CN221920863U - Air-tight sleeve threaded joint for assisting mechanical positioning - Google Patents

Abstract

The utility model discloses an airtight sleeve threaded joint for assisting mechanical positioning, which comprises a first pipe body, a coupling and a second pipe body which are sequentially connected, wherein the coupling, the first pipe body and the second pipe body form a complete pipe column, the inner wall of the coupling is provided with an annular positioning groove, and the cross section of the annular positioning groove is isosceles trapezoid; the annular positioning groove both sides face is provided with interior circular bead, and the relative interior circular bead position of first body and second body is provided with the external shoulder, plays auxiliary sealing effect through interior circular bead and external shoulder to jack-up, and interior circular bead keeps away from annular positioning groove one side still is provided with seal structure, and first body and second body are provided with main seal structure relative seal structure position, and seal structure and main seal structure cooperation play main seal effect. The utility model has the performances of high extrusion resistance, high torsion resistance, high tensile strength and strong sealing, and realizes auxiliary mechanical positioning while meeting the requirement of a continuous oil pipe dragging and fracturing process.

Description

Gas-tight sleeve threaded fittings for mechanical positioning assistance

Technical Field

The utility model belongs to the technical field of oil casing, and in particular relates to a gas-tight casing threaded joint for assisting mechanical positioning.

Background Art

Oil casing is an important material basis in the exploration and development of oil and gas fields, and is an important channel for underground oil and gas resources to reach the ground. Due to the complexity of service conditions, such as increasing temperature and well depth, especially with the emergence of various new drilling and completion technologies and the development of ultra-deep gas fields due to resource demand, conventional API threaded joints can no longer meet application requirements, and gas-tight threaded pipes are needed to achieve this. However, there is no unified standard for gas-tight threads in the industry, and each oil casing manufacturer has different gas-tight threads, which has a great impact on well construction progress and gas well production capacity.

At present, in order to speed up the progress of well construction and improve the production capacity of gas wells, the continuous tubing drag fracturing process has begun to be used extensively. The continuous tubing drag fracturing requires the use of a mechanical positioner. The working principle of the mechanical positioner requires that the connection end face of the casing coupling must have a groove of 15 to 30 mm. However, the existing gas-tight threaded casing mainly adopts the shoulder-to-top method to prevent over-torque, and also plays an auxiliary sealing role. The connection end face gap is basically less than 1.0 mm, which makes the drag fracturing process impossible to implement in the existing gas-tight threaded casing wells.

Utility Model Content

The utility model aims to provide a gas-tight casing threaded joint for auxiliary mechanical positioning, which has the performance of high anti-extrusion, high anti-torsion, high tensile strength and strong sealing, and realizes auxiliary mechanical positioning while meeting the continuous oil pipe dragging fracturing process.

The technical solution adopted by the utility model is that the airtight casing threaded joint for assisting mechanical positioning comprises a first pipe body, a coupling and a second pipe body connected in sequence, the coupling, the first pipe body and the second pipe body form a casing column, an annular positioning groove is provided on the inner wall of the coupling, and the cross section of the annular positioning groove is an isosceles trapezoid;

Inner shoulders are arranged on both side surfaces of the annular positioning groove, and outer shoulders are arranged on the first tube body and the second tube body relative to the inner shoulders, and an auxiliary sealing effect is achieved through the inner and outer shoulders abutting against each other. A sealing structure is also arranged on the side of the inner shoulder away from the annular positioning groove, and a main sealing structure is arranged on the first tube body and the second tube body relative to the sealing structure, and the sealing structure and the main sealing structure cooperate to achieve the main sealing effect.

The utility model is also characterized in that:

The groove depth of the annular positioning groove is 2.5mm~5mm, and the groove width is 25.4mm~30mm; the angle between the inclined surfaces on both sides of the annular positioning groove and the upper bottom of the annular positioning groove is 120°~135°; the distance between the inner shoulder and the adjacent side inclined surface of the annular positioning groove is 10mm~15mm.

The sealing structure includes an inner sealing cone surface arranged on one side of the inner shoulder;

The outer shoulder is located at the end of the first tube body or the second tube body, and the thickness of the outer shoulder is equal to the width of the inner shoulder.

The angle of the inner shoulder is -3° to 0°, and the width of the inner shoulder is 2.5 mm to 6 mm; the taper of the inner sealing cone surface is 1:8, and the length of the inner sealing cone surface is 4 mm to 6 mm.

The inner wall of the coupling is provided with trapezoidal internal threads on both sides of the annular positioning groove, and the outer walls of the first tube body and the second tube body are provided with trapezoidal external threads matching the internal threads;

A cutter groove is arranged at the end of the coupling relative to the internal thread. The cutter groove is located between the inner sealing cone surface and the internal thread. The length of the cutter groove is 2mm to 5mm, and the groove depth of the cutter groove is not greater than the tooth height of the internal thread.

The main sealing structure includes an outer sealing cone surface located on one side of the outer shoulder, and the outer sealing cone surface and the outer thread are connected by a transition cylindrical surface;

The length of the main sealing structure formed by the outer sealing cone surface and the transition cylindrical surface is the same as the combined length of the sealing structure and the backing groove.

The taper of the outer sealing cone surface is 1:8, and the length of the outer sealing cone surface is 4mm to 8mm;

The length of the transition cylindrical surface is 4 mm to 9 mm; the combined length of the sealing structure and the backing groove is 4 mm to 8 mm.

After the coupling is threadedly engaged with the first tube body and the second tube body, the inner sealing cone surface and the outer sealing cone surface are interference fit, and the interference between the inner sealing cone surface and the outer sealing cone surface is 0.3mm-0.6mm; the interference between the inner thread and the outer thread is 0.15mm-0.3mm.

The thread bearing surface angles of the internal thread and the external thread are 0° to 3°, the guide surface angles are 42° to 45°, and the inclination directions of the internal thread and the external thread are opposite.

The taper of the internal thread and the external thread is 1:16, the pitch is 5.05mm-5.1mm, the tooth height is 1.5mm-1.6mm, the tooth groove width is 2.49mm-2.59mm, the tooth width is 2.39mm-2.54mm, and the tooth arcs are arranged at both ends of the tooth, and the radius of the tooth arc is 0.2mm-0.9mm;

After the internal thread and the external thread are meshed, the tooth side clearance is 0.05mm~0.1mm.

The beneficial effects of the utility model are:

(1) The utility model provides an airtight casing threaded joint for assisting mechanical positioning by setting an annular positioning groove in the middle part of the coupling, thereby playing a role in assisting mechanical positioning, and can meet the continuous tubing dragging fracturing process used in the gas well production process; at the same time, the coupling and the pipe body have a double sealing structure of cone-to-cone interference fit and shoulder-to-shoulder top fit, so that the threaded joint has high-pressure gas sealing performance.

(2) The tooth profiles of the internal and external threads of the airtight sleeve threaded joint for assisting mechanical positioning of the utility model are both set to be trapezoidal, and the angle of the thread bearing surface is set to 0-3°, which ensures the connection strength of the thread and is easy to process.

(3) The utility model of the airtight sleeve threaded joint for assisting mechanical positioning is also provided with a back-off groove on the coupling, and the back-off groove also has an oil storage function, the purpose of which is to store excess thread grease when threading and to avoid interference with the thread start buckle to cause sticking.

(4) The thread guide surface angle of the internal thread and the external thread of the airtight casing threaded joint for assisting mechanical positioning of the utility model is set to 42°~45°, the tooth height is 1.5mm~1.6mm, the tooth groove width is 2.49~2.59mm, the tooth width is 0.05~0.10mm smaller than the groove width, and tooth arcs are set at both ends of the tooth. The radius of the tooth arc is 0.20~0.90mm, and the tooth side clearance is 0.05~0.10mm, which is convenient for buckling and leading. At the same time, compared with the traditional on-site construction, the buckle window is 14%~20% of the set arc length, which is increased to 58%~66%, which is convenient for on-site operation, saves the casing operation time, and can achieve quick connection.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic structural diagram of a gas-tight sleeve threaded joint for assisting mechanical positioning according to the utility model;

FIG2 is a schematic structural diagram of an annular positioning groove in a gas-tight sleeve threaded joint for assisting mechanical positioning according to the utility model;

FIG3 is a schematic structural diagram of the internal and external threads in the gas-tight sleeve threaded joint for assisting mechanical positioning according to the utility model.

In the figure, 1. coupling, 2. annular positioning groove, 3. inner shoulder, 4. inner sealing cone, 5. back cutter groove, 6. inner thread, 7. first pipe body, 8. outer shoulder, 9. outer sealing cone, 10. transition cylindrical surface, 11. outer thread, 12. second pipe body.

DETAILED DESCRIPTION

The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

Example 1

As shown in Figure 1, the utility model is an airtight casing threaded joint for assisting mechanical positioning, including a first pipe body 7, a coupling 1 and a second pipe body 12 connected in sequence. The coupling 1, the first pipe body 7 and the second pipe body 12 are screwed together through an internal thread 6 and an external thread 11 to form a casing string. The formed casing string has the same inner diameter and the central axis is a straight line, ensuring smooth flow of the fluid in the pipe body to meet the production and use requirements of the gas field.

The internal thread 6 is located at both ends of the inner side of the coupling 1, and the external thread 11 is located at one end where the first tube body 7 or the second tube body 12 is connected to the coupling 1, and matches the internal thread 6. The internal thread 6 and the external thread 11 act as bearing surfaces and guide surfaces, and the internal thread 6 and the external thread 11 are both trapezoidal; after the internal thread 6 and the external thread 11 are meshed, the tooth side clearance is 0.05mm~0.1mm.

The coupling 1 is provided with a back cutter groove 5 at the end of the internal thread 6, the back cutter groove 5 is located between the internal sealing cone surface 4 and the internal thread 6, the length of the back cutter groove 5 is 2 mm to 5 mm, and the groove depth of the back cutter groove 5 is not greater than the tooth height of the internal thread 6. Excess thread grease can be stored to increase the sealing performance, and the sticking phenomenon of the starting buckle can be avoided.

The inner wall of the coupling 1 is provided with an annular positioning groove 2, and the cross section of the annular positioning groove 2 is an isosceles trapezoid;

Furthermore, as shown in Figure 2, the groove depth H of the annular positioning groove 2 is 2.5mm~5mm, and the groove width B is 25.4mm~30mm; the angle γ between the inclined surfaces on both sides of the annular positioning groove 2 and the upper bottom of the annular positioning groove 2 is 120°~135°; the distance A between the inner shoulder 3 and the adjacent side inclined surface of the annular positioning groove 2 is 10mm~15mm, which can facilitate the advancement and retreat of the boring tool when turning the groove size, and when using the continuous oil pipe dragging fracturing process, it provides a position for the mechanical locator, facilitating the realization of the locator function.

Inner shoulders 3 are provided on both side surfaces of the annular positioning groove 2, and outer shoulders 8 are provided on the first tube body 7 and the second tube body 12 relative to the inner shoulders 3. The inner shoulders 3 and the outer shoulders 8 are abutted against each other to play an auxiliary sealing role. A sealing structure is also provided on the side of the inner shoulder 3 away from the annular positioning groove 2, and a main sealing structure is provided on the first tube body 7 and the second tube body 12 relative to the sealing structure. The sealing structure and the main sealing structure cooperate to play the main sealing role.

The sealing structure includes an inner sealing cone surface 4 arranged on one side of the inner shoulder 3;

The outer shoulder 8 is at the end of the first tube body 7 or the second tube body 12, and the thickness of the outer shoulder 8 is equal to the width of the inner shoulder 3. The purpose is to use the inner shoulder 3 and the outer shoulder 8 to cooperate in a shoulder-to-shoulder manner, thereby ensuring that the inner wall of the first tube body 7, the second tube body 12 and the coupling 1 is smooth and flat after being connected, so that the fluid in the tube body can flow smoothly.

Furthermore, the angle of the inner shoulder 3 is -3° to 0°, and the width of the inner shoulder is 2.5 mm to 6 mm; the taper of the inner sealing cone surface 4 is 1:8, and the length of the inner sealing cone surface 4 is 4 mm to 6 mm.

The main sealing structure includes an outer sealing cone 9 located on one side of the outer shoulder 8, and the outer sealing cone 9 and the outer thread 11 are connected by a transition cylindrical surface 10; the length of the main sealing structure formed by the outer sealing cone 9 and the transition cylindrical surface 10 is the same as the combined length of the sealing structure and the backing groove 5.

Furthermore, the taper of the outer sealing cone surface 9 is 1:8, and the length of the outer sealing cone surface 9 is 4 mm to 8 mm; the length of the transition cylindrical surface 10 is 4 mm to 9 mm; and the length of the combination of the sealing structure and the backing groove 5 is 4 mm to 8 mm.

At the same time, after the coupling 1 is threadedly engaged with the first tube body 7 and the second tube body 12, the inner sealing cone surface 4 and the outer sealing cone surface 9 are interference fit, and the interference between the inner sealing cone surface 4 and the outer sealing cone surface 9 is 0.3mm-0.6mm; the interference between the inner thread 6 and the outer thread 11 is 0.15mm-0.3mm. The coating damage in the coupling 1 can be reduced, and the anti-sticking effect is played.

Example 2

On the basis of Example 1, as shown in Figure 3, in the utility model, the thread bearing surface angle β of the internal thread 6 and the external thread 11 in the airtight sleeve threaded joint for auxiliary mechanical positioning is 0°~3°, the guide surface angle α is 42°~45°, and the inclination directions of the internal thread 6 and the external thread 11 are opposite.

The taper of the internal thread 6 and the external thread 11 are both 1:16, and the pitch is 5.05mm-5.1mm. The present embodiment adopts a pitch of 5.08mm, and the tooth height h is 1.5mm-1.6mm. The taper, pitch and tooth height of the internal and external threads are the same as those of the API trapezoidal thread.

The tooth profile groove width L2 is 2.49mm-2.59mm, and the tooth profile tooth width L1 is 0.05mm-0.10mm smaller than the tooth profile groove width L2. Specifically, the tooth profile tooth width is 2.39mm-2.54mm, and tooth profile arcs R1, R2, R3 and R4 are arranged at both ends of the tooth profile, and the radius of the tooth profile arcs R1, R2, R3 and R4 is 0.2mm-0.9mm; it is convenient for buckling and buckling, and at the same time, compared with the traditional on-site construction, the buckle window is increased from 14%-20% of the set arc length to 58%-66%, which is convenient for on-site operation, and the single casing operation time is reduced from the original 5-8min to 3-5min, saving about 37.5%-40% of the time, and can achieve quick connection.

When the utility model is operated, any end of the coupling 1 is first screwed into the first tube body 7 or the second tube body 12. When screwing in, the internal thread 6 of the coupling 1 and the external thread 11 of the first tube body 7 or the second tube body 12 should be screwed in 3-7 turns first, and the internal and external threads are screwed in manually until they are not screwed in manually. The coupling 1 and the first tube body 7 or the second tube body 12 that have been screwed together by hand are further tightened to the state of interference fit by a screwing machine. During the tightening process, the external thread 11 and the internal thread 6 first form a radial interference fit state, the inner shoulder 3 and the outer shoulder 8 begin to contact, and an axial interference fit is generated to share the excess buckle torque. When a certain torque value is reached, the joint is in a screwed state, and the inner sealing cone surface 4 on the coupling 1 and the outer sealing cone surface 9 on the first tube body 7 or the second tube body 12 have a radial interference fit, forming a very high contact pressure on the contact surface, thereby playing a sealing role.

Example 3

use Specification casing, steel grade is 80S, with coupling 1 outer diameter specified in API standard, and material properties meet industry standard requirements.

Threaded joint parameters: internal and external thread taper is 1:16, pitch is 5.08mm, tooth height h is 1.575mm, guide surface angle α is 42°, load-bearing surface angle β is 3°, internal and external sealing taper is 1:8, internal sealing surface length is 4.00mm, external sealing surface length is 6.00mm, tooth profile arc R1 is 0.70mm, tooth profile arc R2 is 0.20mm, tooth profile arc R3 is 0.30mm, tooth profile arc R4 is 0.90mm; the groove width B of the annular positioning groove 2 is 25.40mm, the groove depth H is 2.50mm, the angle γ between the inclined surfaces on both sides of the annular positioning groove 2 and the upper bottom of the annular positioning groove 2 is 120°, and the distance A between the inner shoulder 3 and the adjacent side inclined surface of the annular positioning groove 2 is 15.00mm.

The connection strength of the casing threaded joint is equal to that of the pipe body, the compression strength reaches 85% of the pipe body, the internal pressure sealing performance reaches 55Mpa, the bending resistance reaches 20° or more than 30 meters, and it meets the requirements of no sticking after 3 times of buckling. The casing threaded joint has excellent internal pressure sealing, external pressure sealing and compression performance. When used on site, it is suitable for continuous tubing drag fracturing. The set position is 2890.14m, the actual positioning is 2890.14m, and the positioning accuracy is 100%. The same specification casing is used for casing lowering. The original casing lowering takes 8 minutes, and the buckle type is used to take 5 minutes per piece, saving 37.5% of the time. The swing arc length of the buckle window is set to 0.8m. After using this buckle type, the original 0.16m is changed to the current 0.46m, forming a large swing buckle, realizing the rapid connection of the casing thread and convenient use.

Example 4

use Specification casing, steel grade is P110, using coupling 1 outer diameter specified in API standard, material properties meet API standard requirements.

Threaded joint parameters: internal and external thread taper is 1:16, pitch is 5.08mm, tooth height h is 1.575mm, guide surface angle α is 45°, load-bearing surface angle β is 0°, internal and external sealing taper is 1:8, internal sealing surface length is 6.00mm, external sealing surface length is 8.00mm, tooth profile arc R1 is 0.90mm, tooth profile arc R2 is 0.30mm, tooth profile arc R3 is 0.20mm, tooth profile arc R4 is 0.70mm; the groove width B of the annular positioning groove 2 is 30.00mm, the groove depth H is 4.00mm, the angle γ between the inclined surfaces on both sides of the annular positioning groove 2 and the upper bottom of the annular positioning groove 2 is 135°, and the distance A between the inner shoulder 3 and the adjacent side inclined surface of the annular positioning groove 2 is 10.00mm.

The connection strength of the casing threaded joint is equal to that of the pipe body, the compression strength reaches 80% of the pipe body, the internal pressure sealing performance reaches 87Mpa, the bending resistance reaches 20° or more than 30 meters, and it meets the requirements of no sticking after 3 times of buckling. The casing threaded joint has excellent internal pressure sealing, external pressure sealing and compression performance. When used on site, it is suitable for continuous tubing drag fracturing. The set position is 3426.20m, the actual positioning is 3426.20m, and the positioning accuracy is 100%. The same specification casing is used for casing lowering. The original casing lowering takes 5 minutes, and the buckle type is used to take 3 minutes per piece, saving 40% of the time. The swing arc length of the buckle window is set to 0.8m. After using this buckle type, the original 0.22m is changed to the current 0.53m, forming a large swing buckle, realizing the rapid connection and convenient use of casing threads.

Claims (10)

1. A gas-tight casing threaded joint for assisting mechanical positioning, comprising a first pipe body (7), a coupling (1) and a second pipe body (12) connected in sequence, wherein the coupling (1), the first pipe body (7) and the second pipe body (12) form a casing string, characterized in that an annular positioning groove (2) is provided on the inner wall of the coupling (1), and the cross section of the annular positioning groove (2) is an isosceles trapezoid; The annular positioning groove (2) is provided with inner shoulders (3) on both sides, and the first tube body (7) and the second tube body (12) are provided with outer shoulders (8) at positions relative to the inner shoulders (3). The inner shoulders (3) and the outer shoulders (8) are abutted against each other to play an auxiliary sealing role. The inner shoulder (3) is also provided with a sealing structure on the side away from the annular positioning groove (2). The first tube body (7) and the second tube body (12) are provided with a main sealing structure at positions relative to the sealing structure. The sealing structure and the main sealing structure cooperate to play a main sealing role. 2. The airtight sleeve threaded joint for assisting mechanical positioning according to claim 1 is characterized in that the groove depth of the annular positioning groove (2) is 2.5mm~5mm, and the groove width is 25.4mm~30mm; the angle between the inclined surfaces on both sides of the annular positioning groove (2) and the upper bottom of the annular positioning groove (2) is 120°~135°; the distance between the inner shoulder (3) and the adjacent side inclined surface of the annular positioning groove (2) is 10mm~15mm. 3. The gas-tight sleeve threaded joint for assisting mechanical positioning according to claim 1, characterized in that the sealing structure comprises an inner sealing cone surface (4) arranged on one side of the inner shoulder (3); The outer shoulder (8) is located at the end of the first tube body (7) or the second tube body (12), and the thickness of the outer shoulder (8) is equal to the width of the inner shoulder (3). 4. The airtight sleeve threaded joint for assisting mechanical positioning according to claim 3 is characterized in that the angle of the inner shoulder (3) is -3° to 0°, and the width of the inner shoulder is 2.5mm to 6mm; the taper of the inner sealing cone surface (4) is 1:8, and the length of the inner sealing cone surface (4) is 4mm to 6mm. 5. The airtight sleeve threaded joint for assisting mechanical positioning according to claim 3, characterized in that the inner wall of the coupling (1) is provided with a partially trapezoidal internal thread (6) on both sides of the annular positioning groove (2), and the outer walls of the first tube body (7) and the second tube body (12) are provided with a partially trapezoidal external thread (11) matching the internal thread (6); The coupling (1) is provided with a tool-reduction groove (5) at the end opposite to the internal thread (6), the tool-reduction groove (5) is located between the inner sealing cone surface (4) and the internal thread (6), the length of the tool-reduction groove (5) is 2 mm to 5 mm, and the groove depth of the tool-reduction groove (5) is not greater than the tooth height of the internal thread (6). 6. The gas-tight sleeve threaded joint for assisting mechanical positioning according to claim 5, characterized in that the main sealing structure comprises an outer sealing cone surface (9) located on one side of the outer shoulder (8), and the outer sealing cone surface (9) and the outer thread (11) are connected by a transition cylindrical surface (10); The length of the main sealing structure formed by the outer sealing conical surface (9) and the transition cylindrical surface (10) is the same as the length of the combination of the sealing structure and the backhoe groove (5). 7. The airtight sleeve threaded joint for assisting mechanical positioning according to claim 6, characterized in that the taper of the outer sealing cone surface (9) is 1:8, and the length of the outer sealing cone surface (9) is 4 mm to 8 mm; The length of the transition cylindrical surface (10) is 4 mm to 9 mm; the combined length of the sealing structure and the tool retreat groove (5) is 4 mm to 8 mm. 8. The airtight sleeve threaded joint for assisting mechanical positioning according to claim 6 is characterized in that after the coupling (1) is threadedly engaged with the first tube body (7) and the second tube body (12), the inner sealing cone surface (4) and the outer sealing cone surface (9) are interference fit, and the interference between the inner sealing cone surface (4) and the outer sealing cone surface (9) is 0.3mm to 0.6mm; the interference between the inner thread (6) and the outer thread (11) is 0.15mm to 0.3mm. 9. The airtight sleeve threaded joint for assisting mechanical positioning according to any one of claims 5 to 8, characterized in that the thread bearing surface angles of the internal thread (6) and the external thread (11) are 0° to 3°, the guide surface angles are 42° to 45°, and the inclination directions of the internal thread (6) and the external thread (11) are opposite. 10. The airtight sleeve threaded joint for assisting mechanical positioning according to claim 9, characterized in that the taper of the internal thread (6) and the external thread (11) are both 1:16, the pitch is 5.05mm-5.1mm, the tooth height is 1.5mm-1.6mm, the tooth groove width is 2.49mm-2.59mm, the tooth width is 2.39mm-2.54mm, and tooth arcs are provided at both ends of the tooth, and the radius of the tooth arc is 0.2mm-0.9mm; After the internal thread (6) and the external thread (11) are meshed, the tooth side clearance is 0.05 mm to 0.1 mm.