RU2378496C1 - Well filters string and method of well filters string assembly - Google Patents

Abstract

FIELD: oil-and gas production.

SUBSTANCE: group of inventions related to oil- and gas production and can be used for water, oil and gas production form subsoil. Well filters string includes filters, which have bearing frame, made of perforated pipe, and filtering element. Filters perforation has variable porosity along its height, increasing to its bottom part due to perforation holes diametre increase or due to quantity of holes increase. Before assembling, well filters marked in relation to their porosity and install according to porosity value decrease form bottom to top.

EFFECT: well filters string discharge capacity increase during operation in reservoirs with variable pressure.

10 cl, 9 dwg

Description

The invention relates to the oil and gas industry and can be used in the extraction of water, oil and gas from the subsoil.

Known downhole filter, which is a steel pipe with holes on which a profiled wire is wound (Gavrilko V.M. Filters of boreholes. M .: Nedra, 1985, p.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 nonwoven material, rigidly lapped by welding and soldering on a tubular frame of the filter against perforations (AS USSR No. 941548, MKI 3 Е21В 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 non-woven 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). Metal rubber was developed at the Samara State Aerospace University (formerly Kuibyshev Aviation Institute) and was used primarily for engine mount dampers. The downhole filter is protected by a casing with holes.

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.

Known downhole well filters according to US patent No. 4771829. These filters contain a perforated pipe and a wire wound in a spiral with a gap between them. The wire is wound on the longitudinal elements.

Disadvantages: a large tolerance on the width of the gap between the rows of wires (up to 40%) leads to the fact that the filter passes particles 40% more than declared, and, in addition, if the filter is transported or lowered, there is a local increase in the gap between the rows of wires by several times, respectively, larger abrasive particles penetrate with the produced product behind the filter, which causes wear on the ground equipment: pump and valves.

Known column well filters according to the patent of Russian Federation No. 2222692. This column contains successively installed downhole filters.

The disadvantage is overflow of the extracted product in the annulus.

This disadvantage is eliminated in the layout of the downhole filters according to the patent of the Russian Federation No. 2260679, prototype. The column of downhole filters contains several downhole filters screwed together, of the same design and an elastic O-ring mounted on one of the filters.

The objective of the invention is to increase the throughput of the column of downhole filters.

The solution of these problems was achieved in the column of downhole filters, including filters having a supporting frame made of a perforated pipe and a filter element, characterized in that the perforation of the filters has a variable downhole height increasing to its lower part. The downhole filter can increase by increasing the diameter of the perforation holes. The filter downhole can increase due to the increase in the number of perforation holes. All downhole filters are marked for proper installation. For all filters, the filter element can be made in the form of at least one filter mesh and at least one drainage mesh. A protective perforated casing can be installed concentrically over the filter element. A protective perforated casing may be made of their expanded metal sheet. The filter element can be made in the form of a wire wound with a gap on the longitudinal stringers installed along the perforated pipe. The filter element of all filters can be made of pressed wire, or of porous metal, or of porous ceramics.

The solution to these problems has been achieved in a method for assembling a column of downhole filters, which involves sequentially screwing up several downhole filters, characterized in that prior to assembly, the downhole filters are marked depending on their downscaling and installed with decreasing downscaling from the bottom up. Well filters can be installed in groups with reduced duty cycle from bottom to top, and filters with the same duty cycle are included in the group.

The proposed technical solution has novelty, inventive step and industrial applicability, i.e. all the criteria of the invention.

The invention is illustrated in the drawings, where

figure 1 presents the column of well filters in the Assembly,

figure 2 - column well filters with filter groups,

figure 3 shows diagrams of changes in the diameter of the perforation holes and the number of holes for filters in the column,

figure 4 shows the first embodiment of the filter element, view A,

figure 5 is a second variant of the filter element, type A,

figure 6 is a third variant of the filter element, type A,

Fig.7 is a fourth variant of the filter element, type A,

in Fig.8 is a fifth embodiment of a filter element, view A,

figure 9 is a sixth embodiment of the filter element, type A.

The column of downhole filters (FIGS. 1 and 2) contains several filters 1 (or filter groups) screwed together in series, each of which has a supporting frame made of perforated pipe 2 with holes B and a filter element 3. In holes B can be installed plugs cut off before operation (not shown in FIGS. 1 ... 9). For proper installation, all downhole filters are labeled 4 on the outer surface, such as a filter number or filter group number. A shoe 5 may be installed in front of the lower filter 1.

Filters 1 or filter groups have different duty cycle, while it decreases from bottom to top. Changing the downhole along the length of the column of downhole filters can be performed continuously or discretely, i.e. filters with the same duty cycle are grouped and installed accordingly so that their duty cycle decreases from bottom to top. A change in the filter duty ratio of filters 1 was achieved either by changing the diameter of the perforation holes B - pos. 6 in Fig. 3, or by changing the number of holes per unit surface - pos. 7.

The filter element 3 can be made of any design. For example, there are six options for the filter element 3 (figure 4 ... 9).

Figure 4 shows a filter element containing a filter screen 8 and a drainage screen 9, figure 5 the same filter element 3 has a perforated protective casing 10, and figure 6 is a perforated protective casing from expanded metal sheet 11. In Fig. .7 shows a filter element made of wire 12 wound on the longitudinal elements 13 in a spiral. In Fig.8 shows a filter element 3 made of porous metal 14, and Fig.9 is a filter element made of porous ceramic 15.

Before operation, the first downhole filter 1 (or the first group of filters) is assembled with the second downhole filter 1 or a group of filters with the same duty cycle, but less than for the first downhole filter 1 (first filter group). The column of downhole filters is lowered into the well for oil or gas production.

The application of the invention allowed the following.

1. To increase the throughput of downhole filters.

2. Create a column of downhole filters that has a very high throughput and has good filtering properties.

3. Ensure long-term operation of the filter without clogging the filter element.

4. Reduce the cost of filters.

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

Claims (10)

1. The column of downhole filters, including filters having a supporting frame made of a perforated pipe, and a filter element, characterized in that the perforation of the filters has a variable porosity in height, increasing to its lower part by increasing the diameter of the perforation holes or by increasing the number perforation holes, while all downhole filters are marked for proper installation. 2. The column of well filters according to claim 1, characterized in that for all filters the filter element is made in the form of at least one filter screen and at least one drainage screen. 3. The column of downhole filters according to claim 2, characterized in that a protective perforated casing is mounted concentrically above the filter element. 4. The column of downhole filters according to claim 3, characterized in that the protective perforated casing is made of expanded metal sheet. 5. The column of downhole filters according to claim 1, characterized in that the filter element is made in the form of a wire wound with a gap on the longitudinal stringers installed along the perforated pipe. 6. The column of downhole filters according to claim 1, characterized in that the filter element of all filters is made of pressed wire. 7. The column of well filters according to claim 1, characterized in that the filter element of all filters is made of porous metal. 8. The column of downhole filters according to claim 1, characterized in that the filter element of all filters is made of porous ceramic. 9. A method of assembling a column of downhole filters, comprising sequentially screwing up several downhole filters, characterized in that prior to assembly, the downhole filters are marked depending on their boreholeness and installed with decreasing boreholeness from the bottom up. 10. The method according to claim 9, characterized in that the downhole filters are installed in groups with a decrease in the duty cycle from bottom to top, and the group includes filters with the same duty cycle.

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