RU2783362C1 - Centrator for rotary column - Google Patents

Abstract

FIELD: oil industry.

SUBSTANCE: invention relates to the oil industry and can be used in production wells for centering the sucker rod string during rotation in tubing, relieving loads on the sucker rod string and is applicable to the installation of a screw rod pump with a ground drive. The centralizer for the rotary string contains the upper and lower cages, the lower and upper travel stops of the centralizer and the centering ribs with bends. Each of the clips consists of a split half-liner with annular protrusions along the outer diameter and a split half-shell. A protrusion is made along the inner diameter from the end of the split half-shells. The centering ribs at the end sections have folds made in the form of elastic arcuate strips and are included in the grooves formed by the protrusions of the detachable half-liners and half-cages. Detachable half-shells are pulled together by fasteners.

EFFECT: increased reliability of fastening of centering ribs in detachable half-liners, the possibility of centering the rotational string coaxially with the inner wall of the tubing, as well as preventing the rotation of the centralizer in the tubing.

1 cl, 7 dwg

Description

The invention relates to the oil industry and can be used in production wells for centering the sucker rod string during rotation in the tubing, relieving loads on the sucker rod string and is applicable to the installation of a screw rod pump with a ground drive.

Known centralizer for sucker rods, containing a housing with a centering element, the housing is made in the form of a cylindrical rod with an annular protrusion and connecting threaded cuts at the end sections, and its centering element is made in the form of a rolling bearing, with an interference fit on the housing to the annular protrusion and is equipped with sealing lids secured to each other by threaded fasteners, while the sealing lids are made with longitudinal cutouts or with through longitudinal holes for the passage of formation fluid, and the sealing ring installed between the sealing lids is made with longitudinal cutouts or with through longitudinal holes (see RF patent for utility model No. 84442, class E21B 17/10, published on February 6, 2009).

The disadvantages of this centralizer are the possibility of turning the centralizer in tubing pipes (tubing) at a small angle of inclination of the well and the presence of a technological gap between the centralizer and the tubing, which does not allow installing the sucker rod string coaxially and directly in the center with respect to the inner wall of the tubing pipes.

It is known to be installed in an oil field, a rod guide, comprising a housing, including connecting first and second housing elements, while the first housing element has an outer wear surface, at least one outer conical surface located radially inward from the outer wear surface and tapering radially along axial direction, the inner surface, the engaging rod and located radially inside from the outer conical surface to capture the outer surface of the rod, the loaded shoulder of the first body element, located radially outside the outer wear surface, the second body element has an outer wear surface, the inner conical engaging surface, located radially inside from the outer wear surface, for axial sliding engagement with at least one outer conical surface of the first housing element, for moving at least part of the housing radially inward towards the gripping position of the rod around the rod, an inner rod engaging surface extending radially inward from the inner conical engaging surface to grip the outer surface of the rod, a loaded shoulder of the second housing element located radially outside the outer wear surface at an axial distance from the loaded shoulder of the first element body, and a clutch located around the first and second body elements in the position of capturing the rod between the loaded shoulders of the first and second body elements and having an inner wear surface for sliding contact with the outer wear surfaces of the first and second body elements and an outer wear surface for contact with the inner tubular the surface of the oil pipeline (see patent for invention RU No. 2374423, publ. 27.11.09, IPC E21B 17/10).

The disadvantages of this rod guide are the impossibility of removing the axial load, low efficiency and low reliability in highly deviated and horizontal wells, where it is difficult to install a string of sucker rods in the center of the tubing, resulting in impacts and abrasion of the rods on the tubing and increases the number breaks and lapels of the sucker rod string. The disadvantages include low maintainability, the impossibility of assessing the condition of the rod inside the devices when diagnosing rods.

A pump rod with a centering element is known, containing a pump rod with lower and upper thrust split sleeves installed on it, consisting of split half-bushings and fasteners tightened together, a centering element is placed between the thrust split sleeves on the pump rod, which consists of a lower and upper split sleeves. semi-inserts containing annular protrusions along the outer diameter, made perpendicular to the axis of the centering element and in one piece with split semi-inserts; lower and upper split half-cage, containing grooves along the inner diameter of the half-cage, made perpendicular to the axis of the centering element; lower and upper clamps, tightened through the mounting holes with fasteners and installed in the grooves of split half-cages, as well as centering ribs made in the form of elastic arcuate strips of a given profile and section, the number of which must be at least three, and the centering ribs at the end sections have bends , included in the grooves of the split half-shells, cutouts are made on the inner flanges of the split half-shells, the number of which corresponds to the number of centering ribs (see patent for invention RU No. 2523267, publ. 20.07.2014, IPC E21B 17/10). The specified sucker rod with a centering element is closer in technical essence to the proposed centralizer for a rotary string, and it can be taken as a prototype.

The disadvantage of the pump rod with a centering element is the low reliability of the split half-cage clamps, from the grooves of which the centering ribs are pulled out during operation of the device, which leads to the failure of the centering element and an emergency in the well.

The technical result of the claimed invention is the creation of a structure that makes it possible to increase the reliability of fixing the centering ribs in detachable half-liners, to center the rotational column coaxially with the inner wall of the tubing, and also to exclude the possibility of turning the centralizer in the tubing.

The set technical result is solved by the described centralizer for a rotary string, containing the upper and lower cages, each of which consists of a split half-liner with annular protrusions along the outer diameter and a split half-shell, the lower and upper limiters of the centralizer travel, centering ribs with folds, made in the form of elastic arcuate slats.

What is new is that a protrusion is made along the inner diameter from the end of the split half-cages, the centering ribs at the end sections have folds that enter the grooves formed by the protrusions of the split half-inserts and half-cages, and the split half-cages are pulled together by fasteners.

The present invention is illustrated by drawings, where:

in fig. 1 shows a centralizer for a rotary string on a sucker rod (front view);

- in Fig. 2 - centralizer for a rotary column, in section (left view);

- in Fig. 3 - centralizer for a rotary column, section A-A;

- in Fig. 4 - clip, section B-B;

- in Fig. 5 - limiter, section В-В;

- in Fig. 6 - well equipped with a screw rod pump with a ground drive;

- in Fig. 7 - photo of the centralizer made according to the claimed invention.

The centralizer for the rotary string (Fig. 1) consists of lower 1 and upper 2 clips, centering ribs 3, lower 4 and upper 5 limiters, which are installed on the pump rod 6.

The centering ribs 3 are made in the form of elastic arcuate strips of a given profile and section, the number of which must be at least three, in Fig. 2, as an option, four centering ribs 3 are shown. The centering ribs 3 at the end sections have folds 7 (Fig. 3) included in the grooves 8 (Fig. 3 and 4) between the detachable half-liners 9 and half-shells 11 (Fig. 3). The number of grooves 8 corresponds to the number of centering ribs 3.

Lower 1 and upper 2 clips (Fig. 1) consist of detachable half-liners 9 (Fig. 3), containing annular protrusions 10 along the outer diameter, made perpendicular to the axis of the sucker rod 6 and in one piece with detachable half-liners 9, respectively; detachable half-shells 11, on the inner diameter from the end there is a protrusion 12; fasteners 13 (Fig. 4), which pull together the detachable half-shells 11 and securely fix the centering ribs 3 in the grooves 8. The protrusions 12 and the annular protrusions 10 are necessary to prevent the bend 7 from coming out of the grooves 8.

The lower 4 and upper 5 limiters (Fig. 1, 3 and 5) are the limiters of the centralizer travel along the pump rod 6. The limiters 4 and 5 consist of split half-bushings 14 and 15 (Fig. 5) and are pulled together by fasteners 16.

Detachable semi-inserts 9 are plain bearings. The use of centering ribs 3 as part of the centralizer will provide concentric placement of pump rods 6 in tubing 17 (Fig. 6) and prevent the pump rods 6 from adhering to the walls of tubing 17. The outer diameter of the centering ribs 3 in the free state is greater than the inner diameter of the pump - compressor pipes 17.

The well, equipped with a surface-driven rod screw pump (Fig. 6), contains a productive formation 18, a casing string 19 with perforations 20, a screw rod pump 21 with a string of sucker rods 6, tubing 17, a drive head 22 with an engine 23, wellhead fitting 24 and fluid transfer line 25.

In FIG. 7 shows a photograph of a centralizer made according to the claimed invention.

Centralizer for rotary columns works as follows.

Before installation in the well, lower 4 and upper 5 stops are installed on the pump rods 6, after which a centralizer for the rotary string is installed between them. When installing the centralizer on the rod, the centering ribs 3 are first inserted into the grooves 8, then with the help of fasteners 13 (Fig. 4) the detachable half-shells 11 are pulled together. When passing through different diameters of the tubing 17 (Fig. 6), due to their thickness of the wall or recess of the couplings, the centering ribs 3 are deformed, move in the radial direction and together with the sucker rods 6 pass further. The elastic force of the centering ribs 3 sets the pump rods 6 in the center of the tubing 17. With an increase in the diameter of the tubing 17, the centering ribs 3 also increase in diameter, when removed from the tubing 17, the centering ribs return to their original position.

When the engine 23 (Fig. 6) of the drive head 22 is turned on, the polished rod (not indicated in Fig. 6) rotates, the pump rod string 6, while the centering element 3 is in a stationary state, ensuring the centering of the pump rod 6 for the entire length. Centralizers are installed on the sucker rod string in places of the greatest intensity of curvature set.

The production of the formation 18 (Fig. 6) through the perforations 20 is lifted by a screw rod pump 21 along the annular gap between the tubing 17 and the pump rod string 6, between the centering ribs 3 and further into the fluid transfer line 25. The pumped liquid is a lubricant for detachable half-liners 9 (Fig. 3). When the pump rod string 6 is rotated, the split half-liners 9, the centering ribs 3 and the half-shells 11 are in a stationary state, only the lower 4 and upper 5 stops rotate with the rods 6.

This design of the centralizer allows reliable operation of screw rod pumps in directional and horizontal wells, as well as centering the rod body relative to the tubing due to the weight of the rods and deviation from the axis of the rods. The proposed centralizer has a low cost and a simple design. The implementation of the split half-cage with a protrusion along the inner diameter will allow you to securely fix the centering ribs in the grooves of the half-cage, and the tightening of the split half-cage with fasteners, according to the claimed invention, will prevent failures due to depressurization of the half-cage.

Claims (1)

A centralizer for a rotary string, containing an upper and lower cage, each of which consists of a split half-liner with annular protrusions along the outer diameter and a split half-shell, the lower and upper limiters of the centralizer travel, centering ribs with bends made in the form of elastic arcuate strips, characterized in that that a protrusion is made along the inner diameter at the end of the split half-shells, the centering ribs at the end sections have folds included in the grooves formed by the protrusions of the split half-inserts and half-shells, and the split half-shells are pulled together by fasteners.

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