CN207363610U - A kind of economical air-tight seal screw joint - Google Patents

Abstract

A kind of economical air-tight seal screw joint is the utility model is related to, belongs to oil casing threaded interconnection technique field.Connector is made of female connector and pin end two parts, and internal thread, cylindrical hole, torque shoulder are machined with female connector, and external screw thread, intermediate incline, planar end surface, inner wall inclined-plane are machined with pin end.The screw thread of pin end and female connector is standard API screw threads, but central diameter is bigger 0.2~0.4mm than API screw thread, and devises torque shoulder.The utility model internal thread and external screw thread radial interference fit simultaneously undertake linkage function, and torque shoulder significantly improves the sealing performance and anti-twisting property of connector, can meet the exploitation requirement of the natural gas well, have the advantages that in-process measurement is simple, interchangeability is strong and cost is low etc..

Description

A kind of economical air-tight seal screw joint

Technical field

A kind of economical air-tight seal screw joint is the utility model is related to, belongs to oil casing threaded interconnection technique field.

Background technology

Oil casing is to be up to upper km even thousands of rice by what oil pipe one by one and casing were connected through a screw thread High-pressure bottle, the various load such as in different well sections, tubing and casing will for a long time bear to stretch, compress, bend, internal pressure, external pressure Effect, screw connection point is link most weak in tubing string.

Oil bushing threaded connector generally can be divided into API nipples and Special threading connector at present.API connectors be according to API standard productions and the connector used, have the advantages of processing is easy to detect, and cost is low, but low, airtight there are joint efficiency Sealing property is unreliable and the shortcomings of anti-twisting property is poor.Therefore, factory develops the more preferable Special threading connector of gas sealing ability, But Special threading connector production process complexity, detection difficult, cost are higher, it is promoted and applied in oil field and be very limited.

In some oil field blocks, oil-gas Layer content is relatively low, is mainly characterized by low pressure, hyposmosis, low yield, be not suitable for use into This higher special buckle product, but API connectors cannot meet that exploitation requires again, it is therefore desirable to exploiting economy type hermetic seal screw thread Connector.

201778676 U of Chinese patent CN disclose a kind of resistance to low pressure gas sealing sleeve pipe connector, including a box cupling and A set of pipe fitting, box cupling are equipped with internal thread, and casing head is equipped with external screw thread, and the internal thread is identical with external screw thread tooth form, interior Screw thread is engaged with external screw thread interference.Its main feature is that being not provided with the sealing surface of metal/metal, rely only on thread interference and realize sealing, So as to reduce cost, but to be that internal and external screw thread tooth form is identical can cause serious stress concentration to shortcoming, make screw thread that thread gluing occur Damage.Connector internal diameter is not concordant with tube inner diameter at the same time, influences downhole tool tripping in, can also turbulent flow formed here.

202544761 U of Chinese patent CN disclose a kind of hermetic seal casing threads that can be exchanged with API round threads and connect Head, including two tube bodies and a box cupling, are provided with external screw thread on tube body, are provided with internal thread on box cupling, on the tube body Externally threaded end devises long nose, and the tip inside of long nose is equipped with male cone (strobilus masculinus) sealing surface, the internal thread on the box cupling It is divided into symmetrical two sections by the internal thread conical surface seal face among box cupling, internal thread root is provided with Gewindefreistiche, male cone (strobilus masculinus) Sealing surface and internal thread conical surface seal face form metal interference and coordinate, and the outer antitorque circular bead surface of master forms gold with the antitorque circular bead surface of interior master Belong to interference fit, the end face of two tube bodies is centrally formed interference docking in box cupling and coordinates.The drawback is that the length of externally threaded end Nose is very thin, is easy to collide with when Oil Field operates and causes to be recessed herein or oval, so as to cause whole connector Scrap.

The content of the invention

The purpose of this utility model is to solve above-mentioned technological deficiency, there is provided a kind of easy to operate, sound construction, be easy to add The nipple of work, favorable sealing property and economy and durability.To achieve the above object, the technical solution of the utility model is：Should Economical air-tight seal screw joint includes female connector and pin end two parts, under tight condition, inner surface and the public affairs of female connector The outer surface of connector is close together.

Internal thread, cylindrical hole, torque shoulder are machined with successively in the inner wall of female connector；Processed successively in the outer wall of pin end There are external screw thread, intermediate incline, inner wall inclined-plane, planar end surface.The wherein length of torque shoulder is L, L=25.4 ± 0.5mm, moment of torsion platform The internal diameter of shoulder is d2, and the internal diameter of pin end is d, and the internal diameter on inner wall inclined-plane is d1, and meets following relation：D1=d2, d1-d=0.5 ~1.2mm.After standard API nipples are tightened, the distance between public access end surface is 25.4mm, so by torque shoulder Width L is set as 25.4 ± 0.5mm.Due to pipe can not possibly pure circle, and there is also wall unevenness, if torque shoulder Internal diameter d2 is interior identical through d with pin end, and torque shoulder can be caused uneven neat with public access end surface, influenced under downhole tool Enter, and turbulent flow formed here.So the diameter d2 of torque shoulder is slightly larger than the internal diameter d of pin end, and in the end of pin end Bore hole processing is carried out, forms inner wall inclined-plane, inner wall inclined-plane diameter d1 is identical with torque shoulder internal diameter d2, inner wall inclined-plane and axis Angle is 3~6o, ensure that junction gentle transition, can not only reduce erosion corrosion caused by turbulent flow, but also facilitate downhole tool Operation.

Further, the internal thread on the external screw thread and female connector on pin end is standard API screw threads, but in internal thread Footpath is bigger 0.2~0.4mm than API screw thread.The purpose of increase thread pitch diameter is the interference volume reduced between internal and external screw thread, makes spiral shell The moment of torsion that line undertakes is shared to torque shoulder, so as to reduce the stress level of screw thread, reduces Thread-sticking risk.

Further, cylindrical hole is set on female connector, thread compound holding tank is formed with the relevant position of pin end, can store up Unnecessary thread compound is deposited, the diameter of cylindrical hole is identical with the bottom of the tooth diameter of adjacent internal thread, so as to avoid influencing the connection of connector Intensity.

Further, after female connector and pin end are tightened, with external screw thread radial interference fit occurs for internal thread, and interference volume is 0.3~0.6mm, mainly plays linkage function；Torque shoulder and planar end surface occur 3 it is axial be interference fitted, interference volume for 0.04~ 0.08mm, plays sealing function, but also can improve the anti-twisting property of connector.

It is using beneficial effect caused by above-mentioned technical proposal：Screw thread is easy to process；Improve the sealing energy of connector Power, its sealability reach more than the 70~80% of special buckle；The anti-twisting property of connector is significantly improved, reaches common API and connects 1.5~3 times of head；Connector internal diameter smoothly transits, and prevents turbulent flow to greatest extent.

Brief description of the drawings

Fig. 1 is the utility model connector axial section.

Fig. 2 is same specification API modular connection profiles.

Fig. 3 is the utility model connector torque shoulder region A enlarged drawings.

Fig. 4 is the utility model threaded engaging region B enlarged drawings.

In figure：1st, female connector；2nd, internal thread；3rd, cylindrical hole；4th, torque shoulder；5th, public access

Head；6th, external screw thread；7th, intermediate incline；8th, inner wall inclined-plane；9th, planar end surface；10th, thread compound stores

Groove；D, the internal diameter of pin end；D1, inner wall inclined-plane internal diameter；D2, torque shoulder internal diameter；α, inner wall are oblique

Face angle.

Embodiment

The utility model will be further described below in conjunction with the accompanying drawings.It is necessarily pointed out that following embodiments are only For being described further to the design, it is impossible to be interpreted as the limitation to the design protection domain, the professional technique people in the field Some nonessential modifications and adaptations that member makes according to the content of the design, still fall within the scope of protection of the utility model.

As Fig. 1 show the utility model connector axial section.It is a kind of taper pipe thread connector, by female connector 1 Formed with 5 two parts of pin end, the outer surface of the inner surface and pin end 5 of female connector 1 is close together under tight condition. Internal thread 2, cylindrical hole 3, torque shoulder 4 are machined with successively in the inner wall of female connector 1；Processed successively in the outer wall of pin end 5 There are external screw thread 6, intermediate incline 7, inner wall inclined-plane 8, planar end surface 9.The length of torque shoulder 4 is L, L=25.4mm, torque shoulder 4 Internal diameter be d2, the internal diameter of pin end 5 is d, and the internal diameter on inner wall inclined-plane 8 is d1, meets following relation：D1=d2, d1-d= 0.8mm。

Fig. 2 is same specification API modular connection profiles.API connectors exist between tightening latter two 5 end face of pin end The gap of long L, according to API standards, L=25.4mm.It was found from Fig. 1 and Fig. 2 contrasts, the utility model adds a length of L Torque shoulder 4, filled up the gap.

Fig. 3 is the utility model connector torque shoulder region A enlarged drawings.Inner wall inclined-plane 8 is concordant with torque shoulder 4, Smoothly transit, inner wall inclined-plane 8 and axis angle α is 3o~6o.The bottom of the tooth diameter of the diameter of cylindrical hole 3 and adjacent internal thread 2 Identical, the dangerouse cross-section area of box cupling will not decline because of the presence of cylindrical hole 3.After connector is tightened, torque shoulder 4 and flush end Axial interference fit occurs for face 9, and interference volume is 0.04~0.08mm, forms contact and seals, while shares screw thread Torque wrench moment, improve the anti-twisting property of connector.

Fig. 4 is the utility model threaded engaging region B enlarged drawings.External screw thread 6 and internal thread 2 are standard API spiral shells Line, after screw thread engagement, in outer screw thread tooth top and internal thread bottom of the tooth and screw thread flank all there are gap, forms leakage path, this It is the inherent shortcoming of standard API Design of Screw Thread.So the utility model set thread pitch diameter it is bigger than API screw thread by 0.2~ 0.4mm, internal and external screw thread interference fit, interference volume is 0.3~0.6mm, undertakes linkage function, while improve seal with screwed joint Property.

Technique effect is verified：The embodiment of the utility model is Φ 139.7 × 7.72mm P110BC casings, female connector 1 Outside diameter be 153.7mm, length is 235.0mm, torque shoulder 4 length 25.4mm, diameter d2=124.9mm.Outside pin end 5 Footpath is 139.7mm, and wall thickness is 7.72mm, internal diameter d=124.26mm, the internal diameter d1=124.9mm on inner wall inclined-plane 8, inclination alpha=4o, Material yield strength 758MPa, tensile strength 862MPa, 2.1 × 105MPa of elasticity modulus.By testing inspection, the company of the connector Connect intensity and reach 2430kN, hermetic seal ability reaches 51.4MPa, and hydraulic seal ability reaches 73.36MPa, and critical external compressive resistance ability reaches To 51.6MPa, anti-twisting property reaches 23520N-m, is more than 3 times of common API connectors.

Claims (5)

1. a kind of economical air-tight seal screw joint, is made of female connector (1) and pin end (5) two parts, in female connector (1) Inner wall be machined with internal thread (2), cylindrical hole (3) successively；External screw thread (6), transition are machined with successively in the outer wall of pin end (5) Inclined-plane (7), inner wall inclined-plane (8), planar end surface (9), it is characterised in that：In female connector（1）Inner wall design torque shoulder (4), it is grown Spend for L, L=25.4 ± 0.5mm, the internal diameter of torque shoulder (4) is d2, and the internal diameter of pin end (5) is d, inner wall inclined-plane (8) it is interior Footpath is d1, and meets following relation：D1=d2, d1-d=0.5~1.2mm.

A kind of 2. economical air-tight seal screw joint according to claim 1, it is characterised in that：On pin end (5) External screw thread (6) is standard API screw threads with the internal thread (2) on female connector (1), but thread pitch diameter is bigger than API screw thread by 0.2 ~0.4mm.

A kind of 3. economical air-tight seal screw joint according to claim 1, it is characterised in that：Inner wall inclined-plane (8) with Axis angle is α, α=3~6o.

A kind of 4. economical air-tight seal screw joint according to claim 1, it is characterised in that：Cylindrical hole (3) it is straight Footpath is identical with the bottom of the tooth diameter of adjacent internal thread.

A kind of 5. economical air-tight seal screw joint according to claim 1, it is characterised in that：Female connector (1) and public affairs After connector (5) is tightened, radial interference fit occurs for internal thread (2) and external screw thread (6), and interference volume is 0.3~0.6mm, moment of torsion platform With planar end surface (9) axial interference fit occurs for shoulder (4), and interference volume is 0.04~0.08mm.