RU2499877C1 - Articulated coupling of pump rods - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: articulated coupling of pump rods includes a composite housing containing upper and lower hollow half-couplings. Half-couplings are connected to each other by means of a hinged connection made in the form of a ball pin. The latter is installed in lower half-coupling by means of connection thread and connected to upper half-coupling in a seat along spherical surface with a gap filled with lubricating liquid. With that, upper half-coupling has stiffeners, and a polyamide gasket is installed at contact point of the ball pin to the seat. The whole assembly is isolated from environment with a rubber gasket and a hold-down dust guard.

EFFECT: structure allows reducing wear of a ball assembly, frequency of folds and breaks of a rod stem as a result of reduction of action of bending and torsion stress in curved sections of the well shaft, contributes to improvement of operation reliability of a hinged coupling of pump rods in controlled directional wells and improvement of overhaul period of rod stem.

Description

The invention relates to the oil and gas industry for use in a mechanized method of oil production using a rod string in a curved wellbore.

Known combined drill rod / cm A.S. USSR No. 1740614, class E21B 17/20, 1992 /, comprising a hollow body with threaded portions at the ends. A hollow tip having a spherical surface in its middle part is installed at one end of the body. At the other end of the housing there is a coupling having an inner spherical surface corresponding to the spherical surface of the tip. At the beginning of the interaction of each successive rod with the drilling rig, the threaded shank of the tip is screwed into the threaded section of the rod body, transmitting torque to all previous rods. However, the known device is not suitable for connecting pump rods.

Known swivel coupling of a rod column / RU 2124109 class. E21B 17/00, 12/27/1998 /, made in the form of a cup with an internal bore and connecting thread for the rods at one end, a split support sleeve rigidly connected to the second end of the cup and provided with a conical bore placed inside the cup at the level of its bore, and half-rods with a spherical head located in the bore of the cup and kinematically connected simultaneously with the conical bore of the split supporting sleeve and the end of the rod screwed into the threaded end of the cup, and the body of the half-rod is placed in the axial hole of the split about sleeve with radial clearance. The disadvantage of this device is the lack of a lubrication system and isolation of the hinge assembly from an external aggressive environment, design complexity, a high likelihood of bending moment at the contact of the half-rod with the spherical tip and the supporting sleeve in the curved sections of the wellbore.

Known coupling of sucker rods / RU 2017930 class. E21B 17/05, 08/15/1994 /, comprising a housing of two parts, each of which is equipped with two rollers located in mutually perpendicular planes, and an articulated joint in the form of a spherical pin, one end of which is rigidly connected to the upper part of the housing, and the other, by means of a coupling with an internal ball sphere - with the lower part of the housing. The disadvantage of this design is the complexity of the design and the inability to rotate the coupling half relative to each other, there is also no lubrication system and isolation of the hinge assembly from an external aggressive environment.

The closest in technical essence of the invention is the connecting sleeve of sucker rods / RU 2211909 C. E21B 17/01, 09/10/2003 /, comprising a composite housing interconnected by a swivel made in the form of a spherical finger. At the same time, this design, as well as the proposed one, provides not only vertical rotation of the housing parts (half-couplings), but also their rotation around its own axis due to the action of loads.

A disadvantage of the known device is the absence of a locking finger ball element, also the design does not provide a lubrication system and isolation from an external aggressive environment (mechanical impurities, water, etc.) of the ball node, which together reduces the reliability of the device.

The objective of the invention is to simplify the design of the articulated coupling of the sucker rods, eliminating the effects of torsional and bending moments of the rod string and increasing the reliability of the product.

The essence of the invention lies in the development of a device of a swivel coupling of sucker rods, providing rotation and mutual rotation of the elements of the rod string in the curved barrel of the lifting pipes, while changing the angle of rotation is inversely proportional to the torque resulting from the frictional force between the rod string and the column of lifting pipes.

This problem is solved by the fact that in the proposed hinged coupling, the housing, consisting of two coupling halves, provides their mutual rotation and rotation relative to each other, using a ball assembly, while the isolation of this assembly from the external environment and preventing the release of lubricating fluid is carried out using rubber gaskets and clamping boot. The peculiarity lies in the fact that the ball assembly includes a lubrication system with a polyamide gasket that provides reduced wear of the rubbing zones, while the ball pin seat is a single housing with an upper coupling half having stiffeners, the ball pin, in turn, is connected to the lower coupling half by connecting thread and is fixed by a lock ring.

Figure 1 presents a diagram of the proposed device (longitudinal section of the device); figure 2 - a view of figure 1; figure 3 - view In figure 1.

The hinge coupling of the sucker rods comprises an upper coupling half 1 including a seat 2 of a spherical pin 3 with stiffening ribs 4 and a lower coupling half 5, with a ball pin 3 connected to it by means of a connecting thread, an abutment collar 6 and a retaining ring 7, connected to a ball assembly. The cavity of the ball assembly, filled with a lubricating fluid 8 with a polyamide gasket 9 inserted at the contact of the ball finger and the seat, is isolated from the external environment by a rubber gasket 10 and a clamping boot 11.

The device operates as follows, in directional and curved wells during the movement of the rod string and the occurrence of bending and torsional forces, in the absence of similar devices above the rod string, the lower coupling half 5 rotates and rotates in the ball assembly, including the saddle 2 of the ball pin and ball finger 3, while the loads from the lower coupling half 5 through the ball pin 3 and the polyamide gasket 9 are transferred to the upper coupling half 1.

When the lower half-coupling 5 is rotated, the clamping boot 11 pushes the rubber gasket 10 to prevent the lubricant 8 from escaping from the ball assembly, which, together with the installed polyamide gasket, reduces the friction force between the seat of the ball pin 2 and the ball pin 3.

The proposed device allows to reduce the wear of the spherical unit, the frequency of bends and breaks of the rod string due to the reduction of the influence of bending and torsion stresses on the curved sections of the wellbore, which together increases the reliability of the articulated coupling of the pump rods in directional wells and increases the overhaul period of the pumping equipment.

Claims (1)

The connecting sleeve of the sucker rods, comprising a composite housing containing a hollow upper and lower coupling halves, interconnected by a swivel made in the form of a spherical pin mounted in the lower coupling half by means of a connecting thread and connected to the upper coupling half in the saddle with a gap, characterized in that that the upper coupling half has stiffeners, the gap is filled with lubricating fluid, a polyamide gasket and the entire ball assembly are installed at the contact of the ball pin with the seat and gilded from the external environment with a rubber gasket and a clamping boot.

Images