RU2258786C1 - Borehole filter - Google Patents

Abstract

FIELD: mining industry, particularly equipment for water intake, oil and gas wells arranged within the interval of production bed made up of soft rock.

SUBSTANCE: borehole filter includes perforated body, filtering jacket made of independent sections with wire winding, packing members and end sleeves connected to perforated body. Filtering jacket is formed of easy-drillable material, for instance of polyethylene or propylene. End sleeves are connected with perforated body by means of shear pin. Packing members of filtering jacket are made as perforated tubes connected to end sleeves. Perforated body has solid outer surface and provided with blind tube having double connection coupling including outer member having tool-joint thread hand orienting in the same direction as that of perforated base, and inner member having opposite tool-joint thread hand.

EFFECT: improved maintainability and increased efficiency of well repair.

3 cl, 1 dwg

Description

The invention relates to the field of mining and can be used for equipment of water, oil, gas wells in the interval of the reservoir, composed of weakly cemented rocks.

Known downhole filter, made in the form of an annular or spiral wire-shaped elements laid on a frame with alternating radial grooves and protrusions with the formation of expanding channels in the direction of fluid movement through the filter [1].

A disadvantage of the known filter is that upon contact with the formation rock during the filtration process, particles of the productive formation become wedged in the holes and compact, which leads to premature clogging and failure of the filter.

Also known is a downhole filter, including a perforated frame with support rods and turns of profiled wire [2].

A disadvantage of the known filter is the low corrosion resistance, complexity and inefficiency of well repair if necessary.

The closest analogue is a downhole filter, which includes a perforated frame, a filter jacket in the form of a set of autonomous sections with a wire winding, gasket elements and ring sleeves connected to a perforated frame [3].

The known filter has a selective ability and provides repair of individual parts of the filter using, for example, acid and other reagents. However, removing the filter from the well, if necessary, an overhaul is extremely complicated due to the fact that the filter components are welded together by welding.

The objective of the present invention is to ensure the maintainability of the filter and increase the efficiency of well repair.

The problem is solved in that in the downhole filter, including a perforated frame, a filter jacket in the form of a set of autonomous sections with a wire winding, gasket elements and end sleeves connected to a perforated frame, the filter jacket is made of easily drilled material, for example, polyethylene or propylene and the end sleeves are connected to the perforated frame by means of shear pins.

Also, the gasket elements of the filter jacket are made in the form of perforated pipes connected to the end sleeves.

In addition, the perforated frame is made with a smooth outer surface and is provided with a blind pipe made with a double coupling, the external one, the tension of the locking thread of which coincides with the direction of the locking thread of the perforated frame, and the internal, the direction of the locking thread of which is opposite.

The invention is illustrated in the drawing.

The filter includes a perforated frame 1, a filter jacket 2, made in the form of autonomous sections with a wire winding 3, end sleeves 4, 5 and gasket elements in the form of perforated pipes 6, connected with end sleeves 4, 5 by means of a threaded connection. The end sleeves are connected to the perforated frame by means of shear pins 7. The perforated frame 1 is made with a smooth outer surface and provided with a blind pipe 8 made with a double coupling made of corrosion-resistant material, an internal coupling 9 made with a locking thread (left), direction which is opposite to the direction of the lock thread of the perforated frame (right), and the external coupling 10, the direction of the lock thread of which coincides with the direction of the lock thread would have a perforated frame.

Mounting grooves 11 are made on the filter jacket 2 and the locking part of the perforated frame.

Depending on the length, the filter may consist of several perforated frames 1 with filter shirts 2.

The downhole filter is lowered into the borehole on a drill string equipped with a sub in the lower part, the nipple locking thread (left) coincides with the locking thread of the internal coupling 9, and after the equipment is equipped with gravel packing, the drill pipe string is removed.

If it is necessary to remove the filter from the well, the drill pipe string is lowered with an adapter, the tool thread of which coincides with the tool thread of the external coupler 10, and after the connection, the drill string continues to rotate, the shear pins 7 are cut off and the perforated frames are freed from the autonomous sections of the filter jacket 2 and can be removed from the well with little traction.

The remaining elements of the filter jacket remaining in the well are drilled and removed by washing and the well is equipped with a new filter, and the extracted filter components after necessary repair and assembly of the fastening of the new sections of the filter jacket to the perforated frame are intended for reuse.

Sources of information

1. USSR author's certificate No. 1213179, Е 21 В, 43/08, 02/23/86.

2. USSR author's certificate No. 1712591, Е 21 В, 43/08, 02/15/92.

3. RF patent No. 2074313, Е 21 В 43/08, 02.27.97.

Claims (3)

1. A downhole filter, including a perforated frame, a filter jacket in the form of autonomous sections with a wire winding, gasket elements and end sleeves connected to a perforated frame, characterized in that the filter jacket is made of easily drilled material, for example, polyethylene or propylene, and the connection with the perforated frame is made by shear pins. 2. The filter according to claim 1, characterized in that the cushioning elements of the filter jacket are made in the form of perforated pipes connected to the end sleeves. 3. The filter according to claim 1, characterized in that the perforated frame is made with a smooth outer surface and is provided with a blind pipe made with a double coupling, the outer one, the direction of the locking thread of which coincides with the direction of the locking thread of the perforated frame, and the inner, the direction of the locking thread which is the opposite.