SU1758207A1 - Device for formation isolation - Google Patents

Abstract

Use: for separation of formations in a well, mainly during casing cementing. SUMMARY OF THE INVENTION: Improving packer reliability by increasing packer rate This is achieved by installing a shell and an additional sealing cuff located under the expanding cone, made of material M, the stiffness of which is greater than the material of the main sealing cuff, and adjacent to the latter along the conical surface with a cone angle smaller than the angle end surface of the expansion cone, and the shell is made of the same material as the expansion cone. 3 il.

Description

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The invention relates to the oil and gas industry, in particular to devices for separating formations in a well, mainly in casing cementing.

A device for step and sleeve cementing is known, comprising a housing with an axial channel and radial holes, a sealing element of the packer mounted on the housing and a pusher coupled to the sealing element of the packer along a conical surface.

A disadvantage of this device is the low packing factor and, therefore, insufficiently reliable operation in the cavernous wellbore.

A drillable packer is also known, comprising a barrel with an axial bore and radial holes, a housing placed concentrically with the barrel and forming with it an annular cavity, a stop mounted on the barrel, a sealing cuff and an expandable cone with a conical end surface in the lower part located in the annular cavity between barrel and casing.

 A disadvantage of this device is the low packing factor, due to the design of the packer element that opens under the action of an expanding cone, which, when it moves downward, stretches the sealing element, which is inserted under it. Thus, the maximum diameter of the sealing element in the open position is limited by the difference between the outer diameter of the casing and the barrel or the thickness of the pack / yarn of the element in an unopened position. However, behind-the-scenes packers included in

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casing composition, have certain limitations on the outer diameter of the casing and the inner diameter of the barrel. The outer diameter of the casing should not exceed a certain critical value, which ensures the free, without landings, the casing in the well. The inner diameter of the barrel should not narrow the flow area of the column, i.e. it cannot be less than the internal diameter of the casing pipe. Thus, in a known device, the difference between the outer diameters of the barrel and the housing can be increased only up to a certain critical value, which limits the packing coefficient.

The aim of the invention is to improve the reliability of packing by increasing the packing factor

This goal is achieved by the fact that the device for segregation of layers, comprising a barrel with an axial channel and radial holes and a housing placed concentrically to the barrel and forming an annular cavity with the barrel, as well as a stop mounted on the barrel, a sealing collar and an expanding cone with a conical end the surface in the lower part, located in the annular cavity, between the barrel and the casing, is provided with a split shell and an additional sealing mazheta located about the annular cavity under the expansion cone made of a material whose rigidity is greater than the strength of the material of the main sealing cuff and adjoined to the latter over a conical surface with a cone angle smaller than the angle of the end surface of the expanding cone, and the shell is made of the same material as the expanding cone.

FIG. 1 shows the proposed device in the transport position; in fig. 2 - the same, in the position when the additional sealing cuff is out of the annular cavity; in fig. 3 - the same, in the position with the packer element maximally opened.

A device for separating formations in a well comprises a barrel 1 with an axial channel and radial holes 2, and a casing 3 placed concentrically with the barrel and forming an annular cavity with it. A 10 m stop cuff 9 is also installed on the barrel. In the annular cavity between the barrel 1 and the casing 3 there is an expanding cone 6 with a conical end surface in the lower part and an additional sealing cuff 7. The expanding cone 6 is held in its initial position with shear pins 5. On the inner surface the casing has a spring retainer 4, designed

to prevent the pressure cone b from returning to the initial position after the removal of the packer force

Additional sealing cuff 7 is made of material, stiffness

0 which has more rigidity of the sealing cuff 9 Sealing cuffs 7 and 9 are coupled to each other along a conical surface with a cone angle smaller than the angle of the end surface of the expanding cone

5 b. A thin shell 8 is installed between the sealing cuffs; it is made of the same material as the expansion cone b

The device works as follows.

The device is lowered into the well as part of the casing. At the end of the flushing of the cement slurry in the casing, pressure is increased, which

5 radial holes 2 in the barrel 1 acts on the expansion cone b. The pressure is increased until the force arising from the action of this pressure on the expansion cone b is in the initial position. After cutting

The 0 pins 5 of the expanding cone 6 move downwards with the additional sealing lip 7, which fits under the sealing lip 9, as a result of which the latter increases in diameter, partially overlapping the borehole (Fig. 2). Since the angle of the conical surface along which the sealing Cuffs, smaller angle of the end surface of the expanding cone, then the strength of the friction on

0, the area of the coupling of cuffs is less than the friction force in the area between the expanding cone 6 and the additional sealing lip 7. The use of a split shell 8 made of the same material as

5 and an expanding cone b, provides comparable friction conditions when an expanding cone b enters the additional cuff 7 and the last one under the main sealing cuff 9. When the expanding cone b and the split sheath 8 are made of metal, and the sealing cuffs 7 and 9 are made of rubber in both In cases of friction is carried out in a metal-rubber pair. Thus, the presence of a split metal nut.

5 and making it from the same material as the expansion cone, as well as a certain ratio of the angle of the conical interface of the sealing lip and the angle of the end surface of the expansion cone, create the conditions for the initial opening of the main sealing lip 9, preventing the additional sealing lip 7 from opening until a certain time .

After the additional sealing cuff comes out of the annular cavity between the barrel and the casing, and when the expansion cone b is moved downwards under the action of increasing force, the latter enters the additional sealing cuff 7, extends it together with the sealing cuff 9 and ensures complete overlapping of the annular gap in the wellbore, i.e. full packer (fig. 3). The expansion cone is held in its final position by the spring retainer A.

Thus, the reliability of the packer operation is increased by providing a higher packer coefficient with a limited outer diameter of the device and a limited thickness of the sealing cuffs.

Claims (1)

Apparatus of the Invention A device for separating formations in a borehole, comprising a barrel with an axial channel and radial bores, a housing placed concentrically with the barrel and forming with it an annular cavity, an emphasis mounted on the trunk, an sealing sleeve and an expanding cone with a conical end surface in the lower part, located in the annular cavity between the barrel and the casing, characterized in that, in order to increase the packer reliability by increasing the packer coefficient, it is provided with a split shell and the additional A sealing cuff located in the annular cavity is provided with an expanding cone made of a material whose rigidity is greater than the material of the main sealing cuff and which is adjacent to the latter along a conical surface with a cone angle smaller than the angle of the end surface of the expanding cone, and the shell is made of the same material as the expansion cone, /about ten -at / / f I YU