Knitted wire fines discriminator

Abstract

Particularly, the knitted wire fluid / gas energy absorber and fines discriminator is designed to provide significantly, enhanced erosion resistance and durability through absorbing energy from fluid moving at elevated and erosive velocities through an energy absorbing and flexible structure, providing also a tortuous path for the fluid / gas, thereby, reducing the risk of sand production and sub terrain erosion damage to tubulars. The wire used for the knitted wire fluid / gas energy absorber and fines discriminator may be made from a range of different materials which possess the desired combination of properties required for this process, and lend themselves to knitting, may be compressed, exhibit desired mechanical strength and flex. Such materials may be: Stainless steel of various grades, metallic alloys of various kinds, (zinc, copper etc), wire made of various fibers such as Kevlar, Aramid and a range of other suitable materials.

Description

[0001] This application claims priority to U.S. patent application Ser. No. 60 / 364,481 filed Mar. 15, 2002.[0002] 1. Technical Field[0003] The present invention relates to producing fluids from wells and in particular to filtering of fluids from wells.[0004] 2. Prior Art Background[0005] In the prior art, a method of producing fluid from wells has been to remove all or substantially all solid particles from the fluid before it entered the production pipe. Oil and gas production from wells in subsurface reservoirs are from time to time hampered by sand production from the reservoir formation. This can lead to excessive wear of the tubulars installed in the well, upset surface production systems and may therefore become a serious safety hazard. In order to combat such problems filters are often installed as part of the tubular string inside the well. Over the years several different methods and filters have been introduced. Some of these methods include gravel packing the well, use of...

AI Technical Summary

Benefits of technology

[0025] The present invention relates to an apparatus that absorbs fluid / gas impact energy thereby reducing tubular erosion damage, secondly to discriminate and filter out sand and other particulate matter from produced fluids. Particularly, the knitted wire fluid / gas energy absorber and fines discriminator is designed to provide significantly, enhanced erosion resistance and durability through absorbing energy from fluid moving at elevated and erosive velocities through an energy absorbing and flexible structure, providing also a tortuous path for the fluid / gas, thereby, reducing the risk of sand production and sub terrain erosion damage to tubulars. Additionally, the invention relates to a knitted wire energy absorber / discriminator that may be used as a fine filter medium for a broad range of particulate materials from the produced fluids Furthermore, the knitted wire fluid / gas energy absorber and fines discriminator can be used to provide known pressure loss in a sub terrain production system by flowing the fluid through a tube / container / vessel where discs / layers of knitted wire of known pressure loss is inserted, thereby effectively creating exact pressure loss, the basic foundation for a production inflow control device, whereby well inflow may be controlled selectively.

[0032] Alternatively to making subassemblies of knitted (and compressed, shaped) elements, --a knitting machine may knit the wire discriminator directly onto, for example, a perforated pipe, a wire wrapped screen, a wire mesh (or braided wire) screen and / or a thin walled perforated support pipe, thereby combining the filter effect of a strong wire wrapped screen with the enhancement of a fine filter medium (provided by the knitted wire fines discriminator) to filter out a very broad range of particulate material.

Problems solved by technology

Oil and gas production from wells in subsurface reservoirs are from time to time hampered by sand production from the reservoir formation.

This can lead to excessive wear of the tubulars installed in the well, upset surface production systems and may therefore become a serious safety hazard.

All of these solutions, however, exhibit limited erosional strength.

1. Easily manufactured to desired filter opening and shape. Knitted wire may be compressed in a press to obtain desired porosity (filter opening). By controlling and combining compression, knit tightness, knit pattern and wire thickness, desired filter shapes may be obtained.

2. Ability to inhibit erosion from fluid jetting. Because of the very long interlinked fiber achieved with the knitting process, these filters are far stronger than cloth type, cellulose type, and other wire mesh type design filters that are made with short fibers having limited (or none) interlinked strength. The knitting process allows the filter to move or stretch in any direction rather than being unidirectional as a woven material, or bi-directional as a braided material. This can allow the filter to be able to conform to the jetting pattern and better resist erosion.

3. Easily cleaned and reused. Although this is not an applicable point for oil and gas well applications, as it is not feasible to remove, clean and reinstall a sand filter in an oil or gas well. (This was however of significant importance in the above mentioned industry applications). Cleaning may however involve the use of a high pressure fluid jet. This is therefore comparable to being exposed to intermittent operational fluid erosion.

4. Filter can be knitted out of many types of wire: metallic, non-metallic, fiber glass, composites and others. The process of knitting the filter allows for many types of material to be used independently or in conjunction with other materials.

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