A connection structure for casing drilling, which includes anti-torsion casing threads

Abstract

The present invention relates to the technical field of oil drilling casing, and discloses a connection structure for casing drilling with anti-twist casing threads, including a connection unit, the connection unit includes a coupling; a casing body, the casing body includes a connection casing; a compensation unit, the compensation unit includes support sleeves symmetrically installed on the coupling, an extrusion cavity is formed at one end of the support sleeve away from each other, and an airbag is arranged inside the extrusion cavity; when torsional bending occurs between the connection unit and the casing body, the connection casing offsets inside the coupling, so that the connection casing squeezes towards the airbag, causing the sealing ring to expand, filling and compensating the connection between the connection unit and the casing body to maintain sealing. Through the setting of the compensation unit and the sealing ring, the present invention can effectively cope with the offset caused by torsional bending at the connection, ensure the sealing effect, can adapt to complex drilling environments, and reduce leakage problems caused by poor sealing.

Description

Technical Field

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

[0002] Currently, casing drilling technology is mainly used in industries such as oil and gas extraction, geological exploration, and specific underground water 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 extraction technology, the traditional connection structure is difficult to adapt to complex drilling environments. In the exploitation operations of highly deviated wells and horizontal wells, the casing needs to extend over a long distance in the wellbore and bear complex mechanical loads. Due to the increased contact area between the casing and the wellbore wall and the curvature of the wellbore trajectory, the friction resistance during casing running into the well increases significantly, resulting in easy deformation of the shoulders when rotating the casing into the well.

[0003] Specifically, the deformation of the shoulders will directly damage the sealing performance at the casing connection, causing the sealing position to deviate from the original designed mating state and even deviate from the optimal sealing position, resulting in sealing failure. Sealing failure not only leads to the leakage of drilling fluid or oil and gas but may also trigger more serious downhole accidents, bringing huge economic losses and safety hazards to oil and gas exploitation operations. Summary of the Invention

[0004] The present invention provides a connection structure for casing drilling with anti-torsion casing threads, which solves the technical problem in the related art that the deformation of the shoulders will directly damage the sealing performance at the casing connection, causing the sealing position to deviate from the original designed mating state and even deviate from the optimal sealing position, resulting in sealing failure.

[0005] The present invention provides a connection structure for casing drilling with anti-torsion casing threads, including a connection unit, the connection unit includes a coupling, a circular boss is provided in the middle of the coupling, clamping grooves are provided at both ends of the circular boss, and a circular guide groove is further provided inside the clamping groove; a casing body, the casing body includes a connecting casing; a compensation unit, the compensation unit includes support sleeves symmetrically installed on the coupling, an extrusion cavity is provided at one end of the support sleeve away from each other, and an airbag is provided inside the extrusion cavity; a sealing ring, the sealing ring is arranged inside the circular guide groove; when torsional bending occurs between the connection unit and the casing body, the connecting casing offsets inside the coupling, causing the connecting casing to squeeze towards the airbag. 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 between the connection unit and the casing body to maintain sealing.

[0006] As a further optimized solution of the present invention, a plurality of pressing plates are annularly arranged inside the extrusion cavity, and a connecting rod is installed on the pressing plate. The connecting rod passes through the extrusion cavity and extends to the outer surface of the support sleeve. A contact plate is installed at one end of the connecting rod away from the pressing plate;

[0007] When the casing body generates torsional bending inside the connecting unit, the connecting sleeve presses the contact plate, driving the pressed contact plate to move synchronously, so that the pressing plate presses a local area of the airbag.

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

[0009] As a further optimized solution of the present invention, a flow channel is opened inside the support sleeve, and one end of the flow channel is communicated with the inside of the airbag. A plurality of connecting channels are annularly distributed inside the coupling, and the connecting channels are communicated with the inside of the sealing ring. The other end of the flow channel away from the airbag is communicated with the inside of the connecting channel.

[0010] As a further optimized solution of the present invention, a first internal thread and a second internal thread are symmetrically opened inside the coupling. The first internal thread and the second internal thread are arranged in a stepped manner, and the diameter of the first internal thread is smaller than that of the second internal thread; first external thread and a second external thread are provided on the surface of the connecting sleeve. The first external thread and the second external thread are arranged in a stepped manner, and the diameter of the first external thread is larger than that of the second external thread.

[0011] As a further optimized solution of the present invention, a first stepped surface is arranged between the first internal thread and the second internal thread, and a second stepped surface is arranged between the first external thread and the second external thread.

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

[0013] As a further optimized solution of the present invention, a snap ring is snap-fitted inside the card slot, and the snap ring is fixedly connected to the connecting sleeve.

[0014] As a further optimized solution of the present invention, an inclined surface is arranged between the snap ring and the second external thread, and the inner wall of the inclined surface is adapted to the sealing ring.

[0015] As a further optimized solution of the present invention, annular cavities are provided at one ends of the card slots 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 snap ring. A first spring is annularly distributed 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: Through the setting of the compensation unit and the sealing ring, the present invention can effectively cope with the offset caused by torsion and bending at the connection, ensuring the sealing effect. When torsion and bending occur between the connection unit and the casing body, the connection casing generates an offset inside the collar, causing the connection casing to squeeze towards the airbag. After being squeezed, the airbag transmits the internal gas to the inside of the sealing ring, causing the sealing ring to expand and filling and compensating the connection to maintain the seal. It can adapt to complex drilling environments and reduce leakage problems caused by poor sealing. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0019] Figure 3 is a partial structural schematic diagram of the connection between the connection unit, the casing body and the compensation unit in the present invention;

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

[0021] Figure 5 is the Figure 4 enlarged view of the structure at A in the present invention;

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

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

[0024] Figure 8 is a three-dimensional internal structural schematic diagram of the collar and the connection casing in the present invention;

[0025] Figure 9 is the Figure 8 enlarged view of the structure at B in the present invention;

[0026] Figure 10 is a three-dimensional sectional structural schematic diagram of the compensation unit in the present invention;

[0027] Figure 11 is of the present invention Figure 10 The enlarged view of the structure at position C in

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

[0029] Now, the subject matter described herein will be discussed with reference to exemplary embodiments. It should be understood that the discussion of these embodiments is only to enable those skilled in the art to better understand and thus implement the subject matter described herein. Without departing from the scope of protection of the content of this specification, changes can be made to the functions and arrangements of the elements discussed. Each example can omit, substitute, or add various processes or components as needed. Additionally, the features described in relation to some examples can also be combined in other examples.

[0030] According to the appended Figure 1 to the appended Figure 5 As shown in the figures, a connecting structure for casing drilling with anti-torsion casing threads includes a connecting unit 100 and a casing body 200; the connecting unit 100 includes a coupling 110, and symmetrically arranged inside the coupling 110 are a first internal thread 120 and a second internal thread 130. In the middle of the coupling 110, there is an annular boss, and card slots 140 are opened at both ends of the annular boss close to the first internal thread 120. An annular guide groove is also opened inside the card slots 140; the casing body 200 includes a connecting casing 210, and a first external thread 220 and a second external thread 230 are opened on the surface of the connecting casing 210.

[0031] Among them, the first internal thread 120 is threadedly connected to the second external thread 230, and the second internal thread 130 is threadedly connected to the first external thread 220. In this embodiment, through the symmetric threaded connection of the first internal thread 120 and the second external thread 230, and the second internal thread 130 and the first external thread 220, the stress at the connection can be evenly distributed, reducing stress concentration and improving the stability and reliability of the connection. When the connecting casing 210 bears tensile force, pressure, and torque, the force can be transmitted more evenly, reducing connection failure caused by excessive local stress.

[0032] It further includes a compensation unit 300 and a sealing ring 500; the compensation unit 300 includes support sleeves 310 symmetrically installed on the coupling 110. At the ends of the support sleeves 310 away from each other inside, there are extrusion cavities 320, and air bags 330 are provided inside the extrusion cavities 320; the sealing ring 500 is arranged inside the annular guide groove. In this embodiment, the compensation unit 300 and the sealing ring 500 can effectively cope with the offset generated by torsional bending at the connection, ensuring the sealing effect.

[0033] When torsional bending occurs between the connection unit 100 and the casing body 200, the connecting casing 210 generates an offset inside the coupling 110, causing the connecting casing 210 to squeeze towards the air bag 330. After being squeezed, the air bag 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 connection unit 100 and the casing body 200 to maintain the seal. Through this dynamic compensation mechanism, it can adapt to complex drilling environments and reduce leakage problems caused by poor sealing.

[0034] According to Att Figure 3 、Att Figure 4 and Att Figure 7 shown, in an alternative 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 that 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 that of the second external thread 230.

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

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

[0037] Furthermore, according to Att Figure 3 、Att Figure 4 and Att Figure 7 shown, a first stepped surface is provided between the first internal thread 120 and the second internal thread 130, and a second stepped surface is provided between the first external thread 220 and the second external thread 230. The settings of the first stepped surface and the second stepped 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 Figure 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. Among them, when the connecting sleeve 210 is offset or vibrates inside the coupling 110, the first sealing ring 160 can maintain close contact with the inner wall of the clamping groove 140 under the action of the first spring 170 to ensure 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 snap ring 240 and the second external thread 230, and the inner wall of the inclined surface 250 is adapted to the sealing ring 500.

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

[0046] When the sealing ring 500 is expanded by gas extrusion, 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 casing body 200 and 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 and improving the installation efficiency and accuracy.

[0048] According to the attached Figure 5 and the attached Figure 8 As shown, in an optional embodiment, 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 connection channels 180 are annularly distributed inside the coupling 110, and the connection 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 connection channel 180.

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

[0050] Among them, when the airbag 330 is squeezed, the gas can be quickly and evenly transmitted to all parts of the sealing ring 500 through the flow channel 380 and the connection channel 180, enabling it to quickly expand and fill the gap at the connection to achieve instant sealing compensation.

[0051] In this embodiment, this 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 attachedFigure 10 and the attached Figure 11 As shown, in an optional embodiment, a plurality of pressing plates 340 are annularly arranged 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.

[0053] It should be noted that in a complex drilling environment, such as during the exploitation of highly deviated wells and horizontal wells, the insufficient torsional resistance of threaded connections leads to connection failures. Especially during the process of casing running into the well, the friction in horizontal wells increases, making it difficult to run the casing. When rotating and running the casing, the shoulder is prone to deformation, resulting in the sealing position deviating from the fit or the optimal fit position, causing leakage.

[0054] Specifically, a torsional bend is generated between the connecting casing 210 and the collar 110. The connecting casing 210 displaces towards the bent side, causing an angle between the connecting casing 210 and the collar 110. This easily leads to gaps between the first external thread 220 and the second external thread 230, as well as between the second internal thread 130 and the first external thread 220. As a result, when the casing body 200 undergoes torsional bending inside the connecting unit 100, the sealing performance is insufficient.

[0055] In this embodiment, when the casing body 200 undergoes torsional bending inside the connecting unit 100, the connecting casing 210 squeezes the contact plate 360, driving the squeezed contact plate 360 to move synchronously, causing the pressing plate 340 to squeeze a local area of the airbag 330. This can more precisely control the extrusion position and force of the airbag 330, thereby achieving more efficient sealing compensation.

[0056] When the casing body 200 undergoes torsional bending, the offset of the connecting casing 210 directly acts on the contact plate 360 and is transmitted to the pressing plate 340 through the connecting rod 350, causing a local area of the airbag 330 to be squeezed. This more precisely transmits the gas to the parts where the sealing ring 500 needs compensation. It not only improves the sealing effect but also can adapt to torsional bends in different directions and degrees, enhancing the reliability and adaptability of the entire connecting unit 100.

[0057] Further, according to the attached Figure 11 As shown, a second spring 370 is provided on the connecting rod 350. One end of the second spring 370 is fixedly connected to the pressing plate 340, and the other end of the second spring 370 is fixedly connected to the inner wall of the extrusion cavity 320. The second spring 370 is in a compressed state and is used to elastically support the connecting casing 210 by the contact plate 360.

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

[0059] Among them, when the connecting sleeve 210 is offset and presses against the contact plate 360, the compression and rebound of the second spring 370 can buffer this offset, making the extrusion and gas transmission of the airbag 330 smoother and avoiding damage to the airbag 330 or the sealing ring 500 caused by sudden strong extrusion.

[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 connection stability and service life.

[0061] The above describes the embodiments of the specific implementation manner, but this embodiment is not limited to the above specific implementation manner. The above specific implementation manner is merely illustrative rather than restrictive. Under the inspiration of this embodiment, those of ordinary skill in the art can also make many forms, all of which fall within the protection scope of this embodiment.

Claims

1. A connecting structure for casing drilling with anti-torsion casing threads, characterized in that, Comprising: A connecting unit (100), the connecting unit (100) includes a coupling (110), a central portion of the coupling (110) is provided with an annular boss, both ends of the annular boss are provided with clamping grooves (140), and an annular guide groove is further provided inside the clamping groove (140); A casing body (200), the casing body (200) includes a connecting casing (210); A compensation unit (300), the compensation unit (300) includes support sleeves (310) symmetrically mounted on the coupling (110), an extrusion cavity (320) is provided at one end of the support sleeve (310) away from each other, and an airbag (330) is provided inside the extrusion cavity (320); A sealing ring (500), the sealing ring (500) is disposed inside the annular guide groove; When torsional bending occurs between the connecting unit (100) and the casing body (200), the connecting casing (210) is displaced inside the coupling (110), so that the connecting casing (210) squeezes the airbag (330), and the airbag (330) transfers the internal gas to the inside of the sealing ring (500) after being squeezed, causing the sealing ring (500) to expand, filling and compensating the connection between the connecting unit (100) and the casing body (200) to maintain sealing; A plurality of pressing plates (340) are annularly arranged inside the extrusion cavity (320), and a connecting rod (350) is mounted 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), and a contact plate (360) is mounted at one end of the connecting rod (350) away from the pressing plate (340); When the casing body (200) undergoes torsional bending inside the connecting unit (100), the connecting casing (210) squeezes the contact plate (360), driving the squeezed contact plate (360) to move synchronously, so that the pressing plate (340) squeezes a local area of the airbag (330).

2. A connection structure for casing drilling with anti-torsion casing threads according to claim 1, characterized in that, A second spring (370) is provided on the connecting rod (350), and the second spring (370) is in a compressed state, for controlling the contact plate (360) to elastically support the connecting casing (210).

3. A connection structure for casing drilling with anti-torsion casing threads 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 communicated with the inside of the airbag (330), a plurality of connecting channels (180) are annularly distributed inside the coupling (110), and the connecting channels (180) are communicated with the inside of the sealing ring (500), and the other end of the flow channel (380) away from the airbag (330) is communicated with the inside of the connecting channel (180).

4. A connecting structure for casing drilling with anti-torsion casing threads according to claim 1, characterized in that, The inside of the collar (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 stepped manner, and the diameter of the first internal thread (120) is smaller than that 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 stepped manner, and the diameter of the first external thread (220) is larger than that of the second external thread (230).

5. A connecting structure for casing drilling with anti-torsion casing threads according to claim 4, characterized in that, A first stepped surface is provided between the first internal thread (120) and the second internal thread (130), and a second stepped surface is provided between the first external thread (220) and the second external thread (230).

6. The connecting structure with anti-torsion casing thread for casing drilling according to claim 5, characterized in that, A first groove is provided on the first stepped surface, a second groove is provided on the second stepped surface, and a second sealing ring (400) is provided between the first groove and the second groove.

7. A connecting structure for casing drilling with anti-torsion casing threads according to claim 1, characterized in that, A snap ring (240) is snap-fitted inside the card slot (140), and the snap ring (240) is fixedly connected to the connecting sleeve (210).

8. A connection structure for casing drilling with an anti-torsion casing thread according to claim 7, characterized in that, An inclined surface (250) is provided between the snap ring (240) and the second external thread (230), and the inner wall of the inclined surface (250) is adapted to the sealing ring (500).

9. A connecting structure for casing drilling with anti-torsion casing threads according to claim 7, characterized in that, Annular cavities (150) are provided at one end of the card slots (140) close to each other. A first sealing ring (160) is provided inside the annular cavities (150), and a sealing groove (161) is provided on the first sealing ring (160). The sealing groove (161) abuts against the snap ring (240). First springs (170) are annularly distributed between the annular cavities (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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