Abstract:
The present invention provides for a seal or barrier comprising strands that are woven or wrapped in an overlapping manner such as, for example, helical or circumferential patterns.

Description:
[0001]    This application is a continuation of application Ser. No. 10/904,722 filed on Nov. 24, 2004, incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    It is often desirable to block or restrict the flow of fluids or solid particulates in a well. For example, a seal between a downhole tool and a well casing such as is commonly found in a packer may be used to prevent or restrict fluid flow between formations. A tool may also require a seal or fluid barrier within the internal structure of the tool, say between an inner mandrel and an outer housing. 
         [0003]    In the prior art, braided rope packing has been used to form a seal element or barrier for downhole tools, particularly in valves. The packing is cut and wrapped around a mandrel in a mold and pressed into a desired shape. The rope packing holds that shape while being installed over a mandrel or into a tool. Compressing the braided rope packing creates a seal or barrier. Elastomers, cast or milled to a desired shape, have also been used to form a seal element or barrier in downhole tools. 
       SUMMARY 
       [0004]    The present invention provides for a seal or barrier comprising strands that are woven or wrapped in an overlapping manner such as, for example, helical or circumferential patterns. 
         [0005]    Advantages and other features of the invention will become apparent from the following description, drawings, and claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0006]      FIG. 1  is a plan view of a seal or fluid/solids barrier constructed in accordance with the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0007]    Referring to  FIG. 1 , a seal or fluid barrier  10  comprises strands  12  woven in a overlapping or mesh pattern. The pattern may be helical, circumferential, orthogonal, or some other arrangement of strands  12 . Strands  12  are preferably metal, but could be some other natural or synthetic material such as nylon or fabric with a polytetrafluoroethylene laminate (e.g., GORE-TEX®). Strands  12  may be circular or angular in cross-section and may be of various lengths. Variations in the strand cross-sections and lengths can be used to meet particular performance objectives. Strands  12  may be impregnated or coated with an elastomer or other conformable material to form a composite seal or barrier  10 . In an alternative embodiment, in place of woven strands, smaller, shorter strands  12  can be simply layered and pressed into a desired shape to form seal  10 . 
         [0008]    In operation, seal  10  is installed on or in a tool and compressed to block or restrict the passage of fluid therethrough. Seal  10  can be used to isolate wellbore fluids, hold pressure, prevent sand production, or allow sufficiently small particles to pass through. Seal  10  may be used to support cement or to plug a wellbore, for example, when the wellbore is to be plugged and abandoned. For sand retention, the weaving density and setting force can be varied to produce the desired pore space in seal  10 . By controlling the pore space and permeability of seal  10 , a fluid barrier may be obtained by creating a labyrinth effect or tortuous path for fluid flow, thereby effectively preventing fluid communication. 
         [0009]    Using various metals and/or other materials to weave or otherwise form seal  10 , seal  10  can be used in various wellbore environments. Those environments include, but are not limited to, extremely low or high temperature wellbores, or highly corrosive or relatively non-corrosive wellbore environments. Pressure holding requirements may vary from an absolute seal to one in which fluid flow is merely restricted. Seal  10  can be used in such widely differing applications by adjusting the setting (compressive) force applied. 
         [0010]    Depending on the shape and length of seal  10 , seal  10  can be run through small diameter openings (e.g., one inch) and set in a wide range of outer diameters. For example, seal  10  may be run through tubing, but set in casing. Seal  10  can be used over many different casing sizes and weight ranges, thus reducing the number of designs required. In addition, seal  10  can be used in wellbore applications in which impairments exist in the casing that restrict access by standard oilfield tools. 
         [0011]    Although only a few example embodiments of the present invention are described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the example embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the following claims. It is the express intention of the applicant not to invoke 35 U.S.C. §112, paragraph 6 for any limitations of any of the claims herein, except for those in which the claim expressly uses the words ‘means for’ together with an associated function.