RU2718580C1 - Gas-tight threaded connection of tubing string - Google Patents

Abstract

FIELD: oil and gas industry.SUBSTANCE: gas-tight threaded connection of tubing string includes coupling and nipple parts, on which there are thrust trapezoidal taper thread with conicity of 1:16. Connection is made with sealing unit formed by contacting between each other end face surfaces made on coupling and nipple and located at angle 6° to axial thread line. On the sleeve there is a protective belt for redistribution of radial loads on the body of the coupling and prevention of thread snacking, which is a channel with a smooth wall, which is a continuation of the side wall of the cone of the support conical trapezoidal thread, the generatrix of which is drawn along the recesses of this thread. Channel extends outward from the outer thread turn by 5–7 mm.EFFECT: invention is intended for gas-tight threaded connection of tubing string.1 cl, 3 dwg

Description

The invention relates to the oil and gas industry and is intended for gas-tight threaded connection of tubing.

A threaded joint for steel pipes is known, comprising a nipple and a sleeve having each contact surface including a contact surface of a threaded part and a contact surface of a non-threaded part intended to contact metal surfaces, a first deposited layer formed by deposition of a Sn-Bi alloy or deposition of a Sn alloy -Bi-Cu on at least part of the contact surface of at least one of the nipple and coupling RU 2364781 C1, 08.20.2009).

A threaded connection for steel pipes is known, comprising a pin including a box containing a portion with an internal thread that is connected by a threaded connection to a portion with an external thread to form a threaded portion, a sealing surface, a pin, in which the pin and box are connected by threaded connection (US 2014116560 A1 05/01/2014).

In the patent of the Russian Federation No. 158152 dated 12/20/2015, a high-tight threaded connection of tubing is disclosed, including the sleeve and nipple parts, on which persistent trapezoidal tapered threads with a taper of 1:16 are made. The connection is made with a sealing assembly formed by contacting thrust end surfaces made on the coupling and nipple and located at an angle to the axial line of the thread. The angle of the end sealing element f1 relative to the normal to the axis of the thread of the nipple is less than the angle of the corresponding end sealing element f2 on the coupling, while the angle of the radial sealing element f3 relative to the axis of the thread of the nipple is also smaller than the angle of the corresponding radial sealing element f4 on the sleeve, and the sharp edge of the end stop ledge the coupling is rounded so that the circumference of the fillet is tangent to the surface of the end sealing element of the coupling, and the center of the radius Anna is on the inner circumference of the coupling line diameter along the connection axis, wherein the radius of curvature of not less than 2mm.

The technical problem of known threaded joints is a violation of the tightness of the connection, insufficient service life of the coupling due to its gradually accumulating deformations, the risk of biting the thread.

As the closest analogue, a threaded connection in the Russian Federation No. 158152 of 12/20/2015 can be taken.

The proposed gas-tight threaded connection of tubing includes a sleeve and a nipple part, on which thrust trapezoidal tapered threads with a taper of 1:16 are made, the connection is made with a sealing assembly formed by contacting thrust end surfaces made on the coupling and nipple and located at an angle 6 ° to the centerline of the thread.

Distinctive features of the proposed gas-tight threaded connection are: the presence on the coupling of a protective belt, which performs the functions of redistributing radial loads on the coupling body and preventing biting of the thread.

The protective girdle is a channel with a smooth wall, which is a continuation of the side wall of the cone of a persistent conical trapezoidal thread, the generatrix of which is drawn along the troughs of this thread, the channel extends 5-7 mm outward from the outer turn of this thread.

The technical results are the prevention of thread biting, reduction of the clutch deformation, increase of the sealing reliability, increase in the service life of the threaded joint.

The invention is shown in FIGS. 1-3.

Figure 1 - General view of a threaded connection,

figure 2 - protective belt,

figure 3 is a comparative analysis of the properties of the proposed coupling and the known similar coupling.

In FIG. 1 to 3 are indicated:

1 - coupling

2 - nipple

3 - a protective belt.

The claimed invention is made with a persistent end sealing unit, which ensures the occurrence of elastic deformations of surfaces. This assembly forms a metal-metal seal and provides high tightness of the joint under multidirectional loads.

The coupling is elongated by 5-7 mm with the formation of a protective belt, with which, when screwing, radial loads are transferred to the coupling body, which prevents the deformation of its weak points.

Due to the presence of such a protective belt, the thread is not afraid of excess torque.

The presence of a protective belt also prevents biting of the thread when screwing in.

The device operates as follows.

When tightening the thread in difficult operating conditions at the well, the preliminary turns are screwed more reliably, which prevents the thread from biting.

When the nipple is screwed into the coupling, as a result of the interference, radial forces appear in the thread, which in turn bring the area of the first threads of the coupling thread to yield strength, as a result of which the connection is unreliable. The elongated part of the clutch forms a protective band that holds radial loads and transfers them to the middle of the clutch body, which is confirmed by laboratory studies and theoretical calculations presented in Fig. 3.

Claims (1)

A gas-tight threaded connection of tubing, including a sleeve and a nipple part, on which thrust trapezoidal tapered threads are made with a taper of 1:16, and the connection is made with a sealing assembly formed by contacting thrust end surfaces made on the coupling and nipple and located under angle of 6 ° to the axial line of the thread, characterized in that a protective band is made on the coupling to redistribute radial loads on the coupling body and prevent biting threads, which is a channel with a smooth wall, which is a continuation of the side wall of the cone thrust conical trapezoidal thread generatrix is held by this thread troughs, with the channel extends outwardly from the outer loop of the thread is 5-7 mm.

Images