RU2347891C2 - Well filter and its manufacturing method - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention is applicable to the oil and gas industry and can be used in oil and gas production. The well filter includes a support frame made from a perforated pipe and a filtering element installed on the support frame and covered with a protective housing. The housing is made from expanded metal sheets. When manufacturing the filter, the pipe is perforated and the filtering element and protective housing are installed concentrically therewith. Longitudinal plates are welded to the lateral sides of each expanded metal sheet to be welded to each other at the time of filter assembly. Circular plates are then installed onto the circular butt welds of the expanded metal sheets.

EFFECT: no burn-through of filtering elements during welding, an improved filtration capacity and liquid and gas filtration quality, and an increased filter life.

6 cl, 6 dwg

Description

The invention relates to the oil and gas industry and can be used in the extraction of liquids and gases from the bowels.

Known downhole filter, which is a steel pipe with holes on which a profiled wire is wound (Gavrilko V.M. Filters for boreholes. M., Nedra, 1985, pp. 7-9).

The main disadvantage of this design is the change in the inter-turn gaps when installing the filter in the well, the lack of protection of the filter mesh from mechanical influences during transportation and installation of the filter, which negatively affects the quality of filtration.

Known downhole filter, consisting of a supporting tubular perforated frame and a fibrous filter coating made in the form of individual plates of wire non-woven material, rigidly lapped by welding and soldering on a tubular frame of the filter against perforation holes (USSR author's certificate No. 941548, MKI 3 ЕВВ 43/08, publ. 1982).

The main disadvantage of this design is the presence of welded zones, which over time activates the processes of metal corrosion. The snug fit of the filter element to the perforated pipe significantly reduces the filtration zone, which is limited by the area of the hole in the pipe. There is no protection of the filter element from mechanical influences during transportation and installation of the filter.

A known filter design according to the patent of the Russian Federation for utility model No. 51644, consisting of a supporting frame made of perforated pipe, and a filter coating of wire nonwoven material, the filter coating is made in the form of a tubular element and is mounted on the supporting frame in the grooves of the support rings fixed by the sub. Between the filter coating and the supporting frame there is a drainage layer made in the form of a spiral of wire wound on a supporting frame. This spiral forming the drainage layer may be made of spring wire. The tubular filter element is made of wire non-woven material obtained by pressing wire (metal rubber). The metal rubber was developed at the Samara State Aerospace University (formerly Kuibyshev Aviation Institute, Appendix 1) and was used primarily for engine mount dampers. The downhole filter is protected by a casing with holes.

Known downhole filter and method of its manufacture according to the patent of the Russian Federation for utility model No. 38833, a prototype of the method and device. The filter contains a perforated pipe on which a concentric filter element is mounted and, on the outside, a protective casing made of expanded metal sheets.

In the manufacture of the filter, the pipe is perforated, a filter element is installed, then a protective casing is installed and welded with longitudinal seams. Ring joints remain open.

The disadvantage of this method and filter is the possibility of burning the filter element when welding the protective casing. The thickness of the protective casing is 0.6 ... 0.8 mm.

A disadvantage of the known filter design is the rapid clogging of the filter element with mechanical impurities. The protective casing with holes (radial gaps) does not fulfill the function of protecting the filter element from clogging of mechanical particles by large particles, performing the function of protecting the filter from mechanical damage during transportation and installation. In addition, the protective casing with radial clearances creates increased resistance when the fluid passes through the protective casing, which reduces the rate of fluid flow to the filter element and, accordingly, reduces the throughput of the downhole filter.

The objective of the invention: to prevent burning of the filter element during welding, to increase the throughput and quality of cleaning liquids and gases entering the filtration, and to increase the service life of the downhole filter.

The solution to this problem was achieved in a downhole filter, including a supporting frame made of a perforated pipe, and a filter element mounted on a supporting frame and covered with a protective casing made of expanded metal sheets, characterized in that longitudinal welded sheets are welded on both sides of each expanded metal sheet plates that are welded to each other during assembly, and the annular joints of expanded metal sheets are closed by annular plates. The longitudinal plates extend one below the other by an amount less than the length of the protrusion of the edge of the longitudinal plates beyond the edge of the expanded metal sheet. Cut-off plugs are installed in the holes of the perforated pipe. The filter element contains at least one filter and at least one drainage mesh.

The solution to this problem was achieved in a method of manufacturing a downhole filter, including perforating the pipe, installing a concentric filter element and a protective casing from expanded metal sheets with their subsequent welding along the longitudinal joints, characterized in that longitudinal ones are welded to the longitudinal sides of the expanded metal sheets before assembly plates, after the installation of expanded metal sheets and their welding, ring plates are installed on the transverse joints. The protective cover is tightened with clamps before welding.

The proposed technical solution has novelty, inventive step and industrial applicability, that is, all the criteria of a utility model.

The novelty and inventive step is confirmed by patent research, and industrial applicability is not in doubt, because An experimental batch of filters using similar technology was manufactured and successfully tested.

The essence of the utility model is illustrated in figure 1 ... 6, where:

figure 1 shows the filter

figure 2 shows a view,

figure 3 ... 5 shows a section along BB,

figure 6 shows the appearance of expanded metal sheet.

The downhole filter (figure 1) contains a frame made of perforated pipe 1, with holes "B" on the side surface, the nipple part 2, the coupling part 3, the filter element 4 mounted concentrically perforated pipe 1, and a protective casing 5 made of expanded metal sheets, with plates 6 and 7, welded in advance on both sides of expanded metal sheets 5.

The filter element 4 contains at least one filter layer 8 and at least one drainage layer 9. Figure 2 shows a variant with one filter layer 8 and two drainage layers 9. The filter layer 4 can be performed, for example, from metal rubber.

The annular joints are closed by an annular plate 10. In the openings “B”, cut-off plugs 11 can be installed (Fig. 1).

FILTER MANUFACTURING OPERATIONS

When assembling the downhole filter, the perforated pipe 1 is made first of all; for this, holes “B” are drilled in it with a diameter of 10 ... 20 mm.

If it is necessary to install shear plugs 11, then through holes are cut through holes “B” and screw shear plugs 11 are screwed into threads pre-lubricated with epoxy resin. If the shear plugs 11 are not used, for example, for injection wells, then the thread is not cut.

A filter element 4 (filter elements) is installed on the surface of the pipe 1, concentrically to it, practically over a length of 90 ... 95% of the total length of the filter. The filter element 4 can be of any design: wire, mesh, made of metal rubber, made of porous ceramic. The remaining filter length is used for threading the nipple part 2 of the mounting of the coupling part 3 and for gripping the filter with a drill bit when screwing the filter with the casing. Expanded metal sheets 5 are prepared by welding longitudinal plates 6 and 7 to two sides.

Expanded metal sheets 5 with longitudinal plates 6 and 7 bend the filter concentrically. Before welding, the protective casing is pulled together with clamps, which are removed after welding (clamps are not shown in FIGS. 1 ... 6). The longitudinal plates 6 and 7 are overlapped and welded together (FIGS. 3 and 4). On the annular joints of expanded metal sheets 5, the lamellar plates 10 are welded overlap (FIG. 2).

The annular plates 10 protect the annular joints “G” of expanded metal sheets 5 from deformation during transportation and descent of the filter into the well.

Application of the utility model allowed:

1. To prevent burning of the filter element when welding the protective casing.

2. Create a filter that has a very high throughput and has good filtering properties.

3. Ensure continuous operation of the filter without clogging.

4. To prevent clogging of the filter when it is lowered into the well.

5. Simplify the design of the filter.

6. Reduce the cost of the filter.

7. Automate and mechanize filter production.

The well filter passed bench and industrial tests and showed high filtering ability and operational reliability.

Claims (6)

1. A downhole filter, comprising a supporting frame made of a perforated pipe, and a filter element mounted on a supporting frame and closed with a protective casing made of expanded metal sheets, characterized in that longitudinal plates are welded on both sides of each expanded metal sheet, which during assembly are welded to each other, and the annular joints of expanded metal sheets are closed by annular plates. 2. The downhole filter according to claim 1 or 2, characterized in that the longitudinal plates extend one below the other by an amount shorter than the protrusion length of the edge of the longitudinal plates beyond the edge of the expanded metal sheet. 3. The downhole filter according to claim 1 or 2, characterized in that shear plugs are installed in the holes of the perforated pipe. 4. The downhole filter according to claim 1 or 2, characterized in that the filter element contains at least one filter and at least one drainage mesh. 5. A method of manufacturing a downhole filter, including perforating the pipe, installing a concentric filter element and a protective casing from expanded metal sheets with their subsequent welding along the longitudinal joints, characterized in that longitudinal plates are welded to the longitudinal sides of the expanded metal sheets before assembly, after installation of expanded metal sheets and their welding, ring plates are installed on the ring joints. 6. A method of manufacturing a downhole filter according to claim 5, characterized in that the protective casing before welding is pulled together with clamps.

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