Casing centralizer with adjustable outer diameter

Abstract

The utility model relates to a casing centralizer with an adjustable outer diameter. According to the technical scheme, the centralizer comprises a center pipe, a centralizing piece, a piston, a ball seat short section, a throwing ball and a casing coupling. The upper end of the casing coupling is connected with a ball seat short section through threads, the central pipe comprises a cylinder, and the lower end of the casing coupling is connected with the cylinder through threads. The piston sleeves the middle upper part of the outer circumference of the barrel; the centralizing piece is placed on the lower middle portion of the outer circumference of the cylinder, the lower portion of the outer circumference of the cylinder is in threaded connection with a fixing sleeve, the upper portion of the outer circumference is in threaded connection with a piston outer sleeve, and the piston and the piston outer sleeve are fixed through piston shear pins. A drilling fluid inlet hole is formed in the circumference of the upper portion of the barrel, and the upper end of the piston is located on the lower side of the drilling fluid inlet hole. The centralizer has the advantages that the drilling fluid compresses the piston to increase the outer diameter of the centralizing pieces, the outer diameter of the centralizer can be adjusted by setting the number of the centralizing pieces and the pressure of the drilling fluid, and the centralizer is suitable for a well which is large in supporting force and not prone to tripping into a conventional centralizer.

Description

Technical Field

[0001] The utility model relates to the technical field of cementing tools, in particular to a casing centralizer with adjustable outer diameter. Background Art

[0002] The casing centralizer is one of the important devices commonly used in the field of oil and gas drilling. Its function is to make the casing be located in the center of the wellbore, ensure that the downhole casing is centered, and improve the cementing quality.

[0003] The existing traditional centralizers are mainly conventional rigid centralizers. Although they have a simple structure, they have a large resistance to insertion and are difficult to pass through complex boreholes with reduced diameter. Later, centralizers with adjustable outer diameters appeared. For example, Chinese Patent No. 201921379001.6 discloses an outer diameter adjustment device for a centralizer and a variable diameter centralizer, including: a hoop for tightening the elastic centralizer strip of the centralizer, a cylinder body, a piston body connected to the cylinder body, a sleeve portion sleeved on the end of the piston body, used to lock the piston body to prevent the piston body from moving into the cylinder body; a cover plate cooperates with the end of the piston body to prevent the sleeve portion from detaching from the piston body when the piston body is locked by a pin; the technical problem that the centralizer in the prior art is not convenient to use in a wellbore with an irregular well section is alleviated. However, this type of centralizer is large in size and inconvenient to operate, which can easily cause the casing of complex wells to encounter obstructions or poor cementing quality during the lowering process, affecting the casing lowering ability, and the casing centering effect is poor, which greatly affects the cementing quality. In addition, this type of centralizer has a complex structure and a cumbersome manufacturing process.

[0004] Therefore, in order to improve the above situation, it is necessary to propose a casing centralizer with adjustable outer diameter to overcome the above technical problems. Utility Model Content

[0005] The utility model aims to provide a casing centralizer with adjustable outer diameter in view of the above-mentioned defects in the prior art, thereby solving the problem that the casing of a complex wellbore encounters resistance or poor cementing quality during the lowering process.

[0006] The utility model mentions a casing straightener with adjustable outer diameter, and its technical solution is: it includes a center tube, a straightening plate, a piston, a ball seat short section, a ball and a casing coupling; the upper end of the casing coupling is connected to the ball seat short section by a thread, the center tube includes a cylinder, and the lower end of the casing coupling is connected to the cylinder by a thread; the piston sleeve is arranged in the middle and upper part of the outer circumference of the cylinder; the straightening plate material is an elastic element, the straightening plate is arranged in the middle and lower part of the outer circumference of the cylinder, the lower part of the outer circumference of the cylinder is threadedly connected with a fixing sleeve, the upper part of the outer circumference of the cylinder is threadedly connected with a piston sleeve, and the piston and the piston sleeve are fixed by a piston shear pin; the upper circumference of the cylinder is provided with a drilling fluid inlet hole, and the upper end of the piston is located at the lower side of the drilling fluid inlet hole.

[0007] Preferably, a fifth sealing ring is provided on the inner side of the piston and the outer side of the cylinder; and a fourth sealing ring is provided on the outer side of the piston and the inner side of the piston sleeve.

[0008] Preferably, the ball seat short section includes a conversion joint, a supporting ring, an annular sleeve, a ball seat and a ball seat tray; the inner side of the upper part of the conversion joint is provided with an internal thread of the casing, and the supporting ring is connected to the root of the internal thread of the casing by a thread; the middle and upper part of the inner side of the cylinder body of the conversion joint is provided with an internal thread, and the outer side of the annular sleeve is provided with an external thread, and the annular sleeve is connected to the middle and upper part of the inner cylinder of the conversion joint by a thread; a first sealing ring is provided on the inner side of the cylinder body and the outer side of the annular sleeve of the conversion joint; the ball seat is fixed to the inner side of the annular sleeve by a ball seat shear pin; a reducing step is provided on the lower part of the inner side of the cylinder body of the conversion joint, and the ball seat tray is placed on the reducing step.

[0009] Preferably, the support ring is a circular ring, and a conical surface is provided on the upper side of the inner hole of the support ring. The distance between the outer diameter of the upper large circle of the conical surface and the outer circumference of the upper end is smaller than the diameter of the pitched ball.

[0010] Preferably, the ball seat is a cylinder, including a ball seat body, a through hole is provided inside the ball seat body, and the diameter of the through hole is smaller than the diameter of the ball; an annular cone surface is provided on the inner upper part of the ball seat body, a sealing groove is provided on the outer upper part of the ball seat body, an annular groove is provided on the outer lower part of the ball seat body, and a second sealing ring is provided on the outer side of the ball seat and the inner side of the annular sleeve.

[0011] Preferably, the ball seat tray comprises a tray body, the tray body is provided with a plurality of through holes of equal diameter, and the diameter of the through holes is smaller than the diameter of the pitched ball.

[0012] Preferably, the straightening piece is strip-shaped, comprising an arched portion, an upper straight edge portion is provided at the upper end of the arched portion, and a lower straight edge portion is provided at the lower end of the arched portion.

[0013] Preferably, the number of the straightening pieces is 8-16.

[0014] Preferably, the number of the straightening pieces is 12.

[0015] Preferably, a third sealing ring is provided between the lower end of the casing coupling and the upper portion of the outer side of the cylinder.

[0016] The beneficial effects of the utility model are:

[0017] By adopting the casing centralizer of the technical solution, the centralizer pieces are not compressed when lowering, the outer diameter of the centralizer is small, the resistance is small when lowering the casing, and the casing is easily lowered.

[0018] The outer diameter of the centralizer is increased by compressing the piston with drilling fluid, and the outer diameter of the centralizer can be adjusted by setting the number of centralizers and the pressure of drilling fluid. The centralizer has a greater centralizing force than conventional fixed casing centralizers, and is particularly suitable for wells with large support forces and where it is difficult to insert conventional centralizers. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a three-dimensional diagram of the utility model;

[0020] Figure 2 It is a half-section view of the utility model;

[0021] Figure 3 A three-dimensional image of a tee

[0022] Figure 4 A three-dimensional image of a ball tray

[0023] Figure 5 A stereogram of the straightening film

[0024] In the figure: 10, ball seat short section; 20, casing coupling; 30, piston assembly; 40, straightening piece; 50, fixing sleeve; 60, center tube;

[0025] 11. conversion joint; 12. support ring; 13. pitching ball; 14. annular sleeve; 15. first sealing ring;

[0026] 16. Ball seat shear pin; 17. Ball seat; 18. Second sealing ring; 19. Ball seat tray;

[0027] 171, ball seat body; 172, annular cone surface; 173, sealing groove; 174, annular groove;

[0028] 191, tray body; 192, through hole; 21, third sealing ring; 31, piston jacket; 32, fourth sealing ring; 33, fifth sealing ring; 34, piston; 35, piston shear pin;

[0029] 41. upper straight edge portion; 42. arched portion; 43. lower straight edge portion;

[0030] 61. Cylinder; 62. Drilling fluid inlet hole; 63. First external thread; 64. Second external thread DETAILED DESCRIPTION

[0031] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0032] like Figure 1 to Figure 2As shown, a casing straightener with adjustable outer diameter comprises a center pipe 60, a straightening piece 40, a piston 30, a ball seat short section 10, a ball 13 and a casing coupling 20; the upper end of the casing coupling 20 is connected to the ball seat short section 10 by a thread, the center pipe 60 comprises a cylinder 61, and the lower end of the casing coupling 20 is connected to the cylinder 61 by a thread; the piston 30 is sleeved on the middle and upper part of the outer circumference of the cylinder 61; the straightening piece 40 is made of an elastic element, and the straightening piece 40 is placed on the middle and lower part of the outer circumference of the cylinder 61; the lower part of the outer circumference of the cylinder 61 is threadedly connected with a fixing sleeve 50, and the upper part of the outer circumference of the cylinder 61 is threadedly connected with a piston sleeve 31, and the piston 30 and the piston sleeve 31 are fixed by a piston shear pin 35; a drilling fluid inlet hole 62 is provided on the upper circumference of the cylinder 61, and the upper end of the piston 30 is located at the lower side of the drilling fluid inlet hole 62.

[0033] A fifth sealing ring 33 is disposed on the inner side of the piston 30 and the outer side of the cylinder 61 ; a fourth sealing ring 32 is disposed on the outer side of the piston 30 and the inner side of the piston sleeve 31 .

[0034] The ball seat short section 10 includes a conversion joint 11, a supporting ring 12, an annular sleeve 14, a ball seat 17 and a ball seat tray 19; the inner side of the upper part of the conversion joint 11 is provided with an internal thread of the casing, and the supporting ring 12 is connected to the root of the internal thread of the casing by threading; the middle and upper part of the inner side of the cylinder body of the conversion joint 11 is provided with an internal thread, and the outer side of the annular sleeve 14 is provided with an external thread, and the annular sleeve 14 is connected to the middle and upper part of the inner cylinder of the conversion joint 11 by threading; the inner side of the cylinder body of the conversion joint 11 and the outer side of the annular sleeve 14 are provided with a first sealing ring 15; the ball seat 17 is fixed to the inner side of the annular sleeve 14 by a ball seat shear pin 16; the lower part of the inner side of the cylinder body of the conversion joint 11 is provided with a diameter reducing step, and the ball seat tray 19 is placed on the diameter reducing step.

[0035] The support ring 12 is a toroidal body, and a conical surface is provided on the upper side of the inner hole of the support ring 12. The distance between the upper large circle of the conical surface and the outer diameter of the upper end outer circumference is smaller than the diameter of the pitched ball.

[0036] like Figure 3 As shown, the ball seat 17 is a cylinder, including a ball seat body 171, a through hole is provided inside the ball seat body 171, and the diameter of the through hole is smaller than the diameter of the ball 13; an annular cone surface 172 is provided on the inner upper part of the ball seat body 171, a sealing groove 173 is provided on the outer upper part of the ball seat body 171, and an annular groove 174 is provided on the outer lower part of the ball seat body 171, and a second sealing ring 18 is provided on the outer side of the ball seat 17 and the inner side of the annular sleeve 14.

[0037] like Figure 4As shown, the ball seat tray 19 includes a tray body 191 , and the tray body 191 is provided with a plurality of through holes 192 of equal diameter, and the diameter of the through holes 192 is smaller than the diameter of the pitching ball 13 .

[0038] like Figure 5 As shown, the straightening piece 40 is strip-shaped and includes an arched portion 42 . An upper straight edge portion 41 is provided at the upper end of the arched portion 42 , and a lower straight edge portion 43 is provided at the lower end of the arched portion 42 .

[0039] The number of the straightening plates 40 is 8-16, preferably 12.

[0040] A third sealing ring 21 is provided between the lower end of the casing coupling 20 and the upper outer portion of the cylinder 61 .

[0041] During operation, the casing straightener is installed at the designed position of the casing string, and the casing string is lowered. After the casing is lowered, the ball 13 is dropped, and the ball 13 falls on the annular conical surface 172 of the ball seat 17. The pressure is held, and the ball seat shear pin 16 is sheared off. The ball seat 17 falls onto the ball seat tray 19, and the pressurized drilling fluid enters the cylinder 61 from the through hole 192, and then enters the annular cavity on the upper part of the piston 30 through the drilling fluid entry hole 62 of the cylinder 61. After the piston 30 is pressurized, the piston shear pin 35 between the piston sleeve 31 is sheared off and then moves downward. The piston 30 pushes the straightening plate 40 downward, and the arched portion 42 of the straightening plate 40 protrudes outward, and the straightening casing is centered.

[0042] When the centralizer is lowered, the centralizer sheet 40 is not compressed, the outer diameter of the centralizer is small, the resistance is small when the casing is lowered, and it is easy to lower; the outer diameter of the centralizer sheet 40 is increased by compressing the piston 30 with drilling fluid, and the outer diameter of the centralizer can be adjusted by setting the number of centralizer sheets 40 and the pressure of the drilling fluid. The centralizer has a greater centralizing force than a conventional fixed casing centralizer, and is particularly suitable for wellbores with large supporting force and where it is not easy to lower a conventional centralizer.

[0043] The sealing rings installed in various places mainly play a sealing role to prevent leakage of drilling fluid and provide stable drilling fluid pressure.

[0044] The above is only a preferred embodiment of the utility model. Any person skilled in the art may modify the utility model by using the above technical solution or modify it into an equivalent technical solution. Therefore, any simple modification or equivalent transformation based on the technical solution of the utility model shall fall within the scope of protection claimed by the utility model.

Claims

1. A casing centralizer with adjustable outer diameter, characterized in that: The invention comprises a central tube (60), a straightening piece (40), a piston (30), a ball seat short section (10), a ball (13) and a casing coupling (20); the upper end of the casing coupling (20) is connected to the ball seat short section (10) by means of a thread; the central tube (60) comprises a cylinder (61); the lower end of the casing coupling (20) is connected to the cylinder (61) by means of a thread; the piston (30) is sleeved on the middle and upper part of the outer circumference of the cylinder (61); the straightening piece (40) is made of an elastic element. The straightening piece (40) is arranged at the middle and lower part of the outer circumference of the cylinder (61); the lower part of the outer circumference of the cylinder (61) is threadedly connected to a fixing sleeve (50); the upper part of the outer circumference of the cylinder (61) is threadedly connected to a piston sleeve (31); the piston (30) and the piston sleeve (31) are fixed by a piston shear pin (35); the upper circumference of the cylinder (61) is provided with a drilling fluid inlet hole (62); the upper end of the piston (30) is located at the lower side of the drilling fluid inlet hole (62).

2. The casing centralizer with adjustable outer diameter according to claim 1, characterized in that: A fifth sealing ring (33) is provided on the inner side of the piston (30) and the outer side of the cylinder (61); and a fourth sealing ring (32) is provided on the outer side of the piston (30) and the inner side of the piston sleeve (31).

3. The casing centralizer with adjustable outer diameter according to claim 1, characterized in that: The ball seat short section (10) comprises a conversion joint (11), a supporting ring (12), an annular sleeve (14), a ball seat (17) and a ball seat tray (19); the inner side of the upper part of the conversion joint (11) is provided with a casing internal thread, and the supporting ring (12) is connected to the root of the casing internal thread by means of a thread; the middle and upper part of the inner side of the cylinder body of the conversion joint (11) is provided with an internal thread, the outer side of the annular sleeve (14) is provided with an external thread, and the annular sleeve (14) is connected to the middle and upper part of the inner cylinder of the conversion joint (11) by means of a thread; the inner side of the cylinder body of the conversion joint (11) and the outer side of the annular sleeve (14) are provided with a first sealing ring (15); the ball seat (17) is fixed to the inner side of the annular sleeve (14) by means of a ball seat shear pin (16); the lower side of the inner side of the cylinder body of the conversion joint (11) is provided with a diameter reducing step, and the ball seat tray (19) is placed on the diameter reducing step.

4. The casing centralizer with adjustable outer diameter according to claim 3, characterized in that: The support ring (12) is a circular ring, and a conical surface is provided on the upper side of the inner hole of the support ring (12). The distance between the outer diameter of the upper large circle of the conical surface and the outer circumference of the upper end is smaller than the diameter of the pitched ball.

5. The casing centralizer with adjustable outer diameter according to claim 3, characterized in that: The ball seat (17) is a cylindrical body, comprising a ball seat body (171), wherein a through hole is provided inside the ball seat body (171), wherein the diameter of the through hole is smaller than the diameter of the pitched ball (13); an annular conical surface (172) is provided at the inner upper portion of the ball seat body (171), a sealing groove (173) is provided at the outer upper portion of the ball seat body (171), and an annular groove (174) is provided at the outer lower portion of the ball seat body (171); and a second sealing ring (18) is provided on the outer side of the ball seat (17) and the inner side of the annular sleeve (14).

6. The casing centralizer with adjustable outer diameter according to claim 3, characterized in that: The ball seat tray (19) comprises a tray body (191), and a plurality of through holes (192) of equal diameter are provided on the tray body (191), wherein the diameter of the through holes (192) is smaller than the diameter of the pitched ball (13).

7. The casing centralizer with adjustable outer diameter according to claim 1, characterized in that: The straightening piece (40) is strip-shaped and comprises an arched portion (42). An upper straight edge portion (41) is provided at the upper end of the arched portion (42), and a lower straight edge portion (43) is provided at the lower end of the arched portion (42).

8. The casing centralizer with adjustable outer diameter according to claim 7, characterized in that: The number of the straightening pieces (40) is 8-16.

9. The casing centralizer with adjustable outer diameter according to claim 8, characterized in that: The number of the straightening plates (40) is 12.

10. The casing centralizer with adjustable outer diameter according to claim 1, characterized in that: A third sealing ring (21) is provided between the lower end of the casing coupling (20) and the upper portion of the outer side of the cylinder (61).

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