RU2729375C1 - Downhole filter - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil and gas industry, in particular, to filtration of oil and gas. Downhole filter comprises nipples and a filtering element comprising stringers laid parallel to the downhole filter axis between the limiting rings and coiled turns of the profiled wire wound thereon. Stringers feature T-shaped cross-section with posts and shelves, their flanges contact with coils of profiled wire.

EFFECT: reduced weight and simplified design while maintaining strength and efficient cleaning.

8 cl, 2 tbl, 13 dwg

Description

The invention relates to the oil and gas industry, specifically to oil and gas filtering means.

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 support 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 well filter, the laboriousness of manufacture, 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 made 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 gaps when running the well screen, 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, covered 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, the complexity of the design and the possibility of deformation of the turns of the profiled wire.

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

The solution to this problem is achieved in a downhole filter containing nipples 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, in that the stringers are made of "T" -shaped cross-section with struts and shelves, their shelves are in contact with the turns of the profiled wire.

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

H ₂ = (2.5 ... 3.0) B ₁ , where:

Н ₂ - stringer height,

B ₁ is the width of the stringer base.

The contact surfaces of the stringer shelves can be made rounded, while the radius of the rounding is made from the ratio:

R = 0.5 (V _f -2H ₂ ), where:

R - flange radius,

D _f - outer diameter of the filter element,

H ₂ - stringer height.

The profiled 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 axis of the well screen 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 equal to the inner diameter of the filter:

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 filter:

_VNS D <D _ext.

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

_VNS D <D _ext.

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 version of the stringer,

- in Fig. 4 shows the second version of the stringer,

- in Fig. 5 shows the first version of the profiled wire,

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

- in Fig. 7 shows the end of the stringer and its installation in the stop ring, the first option,

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

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

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

- in Fig. 11 shows view A,

- Fig. 12 shows a 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,

shelf 12,

inner base 13,

contact surface 14,

outer edge 15,

inner edge 16,

lateral 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 - stringer height,

D _vn - the inner diameter of the filter,

D _vnc - inner diameter of the stringers installation,

D _m - outer diameter of the coupling,

D _f - the diameter of the filter element,

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

b - stringer width,

B ₁ - width of the stringer base,

B ₂ - stringer shelves,

δ ₁ - filter gap,

δ ₂ - the gap between the stringers,

t - step of installing stringers,

R - radius of rounding of the contact surface,

r ₁ - 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.

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

Stringers 5 (Fig. 3) are made "T" -shaped in cross-section. They have a post 11, a shelf 12, an inner base 13, a contact surface 14, which can be made with a rounding radius R (Fig. 6). The height of the stringers 5 should be made from the ratio:

H₂= (2.5 ... 3.0) V₂, Where:

Н ₂ - the height of the stringer 5,

B ₂ - the width of the shelf 12 of the stringer 5.

Proof of the optimality of the specified ratio of sizes.

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

W is the moment of resistance to bending,

Н ₂ - the height of the stringer 5,

B ₁ - the width of the base of the stringer 5.

In addition, the shelf 12 of the stringer 5 with a width of ₂ significantly increases the bending moment (FIGS. 3 and 4).

From this formula it follows that with an increase in the height of the stringer δ - Н _2, 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 due to the possibility of destruction of the filter element when running into the well.

Conclusion from Table 1

With H ₂ / B ₁ more than 2.5, the bending resistance of the frame on stringers is equal (or more) to the bending resistance of a solid pipe, and with H ₂ / B ₁ = 3.0 it exceeds by 27%, however, a further increase in height is impossible due to the limitation the diametrical dimension of the well screen and restrictions on the diameter of the well.

In this case, the height Н ₂ / В ₁ = 3.0 can be achieved due to the partial blocking of the inner cavity 10 to a height of 3 to 5 mm, depending on the diameter of the well screen and the thickness of its wall, i.e. the condition should be met:

D _vn - D _vnm = 6 ... 10 mm, which leads to blockage of the pipe section by 3 ... 5%.

The possibility of implementing this range of aspect ratios is shown in table. 2, data in which partly 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 2 it follows that the height of the filtering element is H ₀ = 13.5 ... 16.0 mm.

With the height of the profiled wire 7 equal to 3 mm, we have the height H ₂ (Fig. 3) of the stringers 5: H ₂ = 10, 5 ... 13.0 mm, which is sufficient for the manufacture of thin-walled profiled rolled products.

The profiled wire 7 can be made in two versions of FIG. 5 and 6.

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

Radial rounding of the inner face 16 is made with a radius r ₁ (Fig. 5), while the optimal rounding radius is:

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,

a - the width of the profiled wire 7.

FIG. 6 shows the second version of the profiled wire 7, made in cross-section in the shape of a trapezoid, the outer edge 15 and the inner edge 16 facing the axis OO of the well screen.

FIG. 7 shows the embedding of the ends 18 of the stringers 5 into the radial grooves 19 of the stop rings 6.

The restraining rings 6 contain an inner end 20, inner chamfers 21, an outer end 22, and an outer chamfer 23 and a recess 24 at a smaller diameter for joining to the nipple 1. The ends 18 of the stringers 5 have cutouts 25.

In this case, the condition is fulfilled:

D _vns ≤D _ext ,

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

D _vn - inner diameter of the filter (nipples 1 and stop rings 6).

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. Ends 18 of stringers 5 can be placed before welding in radial grooves 19 made with uniform pitch on ends 20 of stop rings 6. Internal chamfer 21 is intended for welding seam 8.

FIG. 9 shows the end 18 of the stringer 5, the second option and its installation in the restricting ring 6, in which:

_VNS D <D _ext.

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

D _vn - the inner diameter of the filter (in the nipples 1 and the restricting rings 6) FIG. 10 shows the connection of the filter element 2 with the restricting ring 6, and FIG. 11 type B, while it is necessary to observe the ratio:

D _f ≤D _m ,

where D _f is the maximum outer diameter of the filter element,

D _m - outer diameter of the sleeve (Fig. 7).

FIG. 12 shows a stop ring 6, and FIG. 13 shows a view B of the stop ring 6. The stop ring 6 has an external chamfer 23 at the larger diameter of the outer end 22 and a cut 25 at the 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.

Filtering elements 4 are made on mandrels (not shown in Fig. 1 ... 13) by uniform arrangement of stringers 5 with a pitch t around the circumference and by contract welding 9 to them of profiled wire 7 (Fig. 2).

The filter elements 4 are welded on both sides to the restricting rings 6 with welding seams 8 (Figs. 1 and 2).

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 casing (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 (Fig. 11) enters the inner cavity 10.

The degree of filtration depends mainly on the gap δ ₁ between the turns of the profiled wire 7 and is set by the customer, usually in the range from 0.1 to 1.0 mm. At the same time, there is no deformation of the turns of the profiled wire 7 during manufacture, during transportation and lowering of the downhole filter into the well. This is achieved due to the large contact area of the profiled wire 7 with the stringers 5 during their welding.

Passing further through the gaps 8 ₂ between the stringers 5 (Fig. 13), the cleaned produced product enters the inner cavity 10 of the well screen.

The proposed design provides improved filtration due to the stability of the lateral gap δ ₁ and increases its strength due to the proposed "T" -shaped profile of stringers 5, the ratio of its dimensions, contributing to an increase in the moment of resistance to bending, and welding of the turns of profiled wire 7 by contact welding 9 wide stringer shelf.

Application of the invention allowed:

- to reduce the weight of the downhole screen by 30 ... 50% while maintaining its strength due to the profile of the stringers, namely, the use of "T" -shaped cross-section stringers will increase the bending strength of the downhole screen due to the high height of the stringer base and the presence of a wide flange,

- forgive the design of the downhole filter,

- to improve the cleaning of the extracted product by reducing the deformation of the shaped wire during welding and running into the well for the selected profiles and aspect ratios for stringers and shaped wire.

Claims (23)

1. A downhole filter containing nipples 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 on them, characterized in that the stringers are made of "T" -shaped cross-section with racks and shelves, their shelves are in contact with the turns of the profiled wire. 2. The downhole filter according to claim 1, characterized in that the height of the stringers is made from the ratio: H ₂ = (2.5 ... 3.0) B ₁ , where: Н ₂ - stringer height, B ₁ is the width of the stringer base. 3. Downhole filter according to claim 1 or 2, characterized in that the contact surfaces of the stringer flanges are made rounded, while the radius of the rounding is made from the ratio: R = 0.5 (D _f - 2H ₂ ), where: R - flange radius, D _f - outer diameter of the filter element, H ₂ - stringer height. 4. Downhole filter according to claim 1 or 2, 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. 5. The downhole filter according to claim 4, characterized in that the radial rounding of the cross-section of the apex of the profiled wire 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. 6. Downhole filter according to claim 1 or 2, characterized in that the stingers are laid in such a way that the inner diameter of the stringers is equal to the inner diameter of the filter: _VNS D = D _ext. where: D _vnc - inner diameter of the stringers installation, D _vn, is the inner diameter of the filter. 7. Downhole filter according to claim 1 or 2, characterized in that the stingers are stacked during assembly in such a way that the inner diameter of the stringers is less than the inner diameter of the filter: _VNS D <D _ext. 8. The downhole filter according to claim 1 or 2, 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 filter: D _int > D _int .

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