Self-adaptive casing centralizer

Abstract

The utility model relates to a self-adaptive casing centralizer. According to the technical scheme, the centralizer comprises an inner pipe, elastic centralizing pieces, rigid centralizing strips and springs, clamping plates are evenly distributed on the outer sides of the upper end and the lower end of the inner pipe, channels are formed by the clamping plates and the outer side of the inner pipe, the elastic centralizing pieces are made of elastic materials, and each elastic centralizing piece comprises a middle arching part and straight edge parts at the two ends. The straight edge portions at the two ends of the elastic centralizing piece are inserted into the channel, the rigid centralizing strip is arranged on the outer side of the middle of the inner pipe, the elastic centralizing piece and the rigid centralizing strip are correspondingly arranged, and a spring is arranged between the elastic centralizing piece and the rigid centralizing strip. The casing centralizer has the advantages that the casing centralizer is installed at the design position of a casing string, the centralizer is expanded under the action of spring force according to the condition of a borehole outside a casing, and the casing centralizer is self-adaptive to the actual condition of the borehole outside the casing; by changing the specification and the length size of the spring, different borehole conditions can be adapted.

Description

Technical Field

[0001] The utility model relates to the technical field of cementing tools, in particular to an adaptive casing centralizer. 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 rigid centralizers with simple structures and are difficult to be used in complex wellbores with different diameters. Later, adaptive casing centralizers appeared, such as publication number CN116877002 A, which discloses an adaptive casing centralizer used in oil field development. The servo motor drives the long gear on the rotating shaft to rotate clockwise, acting on the rack part, so that the drive plate moves into the guide groove and drives several groups of cutter bars to move linearly toward the well wall, and the tip of the cutter is directly inserted into the well wall. However, this type of centralizer is electrically driven, with a complex structure and damage to the cutter container, which easily causes poor casing centering effect in complex wellbores and affects the cementing quality.

[0004] Therefore, in order to improve the above situation, it is necessary to propose an adaptive casing centralizer to overcome the above technical problems. Utility Model Content

[0005] The purpose of the utility model is to provide an adaptive casing centralizer for the above-mentioned defects in the prior art, thereby solving the problem that the centralizer cannot adapt to multiple wellbore specifications and the cementing quality is poor.

[0006] An adaptive casing straightener, whose technical solution is: comprising an inner tube, an elastic straightening piece, a rigid straightening strip, and a spring, wherein clamping plates are evenly distributed on the outer sides of the upper and lower ends of the inner tube, and the clamping plates and the outer side of the inner tube form a channel, the elastic straightening piece is made of elastic material, and the elastic straightening piece comprises a middle arched portion and straight edges at both ends, and the straight edges at both ends of the elastic straightening piece are inserted into the channel, the rigid straightening strip is arranged on the outer side of the middle part of the inner tube, the elastic straightening piece and the rigid straightening strip are arranged correspondingly, and a spring is arranged between the elastic straightening piece and the rigid straightening strip.

[0007] Preferably, a reducing nipple is provided at the lower portion of the inner tube, an outer side of the lower end of the reducing nipple is provided with an external thread, and the lower end of the reducing nipple is connected to an adjusting nipple through threads.

[0008] Preferably, the rigid straightening bar comprises a straightening bar body, both ends of which are provided with inclined surfaces, the inner side of the straightening bar body is connected to the outer side of the inner tube by welding; an annular groove is provided in the middle of the outer side of the straightening bar body, a cylindrical protrusion is provided in the middle of the annular groove, an annular baffle is provided on the upper part of the annular groove, and semicircular holes are provided around the inner side of the annular baffle.

[0009] Preferably, the outer diameter of the cylindrical protrusion is smaller than the inner diameter of the spring.

[0010] Preferably, a fixed shaft and a fixed rod are provided inside the arched portion of the elastic straightening piece, a circular plate is provided at one end of the fixed rod, and the other end of the fixed rod is welded to the inner side of the arched portion.

[0011] Preferably, the outer diameter of the fixed shaft is smaller than the inner diameter of the spring.

[0012] Preferably, the fixing rod is an elastic rod, the diameter of the fixing rod is equal to the diameter of the semicircular hole, and the diameter of the circular plate is larger than the diameter of the semicircular hole.

[0013] Preferably, the number of the fixing rods is 4.

[0014] The beneficial effects of the utility model are:

[0015] By adopting the casing centralizer of the above technical solution, it is installed at the designed position of the casing string. According to the wellbore condition outside the casing, the centralizer is expanded under the action of the spring force and adapts to the actual condition of the wellbore outside the casing; by changing the specifications and length of the spring, it can adapt to different wellbore conditions.

[0016] The spring is guided by the cylindrical protrusion inside the straightening strip and the fixed shaft inside the straightening piece. The spring does not change direction when stressed and the spring force does not weaken. Multiple fixing rods surround the outer circumference of the spring to protect the spring from falling off, thereby improving the straightening efficiency and thus improving the cementing quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a three-dimensional diagram of the utility model;

[0018] Figure 2 It is a half-section view of the utility model;

[0019] Figure 3 for Figure 2 A partial view of;

[0020] Figure 4 The front view of the rigid straightening bar

[0021] Figure 5 A three-dimensional image of an elastic straightening plate

[0022] In the figure: 10, inner tube; 20, elastic straightening piece; 30, rigid straightening strip; 40, adjustment nipple; 50, spring;

[0023] 120, pallet; 121, channel; 130, reducer nipple;

[0024] 211, straight edge; 212, arched portion; 220, fixed rod; 221, circular plate; 230, fixed axis

[0025] 310, the body of the straightening strip; 311, the cylindrical protrusion; 312, the annular baffle; 313, the annular groove;

[0026] 314. Semicircular hole. DETAILED DESCRIPTION

[0027] 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.

[0028] like Figures 1 to 5 As shown, an adaptive casing straightener comprises an inner tube 10, an elastic straightening piece 20, a rigid straightening strip 30, and a spring 50. Clamps 120 are evenly distributed on the outer sides of the upper and lower ends of the inner tube 10. The clamps 120 and the outer side of the inner tube 10 form a channel 121. The elastic straightening piece 20 is made of elastic material. The elastic straightening piece 20 comprises a middle arched portion 212 and straight edge portions 211 at both ends. The straight edge portions 211 at both ends of the elastic straightening piece 20 are inserted into the channel 121. The rigid straightening strip 30 is arranged on the outer side of the middle part of the inner tube 10. The elastic straightening piece 20 and the rigid straightening strip 30 are arranged correspondingly. Preferably, four elastic straightening pieces 20 and four rigid straightening strips 30 are each provided. A spring 50 is provided between the elastic straightening piece 20 and the rigid straightening strip 30.

[0029] A reducing nipple 130 is disposed at the lower portion of the inner tube 10 . An external thread is disposed on the outer side of the lower end of the reducing nipple 130 . The lower end of the reducing nipple 130 is connected to an adjusting nipple 40 via threads.

[0030] The rigid straightening bar 30 includes a straightening bar body 310, both ends of which are provided with inclined surfaces, and the inner side of the straightening bar body 310 is connected to the outer side of the inner tube 10 by welding; an annular groove 313 is provided in the middle of the outer side of the straightening bar body 310, a cylindrical protrusion 311 is provided in the middle of the annular groove 313, an annular baffle 312 is provided on the upper part of the annular groove 313, and semicircular holes 314 are provided around the inner side of the annular baffle 312.

[0031] The outer diameter of the cylindrical protrusion 311 is smaller than the inner diameter of the spring 50 .

[0032] A fixing shaft 230 and a fixing rod 220 are disposed inside the arched portion 212 of the elastic straightening piece 20 . A circular plate 221 is disposed at one end of the fixing rod 220 , and the other end of the fixing rod 220 is welded to the inner side of the arched portion 212 .

[0033] The outer diameter of the fixed shaft 230 is smaller than the inner diameter of the spring 50 .

[0034] The fixing rod 220 is an elastic rod. The diameter of the fixing rod 220 is equal to the diameter of the semicircular hole 314 . The diameter of the circular plate 221 is greater than the diameter of the semicircular hole 314 .

[0035] The number of the fixing rods 220 is four.

[0036] During operation, firstly, the spring 50 is sleeved on the outside of the cylindrical protrusion 311 of the straightening strip body 310, the circular plates 221 at the ends of the four fixing rods 220 of the elastic straightening piece 20 are inserted into the annular groove 311 of the straightening strip body 310, and the rods of the fixing rods 220 are placed against the semicircular holes 314 of the annular baffle 312. The upper inner cavity of the spring 50 is sleeved on the outside of the fixing shaft 230 of the elastic straightening piece 20; the fixing rod 220 moves outward under the action of the spring force until the lower circular plate 221 is limited by the annular baffle 312. The straight edge portions 211 at both ends of the elastic straightening piece 20 are inserted into the channel 121. The adjusting nipple 40 is threadedly connected to the reducing nipple 130 at the lower end of the inner tube 10. The casing centralizer is sleeved on the outside of the casing. According to the casing design, the distance from the lower oil tank coupling can be adjusted by adjusting the short section 40 to fine-tune the height of the casing centralizer.

[0037] The centralizer is lowered into the casing string and installed at the designed position of the casing string. When the centralizer is lowered, the elastic centralizer piece is compressed. When the centralizer reaches the designed position of the casing string, according to the wellbore condition outside the casing, the centralizer is expanded under the action of the spring force and adapts to the actual wellbore condition outside the casing. By changing the specifications and length of the spring, it can adapt to different wellbore conditions. On the other hand, since the spring is guided by the cylindrical protrusion inside the centralizer bar and the fixed shaft inside the centralizer piece, the spring force does not change direction and the spring force does not weaken; multiple fixed rods surround the outer circumference of the spring to protect the spring from falling off, improve the centralization efficiency, and thus improve the cementing quality.

[0038] 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. An adaptive casing centralizer, characterized in that: The invention comprises an inner tube (10), an elastic straightening piece (20), a rigid straightening strip (30), and a spring (50); the inner tube (10) is evenly distributed with clamping plates (120) on the outer sides of the upper and lower ends; the clamping plates (120) and the outer sides of the inner tube (10) form a channel (121); the elastic straightening piece (20) is made of elastic material; the elastic straightening piece (20) comprises a central arched portion (212) and straight edge portions (211) at both ends; the straight edge portions (211) at both ends of the elastic straightening piece (20) are inserted into the channel (121); the rigid straightening strip (30) is arranged on the outer side of the middle portion of the inner tube (10); the elastic straightening piece (20) and the rigid straightening strip (30) are arranged correspondingly; and a spring (50) is arranged between the elastic straightening piece (20) and the rigid straightening strip (30).

2. The adaptive casing centralizer according to claim 1, characterized in that: A reducing nipple (130) is provided at the lower part of the inner tube (10), an outer thread is provided at the lower end of the reducing nipple (130), and an adjusting nipple (40) is connected to the lower end of the reducing nipple (130) via a thread.

3. The adaptive casing centralizer according to claim 1, characterized in that: The rigid straightening bar (30) comprises a straightening bar body (310), with inclined surfaces provided at both ends of the straightening bar body (310), and the inner side of the straightening bar body (310) is connected to the outer side of the inner tube (10) by welding; an annular groove (313) is provided in the middle of the outer side of the straightening bar body (310), a cylindrical protrusion (311) is provided in the middle of the annular groove (313), an annular baffle (312) is provided on the upper part of the annular groove (313), and semicircular holes (314) are provided around the inner side of the annular baffle (312).

4. The adaptive casing centralizer according to claim 3, characterized in that: The outer diameter of the cylindrical protrusion (311) is smaller than the inner diameter of the spring (50).

5. The adaptive casing centralizer according to claim 4, characterized in that: A fixed shaft (230) and a fixed rod (220) are provided inside the arched portion (212) of the elastic straightening plate (20), a circular plate (221) is provided at one end of the fixed rod (220), and the other end of the fixed rod (220) is welded to the inside of the arched portion (212).

6. The adaptive casing centralizer according to claim 5, characterized in that: The outer diameter of the fixed shaft (230) is smaller than the inner diameter of the spring (50).

7. The adaptive casing centralizer according to claim 6, characterized in that: The fixing rod (220) is an elastic rod, the diameter of the fixing rod (220) is equal to the diameter of the semicircular hole (314), and the diameter of the circular plate (221) is greater than the diameter of the semicircular hole (314).

8. The adaptive casing centralizer according to claim 6, characterized in that: The number of the fixing rods (220) is four.

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