Pull-in rotatable elastic casing centralizer and centralizing method therefor

Abstract

Disclosed in the present invention is a pull-in rotatable elastic casing centralizer, comprising an upper end ring. A plurality of working rib plates are connected to the bottom of the upper end ring. The sides of the plurality of working rib plates away from the upper end ring are jointly connected to a lower end ring. A stop ring is sleeved on the outer wall of the lower end ring. Also disclosed in the present invention is a centralizing method based on a pull-in rotatable elastic casing centralizer. Before entering a wellbore, the centralizer is sleeved on the outer side of a casing, the lower end ring is mounted in a direction toward a wellhead, set screws distributed on the outer side of the stop ring are tightened, and the entire centralizer is fixed to the casing, thereby completing centralization. After the mounting is completed, the stop ring of the centralizer and the casing are fixed relative to each other, and the entire centralizer is pulled into the wellbore along with the casing, so that the resistance during entering is relatively small, and no destructive impact is caused to rib plates of the centralizer due to difficulty in entering. In addition, even if the centralizer encounters resistance in the wellbore, the pull-in design will not cause destructive compression of the rib plates of the centralizer, allowing the centralizer to more easily pass.

Description

Pull-in rotatable casing elastic centralizer and centralizing method thereof

[0001] The present application claims priority to the patent application No. 202410819318.6, filed on June 24, 2024, with the State Intellectual Property Office of China, and entitled "Pull-in rotatable casing elastic centralizer and centralizing method thereof". TECHNICAL FIELD

[0002] The present application belongs to the technical field of oil drilling and cementing, and particularly relates to a pull-in rotatable casing elastic centralizer, and a centralizing method using the same. BACKGROUND

[0003] A casing centralizer is a device for centralizing a casing in a wellbore, which is mainly used in cementing operations, especially during casing running. According to the actual application conditions, structural characteristics, manufacturing processes and materials of the casing centralizer, the casing centralizer is divided into different types. According to the classification of the petroleum industry standard, the casing centralizer is usually divided into elastic centralizers and rigid centralizers. The elastic centralizer is the earliest applied and most widely used type of centralizer, which has lower manufacturing cost, various types, and larger deformation and recovery force. The elastic centralizer can not only ensure the centralization of the casing, but also has good passability for well sections with large variable diameter, reduces the friction resistance of casing running, and improves the uniformity of cementing between the casing and the well wall.

[0004] A casing centralizer is a device installed on a casing string to centralize the casing string in a wellbore. The centralization of the casing in the wellbore is one of the determining factors of the quality of oil and gas well cementing, and the placement of the centralizer is the basis for determining whether the casing is centralized. The centralizer is a component for centralizing and ensuring the concentricity of the casing in the wellbore. The main functions of the casing centralizer are: 1. reducing the eccentricity of the casing, improving the displacement efficiency of cementing, effectively preventing the channeling of cement slurry, and ensuring the cementing quality to achieve good sealing effect; 2. the support of the casing centralizer to the casing reduces the contact area between the casing and the well wall, thereby reducing the friction between the casing and the well wall, which is beneficial to the running of the casing into the well and the movement of the casing during cementing; 3. reducing the sticking of the casing during casing running and reducing the risk of casing running; 4. the casing centralizer can reduce the bending degree of the casing in the well, thereby reducing the wear of the casing by drilling tools or other downhole tools during drilling after the casing is run, and playing a protective role for the casing. In summary, there are various types of casing centralizers, and with the development of drilling towards ultra-deep wells, large displacement wells, horizontal wells and other complex wells, conventional casing centralizers are difficult to meet the needs of downhole construction.

[0005] Most of the elastic centralizers on the market are installed between two stop rings, but this installation method has the following problems: (1) low field installation efficiency, needing to be respectively sleeved into 2 stop rings and centralizers; (2) belonging to a push-in type, the resistance is relatively large when entering the wellbore, it is not easy to enter, and even for some smaller wellbores, it may not be able to enter, resulting in damage to the centralizer; (3) if resistance is encountered in the well, the push-in type is also easy to cause destructive compression of the centralizer rib plate.

[0006] SUMMARY

[0007] The first object of the present application is to provide a pull-in type rotatable casing elastic centralizer, which solves the problem of large resistance of the relative pull-in type when entering the wellbore, resulting in damage to the centralizer.

[0008] The second object of the present application is to provide a centralizing method of the pull-in type rotatable casing elastic centralizer.

[0009] The first technical solution adopted by the present application is a pull-in type rotatable casing elastic centralizer, which comprises an upper end ring, a plurality of working rib plates connected to the bottom of the upper end ring, a lower end ring connected to the side away from the upper end ring of the plurality of working rib plates, and a stop ring sleeved on the outer wall of the lower end ring.

[0010] The first technical solution of the present application is further characterized in that,

[0011] The outer wall of the stop ring is provided with a plurality of jackscrews.

[0012] The inner diameters of the upper end ring and the lower end ring are the same, and the lower end ring is uniformly provided with a plurality of pin mounting holes.

[0013] The working rib plates are uniformly distributed around the upper end ring and the lower end ring, a plurality of pins are welded in the pin mounting holes, and the lower end ring is connected with the stop ring through the pins.

[0014] The inner wall of the stop ring is provided with a pin clamping groove, the pin is arranged in the pin clamping groove, the lower end ring is connected with the stop ring through the pin, and the lower end ring is freely rotated by 360° relative to the stop ring.

[0015] The inner diameters of the upper end ring and the lower end ring are the same, and the lower end ring is uniformly provided with a plurality of block mounting holes.

[0016] The working rib plates are uniformly distributed around the upper end ring and the lower end ring, a plurality of blocks are welded in the block mounting holes, and the lower end ring is connected with the stop ring through the blocks.

[0017] The inner wall of the stop ring is provided with a block clamping groove, the block is arranged in the block clamping groove, the lower end ring is connected with the stop ring through the block, and the lower end ring is freely rotated by 360° relative to the stop ring.

[0018] Another technical solution adopted by the present application is a centralizing method of a pull-in type rotatable casing elastic centralizer, and the specific steps are as follows:

[0019] Before entering the wellbore, the centralizer is sleeved outside the casing, the lower end ring is installed in the direction of the well mouth, the top thread distributed outside the stop ring is tightened, the whole centralizer is fixed to the casing, and the centralization is completed.

[0020] Compared with the prior art, the beneficial effects of the present application are:

[0021] The pull-in type rotatable casing elastic centralizer of the present application is convenient and fast to install on site, and only needs to be sleeved once to realize the installation of the stop ring and the centralizer; only one stop ring needs to be fixed, that is, the stop ring sleeved outside the lower end ring, so that the relative position of the centralizer on the casing is fixed, and at the same time, the free rotation of the centralizer is not affected. After installation is completed, the centralizer stop ring is relatively fixed with the casing through the top thread, and the lower end ring is pulled through the pin or the block, so that the whole centralizer is pulled into the wellbore with the casing, the entering resistance is relatively small, and destructive influence on the centralizer rib plate caused by difficult entering is avoided; in addition, even if the centralizer meets resistance in the wellbore, the pull-in type will not cause destructive compression of the centralizer rib plate, and is more easily passed through. BRIEF DESCRIPTION OF DRAWINGS

[0022] Fig. 1 is a structural schematic view of the pull-in type rotatable casing elastic centralizer of the present application;

[0023] Fig. 2 is a partial enlarged view of Fig. 1A;

[0024] Fig. 3 is a structural schematic view of the pull-in type rotatable casing elastic centralizer of the present application in which the working rib plate is made of spring steel material according to embodiment 4;

[0025] Fig. 4 is a partial enlarged view of Fig. 3B.

[0026] In the figure, 1. upper end ring; 2. lower end ring; 3. working rib plate; 4. stop ring; 5. top thread; 6. pin slot; 7. pin; 8. pin mounting hole; 9. block mounting hole; 10. block; 11. block slot. DETAILED DESCRIPTION

[0027] The present application will be described in detail below in combination with the drawings and specific embodiments.

[0028] The present application provides a pull-in type rotatable casing elastic centralizer, as shown in Fig. 1, which comprises an upper end ring 1, a plurality of working rib plates 3 connected to the bottom of the upper end ring 1, a lower end ring 2 commonly connected to the side away from the upper end ring 1 of the plurality of working rib plates 3, and a stop ring 4 sleeved outside the outer wall of the lower end ring 2; the inner diameters of the upper end ring 1 and the lower end ring 2 are the same, and each working rib plate 3 is uniformly distributed around the circumferential direction of the upper end ring 1 or the lower end ring 2.

[0029] As shown in Fig. 2, the lower end ring 2 is uniformly provided with a plurality of pin mounting holes 8 along the circumferential direction of 360 degrees, each pin mounting hole 8 is welded with a pin 7, the stop ring 4 is sleeved outside the lower end ring 2, the inner side of the stop ring 4 is provided with a pin clamping groove 6, the pin 7 is arranged in the pin clamping groove 6, the stop ring 4 and the lower end ring 2 are connected through the pin 7, and the lower end ring 2 can be freely rotated in the direction of 360 degrees relative to the stop ring 4, and the stop ring 4 is uniformly provided with a plurality of top wires 5 along the circumferential direction of 360 degrees.

[0030] As shown in Fig. 3-4, the lower end ring 2 is uniformly provided with a plurality of block mounting holes 9 along the circumferential direction of 360 degrees, each block mounting hole 9 is welded with a block 10, the stop ring 4 is sleeved outside the lower end ring 2, the inner side of the stop ring 4 is provided with a block clamping groove 11, the block 10 is arranged in the block clamping groove 11, the stop ring 4 and the lower end ring 2 are connected through the block 10, and the lower end ring 2 can be freely rotated in the direction of 360 degrees relative to the stop ring 4, and the stop ring 4 is uniformly provided with a plurality of top wires 5 along the circumferential direction of 360 degrees.

[0031] The application also provides a centralizing method using the pull-in type rotatable casing elastic centralizer, and the specific steps are as follows: before entering the wellbore, the centralizer is sleeved outside the casing, the lower end ring is installed in the direction of the well entrance, the top wires 5 distributed on the outer side of the stop ring 4 are tightened, the whole centralizer is fixed to the casing, and the centralizing is completed.

[0032] The relative position of the centralizer on the casing is fixed, the casing is pulled into the wellbore, the resistance is relatively small, and the destructive influence on the centralizer rib plate caused by the difficulty in entering is avoided; in addition, even if the centralizer meets resistance in the wellbore, the pull-in type will not cause destructive compression of the centralizer rib plate, and the centralizer is more easily passed through.

[0033] Embodiment 1

[0034] The embodiment provides a pull-in type rotatable casing elastic centralizer, as shown in Fig. 1, which comprises an upper end ring 1, a plurality of working rib plates 3 are connected to the bottom of the upper end ring 1, the plurality of working rib plates 3 are commonly connected with a lower end ring 2 away from one side of the upper end ring 1, and the lower end ring 2 is sleeved with a stop ring 4.

[0035] Embodiment 2

[0036] The embodiment provides a pull-in type rotatable casing elastic centralizer, as shown in FIGS. 1-2, which comprises an upper end ring 1, the bottom of the upper end ring 1 is connected with a plurality of working rib plates 3, the side, away from the upper end ring 1, of the plurality of working rib plates 3 is jointly connected with a lower end ring 2, the outer wall of the lower end ring 2 is sleeved with a stop ring 4, the outer wall of the stop ring 4 is provided with a plurality of jackscrews 5, the inner diameters of the upper end ring 1 and the lower end ring 2 are the same, the lower end ring 2 is uniformly provided with a plurality of pin mounting holes 8, the working rib plates 3 are uniformly distributed around the upper end ring 1 and the lower end ring 2, a plurality of pins 7 are welded in the pin mounting holes 8, the lower end ring 2 is connected with the stop ring 4 through the pins 7, the inner wall of the stop ring 4 is provided with pin clamping grooves 6, the pins 7 are arranged in the pin clamping grooves 6, the lower end ring 2 is connected with the stop ring 4 through the pins 7, and the lower end ring 2 can be freely rotated by 360 degrees relative to the stop ring 4.

[0037] Embodiment 3

[0038] The embodiment provides a pull-in type rotatable casing elastic centralizer, as shown in FIG. 3, which comprises an upper end ring 1, the bottom of the upper end ring 1 is connected with a plurality of working rib plates 3, the working rib plates 3 are made of spring steel, the side, away from the upper end ring 1, of the plurality of working rib plates 3 is jointly connected with a lower end ring 2, and the outer wall of the lower end ring 2 is sleeved with a stop ring 4.

[0039] Embodiment 4

[0040] The embodiment provides a pull-in type rotatable casing elastic centralizer, as shown in FIGS. 3 and 4, which comprises an upper end ring 1, the bottom of the upper end ring 1 is connected with a plurality of working rib plates 3, the working rib plates 3 are made of spring steel, the side, away from the upper end ring 1, of the plurality of working rib plates 3 is jointly connected with a lower end ring 2, the outer wall of the lower end ring 2 is sleeved with a stop ring 4, the outer wall of the stop ring 4 is provided with a plurality of jackscrews 5, the inner diameters of the upper end ring 1 and the lower end ring 2 are the same, the lower end ring 2 is uniformly provided with a plurality of block mounting holes 9, the working rib plates 3 are uniformly distributed around the upper end ring 1 and the lower end ring 2, a plurality of blocks 10 are welded in the block mounting holes 9, the lower end ring 2 is connected with the stop ring 4 through the blocks 10, the inner wall of the stop ring 4 is provided with block clamping grooves 11, the blocks 10 are arranged in the block clamping grooves 11, the lower end ring 2 is connected with the stop ring 4 through the blocks 10, and the lower end ring 2 can be freely rotated by 360 degrees relative to the stop ring 4.

[0041] The pull-in type rotatable casing elastic centralizer provided by the embodiment is convenient and fast to install on site, can realize the installation of the stop ring 4 and the centralizer after being sleeved once, can realize the fixing of the relative position of the centralizer on the casing by fixing only one stop ring 4, i.e., sleeving the stop ring 4 outside the lower end ring 2, and can realize the free rotation of the centralizer without affecting the relative position of the centralizer on the casing. After installation, the stop ring 4 of the centralizer is fixed relative to the casing, is pulled into the wellbore along with the casing, enters a relatively small resistance, and will not cause a destructive impact on the rib plates of the centralizer due to difficulty in entering. In addition, even if the centralizer meets resistance in the wellbore, the pull-in type will not cause a destructive compression of the rib plates of the centralizer, and the centralizer is more likely to pass through.

Claims

1. A pull-in rotatable sleeve elastic centralizer, characterized in that, The utility model provides an upper end ring (1) is connected with a plurality of working rib plate (3) at the bottom, a plurality of working rib plate (3) is connected with lower end ring (2) away from the side of upper end ring (1), the outer wall of lower end ring (2) is sleeved with stop ring (4).

2. The pull-in rotatable sleeve elastic centralizer of claim 1, wherein, The outer wall of the stop ring (4) is provided with a plurality of jackscrews (5).

3. The pull-in rotatable sleeve elastic centralizer of claim 1, wherein, The upper end ring (1) and the lower end ring (2) have the same inner diameter, and the lower end ring (2) is uniformly provided with a plurality of pin mounting holes (8).

4. The pull-in rotatable sleeve elastic centralizer of claim 3, wherein, The working rib plates (3) are uniformly distributed around the upper end ring (1) and the lower end ring (2), a plurality of the pin mounting holes (8) are welded with pins (7), and the lower end ring (2) is connected with the stop ring (4) through the pins (7).

5. The pull-in rotatable sleeve elastic centralizer of claim 4, wherein, The inner wall of the stop ring (4) is provided with a pin clamping groove (6), the pin (7) is arranged in the pin clamping groove (6), the lower end ring (2) is connected with the stop ring (4) through the pin (7), and the lower end ring (2) is freely rotated by 360 degrees relative to the stop ring (4).

6. The pull-in rotatable sleeve elastic centralizer of claim 1, wherein, The upper end ring (1) and the lower end ring (2) have the same inner diameter, and the lower end ring (2) is uniformly provided with a plurality of block mounting holes (9).

7. The pull-in rotatable sleeve elastic centralizer of claim 6, wherein, The working rib plates (3) are uniformly distributed around the upper end ring (1) and the lower end ring (2), a plurality of the block mounting holes (9) are welded with blocks (10), and the lower end ring (2) is connected with the stop ring (4) through the blocks (10).

8. The pull-in rotatable sleeve elastic centralizer of claim 7, wherein, The inner wall of the stop ring (4) is provided with a block clamping groove (11), the block (10) is arranged in the block clamping groove (11), the lower end ring (2) is connected with the stop ring (4) through the block (10), and the lower end ring (2) is freely rotated by 360 degrees relative to the stop ring (4).

9. A pull-in rotatable sleeve elastic centralizer, characterized in that, It comprises: an upper end ring (1); a lower end ring (2); a plurality of working rib plates (3), both ends of each working rib plate (3) are connected with the upper end ring (1) and the lower end ring (2) respectively; a stop ring (4) is sleeved on the lower end ring (2), and the lower end ring (2) is rotatably arranged relative to the stop ring (4).

10. The pull-in type rotatable sleeve elastic centralizer according to claim 9, wherein, each working rib plate (3) is arranged in the circumferential direction of the upper end ring (1) and / or the lower end ring (2).

11. The pull-in rotatable sleeve elastic centralizer of claim 9, wherein, The lower end ring (2) is provided with a plurality of mounting portions, and each mounting portion is uniformly arranged in the circumferential direction of the lower end ring (2); each mounting portion is provided with a connecting piece, and the lower end ring (2) is connected with the stop ring (4) through the connecting piece.

12. The pull-in rotatable sleeve elastic centralizer of claim 11, wherein, The mounting portion is a pin mounting hole (8), the connecting piece is a pin (7), the pin (7) is welded in the pin mounting hole (8), and the pin (7) is connected with the stop ring (4).

13. The pull-in rotatable sleeve elastic centralizer of claim 11, wherein, The mounting portion is a block mounting hole (9), the connecting piece is a block (10), the block (10) is welded in the block mounting hole (9), and the block (10) is connected with the stop ring (4).

14. A method of righting using a pull-in rotatable casing elastic centralizer according to any one of claims 1-13, characterized in that, The specific steps are as follows: before entering the wellbore, the centralizer is sleeved outside the casing, the lower end ring (2) is installed in the direction of the well mouth, the top thread (5) distributed outside the stop ring (4) is tightened, the whole centralizer is fixed to the casing, and the centralizing is completed.

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