Fast-setting expanding metal

Abstract

The invention relates to a downhole tool (200), a method for sealing within a well system, and a well system. The downhole tool (200), in at least one aspect, includes a tubular element (210) and one or more expanding metal sealing elements (270) positioned around the tubular element (210). In at least one aspect, the expanding metal sealing element(s) (270) comprise a metal designed to expand in response to hydrolysis and have a surface area to volume ratio (SA:V) of at least 2 cm⁻¹. Figure 2A

Description

Title of the invention: Rapid setting expandable metal

[0001] CROSS-REFERENCE TO AN ASSOCIATED REQUEST

[0002] This application claims priority from U.S. application No. 17 / 334,099, filed on May 28, 2021, entitled “RAPID-SET EXPANSIBLE METAL”, commonly attributed with this application.

[0003] CONTEXT

[0004] Sealing and anchoring devices, among other related devices, are common in oil and gas applications. Unfortunately, current sealing and anchoring devices are limited by the materials they comprise and the conditions under which they are installed. More specifically, the material chosen and the downhole conditions often limit the speed at which current sealing and anchoring devices can be installed.

[0005] BRIEF DESCRIPTION

[0006] Reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

[0007] [Fig.1] illustrates a well system designed, manufactured and used according to one or more embodiments of the invention, the well system including a downhole tool designed, manufactured and used according to one or more embodiments of the invention;

[0008] [Fig.2A][Fig.2B][Fig.2C] illustrate different deployment states for a downhole tool designed, manufactured and used according to one aspect of the invention;

[0009] [Fig.3A][Fig.3B][Fig.3C] illustrate different deployment states for a downhole tool designed, manufactured and used according to one aspect of the invention;

[0010] [Fig.4A][Fig.4B][Fig.4C] illustrate different deployment states for a downhole tool designed, manufactured and used according to one aspect of the invention;

[0011] [Fig.5A][Fig.5B][Fig.5C] illustrate different deployment states for a downhole tool designed, manufactured and used according to one aspect of the invention;

[0012] [Fig.6A][Fig.6B][Fig.6C] illustrate different deployment states for a downhole tool designed, manufactured and used according to one aspect of the invention;

[0013] [Fig.7A][Fig.7B][Fig.7C] illustrate different deployment states for a downhole tool designed, manufactured and used according to one aspect of the invention;

[0014] [Fig.8A][Fig.8B][Fig.8C][Fig.8D][Fig.8E] illustrate different deployment states for a downhole tool designed, manufactured and used according to one aspect of the invention;

[0015] [Fig.9A][Fig.9B][Fig.9C][Fig.9D][Fig.9E] illustrate different deployment states for a downhole tool designed, manufactured and used according to one aspect of the invention;

[0016] [Fig.10A][Fig.10B][Fig.10C][Fig.10D][Fig.10E] illustrate different states of development bending for a down-the-hole tool designed, manufactured and used according to one aspect of the invention;

[0017] [Fig.llA][Fig.llB][Fig.llC][Fig.llD] illustrate different deployment states for a downhole tool designed, manufactured and used according to one aspect of the invention;

[0018] [Fig.12A][Fig.12B][Fig.12C][Fig.12D] illustrate different deployment states for a downhole tool designed, manufactured and used according to one aspect of the invention; and

[0019] [Fig.13A][Fig.13B][Fig.13C][Fig.13D] illustrate different deployment states for a downhole tool designed, manufactured and used according to one aspect of the invention; DETAILED DESCRIPTION

[0020] In the following drawings and descriptions, identical parts are generally indicated throughout the description and all drawings by the same numerical reference numerals, respectively. The figures drawn are not necessarily to scale. Certain features of the invention may be represented at an exaggerated scale or in a somewhat simplified form, and it is possible that certain details of some elements may not be shown for the sake of clarity and conciseness. The present invention can be implemented in various embodiments.

[0021] Specific embodiments are described in detail and illustrated in the drawings, it being understood that this description is to be considered as an example of the principles of the invention and is not intended to limit the invention to that illustrated and described herein. It should be fully understood that the various teachings of the embodiments described herein can be employed separately or in any suitable combination to produce the desired results.

[0022] Unless otherwise specified, the use of the terms "connect," "engage," "couple," "attach," or any similar term describing an interaction between elements is not intended to limit the interaction to a direct interaction between the elements and may also include an indirect interaction between the described elements. Unless otherwise specified, the use of the terms "up," "upper," "upward," "upwell," "upstream," or similar terms should be interpreted as generally moving from the formation toward the ground surface; likewise, the use of the terms "down," "lower," "downward," "downhole," or similar terms should be interpreted as generally moving toward the bottom, the terminal end of a well, regardless of the wellbore's orientation.The use of one or more of the preceding terms should not be interpreted as designating positions along a perfectly vertical axis. Unless otherwise indicated, the use of the term "subterranean formation" should be interpreted as encompassing both areas below the exposed Earth's surface and areas... located below the Earth's surface covered by water, such as oceans or bodies of fresh water.

[0023] The present invention recognizes that current sealing and / or anchoring devices, particularly those using conventional elastomeric materials, have certain drawbacks. More specifically, the present invention recognizes that high temperature limitations, low temperature sealing limitations, swabbing problems during operation, extrusion problems over time, and the inability to conform to irregular shapes, among other problems associated with conventional elastomeric sealing and / or anchoring devices, make said sealing and / or anchoring devices less than desirable in certain applications.The present invention, based on these observations, has thus recognized that sealing and / or anchoring devices using an expandable / expanded metal address many concerns related to sealing and / or anchoring devices using conventional elastomeric materials.

[0024] The present invention further recognizes the importance of rapidly securing expanding / expandable metal sealing and / or anchoring devices, for example, to compete with traditional hydraulic and / or mechanically actuated sealing and / or anchoring devices. The present invention recognizes that expanding metal reacts only on exposed surfaces, and therefore, by increasing the surface area, the chemical reaction required to secure expanding / expanded metal sealing and / or anchoring devices can be significantly increased. Accordingly, the present invention details numerous ways of increasing the exposed surface area of ​​the expanding metal.

[0025] Figure 1 illustrates a well system 100 designed, manufactured, and used according to one or more embodiments of the invention, the well system 100 including a downhole tool 150 designed, manufactured, and used according to one or more embodiments of the invention. The downhole tool 150, in at least one embodiment, is a sealing and / or anchoring tool and may therefore include one or more sealing elements 155. The terms "sealing tool" and "sealing element," as used herein, are intended to include both tools and elements that join two surfaces together in a watertight manner, as well as tools and elements that fix two surfaces together.

[0026] The well system 100 includes a borehole 110 extending from a ground surface 120 into one or more subsurface areas 130. Once completed, the well system 100 can be designed to produce reservoir fluids and / or inject fluids into the subsurface areas 130. As those skilled in the art will recognize, the borehole 110 can be fully cased, partially cased, or can be an open-hole borehole. In the illustrated embodiment From [Fig.1], the borehole 110 is at least partially cased, and is thus lined with casing or lining 140. The casing or lining 140, as illustrated, can be held in place by cement 145.

[0027] An example of a downhole tool 150, in one or more embodiments, is coupled to a transport means 160 extending from a wellhead 170 into the borehole 110. The transport means 160 may be a coiled casing and / or a column of butt-jointed casings, among other things, and remain within the scope of the invention. For example, the transport means 160 may be a working column, an injection column, and / or a production column. In at least one embodiment, the downhole tool 150 may include a bridge plug, a fracturing plug, a packer, and / or another sealing tool, having one or more sealing elements 155 to ensure sealing against the borehole wall 110 (for example, the casing 140, a casing, and / or bare rock in an open-hole context).The sealing element(s) 155 can isolate an interval of the borehole 110 above the sealing element(s) 155 from an interval of the borehole 110 below the sealing element(s) 155, for example, so that a pressure differential can exist between the intervals.

[0028] According to one embodiment of the invention, the downhole tool 150 may comprise a tubular component (for example, a mandrel, a base tube, etc.), and one or more expanding metal sealing elements positioned around the tubular component, the expanding metal sealing element(s) comprising a metal designed to expand in response to hydrolysis and having a surface area to volume ratio (SA:V) of at least 2 cm¹. According to another embodiment of the invention, the downhole tool 150 may comprise a tubular component, and a set of separate individual fragments of expanding metal positioned around the tubular component, the set of separate individual fragments of expanding metal comprising a metal designed to expand in response to hydrolysis.

[0029] This results in one or more expanding metal sealing elements extending between two surfaces. The term "expandable metal," as used here, refers to the expandable metal in a pre-expansion form. Similarly, the term "expanded metal," as used here, refers to the expanded metal resulting after the expandable metal has been subjected to a reactive fluid, as described below. The expanded metal, according to one or more aspects of the invention, comprises a metal that has expanded in response to hydrolysis. In some embodiments, the expanded metal includes unreacted residual metal. For example, in some embodiments, the expanded metal is intentionally designed to include unreacted residual metal. The unreacted residual metal has the advantage of allowing the expanded metal to self-heal if cracks or other defects subsequently appear, or For example, to accommodate changes in the diameter of the tubing or mandrel due to variations in temperature and / or pressure. However, other embodiments may exist in which no unreacted residual metal is present in the expanded metal.

[0030] In certain embodiments, the expandable metal can be described as expanding into a cement-like material. In other words, the expandable metal transitions from a metal to micron-scale particles, which then expand and interlock to essentially seal two or more surfaces together. In some embodiments, the reaction can occur in less than two days in a reactive fluid and at downhole temperatures. However, the reaction time can vary, depending on the reactive fluid, the expandable metal used, the downhole temperature, and, as discussed in detail here, the surface area to volume (SA:V) ratio of the expandable metal.

[0031] In some embodiments, the reactive fluid may be a brine solution such as may be produced during well completion activities, and in other embodiments, the reactive fluid may be one of the additional solutions discussed herein. The expandable metal is electrically conductive in some embodiments. The expandable metal may be machined to any specific size / shape, extruded, formed, cast, or otherwise conventionally shaped to obtain the desired form of a metal, as will be discussed in more detail below. In at least some embodiments, the expandable metal is a collection of separate individual fragments of expandable metal. The expandable metal, in some embodiments, has a yield strength greater than approximately 8,000 psi (55.15 MPa), for example, 8,000 psi + / - 50%.

[0032] The hydrolysis of the expandable metal can create a metal hydroxide. The metal-forming properties of alkaline earth metals (Mg - Magnesium, Ca - Calcium, etc.) and transition metals (Zn - Zinc, Al - Aluminum, etc.) in hydrolysis reactions demonstrate structural characteristics favorable to use with the present invention. Hydration leads to an increase in the size of the hydration reaction and results in the formation of a metal hydroxide that can precipitate from the fluid.

[0033] The hydration reactions of magnesium are:

[0034] Mg + 2H2O → Mg(OH)2 + H2

[0035] where Mg(OH)2 is also known as brucite. Another hydration reaction uses the hydrolysis of aluminum. The reaction forms a material known as gibbsite, bayerite, boehmite, aluminum oxide, and nordstrandite, depending on the form. The possible hydration reactions for aluminum are:

[0036] Al + 3H2O A1(OH)3 + 3 / 2 H2

[0037] Al + 2H2O -> Al O(OH) + 3 / 2 H2

[0038] Al + 3 / 2 H2O -> A12O3 + 3 / 2 H2

[0039] Another hydration reaction uses the hydrolysis of calcium. The hydration reaction for calcium is:

[0040] Ca + 2H2O → Ca(OH)2 + H2

[0041] where Ca(OH)2 is known as portlandite and is a common hydrolysis product of Portland cement. Magnesium hydroxide and calcium hydroxide are considered relatively insoluble in water. Aluminum hydroxide can be considered an amphoteric hydroxide, which has solubility in strong acids or strong bases. Alkaline earth metals (e.g., Mg, Ca, etc.) work well for the expandable metal, but transition metals (Al, etc.) also work well for the expandable metal. In one embodiment, the metal hydroxide is dehydrated by swelling pressure to form a metal oxide.

[0042] In one embodiment, the expandable metal used may be a metal alloy. The expandable metal alloy may be an alloy of the base expandable metal with other elements in order to adjust either the strength of the expandable metal alloy, or the reaction time of the expandable metal alloy, or the strength of the resulting metal hydroxide by-product, among other adjustments. The expandable metal alloy may be alloyed with elements that improve the strength of the metal, such as, but not limited to, Ai - Aluminum, Zn - Zinc, Mn - Manganese, Zr - Zirconium, Y - Yttrium, Nd - Neodymium, Gd - Gadolinium, Ag - Silver, Ca - Calcium, Sn - Tin, Re - Rhenium, and Cu - Copper.In some embodiments, the alloy may be alloyed with a corrosion-promoting dopant, such as Ni (nickel), Fe (iron), Cu (copper), Co (cobalt), Ir (iridium), Au (gold), C (carbon), Ga (gallium), In (indium), Mg (mercury), Bi (bismuth), Sn (tin), and Pd (palladium). The expandable metal alloy may be constructed in a solid-solution process where the elements are combined with molten metal or a metal alloy. Alternatively, the expandable metal alloy could be constructed using a powder metallurgy process. The expandable metal may be cast, forged, extruded, sintered, welded, rolled, turned, stamped, eroded, or a combination thereof. The metal alloy may be a mixture of the metal and a metal oxide. For example, a mixture of aluminum powder and aluminum oxide can be ground together to increase the reaction rate.

[0043] Optionally, non-expandable components may be added to the starting metallic materials. For example, ceramic, elastomer, plastic, epoxy, glass, or non-reactive metal components may be embedded in the expandable metal or coated onto the surface of the expandable metal. In still other modes In this process, non-expansive components include metallic fibers, composite weaves, polymer ribbons, and ceramic granules, among others. Alternatively, the starting expandable metal can be a metal oxide. For example, calcium oxide (CaO) with water will produce calcium hydroxide in an energetic reaction. Due to the higher density of calcium oxide, it can have a volumetric expansion of 260% (e.g., the conversion of 1 mole of CaO can result in a volume increase from 9.5 cc to 34.4 cc). In another variation, the expandable metal is formed in a serpentinite reaction, a hydration and metamorphic reaction. In yet another variation, the resulting material resembles a mafic material. Additional ions can be added to the reaction, including silicate, sulfate, aluminate, carbonate, and phosphate.The metal can be alloyed to increase reactivity or to control oxide formation.

[0044] The expandable metal can be designed in various ways, as long as an adequate volume of material is available for complete expansion. For example, the expandable metal can be formed into a single long element, several short elements, rings, among other shapes. In another embodiment, the expandable metal can be formed into a long expandable metal wire, which can in turn be wound around a downhole element such as a tube. The wire diameters need not be circular in cross-section but can be any shape. For example, the cross-section of the wire could be oval, rectangular, star-shaped, hexagonal, keystone-shaped, hollow braided, woven, twisted, among other shapes, and remain within the scope of the invention.In some other embodiments, the expandable metal is a collection of individual fragments separated from the metal and held together by a bonding agent. In some other embodiments, the expandable metal is a collection of individual fragments separated from the metal and not held together by a bonding agent. Furthermore, a retarding coating may be applied to one or more portions of the expandable metal to delay expansion reactions.

[0045] In at least one other embodiment, voids may exist between adjacent parts of the expandable metal. In at least one embodiment, the voids may be at least partially filled with a material designed to delay the hydrolysis process. In one embodiment, the material designed to delay the hydrolysis process is a fusible alloy. In another embodiment, the material designed to delay the hydrolysis process is a eutectic material. In yet another embodiment, the material designed to delay the hydrolysis process is a wax, an oil, or another non-reactive material. Alternatively, the voids may be at least partially filled with a material designed to accelerate the hydrolysis process. In one embodiment, the material designed to accelerate the hydrolysis process is a reactive powder, such as a salt.

[0046] Reference is now made to Figures 2A to 2C, which illustrate different deployment states for a downhole tool 200 designed, manufactured, and used according to one aspect of the invention. Figure 2A illustrates the pre-expansion of the downhole tool 200, Figure 2B illustrates the post-expansion of the downhole tool 200, and Figure 2C illustrates the post-expansion of the downhole tool 200 containing residual, unreacted expandable metal. As described above, the expandable metal in Figure 2A can be subjected to a suitable reactive fluid inside a wellbore, thus forming the expanded metal shown in Figures 2B and 2C.

[0047] The downhole tool 200, in the embodiment illustrated in Figures 2A to 2C, includes a tubular component 210. The tubular component 210 may comprise any surface that exists inside a borehole while remaining within the scope of the invention. The tubular component 210, in the illustrated embodiment, is centered around a midline (Cl). The downhole tool 200, in at least the embodiment shown in Figures 2A to 2C, further includes a surface 220 positioned around the tubular component 210. In at least one embodiment, the surface 220 is a tubular surface, such as, for example, casing, production casing, etc. In yet another embodiment, the surface 220 is the borehole itself, for example, if an open-hole borehole is used. According to one aspect of the invention, the tubular 210 and the surface 220 form a first space 230 between them.In at least one embodiment, the first space 230 is a ring between the tubular 210 and the surface 220, the ring extending around the midline (Cl). In still other embodiments, the first space 230 does not extend entirely around the midline (Cl), and therefore does not form a ring.

[0048] The downhole tool 200, in at least the embodiment shown in Figures 2A to 2C, further includes a pair of end rings 240 positioned between the tubular section 210 and the surface 220, and inside the first space 230. The downhole tool 200, in one or more embodiments, also includes a sleeve 250 covering the pair of end rings 240. As is evident in the embodiment shown in Figures 2A to 2C, the pair of end rings 240 and the sleeve 250 define a second space 260. In one or more embodiments, the sleeve 250 is a solid sleeve. In yet another embodiment, not shown, the sleeve 250 has one or more openings to allow the reactive fluid to enter the second space 260. In yet another embodiment, the sleeve 250 is a sieve or a metal mesh.

[0049] In at least one embodiment, the pair of end rings 240 and / or the sleeve 250 may comprise a metal designed to expand in response to hydrolysis. In the embodiment illustrated in Figures 2A to 2C, the pair of end rings 240 comprises a non-expandable metal, but the sleeve 250 includes an expanding metal. However, other embodiments exist in which the sleeve 250 comprises a non-expanding metal and the pair of end plates 240 comprises an expanding metal. Still other embodiments exist in which neither the pair of end rings 240 nor the sleeve 250 comprises an expanding metal, or yet other embodiments exist in which both the pair of end rings 240 and the sleeve 250 comprise an expanding metal.

[0050] With reference to [Fig. 2A], one or more expanding metal sealing elements 270 may be placed around the tubular 210, the expanding metal sealing element(s) 270 comprising a metal designed to expand in response to hydrolysis. The expanding metal sealing element(s) 270 may comprise any of the expanding metals described above. In addition to the embodiment of [Fig. 2A], the expanding metal sealing element(s) 270 may have a surface area to volume ratio (SA:V) of at least 2 cm³. In another embodiment, the expanding metal sealing element(s) 270 may have a surface area to volume ratio (SA:V) of at least 5 cm³.In yet another embodiment, the expanding metal sealing element(s) 270 may have a surface area to volume ratio (SA:V) of less than 100 cm¹, and in other embodiments, a surface area to volume ratio (SA:V) between 5 cm¹ and 50 cm²*, or a surface area to volume ratio (SA:V) between 10 cm¹ and 20 cm¹. The specific surface area to volume ratio (SA:V) of the expanding metal sealing element(s) 270 can be chosen based on a desired reaction time for the expanding metal sealing element(s) 270. As discussed above, the higher the surface area to volume ratio (SA:V) (for example, for a given material), the faster the reaction speed will be (for example, for that same material).

[0051] In the embodiment of [Fig. 2A], the expanding metal sealing element(s) 270 are one or more expanding metal wires wound (e.g., helically wound) around the tubular 210. In the illustrated embodiment, the expanding metal wire(s) are positioned inside the second space 260 between the pair of end rings 240 and the sleeve 250. In the embodiment of [Fig. 2A], a single expanding metal wire is wound several times around the tubular 210, as well as back over and over itself. Thus, in the embodiment of [Fig. 2A], three layers of the single expanding metal wire exist around the tubular 210. However, other configurations fall within the scope of the invention. Furthermore, while the expanding metal wire illustrated in [Fig.2A] includes a circular cross-section, other embodiments exist in which the cross-section of the wire could be oval, rectangular, star-shaped, hexagonal, keystone-shaped, hollow braided, woven, twisted, among others, and remain within the framework of . the invention. In addition, the expandable metal wire(s) can be heat-treated to reduce springback. In at least one embodiment, the expandable metal sealing element(s) 270 are stamped to the tubular 210 to prevent voids. In other embodiments, voids are intentionally left or created.

[0052] With reference to [Fig. 2B], this figure illustrates the downhole tool 200 of [Fig. 2A] after the expanding metal sealing element(s) 270 have been subjected to a reactive fluid, thus forming one or more expanding metal sealing elements 280, as discussed above. In the illustrated embodiment, the expanding metal sealing element(s) 270 are transformed into a single expanding metal sealing element 280 when they are made to react appreciably. However, other embodiments exist in which the expanding metal sealing element(s) 270 are transformed into multiple expanding metal sealing elements 280 when they are made to react appreciably. Again, the expanding metal sealing element(s) 280 can function as a gasket, a fastener, or both a gasket and a fastener and remain within the scope of the invention.

[0053] In some embodiments, the hydration time of the expanding metal sealing element(s) 270 differs from the hydration time of one or both elements of the end ring pair 240 and / or the sleeve 250. For example, the larger surface area to volume (SA:V) ratio of the expanding metal sealing element(s) 270, compared to the smaller surface area to volume (SA:V) ratio of the end ring pair 240 and / or the sleeve 250, may cause the expanding metal sealing element(s) 270 to expand in response to hydrolysis more rapidly than the end ring pair 240 and / or the sleeve 250. Furthermore, or alternatively, the expanding metal sealing element(s) 270 may comprise an expanding metal material that reacts more rapidly than the metal material expandable from the pair of end rings 240 and / or sleeve 250.

[0054] With reference to [Fig. 2C], this figure illustrates the downhole tool 200 shown in [Fig. 2A] after the expanding metal sealing element(s) 270 have been subjected to a reactive fluid to form one or more expanding metal sealing elements containing unreacted residual expanding metal 290, as described above. In one embodiment, the expanding metal sealing element(s) containing unreacted residual expanding metal 290 include at least 1% of unreacted residual expanding metal.

[0055] In yet another embodiment, the expanded metal sealing element(s) containing residual unreacted expandable metal 290 include at least 3% of residual unreacted expandable metal. In yet another embodiment of embodiment, the expanded metal sealing element(s) containing residual unreacted expandable metal 290 include at least 10% of residual unreacted expandable metal and, in some embodiments, at least 20% of residual unreacted expandable metal.

[0056] Reference is now made to Figures 3A to 3C, which describe various different manufacturing states for a downhole tool 300 designed, manufactured, and used according to another embodiment of the invention. Figure 3A illustrates the pre-expansion of the downhole tool 300, Figure 3B illustrates the post-expansion of the downhole tool 300, and Figure 3C illustrates the post-expansion of the downhole tool 300 containing residual, unreacted expandable metal. The downhole tool 300 in Figures 3A to 3C is similar in many respects to the downhole tool 200 in Figures 2A to 2C. Consequently, identical reference numbers have been used to designate similar, if not identical, features. The 300 downhole tool differs, essentially, from the 200 downhole tool, in that the 300 downhole tool does not use the 250 sleeve.

[0057] Reference is now made to Figures 4A to 4C, which describe various different manufacturing states for a downhole tool 400 designed, manufactured, and used according to another embodiment of the invention. Figure 4A illustrates the pre-expansion of the downhole tool 400, Figure 4B illustrates the post-expansion of the downhole tool 400, and Figure 4C illustrates the post-expansion of the downhole tool 400 containing residual, unreacted expandable metal. The downhole tool 400 in Figures 4A to 4C is similar in many respects to the downhole tool 200 in Figures 2A to 2C. Consequently, identical reference numbers have been used to designate similar, if not identical, features. The 400 downhole tool differs, essentially, from the 200 downhole tool, in that the 400 downhole tool does not use the 240 end ring pair or the 250 sleeve.Thus, in accordance with this embodiment, the expanding metal sealing element(s) 270 are individually placed inside the first space 230.

[0058] Reference is now made to Figures 5A to 5C, which describe various different manufacturing states for a downhole tool 500 designed, manufactured, and used according to another embodiment of the invention. Figure 5A illustrates the pre-expansion of the downhole tool 500, Figure 5B illustrates the post-expansion of the downhole tool 500, and Figure 5C illustrates the post-expansion of the downhole tool 500 containing residual, unreacted expandable metal. The downhole tool 500 of Figures 5A to 5C is similar in many respects to the downhole tool 200 of Figures 2A to 2C. Consequently, identical reference numbers have been used to designate similar, if not identical, features. The 500 downhole tool differs essentially from the 200 downhole tool in that the tool hole bottom 500 uses a non-circular cross section for its expanding metal sealing element(s) 570. Specifically, in the embodiment of Figures 5A to 5C, the expanding metal sealing element(s) 570 have a star-shaped cross section, among other possible shapes.

[0059] Reference is now made to Figures 6A to 6C, which describe various different manufacturing states for a downhole tool 600 designed, manufactured, and used according to another embodiment of the invention. Figure 6A illustrates the pre-expansion of the downhole tool 600, Figure 6B illustrates the post-expansion of the downhole tool 600, and Figure 6C illustrates the post-expansion of the downhole tool 600 containing residual, unreacted expandable metal. The downhole tool 600 in Figures 6A to 6C is similar in many respects to the downhole tool 200 in Figures 2A to 2C. Consequently, identical reference numbers have been used to designate similar, if not identical, features. The 600 downhole tool differs, essentially, from the 200 downhole tool, in that the 600 downhole tool uses a set of separate individual fragments of expandable metal 670 positioned around the tubular 210.In one embodiment, the set of individual fragments separated from the expandable metal 670 has a surface area to volume ratio (SA:V) of at least 2 cm1. In another embodiment, the set of individual fragments separated from the expandable metal 670 has a surface area to volume ratio (SA:V) of at least 5 cm1. In yet another embodiment, the set of individual fragments separated from the expandable metal 670 has a surface area to volume ratio (SA:V) of less than 100 cm', or alternatively a surface area to volume ratio (SA:V) ranging from 5 cm1 to 50 cm'.

[0060] In certain embodiments, the set of individual fragments separated from the expandable metal 670 is a set of individual pieces separated from different sizes of expandable metal. For example, in certain embodiments, a first volume of a larger fragment from the set of individual fragments separated from the expandable metal 670 represents at least 5 times a second volume of a smaller fragment from the set of individual fragments separated from the expandable metal 670. In another embodiment, a first volume of a larger fragment from the set of individual fragments separated from the expandable metal 670 represents at least 50 times a second volume of a smaller fragment from the set of individual fragments separated from the expandable metal 670. Furthermore, while the embodiment of [Fig.6A] uses fragments of expandable metal 670 of different sizes; other embodiments exist in which each of the fragments of expandable metal 670 is substantially (for example, within 10%) the same. Furthermore, in some embodiments, the set of separate individual fragments of expandable metal 670 may comprise at least two different expandable metals or one. expandable metal and a metal oxide. In one embodiment, the fragments of expandable metal 670 are compressed together to form a loosely bound conglomerate of fragments.

[0061] In embodiment 6A, the set of individual fragments of expandable metal 670 is positioned inside the second space 260 and held in place with the sleeve 250. In yet another embodiment, the individual fragments of expandable metal 670 are held in place with a sieve or mesh material. In other embodiments, one or more of the pairs of end rings 240 and / or the sleeve 250 are not required. For example, in some embodiments, the set of individual fragments of expandable metal 670 is held together by a bonding agent, which may not require the pairs of end rings 240 and / or the sleeve 250. In at least one embodiment, the bonding agent is a salt, which may also be used to accelerate the hydrolysis reaction.

[0062] Reference is now made to Figures 7A to 7C, which describe various different manufacturing states for a downhole tool 700 designed, manufactured, and used according to another embodiment of the invention. Figure 7A illustrates the pre-expansion of the downhole tool 700, Figure 7B illustrates the post-expansion of the downhole tool 700, and Figure 7C illustrates the post-expansion of the downhole tool 700 containing residual, unreacted expandable metal. The downhole tool 700 of Figures 7A to 7C is similar in many respects to the downhole tool 200 of Figures 2A to 2C. Consequently, identical reference numbers have been used to designate similar, if not identical, features. The 700 downhole tool differs, essentially, from the 200 downhole tool, in that the 700 downhole tool uses a plurality of axially stacked expandable metal sealing elements 770.

[0063] In the embodiment of [Fig. 7A], each of the plurality of axially stacked expanding metal sealing elements 770 are separate elements that can move relative to one another. In addition to the embodiment of [Fig. 7A], the plurality of axially stacked expanding metal sealing elements 770 are designed such that voids 780 exist between adjacent parts of the plurality of axially stacked expanding metal sealing elements 770. In addition to the embodiment of [Fig. 7A], a material 790 can at least partially fill the voids 780. In at least one embodiment, the material 790 is designed to delay hydrolysis, as with an oil or a wax. In yet another embodiment, the material 790 is designed to accelerate hydrolysis, as with a salt or an acid anhydride.In addition, the plurality of axially stacked 770 expandable metal sealing elements can have a surface texture for. to facilitate contact with the fluid, including, but not limited to, crenellations, divots, roughness, etc. In addition, some embodiments may use one or more polymer rings, such as elastomer rings, with the axially stacked expandable metal sealing elements 770. The polymer rings may be located at the ends of the axially stacked expandable metal sealing elements 770, or may be intercalated within the axially stacked expandable metal sealing elements 770.

[0064] Reference will now be made to Figures 8A to 8E, which describe various different manufacturing states for a downhole tool 800 designed, manufactured and used according to another embodiment of the invention. [Fig. 8A] illustrates the pre-expansion of the downhole tool 800, [Fig. 8B] illustrates the downhole tool 800 at an initial stage of expansion, [Fig. 8C] illustrates the downhole tool 800 at the mid-stage of expansion, [Fig. 8D] illustrates the post-expansion of the downhole tool 800, and [Fig. 8E] illustrates the post-expansion of the downhole tool 800 containing residual expandable metal that has not reacted. The 800 downhole tool in Figures 8A to 8E is similar in many respects to the 200 downhole tool in Figures 2A to 2C. Accordingly, identical reference numbers have been used to denote similar, if not identical, features.The 800 downhole tool differs, essentially, from the 200 downhole tool, in that the 800 downhole tool uses several separate wires of expandable metal.

[0065] For example, in the embodiment of [Fig. 8A], the downhole tool 800 includes a first expandable metal wire 870a wound around the tubular 210, a second, different expandable metal wire 870b wound around the first expandable metal wire 870a, and a third, different expandable metal wire 870c wound around the second expandable metal wire 870b. The first, second, and third expandable metal wires 870a, 870b, 870c may be made of the same or different materials and may have the same or different reaction rates. However, in the embodiment shown in Figures 8A to 8C, the first, second, and third expandable metal wires 870a, 870b, 870c have different reaction rates.Specific to the embodiment of Figures 8A to 8C, the first expandable metal wire 870a has the fastest reaction speed, the second expandable metal wire 870b has the second fastest reaction speed, and the third expandable metal wire 870c has the slowest reaction speed. The reverse could, however, be true and remain within the scope of the invention.

[0066] In at least one embodiment, the different reaction rates are a function of their different surface-to-volume ratios (SA:V). Thus, in at least one embodiment, the first wire 870a has the highest surface-to-volume ratio (SA:V), the second, different wire 870b has a lower surface-to-volume ratio (SA:V), and the third different yarn 870c has a third lowest surface area to volume ratio (SA:V). For example, in at least one embodiment, the first yarn 870a has a surface area to volume ratio (SA:V) of at least 10 cm1, the second different yarn 870b has a second lower surface area to volume ratio (SA:V) between 5 cm1 and 10 cm*, and the third different yarn 870c has the third lowest surface area to volume ratio (SA:V) between 2 cm1 and 5 cm1.

[0067] In yet another embodiment, the different reaction rates depend on their different materials. For example, a material for the first wire 870a could be chosen to have the fastest reaction rate, a material for the second wire 870b could be chosen to have the medium reaction rate, and a material for the third wire 870c could be chosen to have the slowest reaction rate. However, the opposite could also be true. As shown in Figures 8B to 8D, the expanding metal sealing element 880b, 880c, 880d expands incrementally as each of the first, second, and third expanding metal wires 870a, 870b, 870c expands in response to hydrolysis.

[0068] Reference will now be made to Figures 9A to 9E, which describe various different manufacturing states for a downhole tool 900 designed, manufactured and used according to another embodiment of the invention. [Fig. 9A] illustrates the pre-expansion of the downhole tool 900, [Fig. 9B] illustrates the downhole tool 900 at an initial stage of expansion, [Fig. 9C] illustrates the downhole tool 900 at the mid-stage of expansion, [Fig. 9D] illustrates the post-expansion of the downhole tool 900, and [Fig. 9E] illustrates the post-expansion of the downhole tool 900 containing residual expandable metal that has not reacted. The 900 downhole tool in Figures 9A to 9E is similar in many respects to the 800 downhole tool in Figures 8A to 8E. Consequently, identical reference numbers have been used to designate similar, if not identical, characteristics.The 900 downhole tool differs essentially from the 800 downhole tool in that the 900 uses first, second, and third expandable metal wires 970a, 970b, and 970c that are axially stacked relative to each other. In addition to the embodiment shown in Figures 9A to 9E, the first expandable metal wire 970a has the fastest reaction speed, the second expandable metal wire 970b has the second fastest reaction speed, and the third expandable metal wire 970c has the slowest reaction speed. This is shown in Figures 9B to 9D, with the expanding metal sealing element 980b, 980c, 980d expanding incrementally as each of the first, second, and third expanding metal wires 970a, 970b, 970c expands in response to hydrolysis. However, the opposite could also be true.

[0069] Reference will now be made to Figures 10A to 10E, which describe various different manufacturing states for a downhole tool 1000 designed, manufactured and used according to another embodiment of the invention. Figure 10OA illustrates the pre-expansion of the downhole tool 1000, Figure 1OB illustrates the downhole tool 1000 at an initial stage of expansion, Figure 1OC illustrates the downhole tool 1000 at the mid-expansion stage, Figure 1OD illustrates the post-expansion of the downhole tool 1000, and Figure 1OE illustrates the post-expansion of the downhole tool 1000 containing residual, unreacted expandable metal. The downhole tool 1000 of Figures 10A to 10E is similar in many respects to the downhole tool 900 of Figures 9A to 9E. Consequently, identical reference numbers have been used to designate similar, if not identical, features.The 1000 downhole tool differs essentially from the 900 downhole tool in that the third expandable metal wire 1070c has the fastest reaction rate, the second expandable metal wire 1070b has the second fastest reaction rate, and the first expandable metal wire 1070a has the slowest reaction rate. This is shown in Figures 10B to 10D, with the expanded metal sealing element 1080b, 1080c, 1080d expanding incrementally as each of the first, second, and third expandable metal wires 1070c, 1070b, 1070a expands in response to hydrolysis.

[0070] Reference is now made to Figures 11A to 11D, which describe various different manufacturing states for a downhole tool 1100 designed, manufactured, and used according to another embodiment of the invention. [Fig. 1IA] illustrates the pre-expansion of the downhole tool 1100, [Fig. 1IB] illustrates the downhole tool 1100 at an initial stage of expansion, [Fig. 11C] illustrates the post-expansion of the downhole tool 1100, and [Fig. 11D] illustrates the post-expansion of the downhole tool 1100 containing residual, unreacted expandable metal. The downhole tool 1100 of Figures 11A to 11D is similar in many respects to the downhole tool 200 of Figures 2A to 2C. Consequently, identical reference numbers have been used to designate similar, if not identical, characteristics.The downhole tool 1100 differs essentially from the downhole tool 200 in that the downhole tool 1100 includes one or more second expanding metal sealing elements 1170 positioned around the tubular 210 near the first expanding metal sealing element(s) 270. In at least one embodiment, the second expanding metal sealing element(s) 1170 comprise the metal designed to expand in response to hydrolysis, but have a second surface area to volume ratio (SA:V) of less than 1 cm¹. In at least another embodiment, the second surface area to volume ratio (SA:V) is less than 0.1 cm¹.

[0071] Reference is now made to Figures 12A to 12D, which describe various different manufacturing states for a downhole tool 1200 designed, manufactured and used according to another embodiment of the invention. Figure 12A illustrates the pre-expansion of The 1200 downhole tool is shown in Figures 12A to 12D. Figures 12A to 12D illustrate the 1200 downhole tool at an initial stage of expansion, Figures 11A to 11D illustrate the post-expansion of the 1200 downhole tool, and Figures 12B illustrate the post-expansion of the 1200 downhole tool containing residual, unreacted expandable metal. The 1200 downhole tool in Figures 12A to 12D is similar in many respects to the 1100 downhole tool in Figures 11A to 11D. Consequently, identical reference numbers have been used to designate similar, if not identical, characteristics. The 1200 downhole tool differs, essentially, from the 1100 downhole tool, in that the 1200 downhole tool includes one or more second expanding metal sealing elements 1270 placed around the first expanding metal sealing element(s) 270.In at least one embodiment, the second expanding metal sealing element(s) 1270 comprise the metal designed to expand in response to hydrolysis, but have a second surface area to volume ratio (SA:V) of less than 1 cm1. In at least another embodiment, the second surface area to volume ratio (SA:V) is less than 0.1 cm1.

[0072] Reference will now be made to Figures 13A to 13D, which describe various different manufacturing states for a downhole tool 1300 designed, manufactured and used according to another embodiment of the description. [Fig. 13A] illustrates the pre-expansion of the downhole tool 1300, [Fig. 13B] illustrates the downhole tool 1300 with post-expansion in expandable metal, [Fig. 13C] illustrates the downhole tool 1300 with post-expansion in expandable metal and post-expansion in inflatable elastomer, and [Fig. 13D] illustrates the downhole tool 1300 with post-expansion in expandable metal and post-expansion in inflatable elastomer, and containing residual expandable metal that has not reacted. The 1300 downhole tool in Figures 13A to 13D is similar in many respects to the 200 downhole tool in Figures 2A to 2C.Consequently, identical reference numbers have been used to designate similar, if not identical, features. The downhole tool 1300 differs essentially from the downhole tool 200 in that the downhole tool 1300 includes one or more inflatable elastomers 1240 positioned around the tubular 210. In the illustrated embodiment, the inflatable elastomer(s) 1240 are located on either side of the expandable metal sealing element(s) 270, but they could be located anywhere. In the illustrated embodiment, the inflatable elastomer(s) 1240 inflate more slowly than the expandable metal sealing element(s) 270 expand.

[0073] The aspects described in the present invention include:

[0074] A. A downhole tool, the downhole tool comprising: 1) a tubular component; and 2) one or more expanding metal sealing elements placed around the tubular component, the expanding metal sealing element(s) comprising a metal designed to expand in response to hydrolysis and having a surface area / volume ratio (SA:V) of at least 2 cm1. B. A method for sealing within a well system, the method comprising: 1) the positioning of a downhole tool within a well extending into an underground formation, the downhole tool including: a) a tubular section; and b) one or more expandable metal sealing elements placed around the tubular section, the expandable metal sealing element(s) comprising a metal designed to expand in response to hydrolysis and having a surface area / volume ratio (SA:V) of at least 2 cm³; and 2) subjecting the expandable metal sealing element(s) to a reactive fluid to form one or more expanded metal sealing elements. C. A well system, the well system including: 1) a borehole extending into an underground formation; 2) a means of transport positioned inside the borehole; and 3) a downhole tool coupled to the means of transport, the downhole tool including: a) a tubular component; and b) one or more expandable metal sealing elements placed around the tubular component, the expandable metal sealing element(s) comprising a metal designed to expand in response to hydrolysis and having a surface area to volume ratio (SA:V) of at least 2 cm1. D. A downhole tool, the downhole tool including: 1) a tubular; and 2) an array of separate individual fragments of expandable metal positioned around the tubular, the array of separate individual fragments of expandable metal comprising a metal designed to expand in response to hydrolysis. E. A method for sealing within a well system, the method including: 1) the positioning of a downhole tool within a wellbore extending into an underground formation, the downhole tool including: a) a tubular component; and b) an assembly of separate individual fragments of expandable metal positioned around the tubular component, the assembly of separate individual fragments of expandable metal comprising a metal designed to expand in response to hydrolysis; and 2) subjecting the assembly of separate individual fragments of expandable metal to a reactive fluid to form one or more expanded metal seals.

[0075] F. A well system, the well system comprising: 1) a borehole extending to a subsurface formation; 2) a means of transport positioned inside the borehole; and 3) a downhole tool coupled to the means of transport, the downhole tool comprising: a) a tubular component; and b) a set of individual fragments separated from expandable metal positioned around the tubular, the set of separate individual fragments of expandable metal comprising a metal designed to expand in response to hydrolysis.

[0076] Aspects A, B, C, D, E and F may combine one or more of the following additional elements:

[0077] Element 1: the expanding metal sealing element(s) have a surface / volume ratio (SA:V) of at least 5 cm1.

[0078] Element 2: the expanding metal sealing element(s) have a surface / volume ratio (SA:V) of less than 100 cm1.

[0079] Element 3: the expanding metal sealing element(s) have a surface / volume ratio (SA:V) between 5 cm1 and 50 cm².

[0080] Element 4: the expanding metal sealing element(s) have a surface / volume ratio (SA:V) between 10 cm1 and 20 cm².

[0081] Element 5: The expanding metal sealing element(s) are one or more expanding metal wires wound around the tubular.

[0082] Element 6: the expanding metal sealing element(s) are a first expanding metal wire wound around the tubular and a second different expanding metal wire wound around the first expanding metal wire.

[0083] Element 7: the first wire has a first reaction rate, and the second different wire has a second different reaction rate.

[0084] Element 8: the first wire has a surface-to-volume ratio (SA:V) of at least 10 cm¹ and the second different wire has a second smaller surface-to-volume ratio (SA:V), the second smaller surface-to-volume ratio (SA:V) causing the second different reaction rate to be slower than the first reaction rate.

[0085] Element 9: the first wire comprises a first expandable metal having the first reaction rate and the second different wire comprises a second different expandable metal having a second lower reaction rate.

[0086] Element 10: a sleeve covers the expanding metal sealing element(s).

[0087] Element 11: the sleeve is a solid sleeve.

[0088] Element 12 the sleeve includes openings to allow the reactive fluid to come into contact with the expanding metal sealing element(s).

[0089] Element 13: The expanding metal sealing element(s) are a set of separate individual fragments of expanding metal held in place by the sleeve.

[0090] Element 14: The set of separate individual fragments of expandable metal comprises at least two different expandable metals.

[0091] Element 15: The set of separate individual fragments of expandable metal comprises a plurality of fragments of different sizes of the expandable metal.

[0092] Element 16: The sleeve comprises a metal designed to expand in response to hydrolysis.

[0093] Element 17: The expanding metal sealing element(s) are a plurality of axially stacked expanding metal sealing elements.

[0094] Element 18: The expanding metal sealing element(s) are designed so that voids exist between adjacent parts of the expanding metal sealing element(s).

[0095] Element 19: The process further includes at least partial filling of voids with a material designed to delay hydrolysis.

[0096] Element 20: The process further includes at least partial filling of voids with a material designed to delay hydrolysis.

[0097] Element 21: the expanding metal sealing element(s) are one or more first expanding metal sealing elements, one or more second expanding metal sealing elements being placed around the tubular close to the first expanding metal sealing element(s), one or more second expanding metal sealing elements comprising the metal designed to expand in response to hydrolysis and having a second surface area / volume ratio (SA:V) of less than 1 cm1.

[0098] Element 22: the second surface / volume ratio (SA:V) is less than 1 cm1.

[0099] Element 23: the set of separate individual fragments of expandable metal has a surface area / volume ratio (SA:V) of at least 2 cm1.

[0100] Element 24: the set of separate individual fragments of expandable metal has a surface / volume ratio (SA:V) of at least 5 cm1.

[0101] Element 25: the set of separate individual fragments of expandable metal has a surface / volume ratio (SA:V) of at least 100 cm1.

[0102] Element 26: the set of separate individual fragments of expandable metal has a surface / volume ratio (SA:V) between 5 cm1 and 50 cm1.

[0103] Element 27: The set of individual fragments separated from the expandable metal is a set of individual fragments separated from different sizes of expandable metal.

[0104] Element 28: a first volume of a larger of the set of individual fragments separated from the expandable metal represents at least 5 times a second volume of a smaller of the set of individual fragments separated from the expandable metal.

[0105] Element 29: a first volume of a larger of the set of individual fragments separated from the expandable metal represents at least 50 times a second volume of a smaller of the set of individual fragments separated from the expandable metal.

[0106] Element 30: The set of individual fragments separated from the expandable metal is held together with a bonding agent.

[0107] Element 31: a surface is positioned around the tubular, the tubular and the surface defining a space between them, the set of separate individual fragments of expandable metal being positioned in space.

[0108] Element 32: the set of separate individual fragments of expandable metal has a surface / volume ratio (SA:V) of at least 2 cm1.

[0109] Element 33: the set of separate individual fragments of expandable metal has a surface / volume ratio (SA:V) less than 100 cm1.

[0110] Element 34: The set of individual fragments separated from the expandable metal is a set of individual fragments separated from different sizes of expandable metal, a first volume of a larger of the set of individual fragments separated from the expandable metal represents at least 5 times a second volume of a smaller of the set of individual fragments separated from the expandable metal.

[0111] Element 35: a first volume of a larger of the set of individual fragments separated from the expandable metal represents at least 50 times a second volume of a smaller of the set of individual fragments separated from the expandable metal.

[0112] Element 36: a surface is positioned around the tubular, the tubular and the surface defining a space between them, the set of separate individual fragments of expandable metal being positioned in the space.

[0113] Element 37: the set of separate individual fragments of expandable metal has a surface / volume ratio (SA:V) of at least 5 cm1.

[0114] Element 38: the set of separate individual fragments of expandable metal has a surface / volume ratio (SA:V) of less than 100 cm1.

[0115] Element 39: The set of individual fragments separated from the expandable metal is a set of individual fragments separated from different sizes of expandable metal, a first volume of a larger of the set of individual fragments separated from the expandable metal represents at least 50 times a second volume of a smaller of the set of individual fragments separated from the expandable metal.

[0116] Element 40: a surface is positioned around the tubular, the tubular and the surface defining a space between them, the set of separate individual fragments of expandable metal being positioned in the space.

[0117] The person skilled in the art concerned with this application will understand that further additions, deletions, substitutions and modifications or subsequent additions, deletions, substitutions and modifications may be made to the embodiments described.

Claims

Demands

1. Downhole tool (150, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300), comprising: a tubular (210); and one or more expanding metal sealing elements (155, 270, 570, 880b, 880c, 880d, 980b, 980c, 980d) placed around the tubular (210), the expanding metal sealing element(s) (155, 270, 570, 880b, 880c, 880d, 980b, 980c, 980d) comprising a metal designed to expand in response to hydrolysis and having a surface area / volume ratio (SA:V) of at least 2 cm1.

2. Downhole tool (150, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300) according to claim 1, characterized in that the expanding metal sealing element(s) (155, 270, 570, 880b, 880c, 880d, 980b, 980c, 980d) have a surface area to volume ratio (SA:V) of at least 5 cm³, or optionally in which the expanding metal sealing element(s) (155, 270, 570, 880b, 880c, 880d, 980b, 980c, 980d) have a ratio surface / volume (SA:V) less than 100 cm1.

3. Downhole tool (150, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300) according to claim 1, characterized in that the expanding metal sealing element(s) (155, 270, 570, 880b, 880c, 880d, 980b, 980c, 980d) have a surface area / volume ratio (SA:V) between 5 cm1 and 50 cm1, or optionally wherein the expanding metal sealing element(s) (155, 270, 570, 880b, 880c, 880d, 980b, 980c, 980d) have a surface area / volume ratio (SA:V) between 10 cm1 and 20 cm1.

4. Downhole tool (200, 800, 900, 1000) according to claim 1, characterized in that the expanding metal sealing element(s) (270) are one or more expanding metal wires (270, 870a, 870b, 870c, 970a, 970b, 970c, 1070a, 1070b, 1070c) wound around the tubular (210).

5. Downhole tool (800) according to claim 1, characterized in that the expanding metal sealing element(s) are a first expanding metal wire (870a) wound around the tubular (210) and a second, different expanding metal wire (870b) wound around the first expanding metal wire (870a), or optionally wherein the first wire has a first reaction velocity (870a) and the second wire different (870b) has a second different reaction rate, or possibly wherein the first wire (870a) has a surface area / volume ratio (SA:V) of at least 10 cm¹ and the second different wire (870b) has a second lesser surface area / volume ratio (SA:V), the second lesser surface area / volume ratio (SA:V) causing the second different reaction rate to be slower than the first reaction rate, or possibly wherein the first wire (870a) comprises a first expandable metal having the first reaction rate and the second different wire (870b) comprises a second different expandable metal having a second lesser reaction rate.

6. Downhole tool (150, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300) according to claim 1, characterized in that a sleeve (250) covers the expanding metal sealing element(s) (155, 270, 570, 880b, 880c, 880d, 980b, 980c, 980d).

7. Downhole tool (150, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300) according to claim 6, characterized in that the sleeve (250) is a solid sleeve.

8. Downhole tool (150, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300) according to claim 6, characterized in that the sleeve includes openings therein to allow the reactive fluid to come into contact with the expanding metal sealing element(s) (155, 270, 570, 880b, 880c, 880d, 980b, 980c, 980d).

9. Downhole tool (600) according to claim 6, characterized in that the expanding metal sealing element(s) are a set of separate individual fragments of expanding metal (670) held in place by the sleeve (250), or optionally wherein the set of separate individual fragments of expanding metal (670) comprises at least two different expanding metals, or optionally wherein the set of separate individual fragments of expanding metal (670) comprises a plurality of fragments of different sizes of the expanding metal.

10. Downhole tool (150, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300) according to claim 6, characterized in that the sleeve (250) comprises a metal designed to expand in response to hydrolysis.

11. Downhole tool (700) according to claim 1, characterized in that the expanding metal sealing element(s) are a plurality of stacked expanding metal sealing elements axially (770).

12. A downhole tool (150, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300) according to claim 1, characterized in that the expanding metal sealing element(s) (155, 270, 570, 880b, 880c, 880d, 980b, 980c, 980d) are designed such that voids (780) exist between adjacent parts of the expanding metal sealing element(s) (155, 270, 570, 880b, 880c, 880d, 980b, 980c, 980d), or optionally further including at least the filler partial filling of voids (780) with a material designed to delay hydrolysis, or possibly further including at least partial filling of voids (780) with a material designed to accelerate hydrolysis.

13. Downhole tool (150, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300) according to claim 1, characterized in that the expanding metal sealing element(s) (155, 270, 570, 880b, 880c, 880d, 980b, 980c, 980d) are one or more first expanding metal sealing elements, and further including one or more second expanding metal sealing elements (1170, 1270) placed around the tubular (210) in close proximity to the first expanding metal sealing element(s) (155, 270, 570, 880b, 880c, 880d, 980b, 980c, 980d), the second expanding metal sealing element(s) (1170, 1270) comprising the metal designed to expand in response to hydrolysis and having a second surface area / volume ratio (SA:V) of less than 1 cm1, or possibly in which the second surface area / volume ratio (SA:V) is less than 1 cm1.

14. A method of sealing within a well system (100), comprising: the positioning of a downhole tool (150, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300) within a borehole (110) extending into an underground formation, the downhole tool (150, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300) including: a tubular (210); and one or more expanding metal sealing elements (155, 270, 570, 880b, 880c, 880d, 980b, 980c, 980d) placed around the tubular (210), the expanding metal sealing element(s) (155, 270, 570, 880b, 880c, 880d, 980b, 980c, 980d) comprising a metal designed to expand in response to hydrolysis and having a surface / volume (SA:V) of at least 2 cm³; and the act of subjecting the expanding metal sealing element(s) (155, 270, 570, 880b, 880c, 880d, 980b, 980c, 980d) to a reactive fluid to form one or more expanded metal sealing elements (280, 1080b, 1080c, 1080d).

15. Well system (100), comprising: a borehole (110) extending towards an underground formation; a means of transport (160) positioned inside the borehole (110); and a down-the-hole tool (150, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300) coupled to a means of transport (160), the down-the-hole tool (150, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300) including: a tubular (210); and one or more expanding metal sealing elements (155, 270, 570, 880b, 880c, 880d, 980b, 980c, 980d) placed around the tubular (210), the expanding metal sealing element(s) (155, 270, 570, 880b, 880c, 880d, 980b, 980c, 980d) comprising a metal designed to expand in response to hydrolysis and having a surface area / volume ratio (SA:V) of at least 2 cm1.

Images