Connecting structure with torsion-resistant casing threads for casing drilling

Abstract

The invention relates to the technical field of petroleum drilling casing pipes, and discloses a casing pipe drilling connecting structure containing anti-torque casing pipe threads, which comprises a connecting unit, and the connecting unit comprises a coupling; the sleeve main body comprises a connecting sleeve; the compensation unit comprises supporting sleeves symmetrically installed on the coupling, extrusion cavities are formed in the ends, away from each other, of the interiors of the supporting sleeves, and air bags are arranged in the extrusion cavities; when torsion bending is generated between the connecting unit and the sleeve body, the connecting sleeve shifts in the coupling, so that the connecting sleeve extrudes towards the air bag, the sealing ring expands, filling compensation is conducted on the connecting position of the connecting unit and the sleeve body, and sealing is kept. Through the arrangement of the compensation unit and the sealing ring, deviation caused by torsion and bending at the joint can be effectively coped, the sealing effect is ensured, the device can adapt to the complex well drilling environment, and the leakage problem caused by poor sealing is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of casing for oil drilling, and more particularly to a connection structure with anti-torsion casing threads for casing drilling. Background Art

[0002] At present, casing drilling technology is mainly used in industries such as oil and gas extraction, geological exploration, and specific groundwater resource development. The main difference from traditional drilling technology is that casing is directly used to replace traditional drill pipes and drill collars during the drilling process. With the continuous development of mining technology, traditional connection structures are difficult to adapt to complex drilling environments. In the mining operations of highly deviated wells and horizontal wells, the casing needs to extend a long distance in the wellbore and withstand complex mechanical loads. Due to the increase in the contact area between the casing and the well wall and the curvature of the wellbore trajectory, the friction resistance of the casing when entering the well increases significantly, resulting in the deformation of the shoulder when rotating the casing.

[0003] Specifically, the deformation of the shoulder will directly damage the sealing performance of the casing connection, causing the sealing position to deviate from the original design matching state, or even deviate from the optimal sealing position, resulting in sealing failure. Seal failure will not only lead to leakage of drilling fluid or oil and gas, but may also cause more serious downhole accidents, causing huge economic losses and safety hazards to oil and gas production operations. Summary of the invention

[0004] The present invention provides a connection structure with anti-torsion casing threads for casing drilling, which solves the technical problem in the related art that shoulder deformation directly destroys the sealing performance of the casing connection, causing the sealing position to deviate from the original design matching state or even deviate from the optimal sealing position, resulting in sealing failure.

[0005] The present invention provides a connection structure containing anti-torsion casing threads for casing drilling, comprising a connection unit, wherein the connection unit comprises a coupling, wherein an annular boss is provided in the middle of the coupling, and slots are provided at both ends of the annular boss, and an annular guide groove is provided inside the slot; a casing body, wherein the casing body comprises a connecting casing; a compensation unit, wherein the compensation unit comprises a support sleeve symmetrically mounted on the coupling, an extrusion cavity is provided at one end of the support sleeve that is away from the other end, and an air bag is provided inside the extrusion cavity; a sealing ring, wherein the sealing ring is arranged inside the annular guide groove; when torsion bending occurs between the connection unit and the casing body, the connecting casing is offset inside the coupling, so that the connecting casing is squeezed toward the air bag, and after being squeezed, the air bag transmits the internal gas to the inside of the sealing ring, so that the sealing ring expands, and the connection between the connection unit and the casing body is filled and compensated to maintain the seal.

[0006] As a further optimization scheme of the present invention, a plurality of pressing plates are arranged in an annular shape inside the extrusion chamber, and a connecting rod is installed on the pressing plate, the connecting rod passes through the extrusion chamber and extends to the outer surface of the support sleeve, and a contact plate is installed at one end of the connecting rod away from the pressing plate;

[0007] When the sleeve body is twisted and bent inside the connecting unit, the connecting sleeve presses the contact plate, driving the pressed contact plate to move synchronously, so that the pressure plate presses a local area of ​​the airbag.

[0008] As a further optimization solution of the present invention, a second spring is provided on the connecting rod, and the second spring is in a compressed state and is used to control the contact plate to elastically support the connecting sleeve.

[0009] As a further optimization scheme of the present invention, a flow channel is opened inside the support sleeve, and one end of the flow channel is connected to the interior of the airbag, a plurality of connecting channels are distributed in an annular shape inside the coupling, and the connecting channels are connected to the interior of the sealing ring, and the other end of the flow channel away from the airbag is connected to the interior of the connecting channel.

[0010] As a further optimization scheme of the present invention, the interior of the coupling is symmetrically provided with a first internal thread and a second internal thread, the first internal thread and the second internal thread are arranged in a step-like manner, and the diameter of the first internal thread is smaller than the diameter of the second internal thread; the surface of the connecting sleeve is provided with a first external thread and a second external thread, the first external thread and the second external thread are arranged in a step-like manner, and the diameter of the first external thread is larger than the diameter of the second external thread.

[0011] As a further optimization solution of the present invention, a first step surface is provided between the first internal thread and the second internal thread, and a second step surface is provided between the first external thread and the second external thread.

[0012] As a further optimization solution of the present invention, a first groove is arranged on the first step surface, a second groove is arranged on the second step surface, and a second sealing ring is arranged between the first groove and the second groove.

[0013] As a further optimization solution of the present invention, a clamping ring is clamped and connected inside the clamping groove, and the clamping ring is fixedly connected to the connecting sleeve.

[0014] As a further optimization solution of the present invention, an inclined surface is provided between the clamping ring and the second external thread, and the inner wall of the inclined surface is matched with the sealing ring.

[0015] As a further optimization scheme of the present invention, an annular cavity is provided at one end of the clamping groove that is close to each other, a first sealing ring is arranged inside the annular cavity, and a sealing groove is provided on the first sealing ring, the sealing groove abuts against the clamping ring, and a first spring is distributed in an annular manner between the annular cavity and the first sealing ring, one end of the first spring is fixedly connected to the annular cavity, and the other end of the first spring is fixedly connected to the first sealing ring.

[0016] The beneficial effects of the present invention are as follows: the present invention can effectively deal with the displacement of the connection caused by torsion and bending through the arrangement of the compensation unit and the sealing ring, thereby ensuring the sealing effect; when torsion and bending occur between the connection unit and the casing body, the connecting casing is offset inside the coupling, causing the connecting casing to be squeezed toward the airbag, and after being squeezed, the airbag transmits the internal gas to the inside of the sealing ring, causing the sealing ring to expand, filling and compensating the connection, maintaining the seal, being able to adapt to complex drilling environments, and reducing leakage problems caused by poor sealing. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a three-dimensional structural schematic diagram of the present invention;

[0018] Figure 2 It is a cross-sectional structural schematic diagram of the present invention;

[0019] Figure 3 It is a schematic diagram of the local structure of the connection between the connection unit, the sleeve body and the compensation unit in the present invention;

[0020] Figure 4 It is a three-dimensional cross-sectional structural schematic diagram of the present invention;

[0021] Figure 5 The present invention Figure 4 A magnified view of the structure at center;

[0022] Figure 6 It is a schematic diagram of the three-dimensional structure of the first sealing ring, the sealing groove and the first spring of the present invention;

[0023] Figure 7 It is a schematic diagram of a three-dimensional cross-sectional structure of the casing body of the present invention;

[0024] Figure 8 It is a schematic diagram of the internal three-dimensional structure of the coupling and the connecting sleeve of the present invention;

[0025] Fig. 9 The present invention Figure 8 A magnified view of the structure at B in the middle;

[0026] Fig.10 It is a schematic diagram of a three-dimensional cross-sectional structure of a compensation unit of the present invention;

[0027] Fig.11 The present invention Fig.10 Enlarged view of the structure at point C in the middle.

[0028] In the figure: 100, connecting unit; 110, coupling; 120, first internal thread; 130, second internal thread; 140, retaining groove; 150, annular cavity; 160, first sealing ring; 161, sealing groove; 170, first spring; 180, connecting channel; 200, sleeve body; 210, connecting sleeve; 220, first external thread; 230, second external thread; 240, retaining ring; 250, inclined surface; 300, compensation unit; 310, support sleeve; 320, extrusion cavity; 330, airbag; 340, pressure plate; 350, connecting rod; 360, contact plate; 370, second spring; 380, flow channel; 400, second sealing ring; 500, sealing ring. DETAILED DESCRIPTION

[0029] The subject matter described herein will now be discussed with reference to example embodiments. It should be understood that the discussion of these embodiments is only to enable those skilled in the art to better understand and implement the subject matter described herein, and the functions and arrangements of the elements discussed may be changed without departing from the scope of protection of the contents of this specification. Each example may omit, replace or add various processes or components as needed. In addition, the features described relative to some examples may also be combined in other examples.

[0030] According to the attached Figure 1 To Attachment Figure 5 As shown, a connection structure containing anti-torsion casing threads for casing drilling includes a connection unit 100 and a casing body 200; the connection unit 100 includes a coupling 110, and the interior of the coupling 110 is symmetrically provided with a first internal thread 120 and a second internal thread 130, and the middle of the coupling 110 is provided with an annular boss, and both ends of the annular boss close to the first internal thread 120 are provided with a clamping groove 140, and the interior of the clamping groove 140 is also provided with an annular guide groove; the casing body 200 includes a connecting sleeve 210, and the surface of the connecting sleeve 210 is provided with a first external thread 220 and a second external thread 230.

[0031] The first internal thread 120 and the second external thread 230 are threadedly connected, and the second internal thread 130 and the first external thread 220 are threadedly connected. In this embodiment, the stress at the connection can be evenly distributed, stress concentration can be reduced, and the stability and reliability of the connection can be improved, so that the connecting sleeve 210 can transmit force more evenly when subjected to tension, pressure and torque, and reduce connection failure caused by excessive local force.

[0032] The device also includes a compensation unit 300 and a sealing ring 500; the compensation unit 300 includes a support sleeve 310 symmetrically mounted on the coupling 110, an extrusion cavity 320 is provided at one end of the support sleeve 310 that is away from the other end, and an air bag 330 is provided inside the extrusion cavity 320; the sealing ring 500 is arranged inside the annular guide groove. In this embodiment, the arrangement of the compensation unit 300 and the sealing ring 500 can effectively deal with the deviation caused by torsion and bending at the connection, and ensure the sealing effect.

[0033] When torsion and bending occur between the connecting unit 100 and the casing body 200, the connecting sleeve 210 is offset inside the coupling 110, so that the connecting sleeve 210 is squeezed toward the airbag 330. After being squeezed, the airbag 330 transmits the internal gas to the inside of the sealing ring 500, causing the sealing ring 500 to expand, filling and compensating the connection between the connecting unit 100 and the casing body 200 to maintain the seal. The dynamic compensation mechanism can adapt to complex drilling environments and reduce leakage problems caused by poor sealing.

[0034] According to the attached Figure 3 , Attachment Figure 4 and attached Figure 7 As shown, in an optional embodiment, the first internal thread 120 and the second internal thread 130 are arranged in a stepped manner, and the diameter of the first internal thread 120 is smaller than the diameter of the second internal thread 130; the first external thread 220 and the second external thread 230 are arranged in a stepped manner, and the diameter of the first external thread 220 is larger than the diameter of the second external thread 230.

[0035] It should be noted that the stepped thread can provide better connection strength and sealing performance. The first internal thread 120 with a smaller diameter cooperates with the first external thread 220 with a larger diameter, and the second internal thread 130 with a larger diameter cooperates with the second external thread 230 with a smaller diameter, which can form a tighter fit at the connection, increase the contact area between the threads, and improve the firmness and torsion resistance of the connection.

[0036] At the same time, the stepped design can also guide the installation of the sleeve body 200 to a certain extent, making it easier to align with the connecting unit 100, reducing installation errors and improving installation efficiency.

[0037] Furthermore, according to the attached Figure 3 , Attachment Figure 4 and attached Figure 7 As shown, a first step surface is provided between the first internal thread 120 and the second internal thread 130, and a second step surface is provided between the first external thread 220 and the second external thread 230. The provision of the first step surface and the second step surface can further enhance the sealing performance and structural strength of the connection.

[0038] The cooperation of the first step surface and the second step surface can provide additional support and positioning on the basis of the threaded connection, making the connection more stable. At the same time, the first step surface and the second step surface can also prevent fluid leakage to a certain extent, increasing the reliability of the seal. In addition, the cooperation of the first step surface and the second step surface can also improve the torsion resistance of the threaded connection, prevent the thread from being damaged or loosened due to excessive torsional force, and ensure the long-term stability of the connection.

[0039] According to the attached Figure 3 As shown, in an optional embodiment, a first groove is provided on the first step surface, a second groove is provided on the second step surface, and a second sealing ring 400 is provided between the first groove and the second groove. Specifically, the second sealing ring 400 is provided in the first groove and the second groove to further improve the sealing performance of the connection.

[0040] It should be noted that when the connecting unit 100 and the casing body 200 are tightened, the second sealing ring 400 will be compressed between the first groove and the second groove to form a tight sealing layer, effectively preventing fluid leakage, thereby improving the sealing reliability of the entire connecting structure, and maintaining a good sealing effect even under harsh working conditions such as high pressure and high temperature, thereby enhancing the overall performance and safety of the casing drilling system.

[0041] According to the attached Figure 3 , Attachment Figure 4 and attached Figure 5 As shown, in an optional embodiment, the internal snap-fit ​​connection of the slot 140 is provided with a snap ring 240, and the snap ring 240 is fixedly connected to the connecting sleeve 210. The cooperation between the snap ring 240 and the slot 140 can effectively prevent the connecting sleeve 210 from axially moving inside the coupling 110, thereby improving the stability of the connection. Specifically, the snap ring 240 is snap-fitted into the slot 140, so that it will not easily slide out or shift when subjected to axial force, thereby enhancing the reliability of the connection, and can also withstand additional axial loads to a certain extent, thereby improving the bearing capacity of the entire connection structure, and being suitable for various complex drilling environments.

[0042] Furthermore, according to the attached Figure 5 , Attachment Figure 6 and attached Fig. 9 As shown, an annular cavity 150 is provided at one end close to the card slot 140, a first sealing ring 160 is arranged inside the annular cavity 150, and a sealing groove 161 is provided on the first sealing ring 160, a first spring 170 is distributed in an annular shape between the annular cavity 150 and the first sealing ring 160, one end of the first spring 170 is fixedly connected to the annular cavity 150, and the other end of the first spring 170 is fixedly connected to the first sealing ring 160.

[0043] Specifically, the combined design of the annular cavity 150, the first sealing ring 160 and the first spring 170 can provide additional sealing protection and elastic compensation functions. When the connecting sleeve 210 deviates or vibrates inside the coupling 110, the first sealing ring 160 can maintain close contact with the inner wall of the slot 140 under the action of the first spring 170, ensuring that the sealing effect is not affected.

[0044] According to the attached Figure 7 As shown, in an optional embodiment, an inclined surface 250 is provided between the clamping ring 240 and the second external thread 230 , and the inner wall of the inclined surface 250 is matched with the sealing ring 500 .

[0045] It should be noted that the design of the inclined surface 250 can guide the sealing ring 500 to fill the gap at the connection more evenly when expanding, thereby improving the sealing effect.

[0046] When the sealing ring 500 is squeezed and expanded by the gas, the inclined surface 250 can make its expansion direction match the shape of the connection, ensuring that the sealing ring 500 is in closer contact with the connection unit 100 and the sleeve body 200, reducing the possibility of leakage.

[0047] In addition, the inclined surface 250 can also guide the installation and positioning of the connecting sleeve 210 to a certain extent, making it easier to align with the coupling 110, thereby improving the installation efficiency and accuracy.

[0048] According to the attached Figure 5 and attached Figure 8 As shown, in an optional embodiment, a flow channel 380 is opened inside the support sleeve 310, and one end of the flow channel 380 is connected to the interior of the airbag 330, a plurality of connecting channels 180 are distributed in an annular shape inside the coupling 110, and the connecting channel 180 is connected to the interior of the sealing ring 500, and the other end of the flow channel 380 away from the airbag 330 is connected to the interior of the connecting channel 180.

[0049] Specifically, the design of the flow channel 380 and the connecting channel 180 can ensure that the gas is transmitted from the airbag 330 to the sealing ring 500 more smoothly and evenly.

[0050] When the airbag 330 is squeezed, the gas can be quickly and evenly transmitted to various parts of the sealing ring 500 through the flow channel 380 and the connecting channel 180, so that it can expand rapidly and fill the gap at the connection to achieve instant sealing compensation.

[0051] In this embodiment, the channel layout can also reduce the pressure loss during gas transmission, improve the sealing response speed and effect, and enhance the sealing performance and reliability of the entire connection structure.

[0052] According to the attached Fig.10 and attached Fig.11 As shown, in an optional embodiment, a plurality of pressure plates 340 are arranged in a ring shape inside the extrusion chamber 320, and a connecting rod 350 is installed on the pressure plate 340. The connecting rod 350 extends through the extrusion chamber 320 to the outer surface of the support sleeve 310, and a contact plate 360 ​​is installed at one end of the connecting rod 350 away from the pressure plate 340.

[0053] It should be noted that in complex drilling environments, such as during the exploitation of highly deviated wells and horizontal wells, the insufficient torsional resistance of the threaded connection leads to connection failure, especially during the casing lowering process. The friction resistance of the horizontal well increases, making it difficult to lower the casing. When rotating the lower casing, the shoulder is easily deformed, causing the sealing position to be out of fit or out of the optimal fit position, resulting in leakage.

[0054] Specifically, torsion bending occurs between the connecting sleeve 210 and the coupling 110, and the connecting sleeve 210 is displaced toward the bent side, resulting in an angle between the connecting sleeve 210 and the coupling 110, which can easily lead to gaps between the first external thread 220 and the second external thread 230, and between the second internal thread 130 and the first external thread 220, thereby causing the sleeve body 200 to have insufficient sealing when torsion bending occurs inside the connecting unit 100.

[0055] In this embodiment, when the sleeve body 200 is twisted and bent inside the connecting unit 100, the connecting sleeve 210 squeezes the contact plate 360, driving the squeezed contact plate 360 ​​to move synchronously, so that the pressure plate 340 squeezes a local area of ​​the airbag 330, and can more accurately control the squeezing position and force of the airbag 330, thereby achieving more efficient sealing compensation.

[0056] When the sleeve body 200 is twisted and bent, the deviation of the connecting sleeve 210 will directly act on the contact plate 360, and be transmitted to the pressure plate 340 through the connecting rod 350, so that the local area of ​​the airbag 330 is squeezed, and the gas is more accurately transmitted to the part of the sealing ring 500 that needs to be compensated. Not only does it improve the sealing effect, but it can also adapt to twisting and bending in different directions and degrees, and enhance the reliability and adaptability of the entire connecting unit 100.

[0057] Furthermore, according to the attached Fig.11 As shown, a second spring 370 is provided on the connecting rod 350, and one end of the second spring 370 is fixedly connected to the pressure plate 340, and the other end of the second spring 370 is fixedly connected to the inner wall of the extrusion chamber 320. The second spring 370 is in a compressed state and is used to control the contact plate 360 ​​to elastically support the connecting sleeve 210.

[0058] It should be understood that, by providing the second spring 370 , a certain elastic support can be provided when the connecting sleeve 210 is subjected to an external force, thereby reducing damage to the connecting structure caused by direct impact.

[0059] When the connecting sleeve 210 deviates and squeezes the contact plate 360, the compression and rebound of the second spring 370 can buffer the deviation, making the squeezing of the airbag 330 and the gas transmission smoother, avoiding damage to the airbag 330 or the sealing ring 500 due to sudden and strong squeezing.

[0060] In this embodiment, the elastic support can also automatically adjust the position of the contact plate 360 ​​to a certain extent, adapt to the slight vibration and displacement of the sleeve body 200, and improve the stability and life of the connection.

[0061] An example of the present specific implementation mode is described above, but the present embodiment is not limited to the above-mentioned specific implementation mode, which is merely illustrative and not restrictive. A person skilled in the art may make many forms inspired by the present embodiment, all of which are protected by the present embodiment.

Claims

1. A connection structure with a torsion-resistant casing thread for casing drilling, characterized in that: include: A connection unit (100), the connection unit (100) comprising a coupling hoop (110), an annular boss being provided in the middle of the coupling hoop (110), a clamping groove (140) being provided at both ends of the annular boss, and an annular guide groove being provided inside the clamping groove (140); A sleeve body (200), wherein the sleeve body (200) comprises a connecting sleeve (210); A compensation unit (300), the compensation unit (300) comprising a support sleeve (310) symmetrically mounted on a coupling (110), an extrusion cavity (320) being provided at one end of the support sleeve (310) away from the other end, and an air bag (330) being provided inside the extrusion cavity (320); A sealing ring (500), wherein the sealing ring (500) is arranged inside the annular guide groove; When torsion and bending occur between the connection unit (100) and the sleeve body (200), the connection sleeve (210) is offset inside the coupling (110), causing the connection sleeve (210) to be squeezed toward the airbag (330). After being squeezed, the airbag (330) transmits the internal gas to the inside of the sealing ring (500), causing the sealing ring (500) to expand, thereby filling and compensating the connection between the connection unit (100) and the sleeve body (200) to maintain sealing.

2. A connection structure with anti-torsion casing threads for casing drilling according to claim 1, characterized in that: A plurality of pressing plates (340) are arranged in an annular shape inside the extrusion cavity (320), and a connecting rod (350) is installed on the pressing plate (340). The connecting rod (350) passes through the extrusion cavity (320) and extends to the outer surface of the support sleeve (310). A contact plate (360) is installed at one end of the connecting rod (350) away from the pressing plate (340); When the sleeve body (200) is twisted and bent inside the connection unit (100), the connection sleeve (210) presses the contact plate (360), driving the pressed contact plate (360) to move synchronously, so that the pressure plate (340) presses a local area of ​​the airbag (330).

3. A connection structure with anti-torsion casing threads for casing drilling according to claim 2, characterized in that: The connecting rod (350) is provided with a second spring (370), and the second spring (370) is in a compressed state and is used to control the contact plate (360) to elastically support the connecting sleeve (210).

4. A connection structure with anti-torsion casing threads for casing drilling according to claim 1, characterized in that: A flow channel (380) is provided inside the support sleeve (310), and one end of the flow channel (380) is connected to the inside of the airbag (330). A plurality of connecting channels (180) are distributed in an annular manner inside the coupling (110), and the connecting channels (180) are connected to the inside of the sealing ring (500). The other end of the flow channel (380) away from the airbag (330) is connected to the inside of the connecting channel (180).

5. A connection structure with anti-torsion casing threads for casing drilling according to claim 1, characterized in that: The coupling (110) is symmetrically provided with a first internal thread (120) and a second internal thread (130), the first internal thread (120) and the second internal thread (130) are arranged in a step-like manner, and the diameter of the first internal thread (120) is smaller than the diameter of the second internal thread (130); the surface of the connecting sleeve (210) is provided with a first external thread (220) and a second external thread (230), the first external thread (220) and the second external thread (230) are arranged in a step-like manner, and the diameter of the first external thread (220) is larger than the diameter of the second external thread (230).

6. A connection structure with anti-torsion casing threads for casing drilling according to claim 5, characterized in that: A first step surface is provided between the first internal thread (120) and the second internal thread (130), and a second step surface is provided between the first external thread (220) and the second external thread (230).

7. A connection structure with anti-torsion casing threads for casing drilling according to claim 6, characterized in that: A first groove is provided on the first step surface, a second groove is provided on the second step surface, and a second sealing ring (400) is provided between the first groove and the second groove.

8. A connection structure with anti-torsion casing threads for casing drilling according to claim 1, characterized in that: A clamping ring (240) is clamped and connected inside the clamping groove (140), and the clamping ring (240) is fixedly connected to the connecting sleeve (210).

9. A connection structure with anti-torsion casing threads for casing drilling according to claim 8, characterized in that: An inclined surface (250) is provided between the clamping ring (240) and the second external thread (230), and an inner wall of the inclined surface (250) is adapted to fit the sealing ring (500).

10. A connection structure with anti-torsion casing threads for casing drilling according to claim 8, characterized in that: An annular cavity (150) is provided at one end of the clamping groove (140) that is close to the other end. A first sealing ring (160) is provided inside the annular cavity (150). A sealing groove (161) is provided on the first sealing ring (160). The sealing groove (161) abuts against the clamping ring (240). A first spring (170) is distributed in an annular shape between the annular cavity (150) and the first sealing ring (160). One end of the first spring (170) is fixedly connected to the annular cavity (150), and the other end of the first spring (170) is fixedly connected to the first sealing ring (160).

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