RU2271430C2 - Pipe string coupling - Google Patents

Abstract

FIELD: oil production industry, particularly protection means for tubing string, casing pipe and sucker rod, namely adapted to decrease resilient deformations in weak sections of submersed centrifugal pump to be lowered in deviated well.

SUBSTANCE: coupling comprises body, fixed half-coupling and sliding half-coupling, which is movable relative the body and has spherical outer surface. The fixed half-coupling has spherical inner surface and is screwed into the body. Lower body part is provided with inner spherical surface mating lower part of spherical outer sliding half-coupling surface. Spherical surface of sliding half-coupling is provided with grooves for sealing means receiving and through orifices adapted to connect the grooves with inner surface of sliding half-coupling. Adjusting screws to be inserted in blind smooth orifices formed in sliding half-coupling are arranged in the body. The blind orifice diameters provide sliding half-coupling displacement in azimuth plane without interference in its angular movement relative transversal axis. Annular space between the body and spherical surfaces of half-couplings is filled with graphite grease. Upper part of sliding half-coupling is provided with flat face.

EFFECT: increased operational efficiency of downhole pumping equipment, reduced bending stresses in tubing string, coupling and casing pipe sections arranged in intervals of well deviation increase, improved dynamic pumping equipment characteristics, service life and prevention of fatigue corrosion along with simplified coupling structure.

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Description

The invention relates to the oil and gas industry, in particular to the protection of tubing, casing and rod string and reducing elastic deformation in dangerous sections of the descent installation of a submersible centrifugal pump (UPTsN) in intensely curved wells.

Known coupling designed for rigid and tight connection of tubing without mutual displacement of the axes [1].

A disadvantage of the known device is its low efficiency under conditions of strong curvature of the wellbore of production wells and mainly solves the problem of tightness of the tubing connection in vertical wells and wells of small curvature.

The closest in technical essence to the proposed invention is a hinged device for connecting pipes [2] - prototype.

A disadvantage of the known device is the design complexity of the unit of angular displacement due to the placement of a sleeve with a spherical flange in the hollow body and thereby a significant reduction in the flow area and the inability to use the design in intensely curved wells equipped with sucker rod pump installations (USGN) and armed with rod columns with scrapers -centers.

The aim of the invention is to increase the operating efficiency of deep-well pumping equipment (GND), reduce bending forces in the tubing, couplings and sections of the casing in the range of depths of set of curvature, improve the dynamic characteristics of the GNO, its durability, prevent fatigue corrosion and simplify the design of the connecting sleeve.

The goal is achieved in that the coupling of the tubing containing a housing, a fixed coupling half and a coupling coupling movable relative to the housing having an external spherical surface, according to the invention, the fixed coupling half has an internal spherical surface and is screwed into the housing, in the lower part of which an internal spherical surface is made mating with the lower part of the spherical surface of the movable coupling half, and grooves under the seal are made on the spherical part of the movable coupling coupling holes and through holes connecting them to the inner surface of the movable coupling half, while the housing contains set screws included in blind smooth holes made in the movable coupling half, the diameter of which allows the movable coupling coupling to move in the azimuthal plane without preventing its angular movement relative to the transverse axis moreover, the annular space between the housing and the spherical surfaces of the coupling halves is filled with graphite grease, and in the upper part of the movable coupling half is made chamfer.

The drawing shows a coupling connecting tubing. The coupling of the tubing is located immediately after the installation of the submersible centrifugal pump, as well as between the tubing, in places of intense curvature of the casing string (borehole). The coupling includes a housing 1, a fixed coupling half 2, a movable coupling half 3, o-rings 4 and 5, set screws 6 in the housing 1 and blind smooth holes 7 made with a diameter to move the movable coupling half in the azimuthal plane without preventing its angular movement relative to the transverse axis. The annular space A between the housing and the spherical surfaces of the coupling halves is filled with graphite lubricant during assembly, providing an improvement in the antifriction properties of the coupling material and preventing wear of the contacting surfaces. Chamfer B in the upper part of the movable coupling half prevents “hooks” during geophysical and repair work (destruction of the knockdown valve) in the tubing.

The device operates as follows. When bending forces occur in the sections of the borehole, the movable coupling 3 moves relative to the housing 1 and the fixed coupling half 2, centering the tubing string in the casing, thereby relieving stresses in the body of the tubing from bending loads in the bent wells. Through holes connecting the inner cavity of the movable coupling half 3 with the grooves of the sealing rings 4 and 5, provide additional sealing of the pipe space of the coupling connection.

Using the proposed coupling connecting tubing will "fix" the shape of the wellbore, as well as improve the technological mode of operation of pumping equipment.

Since the value of bending stresses of tubing is comparable to the value of tensile stresses, preventing bending stresses also leads to a decrease in the frequency of breakage of tubing in deviated and spiral wells, creating favorable conditions for the operation of the UTsN, preventing the turn and breakage of USSN rods and thereby increasing the time between failures of the downhole equipment.

Information sources

1. Tubes of oil assortment: Reference. Under the general ed. A.E.Saroyan. - 3rd ed., Revised. and add. - M .: Nedra, 1987, 488 p.

2. Patent RU 2170322, E 21 V 17/05.

Claims (1)

A coupling connecting tubing comprising a housing, a fixed coupling half and a coupling coupling movable relative to the housing, having an external spherical surface, characterized in that the fixed coupling half has an internal spherical surface and is screwed into the housing, in the lower part of which an internal spherical surface is made, mating with the lower part of the spherical surface of the movable coupling half, and grooves for seals and through holes connecting and x with the inner surface of the movable coupling half, wherein mounting screws are located in the housing, which are made into blind smooth holes made in the movable coupling half, the diameter of which allows the movable coupling coupling to move in the azimuthal plane without preventing its angular movement relative to the transverse axis, and the annular space between the housing and the spherical surfaces of the coupling halves are filled with graphite grease, and a chamfer is made in the upper part of the movable coupling half.