Patent Application
20190232202
This invention which is the subject matter of this patent application is directed to a filter element of the woven wire mesh type which is used in filters which may include a sand screen filter used in the production of fluids from an oil or gas well. Sand screen filters are positioned over perforated production tubulars to filter out solid particles prior to the fluid entering the production tubing.
Sand screen filters using woven wire mesh filter elements are well known in the art. One or layers of woven wire mesh of varying pore size are placed over a portion of the production tubing having apertures for the produced well fluids. A support structure is provided for supporting the wire mesh layer(s) and usually a guard is positioned above the assembly for protecting the woven wire mesh.
The woven wire mesh used for the filter screens is standard woven wire mesh of uniform pore size. According to the particular weave pattern, the pore shapes can be square, rectangular or other geometric shapes but in any event the pores are formed by longitudinal and transverse wires so as to define uniform size and shape over the entire extent of the mesh.
The present invention is to form a woven wire mesh with non-uniform pore sizes and or shapes over a substantial portion of its area. The so formed woven wire mesh serves as the filter element for a sand screen filter. This creates a multitude of pores of varying sizes and shapes in the filter with the result that not all of the pores will become clogged during use. The presence of varying size and shape pores will accommodate varying conditions within the formation. As a sand screen filter is used in an oil/gas well environment, a layer known as “caking” forms around the filter. It is composed of sand or other particulate material of varying sizes. It has been found that filter layers comprised of woven wire mesh having uniform pores will clog much quicker in certain sand formations than woven wire mesh having varying pore sizes and shapes. While some clogging occurs it has been discovered that the caking formed outside the filter layer forms in such a way that alternate flow passages are formed through the caking. A more permeable filter cake with varied pore geometries builds around the filter screen ensuring that multiple, alternate flow paths form through the cake. In addition, it has been found that backwashing of the filter element is considerably easier due to the irregular sizes and shapes of the pores. The invention can be applied to any of the well-known weave patterns for woven wire mesh including, for example, square, twill, plan Dutch and Dutch twill or combinations of these. The invention is useful also in any filter that includes a woven wire mesh filter element.
As shown in
A first annular, cylindrical filtering sleeve 15 surrounds the production pipe and is secured thereto by an annular collar 12 at 32. A second annular, cylindrical filtering sleeve 16 is optionally positioned around the first annular cylindrical filtering sleeve and may have a pore size equal to, less than or greater than the pore size of first sleeve 15.
A protective shroud 13 having relatively large openings are attached to collar 12 at one end. Outer shroud 13 protects the woven wire mesh and is formed of a relatively rigid sheet material such as stainless steel for example.
As shown in
Alternately the sand screen assembly may be formed in the manner disclosed in U.S. patent application Ser. No. 13/708,124, filed Dec. 7, 2012, the contents of which is expressly incorporated herein by reference thereto.
The number of annular cylindrical filter sleeves can vary from one to several layers. The filters are formed of woven wire mesh having irregularly sized and spaced pores.
Conventional sand screen filters are made with conventional woven metal mesh wherein the pores are formed with a uniform repeating geometry whereas according to the present invention the pores are irregularly shaped and non-repeating.
An example of the woven wire mesh used in this invention is shown in
As can be seen in
In
As shown in
The same is true for the weave pattern shown in
In some cases it is only necessary to vary the distance between either the warp wires or weft wires to achieve the non-uniform distribution of pore sizes.
The woven wire mesh sizes suitable for use in the sand screen filter according to the invention may include wire having a diameter between 0.05 mm to 1.00 mm, preferable 0.1 to 0.5 mm. The average pore size can be 50 microns to 5,000 microns, preferable 100 to 600 microns.
Standard Materials micron cloth in the market place (Dutch Weave, Twill Dutch Weave, Reverse Dutch Weave, Revers Twill Dutch Weave and/or 5 Shaft Weave) with a micron rating of approximate 300 where tested. The maximum air permeability for the tested items was 800 Scfm·sf at 1″ water column. The new weave design with the same micron range had a minimum of 60% more flow under the same test conditions.
Although the present invention has been described with respect to specific details, it is not intended that such details should be regarded as limitations on the scope of the invention, except to the extent that they are included in the accompanying claims.
This application is a continuation of U.S. application Ser. No. 14/597,337 filed Jan. 15, 2015, which is incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 14597337 | Jan 2015 | US |
| Child | 16381773 | US |
