RU228790U1 - Well filter - Google Patents

Abstract

The utility model relates to a technique for extracting a product from wells, namely to well filters for filtering a product extracted from oil, water and gas wells. The device includes a perforated pipe and filter elements installed thereon between the upper and lower couplings with a gap that acts as an internal drainage layer. The filter elements are made in the form of metal meshes with a decreasing mesh cell size from the outside to the inside. A perforated branch pipe is installed on the outside of the outer filter element between the upper and lower couplings, which is telescopically secured relative to the perforated pipe with screws that coaxially fix the perforation holes of the perforated pipe and the perforated branch pipe. A well fluid bypass unit is connected to the lower coupling from below, consisting of a branch pipe with radial channels, a two-stage piston and a plug screwed onto the lower end of the branch pipe. The upper stage of the piston is provided with longitudinal through channels and is hermetically installed in the branch pipe opposite its radial channels with the possibility of axial movement, blocking them. From below, the piston with the lower stage rests against a plug equipped with a central hole at the lower end. The longitudinal through channels of the upper stage have the possibility of hydraulic communication with the radial channels of the branch pipe in the upper position of the piston. The quality of purification of the formation fluid is increased. 4 fig.

Description

The utility model relates to a technique for extracting a product from wells, namely to well filters for filtering a product extracted from oil, water and gas wells.

A well filter is known (patent RU No. 2751186, IPC 8 E21B 43/08, published on 12.07.2021), including support rods and turns of profiled wire that form horizontal slots, while the wire in cross-section is made of a triangular shape with one upper flat edge on the outer side of the filter and with two lateral lower edges on the inner side of the filter, while both lateral lower edges are made symmetrical to each other, rounded at the same radius and made concave towards the inner side of the wire cross-section.

The disadvantages of this well filter are:

- firstly, the low quality of purification (filtration) of formation fluid from contaminants (filtrate) in the form of slag, sand, dirt, shavings due to the impossibility of separating the filtrate in stages depending on the fraction (granulometric composition);

- secondly, the parts are technologically complex to manufacture (support rods, profiled wire of a triangular shape with one upper flat edge on the outside of the filter and two lateral lower edges on the inside of the filter), which increases the cost of the finished product; in addition, the filter assembly must be carried out in specialized workshops (laying turns of profiled wiring);

- thirdly, during the operation of the well, the horizontal slots of the filter become clogged with filtrate (chips, dirt, slag), due to which the flow rate of the extracted products of the well decreases, and this requires the extraction of the well filter together with the entire downhole assembly from the well, cleaning of the horizontal slots of the filter, i.e. the filter does not self-clean during operation, and then the well filter with the downhole assembly is lowered into the well again, and for this it is necessary to involve a team of underground well repair, which leads to additional material and financial costs.

The closest in technical essence is a dismountable well filter (patent RU No. 2348795, IPC 8 E21B 43/08, published 10.03.2009), containing a supporting frame made of a perforated pipe and filter elements installed on it between the upper and lower couplings, made in housings, wherein each filter element is made of wire material pressed into perforated housings, which are installed on the perforated pipe with a gap that acts as an internal drainage layer, wherein adjacent housings partially enter each other due to the fact that one side of the housing is made with an annular depression, the outer diameter of which is equal to or less than the inner diameter of the other side of the housing, wherein a part of the length of the housing equal to the length of the depression is not filled with a filter element, the housing is made with an annular bottom, a wire laid in a spiral is installed in the internal drainage layer, each filter element is made multilayer, and the filter layers are separated from each other by intermediate drainage layers made of wire wound in a spiral, and the direction of winding of the wire in adjacent drainage layers differs in direction, wherein the wire of the drainage layer is made of a larger diameter than the wire of the filter element, and the diameter of the wire of the drainage layers increases in the direction from the protective casing to the side surface of the pipe, wherein the housings are made of a sheet with holes or of expanded metal sheet, and the upper and lower rings are welded to the expanded metal sheet, and the annular depression is made on the lower ring.

The disadvantages of this well filter are:

- firstly, low quality of purification (filtration) of formation fluid from contaminants (filtrate) in the form of slag, sand, dirt, shavings due to the impossibility of separating the filtrate in stages depending on the fraction (granulometric composition);

- secondly, the parts are technologically complex to manufacture (each filter element is made of wire material pressed into perforated housings), which increases the cost of the finished product; in addition, the filter assembly must be carried out in specialized workshops (laying wire coils in a spiral, and each filter element is made multi-layered);

- thirdly, during the operation of the well, the filter elements become clogged with the cleaned filtrate (chips, dirt, slag), due to which the flow rate of the extracted products of the well decreases, and this requires the extraction of the well filter together with the entire downhole assembly from the well, cleaning of the filter elements of the filter, i.e. the filter does not self-clean during operation, and then the well filter with the downhole assembly is lowered into the well again, and for this it is necessary to involve a team of underground well repair, which leads to additional material and financial costs.

The technical result of the utility model is to improve the quality of purification (filtration) of formation fluid from contaminants (filtrate).

The technical result is achieved by a well filter, including a perforated pipe and filter elements installed on the perforated pipe between the upper and lower couplings, wherein the filter elements are installed on the perforated pipe with a gap that acts as an internal drainage layer.

What is new is that the filter elements are made in the form of metal meshes with a decreasing mesh cell size from the outside to the inside, and a perforated pipe is installed on the outside of the outer filter element between the upper and lower couplings, which is secured relative to the perforated pipe with screws that coaxially fix the perforation holes of the perforated pipe and the perforated pipe, and the perforated holes are made in the form of vertical through windows, and a well fluid bypass unit is connected to the lower coupling from below, consisting of a pipe with radial channels, a two-stage piston and a plug screwed onto the lower end of the pipe, and the upper stage of the two-stage piston is equipped with longitudinal through channels and is hermetically sealed with the possibility of axial movement in the pipe opposite its radial channels, blocking them, and from below the two-stage piston with the lower stage rests against the plug equipped with a central hole at the lower end, and the longitudinal through channels of the upper stage of the two-stage piston have the possibility of hydraulic communication with the radial channels of the branch pipe in the upper position of the two-stage piston.

Fig. 1 shows the proposed well filter in longitudinal section.

Fig. 2 shows view A of the metal mesh of the well filter.

Fig. 3 shows section B-B of the well filter.

Fig. 4 shows the proposed well filter in longitudinal section during the process of cleaning from filtrate.

The well filter consists of a perforated pipe 1 (see Figs. 1, 3, 4) and filter elements 4', 4''...4 ⁿ (see Figs. 1-4) installed on the perforated pipe 1 between the upper 2 (see Figs. 1, 4) and lower 3 couplings. The filter elements 4', 4''...4 ⁿ are installed on the perforated pipe 1 with a gap that serves as an internal drainage layer 5', 5''...5 ⁿ (see Figs. 1, 3, 4).

Filter elements 4', 4''…4'', installed on a perforated pipe 1 with a gap on drainage layers 5', 5''…5 ⁿ .

The filter elements 4', 4''...4 ⁿ (see Figs. 1, 2, 3, 4) are made in the form of metal meshes 4', 4''...4 ⁿ with decreasing cell size h _n > h ₁ of the filter mesh from the outside inward. A perforated pipe 6 (Fig. 1, 3, 4) is installed on the outside of the outer filter element 4 ⁿ between the upper 2 and lower 3 couplings, which is secured relative to the perforated pipe by screws 7 (Fig. 1, 4) (top and bottom), which coaxially fix the perforation holes 8' (Fig. 1, 2, 4) and 8'' (Fig. 1, 4), respectively, of the perforated pipe 1 and the perforated pipe 6. The perforated holes 8' and 8'' are made in the form of vertical through windows.

In addition, the perforated pipe 6 protects the filter elements 4 from mechanical damage during the process of lowering the well filter into the well.

At the bottom, a bypass unit 9 (Fig. 1, 4) of well fluid is connected to the lower coupling 3, consisting of a branch pipe 10 with radial channels 11, a two-stage piston 12 and a plug 13 screwed onto the lower end of the branch pipe 10.

The upper stage of the two-stage piston 12 is provided with longitudinal through channels 14 and is hermetically sealed with the possibility of axial movement over a length of L in the branch pipe 10 opposite its radial channels 11, blocking them.

From below, the two-stage piston 12 is resting with its lower stage against the plug 13, which is equipped with a central hole 15 at the lower end.

The longitudinal through channels 14 of the upper stage of the two-stage piston 12 have the possibility of hydraulic communication with the radial channels 11 of the branch pipe 10 in the upper position of the two-stage piston 12.

The well filter works as follows.

Depending on the operating conditions of the productive formation, namely the flow rate, the fractional composition of mechanical particles, viscosity, water cut, etc., the sizes of the cells of the metal mesh 4', 4''…4 ⁿ are selected (see Figs. 1 and 2). For example, four metal meshes 4', 4'', 4''', 4'''' with the sizes of the metal cells that satisfy the above condition:

h _n >h ₁

h ₄ >h ₃ >h ₂ >h ₁ =2×2>1.5×1.5>1.0×1.0>0.5×0.5

where h ₄ = 2.0×2.0 is the cell size of the metal mesh 4'''', mm;

h ₃ = 1.5×1.5 cell size of metal mesh 4''', mm;

h ₂ = 1.0×1.0 cell size of metal mesh 4'', mm;

h ₁ = 0.5×0.5 cell size of metal mesh 4', mm;

The upper and lower ends of the metal meshes 4', 4'', 4''', 4'''' are pressed (shown schematically in Fig. 1 and 3) into the ends of the upper 2 and lower 3 couplings, respectively. Between the metal meshes 4', 4'', 4''', 4'''' there are gaps for the drainage layers 5', 5'', 5''', wherein the drainage layers 5', 5'', 5''' are connected from below through radial channels 16 (Fig. 1, 3, 4) made in the lower coupling 3 and communicate with the well. The radial channels 16 are made in the coupling, for example in the amount of 2 pieces and are located at an angle of 180° with respect to each other.

The well filter assembly, as shown in Fig. 1, installed as part of the downhole equipment assembly, for example, below the deep-well sucker rod pump (not shown in Figs. 1-4), is lowered into the well and installed in a given interval of the productive formation. The wellhead equipment is installed and the well is put into operation. In this case, the formation fluid through the perforated holes made in the form of vertical through windows 8'' of the perforated pipe 6 gets onto the cells h ₄ of the metal mesh 4'''', where the formation fluid is filtered from contaminants with a fractional composition of more than 2 mm. Then, the formation fluid being cleaned, having passed through the metal mesh 4'''', gets through the drainage layer 5''' onto the cells h ₃ of the metal mesh 4''', where the formation fluid is filtered from contaminants with a fractional composition of more than 1.5 mm. Contaminants larger than 1.5 mm flow down the drainage layer 5''' and through the radial channels 16 made in the lower coupling 3, flow into the well.

Then, the purified formation fluid that has passed through the metal mesh 4''' passes through the drainage layer 5'' and enters the cells h ₂ of the metal mesh 4'', where the formation fluid is filtered from contaminants with a fractional composition of more than 1.0 mm. Contaminants larger than 1.0 mm flow down the drainage layer 5'' and through the radial channels 16 made in the lower coupling 3, flow into the well.

Then the purified formation fluid, having passed through the metal mesh 4'', through the drainage layer 5' gets onto the cells h ₁ of the metal mesh 4', where the formation fluid is filtered from contaminants with a fractional composition of more than 0.5 mm. Contaminants with a size of more than 0.5 mm flow down the drainage layer 5' and through the radial channels 16 made in the lower coupling 3, flow into the well, and the purified formation fluid through the perforated holes made in the form of vertical through windows 8' of the perforated pipe 1, enters the perforated pipe 1, from where it enters the axial channel of the elevator pipe string (not shown in Figs. 1-4).

The quality of purification of formation fluid from contaminants (filtrate) in the form of slag, sand, dirt, and chips is improved due to step-by-step purification with drainage of filtered particles back into the well, which settle at the well bottom.

During the operation of the well filter, the cells h ₁ , h ₂ , h ₃ , h ₄ , the corresponding metal meshes 4', 4'', 4''', 4'''' become clogged with filtrate (chips, slag, dirt, sand), thereby reducing the throughput capacity of the well filter and reducing the flow rate of the well's extracted products, which is monitored at the wellhead.

To clean the cells h ₁ , h ₂ , h ₃ , h ₄ , the corresponding metal meshes 4', 4'', 4''', 4'''' of the well filter and restore the previous flow rate of the product, the well is stopped. The flushing fluid is pumped into the annular space of the well between the production string and the column of lifting pipes (not shown in Figures 1-4), wherein the flushing fluid from the annular space of the well through the central opening 15 of the plug 13, since the radial channels 11 of the branch pipe 10 are hermetically dug by the two-stage piston 12 (see Fig. 1), enters the sub-piston space 17 (see Fig. 4) under the lower stage of the two-stage piston 12, causing a limited axial movement of the latter upward by a length - L relative to the branch pipe 10 of the bypass unit 9. As a result of the upward movement, the two-stage piston 12 occupies the upper position (see Fig. 4) and the longitudinal through channels 14 of the upper stage of the two-stage piston 12 are hydraulically connected with the radial channels 11 of the branch pipe 10.

At this point, the flushing fluid, the injection of which continues, enters through the above-mentioned channels from the annular space of the well into the perforated pipe 1, while the flushing fluid cleans the cells h ₁ , h ₂ , h ₃ , h ₄ , the corresponding metal meshes 4 ', 4 '', 4 ''', 4 '''' from filtrate build-up (chips, dirt, sludge, sand).

The pumping of the flushing fluid continues for a certain time, during which the filtrate is removed. After which the pumping of the flushing fluid is stopped and the two-stage piston 12, under its own weight, descends downwards relative to the branch pipe and rests against the plug 13, taking its initial position (see Fig. 1), while the two-stage piston 12 hermetically closes the radial channels 11 of the branch pipe 10.

Then the sucker rod pump is restarted and the well continues to be used.

The proposed well filter allows to improve the quality of purification of formation fluid from contaminants (filtrate).

Claims (1)

A well filter comprising a perforated pipe and filter elements mounted on the perforated pipe between upper and lower couplings, wherein the filter elements are mounted on the perforated pipe with a gap that acts as an internal drainage layer, characterized in that the filter elements are made in the form of metal meshes with a decreasing mesh cell size from the outside to the inside, wherein a perforated branch pipe is mounted on the outside of the outer filter element between the upper and lower couplings, which is secured relative to the perforated pipe with screws that coaxially fix the perforation holes of the perforated pipe and the perforated branch pipe, wherein the perforated holes are made in the form of vertical through windows, wherein a well fluid bypass unit is connected to the lower coupling from below, consisting of a branch pipe with radial channels, a two-stage piston and a plug screwed onto the lower end of the branch pipe, wherein the upper stage of the two-stage piston is provided with longitudinal through channels and is hermetically sealed with the possibility of axial movement in the branch pipe opposite its radial channels, blocking them, while from below the two-stage piston with the lower stage rests against the plug, equipped with a central hole at the lower end, and the longitudinal through channels of the upper stage of the two-stage piston have the ability to hydraulically communicate with the radial channels of the branch pipe in the upper position of the two-stage piston.

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