well entering the gap between the fixed pipe 2 and the rotating sleeve 3, and ensure that the fixed pipe 2 and the rotating sleeve 3 can rotate smoothly relative to each other; the specific number of connecting plates 4 can be selected by the staff. The figure shows an example of six connecting plates 4 evenly distributed in the circumference. In this embodiment, the rotating sleeve 3 is fixedly connected to the connecting plates 4; the mounting shell 5 and the connecting shell 51 are located on the left and right sides of the rotating sleeve 3, respectively, and the parts of both away from the rotating sleeve 3 are provided with There is an annular cavity; the spring plate 6 is an existing part, and its specific number is also selected by the staff. The figure shows an example of six spring plates 6 evenly distributed around the circumference, which are used to support the sleeve 1. The mounting shell 5 and the connecting shell 51 are both provided with six sliding grooves evenly distributed around the circumference. The two ends of the spring plate 6 are respectively located in the corresponding sliding grooves on the mounting shell 5 and the corresponding sliding grooves on the connecting shell 51. The cavity on the mounting shell 5 is connected to the sliding groove on its lower side, and the cavity on the connecting shell 51 is also connected to the sliding groove on its lower side; the specific number of blocking blocks 8 can be selected by the staff. The blocking blocks 8 on the mounting shell 5 and the connecting shell 51 are respectively located in the cavities of the two. The blocking blocks 8 are used to limit the movement range of the spring plate 6 located on the lower side.

[0024] like Figures 2-6As shown, guide members 10 are fixedly connected inside both the mounting shell 5 and the connecting shell 51. A compression ring 11 is provided on the guide member 10. A movable plate 12 is slidably connected inside both the mounting shell 5 and the connecting shell 51. The compression ring 11 is used to compress the corresponding movable plate 12. A reset spring is fixedly connected between the mounting shell 5 and the connecting shell 51 and the corresponding movable plate 12. A reset spring is fixedly connected to the side of the blocking block 8 near the central axis of the mounting shell 5. The reset spring on the blocking block 8 is fixedly connected to the corresponding movable plate 12. An inclined ring surface is provided on the guide member 10, and the inclined directions of the inclined ring surfaces on the two guide members 10 are the same.

[0025] In the above scheme, the weight 9 is located outside the rotating sleeve 3, so that when the rotating sleeve 3 is in a horizontal state, the center of gravity of the rotating sleeve 3 and the weight 9 is located on one side of the central axis of the rotating sleeve 3. Thus, when the sleeve 1 is in a horizontal state, the weight 9 drives the rotating sleeve 3 to rotate synchronously under its own weight. The guide 10 on the mounting shell 5 is located in the cavity of the mounting shell 5 on the side close to the rotating sleeve 3, and the guide 10 on the connecting shell 51 is located in the cavity of the connecting shell 51 on the side away from the rotating sleeve 3. The inclined annular surface on the guide 10 faces left. On the side, under normal conditions, the compression ring 11 is located on the inclined ring surface of the corresponding guide 10 and is guided by the inclined ring surface of the guide 10, so that the compression ring 11 is aligned with the corresponding guide 10; the moving plate 12 on the mounting shell 5 and the connecting shell 51 is located in their respective cavities, and the moving plate 12 is always in contact with the corresponding compression ring 11; the compression ring 11 is provided with a notch for the reset spring on the moving plate 12 to pass through, so as to ensure that the compression ring 11 does not collide with the reset spring on the moving plate 12 during the movement.

[0026] like Figure 5 As shown, the inner diameter of the compression ring 11 is larger than the inner diameter of the inclined ring surface on the guide 10, and the outer diameter of the compression ring 11 is smaller than the outer diameter of the inclined ring surface on the guide 10, ensuring that when the sleeve 1 is in a horizontal state, the compression ring 11 can move relative to the guide 10 under its own weight.

[0027] like Figure 4 As shown, the weight of the compression ring 11 is greater than the maximum tension of the reset spring on the moving plate 12, causing the moving plate 12 to move under the compression of the compression ring 11 during the moving process.

[0028] The specific workflow of the above scheme is as follows: When this central stabilizer is needed, it should be used by staff. Figure 1 As shown, the centralizer is fixed to casing 1, and then casing 1 is moved into the well according to the existing operation. Initially, casing 1 moves in the vertical well. When casing 1 enters the horizontal section, casing 1 is horizontal (as shown). Figure 1 As shown), the following description uses the movement of sleeve 1 to the right as an example: When the sleeve 1 is in a horizontal state, the fixed tube 2 and all the parts connected to it are simultaneously in a horizontal state. At this time, the weight 9 drives the rotating sleeve 3 to rotate under the action of gravity. The rotating sleeve 3 drives the mounting shell 5 and the connecting shell 51 to rotate synchronously through all the connecting plates 4. The mounting shell 5 and the connecting shell 51 drive the blocking block 8, the guide 10, the compression ring 11 and the moving plate 12 inside them to rotate synchronously until the weight 9 is directly below the fixed tube 2. At this time, the rotating sleeve 3 stops rotating. The blocking block 8 and the moving plate 12 rotate synchronously to the lower side.

[0029] When casing 1 is located in a horizontal well, the compression ring 11 slides downward relative to the corresponding guide 10 under its own weight (moving to the lower left along the inclined ring surface on the corresponding guide 10). During the movement, the compression ring 11 compresses the corresponding moving plate 12, causing the moving plate 12 to move downward and stretching the return spring on it. The moving plate 12 drives the corresponding blocking block 8 to move downward synchronously through the return spring on it. This causes all the blocking blocks 8 on the mounting shell 5 and all the blocking blocks 8 on the connecting shell 51 to enter the lower sliding groove, thereby limiting the left and right ends of the lower spring plate 6. This prevents the two ends of the spring plate 6 from moving backward, i.e., the spring plate 6 cannot produce elastic deformation. This changes the spring plate 6 from an elastically deformable state to a rigid state, ensuring the stability of the distance between the lower side of casing 1 and the well wall, reducing the probability of eccentricity when casing 1 moves in a horizontal well, ensuring the alignment of casing 1, and improving the overall positional stability of casing 1.

[0030] Example 2 Based on Example 1, this example further optimizes an oil casing sand control and centralizing device.

[0031] like Figures 2-7 As shown, it also includes a fixing ring 13, which is located on the side of the mounting shell 5 away from the rotating sleeve 3. A pressure spring is provided between the fixing ring 13 and the mounting shell 5. The fixing ring 13 is fixedly connected to the sleeve 1. A shielding shell 14 is fixedly connected to the side of the mounting shell 5 near the fixing ring 13. The fixing ring 13 is located inside the shielding shell 14 and rotates and slides with it. A seal is provided between the two. The mounting shell 5 is slidably connected to symmetrically distributed fixing posts 15. A rotating ring is rotatably connected to the side of the fixing ring 13 near the mounting shell 5. The symmetrically distributed fixing posts 15 and the pressure spring on the mounting shell 5 are all fixedly connected to the rotating ring on the fixing ring 13. A moving ring 16 is slidably connected inside the mounting shell 5. The fixing posts 15 are fixedly connected to the moving ring 16. The compression ring 11 inside the mounting shell 5 is located on the moving path of the moving ring 16. The connecting plate 4 is slidably connected to the rotating sleeve 3.

[0032] In the above scheme, the fixing ring 13 is located to the left of the mounting shell 5. The fixing method between the fixing ring 13 and the casing 1 can be welding or other methods, which are selected by the staff and are not specified in detail in this article. The shielding shell 14 is located to the left of the mounting shell 5. The sealing element between the shielding shell 14 and the fixing ring 13 is an existing device, which is not shown in the figure. It is used to improve the sealing between the two and reduce the probability of impurities in the well entering the gap between them. The rotating ring on the fixing ring 13 is located to its right. Under normal conditions, the moving ring 16 is located at the leftmost side of the cavity on the mounting shell 5, so that the moving ring 16 can only move to the right along the cavity of the mounting shell 5. The inner and outer diameters of the moving ring 16 are the same as the inner and outer diameters of the cavity of the mounting shell 5, ensuring that the moving ring 16 can be smoothly squeezed to the corresponding squeezing ring 11 during the movement. When the left squeezing ring 11 is located on the inclined ring surface of the corresponding guide 10, the left side of the squeezing ring 11 is located to the left of the left edge of the corresponding guide 10.

[0033] like Figure 3 and Figure 7 As shown, the rotating sleeve 3 is fixedly connected to the side of the connecting shell 51 with symmetrically distributed extrusion rods 17. The connecting shell 51 is slidably connected to a drive ring 18. The extrusion rods 17 are fixedly connected to the drive ring 18. The extrusion ring 11 inside the connecting shell 51 is located on the moving path of the drive ring 18.

[0034] In the above scheme, the extrusion rod 17 is located on the right side of the rotating sleeve 3, and the drive ring 18 is located on the leftmost side of the cavity of the connecting shell 51, so that the drive ring 18 can only move to the right along the cavity of the connecting shell 51; the inner and outer diameters of the drive ring 18 are the same as the inner and outer diameters of the cavity of the connecting shell 51, respectively.

[0035] like Figure 3 and Figure 4 As shown, the spring constant of the pressure spring on the mounting shell 5 is greater than that of the spring constant of the spring plate 6.

[0036] In the above scheme, the elastic coefficients of the pressure spring on the mounting shell 5 and the spring plate 6 are limited to ensure that the pressure spring on the mounting shell 5 will not be compressed during the movement of the casing 1 in the vertical shaft.

[0037] like Figure 6 As shown, the moving ring 16 and the driving ring 18 are respectively provided with notches for the corresponding moving plate 12 to pass through.

[0038] In the above scheme, the notches on the moving ring 16 and the driving ring 18 are both located on the lower side, ensuring that the moving ring 16 and the driving ring 18 will not collide with the reset spring on the moving plate 12 during the movement.

[0039] The specific workflow of the above scheme is as follows: During the process of rotating the sleeve 3 to drive the mounting shell 5 and the connecting shell 51 to rotate, the rotating sleeve 3 and the mounting shell 5 together drive the fixed column 15, the moving ring 16, the rotating ring on the fixed ring 13 and the pressure spring on the mounting shell 5 to rotate. The rotating sleeve 3 and the connecting shell 51 together drive the extrusion rod 17 and the drive ring 18 to rotate, so that the notches on the moving ring 16 and the drive ring 18 rotate to the lower side.

[0040] As the casing 1 moves to the right within the horizontal well, when the lower spring plate 6 encounters impurities fixed on the well wall, these impurities exert a reverse squeezing force (i.e., a squeezing force to the left) on the lower spring plate 6, causing the lower spring plate 6 to squeeze the left-side blocking block 8. The blocking block 8 drives the mounting shell 5 to move to the left synchronously. The mounting shell 5, through all the connecting plates 4, jointly drives the connecting shell 51 to move to the left, and drives the blocking shell 14 to move to the left synchronously.

[0041] As the mounting shell 5 moves to the left, it compresses the pressure spring on it. Simultaneously, the moving ring 16 moves to the right relative to the mounting shell 5 within the cavity of the mounting shell 5. During this movement, the moving ring 16 gradually contacts the left compression ring 11 and applies a rightward compressive force to the left compression ring 11, causing the compression ring 11 to move to the right relative to the mounting shell 5. During this process, the contact position between the left compression ring 11 and the corresponding moving plate 12 continuously changes. When the compression ring 11 contacts the corresponding guide 10 during its movement, the compression ring 11 is guided upward by the inclined ring surface on the guide 10, thereby gradually reducing the compressive force on the moving plate 12. Under the action of the return spring on the moving plate 12, the moving plate 12 gradually moves upward, and the left moving plate 12 drives the corresponding blocking block 8 to move upward synchronously through its return spring, causing the blocking block 8 to gradually lose contact with the lower spring plate 6.

[0042] Until the pressure spring on the mounting shell 5 contracts to its limit, the moving ring 16 moves to the right relative to the mounting shell 5 to its limit position. At this time, the squeezing ring 11 moves to its initial position relative to the corresponding guide 10. At the same time, the left blocking block 8 loses contact with the left side of the lower spring plate 6. The action of the right blocking block 8 is the same as that of the left. When both the left and right blocking blocks 8 lose contact with the lower spring plate 6, the lower spring plate 6 returns from a rigid state to an elastic state. This allows the lower spring plate 6 to undergo elastic deformation under the pressure of impurities fixed on the well wall during the movement of the casing 1 to the right (the middle of the lower spring plate 6 moves upward and the two ends move to the sides respectively). This ensures that the lower spring plate 6 can pass through the impurities smoothly, reducing the probability of the casing 1 getting stuck during the movement.

[0043] After the lower spring plate 6 passes the aforementioned fixed impurities, it gradually returns to its original position under its own elastic force. At the same time, under the action of the pressure spring on its upper part, the mounting shell 5 drives the connecting shell 51 to return to the right relative to the rotating sleeve 3. During the movement of the mounting shell 5 to the right, the squeezing force of the left moving ring 16 on the squeezing ring 11 gradually decreases, causing the left squeezing ring 11 to gradually move downward and squeeze the moving plate 12. This causes the left blocking block 8 to move downward synchronously, thereby blocking the left side of the spring plate 6 again, so that the lower spring plate 6 changes from elastic to rigid again for subsequent use.

[0044] Example 3 Based on Example 2, this example further optimizes an oil casing sand control and centralizing device.

[0045] like Figure 1 and Figure 2 As shown, a number of guide blocks 20 are fixed to the side of the arc-shaped portion of the spring plate 6 away from the rotating sleeve 3. The guide blocks 20 have a pointed tip on the side near the connecting shell 51. The tip of one of the guide blocks 20 on the spring plate 6 is located at a position away from the central axis of the rotating sleeve 3 on the arc-shaped portion of the spring plate 6.

[0046] In the above scheme, the specific number of guide blocks 20 on the same spring plate 6 can be selected by the staff. The figure shows three guide blocks 20 as an example. When the casing 1 is located in the horizontal well, the tip of the guide block 20 is located on the right side. During the movement of the casing 1, the guide block 20 guides the protruding impurities on the well wall and directs the impurities to both sides, thereby reducing the resistance of the casing 1 during the movement and ensuring the smooth movement of the casing 1. The position of one of the guide blocks 20 is limited, and the obstacle-breaking efficiency of the guide block 20 is improved.

[0047] Although this disclosure has been shown and described with reference to specific exemplary embodiments thereof, those skilled in the art will understand that various changes in form and detail may be made to this disclosure without departing from the spirit and scope of the disclosure as defined in the appended specification and its equivalents.

Claims

1. A sand-controlling centralizer for oil casing, characterized in that it includes: A fixed tube (2) is fixedly connected to a sleeve (1). A rotating sleeve (3) is rotatably connected to the fixed tube (2). A sealing element is provided between the rotating sleeve (3) and the fixed tube (2). The rotating sleeve (3) is provided with several connecting plates (4) evenly distributed circumferentially. Several connecting plates (4) are together fixedly connected to a mounting shell (5) and a connecting shell (51). The mounting shell (5) and the connecting shell (51) are both slidably connected to the sleeve (1). The mounting shell (5) and the connecting shell (51) are both provided with circumferentially evenly distributed sliding grooves. The grooves of the mounting shell (5) and the corresponding grooves on the connecting shell (51) are slidably connected to a spring plate (6). The spring plate (6) is provided with an arc-shaped part. The mounting shell (5) and the connecting shell (51) are slidably connected to a number of evenly distributed blocking blocks (8). The blocking blocks (8) are used to limit the movement range of one of the spring plates (6). A weight (9) is fixed to the side of the rotating sleeve (3) near the blocking block (8). The weight (9) is used to drive the rotating sleeve (3) to rotate relative to the fixed tube (2).

2. A sand-controlling centralizer for oil casing according to claim 1, characterized in that, Guide members (10) are fixedly connected inside both the mounting shell (5) and the connecting shell (51). A compression ring (11) is provided on the guide member (10). A movable plate (12) is slidably connected inside both the mounting shell (5) and the connecting shell (51). The compression ring (11) is used to compress the corresponding movable plate (12). A reset spring is fixedly connected between the mounting shell (5) and the connecting shell (51) and the corresponding movable plate (12). A reset spring is fixedly connected to the side of the blocking block (8) near the central axis of the mounting shell (5). The reset spring on the blocking block (8) is fixedly connected to the corresponding movable plate (12).

3. A sand-controlling centralizer for oil casing according to claim 2, characterized in that, The guide (10) is provided with an inclined annular surface, and the inclined annular surfaces on the two guides (10) have the same inclination direction.

4. A sand-controlling centralizer for oil casing according to claim 3, characterized in that, The inner diameter of the extrusion ring (11) is greater than the inner diameter of the inclined ring surface on the guide (10), and the outer diameter of the extrusion ring (11) is smaller than the outer diameter of the inclined ring surface on the guide (10).

5. A sand-controlling centralizer for oil casing according to claim 2, characterized in that, The weight of the compression ring (11) is greater than the maximum tension of the reset spring on the moving plate (12).

6. A sand-controlling centralizer for oil casing according to claim 2, characterized in that, It also includes a fixing ring (13), which is located on the side of the mounting shell (5) away from the rotating sleeve (3). A pressure spring is provided between the fixing ring (13) and the mounting shell (5). The fixing ring (13) is fixedly connected to the sleeve (1). A shielding shell (14) is fixedly connected to the side of the mounting shell (5) near the fixing ring (13). The fixing ring (13) is located inside the shielding shell (14) and rotates and slides with it. A sealing element is provided between the two. The mounting shell (5) is slidably connected with symmetrically distributed fixing posts (15). The fixing ring (13) A rotating ring is rotatably connected to one side of the mounting shell (5). The symmetrically distributed fixed posts (15) and the pressure springs on the mounting shell (5) are fixedly connected to the rotating ring on the fixed ring (13). A movable ring (16) is slidably connected inside the mounting shell (5). The fixed posts (15) are fixedly connected to the movable ring (16). The compression ring (11) inside the mounting shell (5) is located on the moving path of the movable ring (16). The connecting plate (4) is slidably connected to the rotating sleeve (3). The movable ring (16) is provided with a notch for the corresponding movable plate (12) to pass through.

7. A sand-controlling centralizer for oil casing according to claim 6, characterized in that, The rotating sleeve (3) has symmetrically distributed extrusion rods (17) fixedly connected to one side of the connecting shell (51). A drive ring (18) is slidably connected inside the connecting shell (51). The extrusion rods (17) are fixedly connected to the drive ring (18). The extrusion ring (11) inside the connecting shell (51) is located on the moving path of the drive ring (18). The drive ring (18) is provided with a notch for the corresponding moving plate (12) to pass through.

8. A sand-controlling centralizer for oil casing according to claim 7, characterized in that, The elastic coefficient of the pressure spring on the mounting shell (5) is greater than that of the spring plate (6).

9. A sand-controlling centralizer for oil casing according to claim 7, characterized in that, A plurality of guide blocks (20) are fixed to the side of the arc-shaped portion of the spring plate (6) away from the rotating sleeve (3), and the guide blocks (20) have a pointed tip on the side near the connecting shell (51).

10. A sand-controlling centralizer for oil casing according to claim 9, characterized in that, The tip of one of the guide blocks (20) on the spring plate (6) is located away from the central axis of the rotating sleeve (3) on the arcuate portion of the spring plate (6).

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