RU2387791C1 - Downhole equipment centraliser - Google Patents

Abstract

FIELD: oil and gas production.

SUBSTANCE: downhole equipment centraliser comprising a hollow rod with a socket end, a coupling, a cylinder, a piston pusher and rams partially radially movable forward when travelling along the tapered case. Besides the coupling is provided from beneath; from the top, the hollow rod is equipped with a landing seat, and the cylinder wherein all the movable elements are provided, comprises ram windows and seats between the coupling and the landing seat while being designed to rotate and join a centre tube of the hollow rod; the tapered case is rigidly connected with the piston pusher spring-assisted from beneath to travel longitudinally downwards and rotate about the hollow rod.

EFFECT: rigid and reliable centering of the downhole equipment in the required interval.

3 dwg

Description

The proposal relates to the oil and gas industry, namely, devices for centering downhole equipment.

The well-known "Casing Centralizer" (patent RU No. 2209921, ЕВВ 17/10, publ. Bulletin No. 22 of 08/10/2003), including a cylinder located on the casing, a shear plug, communicating the cylinder cavity with the casing, a piston, centering elements, the cylinder being rigidly connected to the casing, the piston in the lower part made conical, and the centering elements made in the form of split petals of the conical sleeve having a groove from the outside along the perimeter, while the cylindrical part of the conical sleeve is rigidly connected to the casing d, and the lower conical part of the piston is installed with the possibility of interaction with split petals of the conical sleeve. In addition, the piston is made with a longitudinal slot.

The disadvantage of this device is the lack of a mechanism for returning the centering elements to their original transport position, which can lead to their jamming and emergency. In addition, there is no possibility of rotation of the centering elements relative to the casing, which creates additional resistance during operation.

The closest in technical essence and the achieved result is the “Drill tool centralizer” (patent RU No. 2151853, ЕВВ 17/10, publ. Bulletin No. 18 dated 06/27/2000), containing a coupling with which the hollow rod, cover, is connected, dies mounted for movement along the conical body, a sub with hydraulic channels and a cylinder, a piston pusher, a rubber ring, four screws, a cuff, a steel pressure ring and a shoe, and lanterns with holes inside of which are placed Teflon are welded in front of the hydraulic channels new balls, and the plunger piston is cut into four parts by the number of centralizer dies.

The disadvantage of this device is that the centering elements during operation of the drilling tool rotate together with the drill pipe string, which creates additional resistance and vibration during operation and reduces the life of the centralizer dies. As a result, the accuracy of the direction of movement of the centered equipment during operation is reduced (for example, an expander when expanding the wellbore). In addition, during the descent of the tool at a predetermined interval, the centering elements can spontaneously exit to the working position, since they are not fixed in the transport position, which can lead to jamming and an emergency.

The technical task of the proposed centralizer is to create a reliable device with a high working life that works in the required interval, providing accurate rigid centering with an even distribution of forces and, as a result, the exact direction of movement of the downhole equipment and reducing its vibrations.

The technical problem is solved by the centralizer of the downhole equipment, including a hollow rod with a sleeve, a conical body, a cylinder, a piston-pusher and dies made with the possibility of limited radial extension when moving along the conical body.

What is new is that the coupling is located at the bottom, the hollow rod is equipped with a stop at the top, and the cylinder, in which all movable elements are placed, is equipped with ram windows and rotatably mounted between the coupling and the stop and communicated with the central channel of the hollow rod, while the conical body rigidly connected to the spring-loaded bottom piston-pusher with the possibility of longitudinal movement down and rotation relative to the hollow rod.

Figure 1 shows the centralizer of the downhole equipment, a General view with an axial section in the transport position, Figure 2 is a General view with an axial section in the working position, Figure 3 is a section aa.

The downhole equipment centralizer contains a hollow rod 1 (see FIGS. 1 and 2), equipped with a stop 2 on top, a cone body 3, and dies 4 made with limited radial extension when moving along the cone body 3 and engaged with it by means of a “dovetail” tail "5. The conical body 3 is rigidly connected to the piston-pusher 7. The hollow rod 1 is connected from below to the sleeve 8 and, between the stop 2 and the sleeve 8, a cylinder 9 is located with the possibility of rotation, equipped with windows 10 for dies 4. For hydraulic transmission In order to connect the drill pipe and the centered downhole equipment (not shown), the centralizer has connecting threads 12. The dies 4 and the piston-pusher 7 return to their original transport position. by the force of the spring 6, through the pushers 13 (see figure 2), rigidly connected to the conical body 3.

Centralizer downhole equipment operates as follows. The centralizer is installed directly in front of the downhole equipment (expander, flare, etc. not shown in the drawing) using connecting threads 12 (see figure 1). Then, on the drill pipe string, the downhole equipment, together with the centralizer, is lowered to a predetermined interval in which it is necessary to expand the wellbore (not shown in the drawing), flaring or other operations. In this case, the centralizer dies 4 are hidden in the windows 10 of the cylinder 9 and do not touch the well walls due to the force of the spring 6.

After that, flushing fluid is fed into the drill string using a mud pump, and the drill string and downhole equipment begin to rotate. Through the hole 11 in the hollow stem 1, the hydraulic fluid transmits pressure to the piston-pusher 7, which is rigidly connected to the conical body 3, on which the dies 4 are installed by means of the “swallow tail” 5. Compressing the spring 6 through the pushers 13 (see figure 2), the piston-pusher 7 performs a longitudinal downward movement limited by compression of the spring 6, thereby bringing the dies 4 (see Fig. 3), thanks to the conical body 3, to a certain distance in the radial direction, thereby reliably centering the downhole equipment relative to and wells during operation. Cylinder 9 (see FIG. 2), in which all movable elements are placed, is located between the stop 2 of the hollow rod 1 and the coupling 8 with the possibility of rotation relative to the hollow rod 1. As a result, the centering elements perform a translational movement, the rotation of the cylinder 9 is absent - due to the presence of friction forces of the dies 4 on the well walls, which allows them to remain stationary relative to the well walls, thereby preventing wear on the surface of the dies 4 and increasing the life of the centralizer as a whole. After the predetermined interval of the well has been worked out, the mud pump is turned off, the pressure is released, and the spring 6 returns the dies 4 (see FIG. 1) with the conical body 3 and the piston-pusher 7 to the initial transport position. Then the tool is raised at the wellhead.

This design provides a rigid and reliable centering of downhole equipment in the required interval, eliminating unauthorized operations, vibrations and vibrations of this equipment during downhole operations, which together allows high-quality performance of all work with a high working resource of the device itself.

Claims (1)

A downhole equipment centralizer, including a hollow rod with a sleeve, a cone body, a cylinder, a pusher piston and dies made with limited radial extension when moving along the cone body, characterized in that the sleeve is located below, the hollow rod is equipped with a stop on top, and the cylinder in which all movable elements are placed, it is equipped with dice windows and is rotatably mounted between the coupling and the stop and communicated with the central channel of the hollow rod, while the conical body is rigidly connected to the spring bottom pusher with the possibility of longitudinal movement down and rotation relative to the hollow rod.

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