RU2435941C1 - Well filter - Google Patents

Abstract

FIELD: gas and oil production. ^ SUBSTANCE: well filter consists of hollow case with radial channels closed with hollow sheared caps projecting inside case, of lengthwise webbing-stringers outside case, of wire winding in stringers, and of circular support bandages rigidly connecting end surfaces of stringers with wire winding. One part of the hollow shear caps is made of flexible deformed material in form of a cylinder with external and internal conic fringes relative to the case and non-deformed material in kind of a bush. Length of the bush exceeds thickness of a wall of the case and is positioned inside the cylinder with the fringes with force facilitating radial deformation of material of the cylinder at 3-7 % of its axial deformation in a working position of the device. ^ EFFECT: raised reliability of well filter operation. ^ 5 cl, 2 dwg

Description

The invention relates to the oil and gas industry and can be used in the operation of wells.

A well-known filter consisting of a housing with circulation openings, a filter assembly mounted on the housing, an adapter and a housing forming an annular chamber with an adapter and the housing, in which a sleeve with thrust elements is placed (see, for example, SU 2102585).

A disadvantage of the known device is the design complexity - the need to use a special nozzle with a filter to install a control tool to bring the filter into position.

A well-known filter including a hollow casing with radial openings blocked by hollow shear plugs made with an outer annular collar and equipped with sealing rings, and a filter assembly located outside the casing and forming an annular cavity with it, shear plugs are fixed in radial holes by embossing ( see, for example, RU 2182960).

A disadvantage of the known device is its low sealing ability, due to insufficiently reliable fastening of plugs in the radial holes of the housing. As, for example, if it becomes necessary to flush the column equipped with filters, when it is lowered into the well, it is likely that the plugs will be squeezed out into the annulus, which will lead to an emergency, for example, sticking to the column.

The technical result of the invention is to increase the reliability of the downhole filter.

The required technical result is achieved by the fact that the downhole filter includes a hollow body with radial openings covered by hollow shear caps protruding into the body, longitudinal stiffeners - stringers placed outside the body, wire winding placed on the stringers, and ring support bands that rigidly fix the end the surface of the stringers with wire winding, while the hollow shear caps are made one part of an elastic deformable material in the form of a cylinder with an external and internal enney conical rims in relation to the housing and non-deformable material in the form of a sleeve longer than the thickness of the wall of the casing, placed inside the cylinder with rims with a force providing the radial deformation of the cylinder material in 3-7% of the axial deformation in the working position of the device.

Besides:

as an elastic deformable material, rigid rubber or polymeric material is adopted;

steel or aluminum is accepted as a non-deformable material;

caprolon, or fluoroplast, or polyurethane is adopted as the polymeric material;

rubber hardness is accepted in the range of 70-90 Shore units.

Figure 1 shows a General view of the device, figure 2 is a section of this device on a shear cap.

The device includes a hollow body 1 with radial holes 2, overlapped by hollow shear caps 3, protruding into the hollow body 1. Outside the body 1, longitudinal stiffeners - stringers 4. are placed on the stringers 4. Wire winding 5. The end surfaces of the stringers 4 with wire winding 5 on annular supporting bandages are rigidly fixed to them 6. Hollow shear caps 3 are made of one part of an elastic deformable material in the form of a cylinder 7 with external 8 and internal conical 9 rims in relation to the housing 1 and non-deformable material in the form of a sleeve 10 with a length exceeding the wall thickness of the housing 1. The sleeve 10 is placed inside the cylinder 7 with rims with a force that ensures its radial deformation of 3-7% of its axial deformation in the working position of the device.

In addition, figure 1, 2 shows the annular pockets 11 under the outer rim 8 of the cylinder 7. Between the housing 1 and the stringers 4 with wire winding 5 shows the annular cavity 12. On the outer surface of the cylinder 7 is made an annular groove 13 to provide for cutting off the caps 3 in given section. The sleeve 10 is placed inside the cylinder 7 - its cavity 14.

The placement of the sleeve 10 inside the cylinder 7 with a predetermined force - the initial deformation force, provides in the future, when creating a working load, its uniform distribution over the cylinder body and, as a result, the bearing capacity - stability of the hollow shear caps at a given internal pressure. The sealing ability of the hollow shear caps also contributes to the fact that the deformable part of the hollow shear caps exceeds the sleeve length by 5-15% in length. As a result, with excessive internal pressure, the inner rim, with its conical shape, acquires great potential for radial deformation and sealing ability together with the entire body of the deformable material. The necessary ratios of the length of the deformable part of the hollow shear caps and bushings, as well as the necessary range of forces causing radial deformation of the cylinder, were obtained experimentally.

The device operates as follows.

Before the descent of the downhole filter into the well, it is tested with an internal pressure of 10 MPa. After installing the device in a predetermined interval, the well is flushed. Moreover, any working pressure in the casing, including in the installation zone of the downhole filter, is provided by the design of this filter. Radial holes 2 are reliably covered by hollow shear caps 3. After performing all necessary operations in the well, a special head cap (not shown) is lowered into the casing string in the casing string. When the headgear interacts with the hollow shear caps 3 protruding into the body, they are destroyed. As a result, the well fluid flows through the well filter into the casing at a given point in time.

Claims (5)

1. A downhole filter, including a hollow body with radial holes covered by hollow shear caps protruding into the body, longitudinal stiffeners - stringers placed on the outside of the body, wire winding placed on the stringers, and ring support bands that rigidly fix the end surfaces of the stringers with wire winding, while the hollow shear caps are made in one part of the elastic deformable material in the form of a cylinder with external and internal conical rims in relation to the body deformable material is a sleeve longer than the body wall thickness, placed inside the cylinder with rims with a force providing the radial deformation of the cylinder material in 3-7% of the axial deformation in the working position of the device. 2. The downhole filter according to claim 1, characterized in that hard rubber or polymeric material is adopted as an elastic deformable material. 3. The downhole filter according to claim 1, characterized in that steel or aluminum is adopted as the non-deformable material. 4. The downhole filter according to claim 2, characterized in that caprolon or fluoroplast or polyurethane is adopted as the polymeric material. 5. The downhole filter according to claim 1, characterized in that the rubber hardness is adopted in the range of 70-90 Shore units.

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