RU2597899C1 - Centralizer for pipe string run in inclined-horizontal well - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention is intended for alignment of casing, drill pipe and tubing string or lowered to it of downhole equipment. Centralizer for pipe string includes hollow housing installed on it with the possibility of rotation of eccentric cylinder with centering working elements, mounted with possibility of rotation. On external surface of the cylinder on the side of eccentricity of grooves in longitudinal direction to form ribs between them. Centering working elements are mounted on said ribs, one of them on the side of larger eccentricity is made in the form of a roller.

EFFECT: reducing metal consumption, higher efficiency and reliability, expanded applications.

4 cl, 4 dwg

Description

The invention relates to the oil and gas industry and is intended for centering casing, drill and tubing or downhole equipment downhole with it - a deep well pump, a device for lowering a self-sealing packer for washing the filter and the filter itself, etc.

Known centralizer for a drilling tool (see AS No. 1244277, IPC E21B 17/10, published in BI No. 26, 07/15/86), containing a hollow body with connecting elements at the ends, a cylinder mounted on it with the possibility rotation with centering ribs on the side surface.

A disadvantage of the known centralizer is the inefficiency of its use in deviated and horizontal wells due to the possibility of one-sided adjoining of the centering pipes of drill, casing or tubing or other downhole equipment to the walls of the well, since precise alignment is not achieved.

A centralizer is also known (see patent RU No. 2055975, IPC 6E21B 17/10, published in BI No. 7, 03/10/1996), containing a hollow body with connecting elements at the ends, mounted on it with the possibility of rotation of an eccentric cylinder with working centering elements mounted on its side surface with the possibility of rotation.

The well-known centralizer in technical essence is closer to the proposed one and can be adopted as a prototype.

In it, the disadvantages of the analogue are partially eliminated, however, it is not without drawbacks. So, for example, it is also metal-intensive, and due to its design features, its use is limited. So, for example, when trying to use casing as a centralizer, it creates back pressure to the upward flow of cement in the annulus of the well, exerting increased resistance, which can lead to hydraulic fracturing, thereby reducing the cementing quality of deviated and horizontal wells.

The technical task of the present invention is to reduce the metal consumption, increase the efficiency and reliability, expand the scope of its application.

The stated technical problem is solved by the described centralizer comprising a hollow body mounted on it with the possibility of rotation of an eccentric cylinder with centering working elements mounted rotatably.

What is new is that on the outer surface of the cylinder from the side of its eccentricity, samples are made in the longitudinal direction with the formation of ribs between them, while the centering working elements are mounted on these ribs, and one of them from the side of greater eccentricity is made in the form of a roller.

New is the fact that the working elements can be made in the form of rollers or spring-loaded balls, or in combination.

Also new is the fact that the housing can be made in the form of a sleeve or pipe.

New is the fact that its body can be made in the form of a sleeve or pipe, while on the body in the form of a pipe holes are made with a threaded thread for the locking bolts to fix it to the pipe string, or elements for collet fastening can be made.

The presented drawings explain the essence of the invention, where in FIG. 1 shows a general view of the proposed centralizer in partial section, in which the casing is made with communication elements for connecting to the tubing pipe, to the drill or casing string, or to the downhole equipment lowered on the pipes, balls are also visible connecting the casing with an eccentric cylinder mounted on its outer surface.

In FIG. 2 is the same as in FIG. 1, when the housing is made in the form of a nozzle, in which holes for locking bolts are made above and below the eccentric cylinder, and also made elements for collet fastening are visible.

In FIG. 3 is a section along AA of FIG. 1, where the body is visible, an eccentric cylinder with samples made in the longitudinal direction with the formation of ribs, centering cylinder working elements made in the form of rollers mounted on the ribs in cross section.

In FIG. 4 is the same as in FIG. 3, where one of the centering working elements is made in the form of a roller and mounted on the rib from the side of greater eccentricity, and the remaining working elements in the form of spring-loaded balls, in cross section.

The inventive centralizer contains a hollow body, which can be made in the form of a sleeve 1 (see Fig. 1), lowered into the well as part of a pipe string, or in the form of a pipe 2 (see Fig. 2), which allows you to install the centralizer on any part pipe columns. On the bodies 1 and 2, eccentric centering cylinders 3 of the same size are mounted rotatably, connected to the bodies using balls 4 located in the annular grooves 5 and 6 of the body and cylinder, respectively. On the outer surface of the cylinder 3 from the eccentricity side, samples 7-10 are made in the longitudinal direction with the formation of ribs 11-15, on which centering working elements are mounted rotatably. One of the working elements from the side of greater eccentricity is made in the form of a roller 16 mounted on the axis 17 with the possibility of rotation. The working elements can be made in the form of spring-loaded balls 18, or their combination with rollers, as shown in FIG. 4, or in the form of rollers 16, 19 and 20 (see Fig. 3). For the housing, made in the form of a pipe 2, holes 21 are made in it with a threaded thread for locking bolts (bolts are not shown in Fig.) For fixing it to the pipes 22 of the column, and elements on the pipe 2 for collet fastening like this can also be made depicted in FIG. 2.

The centralizer works as follows.

It is lowered into the well on a pipe string - on a casing or drill string, or tubing, placing it in the most critical places of the descent equipment or devices, in which the centering working elements 16, 19, 20, or 18 (see Fig. 3 and 4) touching the walls of the wellbore, in the case of their descent on the casing string, or to the casing wall during descent on the tubing string, roll over, constantly supporting the descent equipment in the center, as well as pipes from bumps and abrasions. In this case, at the slightest deviation from the vertical of the descent equipment, the cylinder 3 from the side of greater eccentricity immediately tends to occupy a vertical position due to the possibility of free rotation around the housing 1 or 2 and eccentricity, thereby self-centering occurs. In a horizontal well, the roller 6, due to the eccentricity of the cylinder, will occupy a lower position based on the wall of the well, as shown in FIG. 3 and 4, providing accurate self-centering.

The technical and economic advantage of the proposal is to reduce the metal consumption, to ensure accurate self-alignment of the pipe string being lowered into the well, which will enable them to be flawlessly lowered into the well and, together with it, the downhole equipment. The supply of the filter for the selection of well products from its horizontal section with the proposed centralizer will prevent it from unilaterally adjoining a horizontal well to the wellbore, which will make it possible to carry out high-quality flushing after descent or from accumulated contaminants during operation. At the filing date, working drawings are developed.

Claims (4)

1. The centralizer for the pipe string, lowered into an inclined horizontal well, including a hollow body mounted on it with the possibility of rotation of the eccentric cylinder with centering working elements mounted for rotation, characterized in that on the outer surface of the cylinder from the side of its eccentricity made in the longitudinal direction with the formation of ribs between them, while the centering working elements are mounted on these ribs, and one of them from the side of greater eccentricity in Full of a roller. 2. The centralizer according to claim 1, characterized in that the working elements can be made in the form of rollers or spring-loaded balls or in a combination thereof. 3. The centralizer according to claim 1, characterized in that its housing can be made in the form of a coupling or pipe. 4. The centralizer according to claim 3, characterized in that on the case in the form of a pipe holes are made with a threaded thread for the locking bolts to fix it to the pipe string or elements for collet fixing can be made.

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