SU1745873A1 - Hydraulic and mechanical mandrel for expanding corrugated patch in casing - Google Patents

Abstract

Hydromechanical dornier head for expanding a corrugated patch in a casing string. The dorner head contains a cone-punch with longitudinal shaped grooves, a housing with a self-sealing tubular diaphragm, windows that are stepped in cross-section, and retractable sectors that are staggered in cross-section are located in them. 4 il.

Description

The invention relates to devices for repairing casing strings of oil, gas and other wells with the aim of restoring tightness and strengthening the wall of the column by installing a steel patch and creating a stressed casing-patch system.

The purpose of the invention is to increase the efficiency of the head by increasing the radial force per sector and increasing the service life.

FIG. 1 shows the dorniru head, a longitudinal section, in the transport position; in fig. 2 - Dorniru head, general view. in working position; in fig. 3 - the same. cross-section when expanding sectors in a pipe with a minimum wall thickness; in fig. 4 - the same, cross section at pressing a plaster in a pipe with the maximum wall thickness.

The hydromechanical dorning head consists of a body 1 with windows, made in the form of stop flanges 2 and a cylinder-cell 3 fixed between the flanges. The hull windows are made stepped in cross section. The nut 4 is tightened on the hollow barrel part of the body: cone-punch 5. thrust flanges 2 and cylinder-cell 3. Cylinder-cell 3 is fixed so that the symmetry planes of the body windows and sectors 6 that are stepped in the transverse direction are aligned with the plane By the symmetry of the longitudinal profile cana of the cone-punch 5. On the barrel part of the body under the cylinder-cell 3 and sectors 6 a self-sealing center tube diaphragm 7 is located, which interacts with large steps of sectors 6.

The device works as follows (Fig. 2).

During the descent into the casing 8, the lower end of the corrugated plaster 9 is placed on the cone-punch 5, and

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the concave beams of the plaster are inserted and abut against the longitudinal grooves of the cone-punch. The patch is worn on the rod 10 and its upper end is fixed by the end of the power cylinders of the mandrel or hydromechanical box.

When creating the working pressure, the locking head enters the patch, expanding it to tight contact with the casing. Under pressure, the self-sealing ends of the cylindrical diaphragm 7 are pressed tightly against the walls of the hollow recess A, creating tightness in the working chamber with virtually no radial expansion.

The central part of the diaphragm 7, expanding, acts on the retractable sectors 6, pressing them against the adhesive patch (Fig. 2).

In this case, the rest of the expanding diaphragm abuts against the stationary inner surface of the cylinder-cell.

Work functions are transferred to a stronger and more durable cylindrical part of the diaphragm.

 The cylindrical diaphragm, expanding, abuts part of its outer surface into the cylinder-cell. As a result, rectangular protrusions or depressions (depending on the degree of extension of the sectors) appear on the diaphragm, corresponding to the supporting surface of the base of each sector. The magnitude of the advancement of the sector varies depending on the wall thickness of the casing, the presence or absence of a plaster.

FIG. Figures 3 and 4 show the limiting cases of the extension of sectors under load: during expansion in a pipe with a minimum wall thickness (Fig. 3) and in a pipe with a maximum wall thickness with a plaster (Fig. 4). The shoulders, which at the same time encircle the diaphragm around the perimeter of the supporting surface of the base of the sector, do not exceed 3-3.5 mm. With smoothed edges and minimal gaps in the window between the sector and the body, the reason for the rapid destruction is excluded.

rubber diaphragm: leaking and subsequent pinching. Even in the event of a diaphragm rush on the ledge (after prolonged use), it is possible to easily restore the necessary pressure in the head and complete the installation of the patch without any accidents or complications. When a diaphragm rushes, fluid may leak only through the gaps in the window between the sector and the housing. When running sector landing in the window, the total area of the gaps does not exceed 20-40 mm2. Taking into account the high coefficient of resistance of a narrow slit-shaped gap and overlapping the main part of it with rubber

diaphragm, the required pressure can be easily restored by a slight increase in the performance of the pump unit.

The total radial force developed by the head is transmitted not to 12, but to the withdrawable sectors. Consequently, under the same working pressure, the force of the radial effect of the sector on doubled corrugations doubles, which guarantees

full adhesion plaster.

Claims (1)

Invention Formula Hydromechanical dorniruyuscha head for expanding the corrugated patch, the casing comprising a cone-punch with longitudinal profiled grooves with a body placed therein the self-tubular decoupling diaphragm and pull sectors tymi steplike in cross-section, mounted with the possibility of reacting more stages with the diaphragm, wherein so as to increase efficiency the head works by increasing the radial force per sector and extending the service life, retractable sectors are stepped in cross section, and the housing has stepped windows in cross section for retractable sectors, and the plane of symmetry of the body windows and the longitudinal profile grooves of the cone-punch are aligned. ge r co 1G "T I / / t f- "O" SIV Fi.Z FIG. four