Screen and method of making the same

Abstract

A screen includes a framework of a first material having one or more openings therethrough defining a fluidic filter, and a substance of a second material positioned within the one or more openings in the framework and configured to be removable from the framework during an electrochemical reaction.

Claims

1. A method of making a screen comprising; brazing particles within a bore of a plug with a filler metal of a first material, the particles being of a second material and the plug of a third material, the second material being more anodic than either of the first material or the third material; exposing the particles, the plug and the filler metal to a fluid; allowing an electrochemical reaction to occur; and removing the particles.

2. The method of making a screen of claim 1, further comprising filling interstices defined between the particles with the filler metal.

3. The method of making a screen of claim 1, wherein the fluid includes an electrolyte.

4. The method of making a screen of claim 1, further comprising selecting the second material to be more anodic than either the first material or the third material.

5. A method for making a screen comprising: disposing a material in a mass wherein the material defines interstitial spaces therein; depositing another material in the interstitial spaces during brazing, wherein the material is more anodic than the another material; and then dissolving the material during an electrochemical reaction leaving the another material as a fluid permeable framework.

6. The method as claimed in claim 5 wherein the material and the another material together are fluid impermeable.

7. The method as claimed in claim 5 wherein the dissolving is by exposing the material to an electrolyte.

8. The method as claimed in claim 7 wherein the electrolyte is naturally occurring.

9. The method as claimed in claim 5 wherein the brazing secures the material in place before dissolution of the material.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike:

(2) FIG. 1 depicts a perspective view of a screen disclosed herein with a substance removed from a framework;

(3) FIG. 2 depicts a perspective view of the screen of FIG. 1 with particles of a second material shown and the framework removed;

(4) FIG. 3; depicts a reproduction of a galvanic chart of common materials

(5) FIG. 4 depicts a cross sectional view of an alternate embodiment of a screen disclosed herein; and

(6) FIG. 5 depicts a cross sectional view of a plurality of the screens of FIG. 1 positioned in a tubular in an earth formation borehole.

DETAILED DESCRIPTION

(7) A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures.

(8) Referring to FIGS. 1 and 2, an embodiment of a screen disclosed herein is illustrated at 10. The screen 10 includes a framework 14 (FIG. 1 only) of a first material 18 having one or more openings 22, with a plurality of the openings 22 being illustrated in this embodiment, that define a fluidic filter 26 and a substance 30 of a second material 34 (FIG. 2 only) that will define the openings 22 as will be discussed in detail hereunder. The substance 30 is configured to be removable from the framework 14 during an electrochemical reaction. The second material 34 is selected to be more anodic than the first material 18 to assure that the second material 34 is removed instead of the first material 18 during an electrochemical reaction as occurs when the screen 10 is exposed to a fluid including an electrolyte. The substance 30 when present in the openings 22 blocks flow of fluid through the openings 22 while once removed allows fluid to flow through a tortuous path defined by the openings 22 to thereby filter fluid flowing therethrough in the process.

(9) The screen 10 of the embodiment illustrated also includes a body 38 having a bore 42 therethrough within which the framework 14 and the substance 30 are positioned. The body 38 is made of a third material 46 that like the first material 18 is more anodic than the second material 34 such that the substance 30 is removed before the body 38 in an electrochemical reaction. In some embodiments, the third material 46 may actually be the same material as the first material 18. Good choices for the materials 18, 34 and 46 are based upon their locations on a galvanic chart of common materials shown in FIG. 3. The first material 18 and the third material 46 should be selected from more noble, or more cathodic, materials on the galvanic chart such as nickel, copper or steels, while the second material 34 should be selected from the less noble, or more anodic, materials such as alloys including one or more of zinc, beryllium and magnesium, for example. Assuring that the second material 34 is far from the first material 18 and third material 46 assures that the second material 34 is removed while not removing much if any of the first material 18 and the third material 46 when electrochemically reacted in an electrolyte. These electrolytes include fluids that may be anticipated to be in an environment where the screen 10 will be deployed, such as, in an earth borehole in a hydrocarbon recovery or a carbon dioxide sequestration application, for example. The electrolyte may be a naturally occurring fluid, such as salt-water brine, for example, or may be pumped to the desired location by an operator when needed.

(10) Referring to FIG. 4, an alternate embodiment of a screen disclosed herein is illustrated at 11. The screen 11 differs from the screen 10 in that the framework 15 is not random but instead has a regular and repeating pattern that defines regular and repeating openings 23 that are of consistent size and shape. The framework 15 may be made by filling spaces defined between a plurality of lattices that are stacked together (not shown) with the first material 18. After the framework 15 is made the lattices (fabricated of the second material 34) are dissolved and removed from the framework 15, thereby leaving only the framework 15 to serve as the screen 11 for filtering fluid flowable therethrough.

(11) Referring to FIG. 5, the screen 10 is illustrated in an application for which the screen 10, including the body 38, is well suited, the downhole completion industry. A plurality of the screens 10 are fixedly positioned within holes 47 in a tubular 48 positioned within a borehole 49 in an earth formation 51. In this application the tubular 48 can be positioned within the borehole 49 while the screens 10 are blocked to fluid flow therethrough by the substance 30. When desired, the screen 10 is exposed to an electrolyte to initiate the electrochemical reaction. Once the second material 34 is disintegrated the substance 30 can be removed from the screens 10 thereby leaving a plurality of filtered flow passageways (defined by the framework 14) through a wall 52 of the tubular 48.

(12) One embodiment of the screen 10 disclosed herein is made with a brazing process. A plurality of particles 50, such as pellets or beads, for example, of the second material 34 are packed within the bore 42 and brazed together and to the body 38 with a filler metal 54. The filler metal 54 while molten fills the interstices 58 defined between the particles 50 before solidifying. Once the filler metal 54 is solidified it forms the framework 14. The filler metal 54 is made of the first material 28 while the particles 50 are made of the second material 34. The particles 50 are removed during an electrochemical reaction when the screen 10 is exposed to an electrolyte leaving just the framework 14 with the openings 22 therethrough. The foregoing construction leaves the framework 14 with the openings 22 of various sizes and shapes that are somewhat random and form a torturous path for fluid to flow therethrough.

(13) While the invention has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims. Also, in the drawings and the description, there have been disclosed exemplary embodiments of the invention and, although specific terms may have been employed, they are unless otherwise stated used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention therefore not being so limited. Moreover, the use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another. Furthermore, the use of the terms a, an, etc. do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item.