Special thread for sleeve connection

Abstract

A special thread for casing pipe connection relates to the technical field of petroleum casing pipe connection and comprises a casing pipe and a casing pipe coupling, two-stage trapezoidal structure threads are respectively processed at the ends of the casing pipe and the casing pipe coupling, and the casing pipe is connected with the casing pipe coupling through the two-stage trapezoidal structure threads. A section of triangular threads is machined between the threads of the two-stage trapezoidal structure of the casing pipe, soft metal is fixedly connected between the threads of the two-stage trapezoidal structure of the casing pipe coupling, and after the casing pipe is in threaded connection with the casing pipe coupling, the soft metal is extruded by the triangular threads. And the soft metal is extruded to fill the space between the threads of the two-stage trapezoidal structure to form metal sealing. A clamping block is arranged on the casing pipe, a clamping groove is formed in the casing pipe coupling, and the clamping block is matched with the clamping groove through an inclined surface, so that when the casing pipe and the casing pipe coupling are subjected to tensile force, part of the tensile force acts between the clamping block and the clamping groove instead of completely acting on the threaded connection part, and the threaded connection part is protected from being snapped. The tensile strength and the sealing performance of casing pipe buckle connection are improved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of petroleum casing connection, and particularly relates to a special thread for casing connection. BACKGROUND

[0002] The petroleum casing is a steel pipe for supporting the well wall of an oil or gas well to ensure the normal operation of the whole oil well after drilling and completion.

[0003] With the development of deep wells, ultra-deep wells, high-pressure gas wells, directional wells and acid environment wells, higher requirements are put forward for the service performance of the petroleum casing, and the casing with the thread connection form of the trapezoidal structure is prone to breakage and leakage in complex well conditions. SUMMARY

[0004] In order to solve the problems of easy breakage and easy leakage at the casing buckle, the utility model provides a special thread for casing connection, which greatly improves the tensile strength of the connection at the casing buckle and the sealing performance of the casing connection.

[0005] A section of soft metal is additionally arranged between the two sections of trapezoidal thread connections, and a triangular thread connection is arranged between the two sections of trapezoidal thread connections.

[0006] The technical scheme provided by the utility model is as follows: a special thread for casing connection, comprising a casing and a casing coupling, the ends of the casing and the casing coupling are respectively provided with two sections of trapezoidal structure threads, the casing and the casing coupling are connected through the two sections of trapezoidal structure threads, a section of triangular thread is arranged between the two sections of trapezoidal structure threads of the casing, a soft metal is fixedly connected between the two sections of trapezoidal structure threads of the casing coupling, after the casing and the casing coupling are threadedly connected, the triangular thread extrudes the soft metal, and the soft metal is extruded to fill the space between the two sections of trapezoidal structure threads to form a metal seal.

[0007] Further technical scheme is that the soft metal is lead or tin, and the soft metal is solidified in the inside of the casing coupling after being melted.

[0008] Further technical solutions are: the end of the casing collar is provided with a limiting slot penetrating the inside and outside of the casing collar, a clamping block is arranged in the limiting slot, the clamping block can slide in the limiting slot, correspondingly, the outer wall of the casing is provided with an annular clamping groove, the inner side of the clamping block can extend into the clamping groove, the clamping groove near the thread side of the trapezoidal structure is provided with an inclined surface, correspondingly, the clamping block on this side is also provided with an inclined surface with the same slope, the casing collar is threadedly connected with a top nail, and the top nail limits the clamping block in the limiting slot.

[0009] Further technical solutions are: the clamping block is provided with a wing plate, and the wing plate is located in the length direction of the casing collar.

[0010] Compared with the prior art, the beneficial effects of the present application are that:

[0011] 1. The clamping block is arranged, when the casing and the casing collar are subjected to tension, the clamping block can limit the casing, so that all the tension is not applied to the threaded connection, thereby avoiding that the casing thread is pulled off. The clamping block and the clamping groove are matched through the inclined surface, so that no matter how the position of the clamping groove is after the casing is screwed on the casing collar, the clamping block and the clamping groove can be perfectly attached by adjusting the extension amount of the clamping block in the clamping groove, so as to limit the position.

[0012] 2. The present application is provided with the cooperation between the soft metal and the triangular thread between the two trapezoidal structure threads, the triangular thread extrudes the soft metal, so that the soft metal fills the space between the two trapezoidal structure threads, and since the soft metal does not have compressibility, the soft metal can play a very sealing role, so that the sealing property of the threaded connection is improved again. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 It is the overall structure schematic view of the present application.

[0014] Figure 2 It is Figure 1 It is the local enlarged view of A in the figure.

[0015] Figure 3 It is the unfolded view of the outer contour of the casing collar provided with the clamping block in the present application.

[0016] In the figure: 1, casing collar; 2, casing; 3, trapezoidal structure thread; 4, soft metal; 5, triangular thread; 6, top nail; 7, clamping block; 8, clamping groove; 9, inclined surface; 10, wing plate; 11, limiting slot. DETAILED DESCRIPTION

[0017] In order to make the technical problems, technical schemes and beneficial effects to be solved by the utility model clearer and more apparent, the utility model will be further described in detail below in combination with the drawings and embodiments.

[0018] The embodiment comprises a casing 2 and a casing collar 1, and the ends of the casing 2 and the casing collar 1 are respectively provided with two-stage trapezoidal structure threads 3, the casing 2 and the casing collar 1 are connected through the two-stage trapezoidal structure threads 3, and the above is a technology that already exists in the prior art and will not be described herein.

[0019] With reference to Figure 1 The innovation of the embodiment lies in that a section of triangular thread 5 is processed between the two-stage trapezoidal structure threads 3 of the casing 2, and a soft metal 4 is fixedly connected between the two-stage trapezoidal structure threads 3 of the casing collar 1, after the casing 2 and the casing collar 1 are threadedly connected, the triangular thread 5 extrudes the soft metal 4, the soft metal 4 is extruded to fill the space between the two-stage trapezoidal structure threads 3 to form a metal seal, and since the soft metal 4 is incompressible, the soft metal 4 can play a very sealing role, so that the sealing property of the thread connection is improved again.

[0020] The soft metal 4 is lead or tin, and the soft metal 4 is solidified in the inside of the casing collar 1 after being melted.

[0021] With reference to Figure 2 And Figure 3 Another innovation of the embodiment lies in that the end of the casing collar 1 is provided with a limiting groove 11 penetrating the inside and outside of the casing collar 1, in the embodiment, two limiting grooves 11 are arranged in the circumference of the casing collar 1, a clamping block 7 is arranged in the limiting groove 11, the clamping block 7 can slide in the limiting groove 11, correspondingly, the outer wall of the casing 2 is provided with an annular clamping groove 8, the inside of the clamping block 7 can extend into the clamping groove 8, the clamping groove 8 near the trapezoidal structure thread 3 is provided with an inclined surface 9, correspondingly, the clamping block 7 on this side is also provided with an inclined surface 9 with the same gradient, no matter how the position of the clamping groove 8 relative to the clamping block 7 is after the casing 2 is screwed on the casing collar 1, the two inclined surfaces 9 can be perfectly tightly attached by adjusting the extension amount of the clamping block 7 in the clamping groove 8, so as to play a limiting role. When the casing 2 and the casing collar 1 are subjected to a pulling force, the clamping block 7 can limit the casing 2, so as to avoid all the pulling force acting on the thread connection, thereby avoiding the thread connection of the casing 2 being pulled off.

[0022] As shown in Figure 3 The casing collar 1 is threadedly connected with a jack 6, in the embodiment, there are four jacks 6, and the jack 6 limits the clamping block 7 in the limiting groove 11.

[0023] The card block 7 is provided with a wing plate 10, which is arranged along the length direction of the casing collar 1. The wing plate 10 can play a good reinforcing role and strengthen the strength of the card block 7.

[0024] In conclusion, the casing 2 connecting structure of the embodiment plays an effect of improving the tensile strength and sealing performance of the casing 2.

Claims

1. A premium thread for casing connections, comprising a casing (2) and a casing collar (1), the ends of the casing and the casing collar (1) are respectively provided with two-stage trapezoidal structure threads (3), the casing (2) and the casing collar (1) are connected through the two-stage trapezoidal structure threads (3), characterized in that: A triangular thread (5) is processed between the two-stage trapezoidal threads (3) of the casing (2), and a soft metal (4) is fixed between the two-stage trapezoidal threads (3) of the casing coupling (1), after the casing (2) is threadedly connected with the casing coupling (1), the triangular thread (5) extrudes the soft metal (4), and the soft metal (4) is extruded to fill the space between the two-stage trapezoidal threads (3) to form a metal seal.

2. A premium thread for use in casing connections according to claim 1 characterized in that: The soft metal (4) is lead or tin, and the soft metal (4) is solidified in the inside of the casing coupling (1) after being melted.

3. A premium thread for use in casing connections according to claim 1, characterized in that: The end of the casing coupling (1) is provided with a limiting slot (11) penetrating the inside and outside of the casing coupling (1), a clamping block (7) is arranged in the limiting slot (11), the clamping block (7) can slide in the limiting slot (11), correspondingly, the outer wall of the casing (2) is provided with an annular clamping slot (8), the inside of the clamping block (7) can extend into the clamping slot (8), the clamping slot (8) near the trapezoidal thread (3) is provided with an inclined surface (9), correspondingly, the clamping block (7) on this side is also provided with an inclined surface (9) with the same inclination, the casing coupling (1) is threadedly connected with a top nail (6), and the top nail (6) limits the clamping block (7) in the limiting slot (11).

4. A premium thread for use in casing connections according to claim 3, characterized in that: The clamping block (7) is provided with a wing plate (10), and the wing plate (10) is located in the length direction of the casing coupling (1).

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