RU2730728C1 - Downhole filter - Google Patents

Abstract

FIELD: oil and gas industry.SUBSTANCE: invention relates to oil and gas industry, particularly, to oil and gas filtration. Downhole filter includes nipples, a coupling and a filtering element containing stringers laid parallel to the well filter axis between the limiting rings, and coils of the profiled wire wound on them. Stringers have "S"-shaped or "Z"-shaped cross-section, are located radially and one their base contacts with coils of profiled wire.EFFECT: reduced weight of the filter while maintaining strength.8 cl, 1 tbl, 13 dwg

Description

The invention relates to the oil and gas industry, in particular - to the means of filtering oil and gas.

Known slotted well filter according to the RF patent for useful model No. 71694, IPC E21B 43/08, publ. 03/20/2008

The filter contains a perforated pipe on which longitudinal supporting elements are installed, on the outer surface of which a wire is wound with the formation of gaps between the turns, while the wire is welded or soldered to the longitudinal elements, and the ratio of the pitch of the longitudinal elements to their height is made in the range from 1.0 up to 10. A filter mesh is installed between the pipe and the longitudinal support elements. A wire is wound between the supporting longitudinal elements and the filter mesh, which acts as a drainage layer. A drainage mesh is installed between the pipe and the filter mesh. A drainage mesh is installed between the longitudinal support elements and the filter mesh.

The disadvantages of the filter are the complexity of the design of the downhole filter, labor-intensive manufacturing, low reliability and rapid abrasive wear of the filter element.

Known downhole filter according to the RF patent for invention No. 2507384, IPC E21B 43/08, publ. 20.02.2014

This slotted borehole filter contains a perforated carrier pipe and a slotted filter element made of wire wound on longitudinal elements in a spiral, and the cross-section of the wire wound in a spiral is made pentagonal, one of the edges of the wire is parallel to the longitudinal axis of the filter and forms its outer surface, and each lateral side is made with two edges, the upper ones form a filtering gap, and the lower ones converge, forming an acute angle.

Disadvantages: low strength of the wire of the filter element, which leads to a change in the clearances when running the downhole filter, and rapid abrasive wear of the “narrowest point” of the filter element.

Known frameless downhole filter according to the RF patent for invention No. 2606470, IPC В21В 43/08, publ. 01/10/2017, prototype.

This frameless downhole filter contains two nipples and at least one filter element, closed by a protective casing having holes and made between the stop rings, in that each filter element is laid on longitudinal elements, and both nipples are welded to the extreme stop rings, an annular casing is installed inside the filter without an annular gap, inside which a means for swirling the extracted product is installed with an annular gap. The filter element can be made slotted in the form of a wire wound on the longitudinal elements in a spiral.

Disadvantages: high weight, commensurate with the weight of the frame filter and design complexity.

The objective of the invention is to reduce the weight and simplify the design of the well screen while providing effective cleaning.

The solution to this problem is achieved in a downhole filter containing nipples, a sleeve and a filter element containing stringers laid parallel to the axis of the downhole filter between the restricting rings, and profiled wire turns wound around them, characterized in that the stringers are made "S" -shaped or "Z "- shaped cross-section, placed radially and one of their base contacts with the turns of the profiled wire.

The shaped wire can be made of a triangular cross-section with a radius rounding of the apex facing the axis of the well screen.

Radial rounding of the vertex facing the well screen axis can be performed from the condition:

R ₁ = (0.2 ... 0.25) a, where:

R _{1 -} radius of rounding of the vertex,

a - the width of the profiled wire.

The stingers can be laid in such a way that the inner diameter of the stringers is larger than the inner diameter of the stop rings:

_VNS D> D _ext.

The stingers can be laid in such a way that the inner diameter of the stringers is equal to the inner diameter of the stop rings:

D = D _{VNS corolla,}

where: D _vnc - inner diameter of the stringers installation,

D _vn , is the inner diameter of the stop rings.

The stingers can be laid in such a way that the inner diameter of the stringers is less than the inner diameter of the stop rings:

_VNS D <D _ext.

The outer diameter of the filter element can be made smaller than the outer diameter of the sleeve:

D _f <D _m .

The essence of the invention is illustrated in the drawings Fig. 1-13, where:

- in Fig. 1 shows a well filter,

- in Fig. 2 shows the filter element,

- in Fig. 3 shows the first option for laying stringers,

- in Fig. 4 shows the second option for laying the stringer,

- in Fig. 5 shows the third option for laying stringers,

- in Fig. 6 shows the first version of the profiled wire,

- in Fig. 7 shows the second version of the profiled wire,

- in Fig. 8 shows the end of the stringer and its installation in the stop ring, the first option,

- in Fig. 9 shows the end of the stringer and its installation in the restricting ring, the second option,

- in Fig. 10 shows the assembly of the filter element,

- in Fig. 11 shows view A,

- in Fig. 12 shows the limit ring,

- in Fig. 13 shows view B.

Description notation:

nipple 1,

clutch 2,

centralizer 3,

filter element 4,

stringer 5,

restrictive ring 6,

profiled wire 7,

welding seam 8,

contact welding 9,

inner cavity 10,

rack 11,

inner base 12,

outer base 13,

contact surface 14,

outer edge 15,

inner edge 16,

side edge 17,

end of stringer 18,

radial groove 19,

inner end 20,

inner chamfer 21,

outer end 22,

outer chamfer 23,

inner groove 24,

cutout 25,

H ₀ - the height of the filter element,

H ₁ - the height of the cross-section of the profiled wire.

Н ₂ - the height of the stringer profile,

D _vn - the inner diameter of the filter,

D _fns - inner diameter of stringers installation,

D _m - outer diameter of the coupling,

D _f - the diameter of the filter element,

a - width of the cross-sectional profile of the profiled wire

b - stringer width,

b ₁ - the minimum width of the stringer in the section,

b ₂ - maximum width of the stringer in section,

δ ₁ - filter gap,

δ ₂ - the gap between the stringers,

t - step of installing stringers,

R ₁ - radius of rounding of the contact surface,

r - radius of rounding of the vertex.

The downhole filter (Fig. 1 ... 13) is designed to clean oil or gas.

The downhole filter (Fig. 1) contains nipples 1, a sleeve 2 on the upper nipple 1, and a centralizer 3 can be installed.

The filter element 4 (Fig. 2) contains stringers 5, laid parallel to the axis of the OO downhole filter between the limiting rings 6, and wound on them turns of profiled wire 7 of triangular section.

Connections of nipples 1 with stop rings 6 and stop rings 6 with filter elements 4 are made with welds 8.

The connection of the profiled wire 7 with the stringers is made by resistance welding 9.

An internal cavity 10 is formed inside the filter, in which the purified production product is located.

Stringers 5 (Fig. 3) are made "S" -shaped or "Z" -shaped in cross-section.

The height of the stringers can be made from the ratio:

H ₁ = (2.3 ... 2.8) in ₁ where:

H ₁ - stringer height,

in ₁ - the width of the larger base of the stringer.

H ₁ - stinger height 5.

The thickness of the stringers 5 (Fig. 3) δ can be made from the ratio:

δ = (0.2 ... 0.3) in ₁ where:

δ is the thickness of the stringer 3,

δ ₁ - the gap between the rows of profiled wire,

δ ₂ - the gap between the rows of stringers,

in ₁ - the width of the larger base of the stringer.

Proof of the optimality of the specified ratio of dimensions for determining the height of the stringer H ₁ .

It is known from the resistance of materials (for a rectangular profile):

, где:

where:

W is the moment of resistance to bending,

H ₁ - stringer height 5,

b ₁ - minimum stringer width 5.

If the width of the stringer 5 is constant, then b is taken (FIGS. 4 and 5).

From this formula it follows that with an increase in the height of the stringer 5 - H _1, its bending resistance increases with a quadratic dependence (Table 1). However, the upper redistribution is limited by the outer diametrical dimension of the downhole filter: it is impossible to make the filter element 4 with a diameter greater than the outer diameter of the sleeve 7 because of the possibility of destruction of the filter element when running into the well.

In more detail, the proof of the optimality of the stated ratio of sizes and the possibility of implementation are given some data in Table 1, partially borrowed from GOST 633 - 80 Tubing pipes and couplings to them. Technical conditions. It is possible to use pipes in accordance with GOST 632 - 80. Casing pipes and couplings for them. Technical conditions.

From table. 1 it follows that the height of the filter element is H ₀ = 13.5 ... 16.0 mm.

With the height of the profiled wire 7 H ₁ equal to 3 mm, given that H ₀ = H ₁ + H ₂ , we have the height H ₂ (Fig. 3) of stringers 5:

Н ₂ = 10.5 ... 13.0 mm, which is quite enough for the manufacture of thin-walled profiled rolled products.

Technologies for the manufacture of thin-walled profiled rolled products are known from US Pat. RF No. 2163869, IPC B21D 26/06, publ. 03/10/2001 and US Pat. RF No. 2338620, IPC B21J 5/12, publ. 10.10.2007.

Stringers 5 have a post 11, a first base 12 and a second base 13, a contact surface 14, which can be made with a rounding radius R (Fig. 3).

The profiled wire 7 of the section can be made in two versions (Fig. 5 and 6).

The first version of the profiled wire 7 (Fig. 5) is made of a triangular cross-section, having an outer edge 15, an inner edge 16, as well as two side edges 17 and a radius rounding.

Radial rounding is made with radius r ₁ (Fig. 5), while the optimal rounding radius:

r ₁ = (0.2 ... 0.25) a ,

Where: r ₁ is the radius of the radius at the apex of the cross-section of the profiled wire 7, where:

a - the width of the profiled wire 7.

The height H _{1 is} approximately 3 mm.

FIG. 6 shows a second version of a profiled wire 7 made in cross-section in the shape of a trapezoid, the larger base 15 of which is facing the side of the profiled wire 7. the smaller base 16 is facing the axis of the OO downhole filter and two side faces 17.

FIG. 7 shows the end 18 of the stringer 5 with a recess 25 and its installation in the stop ring 6, the first option, in which:

D _VNS ≥D _corolla,

where: D _vnc - internal diameter of the stringers 5,

D _vn, - inner diameter of nipples 1 and stop rings 6.

The ends 18 of the stringers 5 can, before welding, be laid in radial grooves 19 made with a uniform pitch on the ends 20 of the stop rings 6.

The stop ring 6 has an external chamfer 23 and an internal flow 24 at the outer end 22.

The inner chamfer 21 is intended for the weld seam 8.

FIG. 8 shows the end 18 of the stringer 5 with a cutout 25 and its installation in the restricting ring 6, the first option, in which:

D = D _{VNS corolla,}

where: D _vnc - internal diameter of the stringers 5,

D _vn, - inner diameter of nipples 1 and stop rings 6.

The ends 18 of the stringers 5 before welding can be laid in radial grooves 19 made with a uniform pitch on the ends 20 of the stop rings 6. The inner chamfer 21 is intended for the weld 8.

FIG. 9 shows the end of the stringer 5, the second option and its installation in the restricting ring 6, in which:

D _vns ≤D.

FIG. 10 shows the connection of the filter element 4 with the restricting ring 6, and FIG. 11 - view B, while it is necessary to observe the ratio:

D _max ≤D _m ,

where: D _max - the maximum diameter of the filter element,

D _m - outer diameter of coupling 2

FIG. 12 shows a stop ring 6, and FIG. 13 shows a view B of the stop ring 6. The stop ring 6 has inner and outer chamfers 21 and 23 and an inner groove 24 at a smaller diameter for joining to the nipple 1.

Well screen assembly

When assembled separately (Fig. 1 ... 13), nipples 1, stop rings 6 and filter elements 4 are made.

The filter elements 4 are welded on both sides to the restrictive rings 6 with welding seams 8.

The nipples 1 are welded to the stop rings 6 with welding seams 8 too.

WELL FILTER OPERATION

The downhole filter is designed to clean oil or gas from impurities (Fig. 1 ... 13). For this, the downhole filter is installed in the production string (not shown). Oil (gas) through the gap δ ₁ between the turns of the profiled wire 7 and then through the gaps between the stringers 5 - δ ₂ . enters the inner cavity 10.

The degree of filtration depends mainly on the gap δ ₁ and is set by the customer, usually in the range from 0.1 to 1.0 mm. In this case, the deformation of the turns of the profiled wire 7 during manufacture, during transportation and lowering of the well screen into the well is not permissible. This is achieved by contacting the profiled wire 7 with the stringers 5 during their welding due to their larger contact area.

Passing through the gaps δ ₂ between the stringers 5 (Fig. 11) into the inner cavity 10, the product is cleaned.

The proposed design provides improved filtration due to the stability of the side gap δ ₁ and increases its strength due to the proposed profiles of stringers 5 and profiled wire 7.

Application of the invention allowed:

- to reduce the weight of the downhole filter by 30 ... 50% while maintaining its strength,

- forgive the design of the well filter,

- to improve the cleaning of the produced product by reducing the deformation of the turns of the profiled wire during assembly and when running the well screen into the well.

Claims (16)

1. A downhole filter containing nipples, a sleeve and a filter element containing stringers laid parallel to the axis of the downhole filter between the stop rings, and coils of profiled wire wound around them, characterized in that the stringers are made "S" -shaped or "Z" -shaped cross-section, placed radially and one of their base contacts the turns of the profiled wire. 2. Downhole filter according to claim 1, characterized in that the profiled wire is made of a triangular cross-section with a radius rounding of the apex facing the axis of the downhole filter. 3. The downhole filter according to claim 2, characterized in that the radius rounding of the apex facing the axis of the downhole filter is made from the condition: R ₁ = (0.2 ... 0.25) a, where: R _{1 -} radius of rounding of the vertex, a - the width of the profiled wire. 4. The downhole filter according to claim 1, characterized in that the stingers are stacked during assembly in such a way that the inner diameter of the stringers is greater than the inner diameter of the restraining rings: _VNS D> D _ext. 5. The downhole filter according to claim 1, characterized in that the stingers are stacked during assembly so that the inner diameter of the stringers is equal to the inner diameter of the restricting rings: _VNS D = D _ext. where: D _vnc - inner diameter of the stringers installation, D _vn , is the inner diameter of the stop rings. 6. Downhole filter according to claim 1, characterized in that the stringers are stacked during assembly in such a way that the inner diameter of the stringers is less than the inner diameter of the restraining rings: _VNS D <D _ext 7 _. The well filter according to claim 1, characterized in that the outer diameter of the filter element is less than the outer diameter of the sleeve: D _f <D _m.

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