Voltage to Accelerate/Decelerate Expandable Metal

This application is a divisional of U.S. application Ser. No. 17/151,468, filed on Jan. 18, 2021, entitled “VOLTAGE TO ACCELERATE/DECELERATE EXPANDABLE METAL,” which claims the benefit of U.S. Provisional Application Ser. No. 62/962,901, filed on Jan. 17, 2020, entitled “VOLTAGE TO ACCELERATE EXPANDABLE METAL,” both of which are commonly assigned with this application and incorporated herein by reference in its entirety.

Wellbores are drilled into the earth for a variety of purposes including accessing hydrocarbon bearing formations. A variety of downhole tools may be used within a wellbore in connection with accessing and extracting such hydrocarbons. Throughout the process, it may become necessary to isolate sections of the wellbore in order to create pressure zones. Downhole tools, such as frac plugs, bridge plugs, packers, and other suitable tools, may be used to isolate wellbore sections.

The aforementioned downhole tools are commonly run into the wellbore on a conveyance, such as a wireline, work string or production tubing, Such tools often have either an internal or external setting tool, which is used to set the downhole tool within the wellbore and hold the tool in place, and thus function as a wellbore anchor. The wellbore anchors typically include a plurality of slips, which extend outwards when actuated to engage and grip a casing within a wellbore or the open hole itself, and a sealing assembly, which can be made of rubber and extends outwards to seal off the flow of liquid around the downhole tool.

In the drawings and descriptions that follow, like parts are typically marked throughout the specification and drawings with the same reference numerals, respectively. The drawn figures are not necessarily, but may be, to scale. Certain features of the disclosure may be shown exaggerated in scale or in somewhat schematic form and some details of certain elements may not be shown in the interest of clarity and conciseness.

The present disclosure may be implemented in embodiments of different forms. Specific embodiments are described in detail and are shown in the drawings, with the understanding that the present disclosure is to be considered an exemplification of the principles of the disclosure, and is not intended to limit the disclosure to that illustrated and described herein. It is to be fully recognized that the different teachings of the embodiments discussed herein may be employed separately or in any suitable combination to produce desired results. Moreover, all statements herein reciting principles and aspects of the disclosure, as well as specific examples thereof, are intended to encompass equivalents thereof. Additionally, the term, “or,” as used herein, refers to a non-exclusive or, unless otherwise indicated.

Unless otherwise specified, use of the terms “connect,” “engage,” “couple,” “attach,” or any other like term describing an interaction between elements is not meant to limit the interaction to direct interaction between the elements and may also include indirect interaction between the elements described.

Unless otherwise specified, use of the terms “up,” “upper,” “upward,” “uphole,” “upstream,” or other like terms shall be construed as generally toward the surface of the well; likewise, use of the terms “down,” “lower,” “downward,” “downhole,” or other like terms shall be construed as generally toward the bottom, terminal end of a well, regardless of the wellbore orientation. Use of any one or more of the foregoing terms shall not be construed as denoting positions along a perfectly vertical or horizontal axis. Unless otherwise specified, use of the term “subterranean formation” shall be construed as encompassing both areas below exposed earth and areas below earth covered by water, such as ocean or fresh water.

Referring to, depicted is a perspective view of a well systemincluding an exemplary operating environment that the apparatuses, systems and methods disclosed herein may be employed. For example, the well systemcould use a downhole tool according to any of the embodiments, aspects, applications, variations, designs, etc. disclosed in the following paragraphs. The term downhole tool, as used herein and without limitation, includes frac plugs, bridge plugs, packers, and other tools for fluid isolation, as well as wellbore anchors, among any other downhole tools employing expandable metal.

The well systemillustrated in the embodiment ofincludes a wellboreformed in a subterranean formation. As those skilled in the art appreciate, the wellboremay be fully cased, partially cased, or an open hole wellbore. In the illustrated embodiment of, the wellboreis partially cased, and thus includes a cased regionand an open hole region. The cased region, as is depicted, may employ casingthat is held into place by cement.

The well systemillustrated inadditionally includes a downhole conveyancedeploying a downhole tool assemblywithin the wellbore. The downhole conveyancecan be, for example, tubing-conveyed, wireline, slickline, work string, or any other suitable means for conveying the downhole tool assemblyinto the wellbore. In one particular advantageous embodiment, the downhole conveyanceis American Petroleum Institute “API” pipe.

The downhole tool assembly, in the illustrated embodiment, includes a downhole tooland a wellbore anchor. The downhole toolmay comprise any downhole tool that could be positioned within a wellbore. Certain downhole tools that may find particular use in the well systeminclude, without limitation, sealing elements, sealing packers, elastomeric sealing packers, non-elastomeric sealing packers (e.g., including plastics such as PEEK, metal packers such as inflatable metal packers, as well as other related packers), liners, an entire lower completion, one or more tubing strings, one or more screens, one or more production sleeves, etc. Thewellbore anchormay comprise any wellbore anchor that could anchor the downhole toolwithin a wellbore. In certain embodiments, the downhole toolis deployed without the wellbore anchor, and in certain other embodiments the wellbore anchoris deployed without the downhole tool.

In accordance with the disclosure, at least a portion of the downhole toolor the wellbore anchormay include expandable metal. In some embodiments, all or part of the downhole toolor the wellbore anchormay be fabricated using expandable metal configured to expand in response to hydrolysis. The expandable metal, in some embodiments, may be described as expanding to a cement like material. In other words, the expandable metal goes from metal to micron-scale particles and then these particles expand and lock together to, in essence, fix the downhole toolor the wellbore anchorin place. The reaction may, in certain embodiments, occur in less than 2 days in a reactive fluid and in downhole temperatures. Nevertheless, the time of reaction may vary depending on the reactive fluid, the expandable metal used, and the downhole temperature, as well as other aspects discussed further below.

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, pre-expansion, is electrically conductive in certain embodiments. The expandable metal may be machined to any specific size/shape, extruded, formed, cast or other conventional ways to get the desired shape of a metal, as will be discussed in greater detail below. The expandable metal, pre-expansion, in certain embodiments has a yield strength greater than about 8,000 psi, e.g., 8,000 psi+/−50%. In other embodiments, the expandable metal is a slurry of expandable metal particles.

The hydrolysis of any metal can create a metal hydroxide. The formative properties of alkaline earth metals (Mg—Magnesium, Ca—Calcium, etc.) and transition metals (Zn—Zinc, Al—Aluminum, etc.) under hydrolysis reactions demonstrate structural characteristics that are favorable for use with the present disclosure. Hydration results in an increase in size from the hydration reaction and results in a metal hydroxide that can precipitate from the fluid.

The hydration reactions for magnesium is:

where Mg(OH)is also known as brucite. Another hydration reaction uses aluminum hydrolysis. The reaction forms a material known as Gibbsite, bayerite, and norstrandite, depending on form. The hydration reaction for aluminum is:

Another hydration reactions uses calcium hydrolysis. The hydration reaction for calcium is:

Where Ca(OH)is known as portlandite and is a common hydrolysis product of Portland cement. Magnesium hydroxide and calcium hydroxide are considered to be relatively insoluble in water. Aluminum hydroxide can be considered an amphoteric hydroxide, which has solubility in strong acids or in strong bases.

In an embodiment, the expandable metal used can be a metal alloy. The metal alloy can be an alloy of the base metal with other elements in order to either adjust the strength of the metal alloy, to adjust the reaction time of the metal alloy, or to adjust the strength of the resulting metal hydroxide byproduct, among other adjustments. The metal alloy can be alloyed with elements that enhance the strength of the metal such as, but not limited to, Al—Aluminum, Zn—Zinc, Mn—Manganese, Zr—Zirconium, Y—Yttrium, Nd—Neodymium, Gd—Gadolinium, Ag—Silver, Ca—Calcium, Sn—Tin, and Re—Rhenium, Cu—Copper. In some embodiments, the alloy can be alloyed with a dopant that promotes corrosion, such as Ni—Nickel, Fe—Iron, Cu—Copper, Co—Cobalt, Ir—Iridium, Au—Gold, C—Carbon, gallium, indium, mercury, bismuth, tin, and Pd—Palladium. The metal alloy can be constructed in a solid solution process where the elements are combined with molten metal or metal alloy. Alternatively, the metal alloy could be constructed with a powder metallurgy process. The expandable metal can be cast, forged, extruded, a combination thereof, or may be a slurry of expandable metal particles.

Optionally, non-expanding components may be added to the starting expandable metal. For example, ceramic, elastomer, glass, or non-reacting metal components can be embedded in the expandable metal or coated on the surface of the metal. Alternatively, the starting expandable metal may be the 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, this can have a 260% volumetric expansion where converting 1 mole of CaO goes from 9.5 cc to 34.4 cc of volume. In one variation, the expandable metal is formed in a serpentinite reaction, a hydration and metamorphic reaction. In one variation, the resultant material resembles a mafic material. Additional ions can be added to the reaction, including silicate, sulfate, aluminate, and phosphate. The expandable metal can be alloyed to increase the reactivity or to control the formation of oxides.

The expandable metal can be configured in many different fashions, as long as an adequate volume of material is available for fully expanding. For example, the expandable metal may be formed into a single long tube, multiple short tubes, rings, alternating steel and swellable rubber and expandable metal rings, among others. Additionally, a coating may be applied to one or more portions of the expandable metal to delay the expanding reactions.

In application, the downhole tool assemblycan be moved down the wellborevia the downhole conveyanceto a desired location. Once the downhole tool assembly, including the downhole tooland/or the wellbore anchorreaches the desired location, one or both of the downhole tooland/or the wellbore anchormay be set in place according to the disclosure. In one embodiment, one or both of the downhole tooland/or the wellbore anchorinclude the expandable metal, and thus are subjected to a wellbore fluid sufficient to expand the one or more expandable metal members into contact with a nearby surface, and thus in certain embodiments seal or anchor the one or more downhole tools within the wellbore.

In the embodiment of, the downhole tooland/or the wellbore anchorare positioned in the open hole regionof the wellbore. The downhole tooland/or the wellbore anchorincluding the expandable metal are particularly useful in open hole situations, as the expandable metal is well suited to adjust to the surface irregularities that may exist in open hole situations. Moreover, the expandable metal, in certain embodiments, may penetrate into the formation of the open hole regionand create a bond into the formation, and thus not just at the surface of the formation. Notwithstanding the foregoing, the downhole tooland/or the wellbore anchorare also suitable for a cased regionof the wellbore.

In certain embodiments, it is desirable or necessary to accelerate and/or decelerate the expansion of the expandable metal. The present disclosure has recognized that a voltage (e.g., provided via a power source, whether uphole or downhole) may be used to accelerate and/or decelerate the expansion process. Accordingly, the applied voltage may be used to accelerate and/or decelerate the setting of any downhole tool that includes the expandable metal. In accordance with one embodiment, a first electrode is located between a first connection of a power source and the expandable metal, and a second electrode is located between a second connection of the power source and a downhole conductive feature. In accordance with this embodiment, the expandable metal is a first side of the electrical circuit, wherein the downhole conductive feature is the second side of the electrical circuit. In at least one embodiment, the electrodes are configured so that at least part of the electrical current passes through fluid surrounding the expandable metal. For example, at least a portion of one or both of the first electrode or the second electrode could be exposed to the wellbore fluid surrounding the expandable metal.

A positive voltage may be applied so that the expandable metal spends at least part of its time as an anode of the circuit. In one embodiment, the positive voltage accelerates the expansion process by up to at least 2×. In another embodiment, the positive voltage accelerates the expansion process by up to at least 5×. In yet another embodiment, the positive voltage accelerates the expansion process by up to at least 10×, and in yet another embodiment of 20× or 100×, or more.

In another embodiment, a negative voltage may be applied so that the expandable metal spends at least part of its time as a cathode of the circuit. In one embodiment, the negative voltage decelerates the expansion process by up to at least 2×. In another embodiment, the negative voltage protects the expanded metal from acid corrosion. For example, a voltage of −2.8 volts may be used to protect a magnesium containing expandable metal from corrosion, a voltage of −1.8 volts may be used to protect an aluminum containing expandable metal from corrosion, and a voltage of −1 volts may be used to protect a zinc containing expandable metal from corrosion, among others.

The electrical power can be applied from a battery, an electrical cable, or from a downhole power generator. In at least one embodiment, the downhole power generator is fluid flow turbine. The voltage, in at least one embodiment, is between 0.01 volts and 200 volts. In yet another embodiment, the voltage is between 0.5 volts and 10 volts. In at least one embodiment, the electrical current is between 0.5 milliamps and 100 amps, and in yet another embodiment is between 0.05 amps and 5 amps.

The power supply can be started from a timer, a transmitted signal through a wire, a transmitted signal sent wirelessly, or from a sensing of the operation of the wellbore, among other mechanisms. In at least one other embodiment, temperature change through fluid swapping could be used as the signal to start the power supply.

Referring to, depicted is a perspective view of an alternative embodiment of a well systemincluding an exemplary operating environment that the apparatuses, systems and methods disclosed herein may be employed. The well systemis similar in many respects to the well stem. Accordingly, like reference numbers have been used to indicate similar, if not identical, features. The well system, in contrast to the well system, includes a wellbore tubular(e.g., liner hanger) extending from the casinginto the open hole region. The well systemadditionally includes one or more downhole packerslocated in the open hole region, thereby isolating the various different production zones within the well system. In accordance with at least one embodiment, the one or more downhole packersinclude the expandable metal configured to expand in response to hydrolysis in accordance with the disclosure. Additionally, the one or more downhole packersare operable to receive a voltage as the expandable metal is expanding in response to wellbore fluid.

In one embodiment, the power (e.g., voltage) is delivered from an electric line, such as a TEC (tubing encapsulated conductor), coupled to an uphole power source. The electric linemay be connected to sensors and actuators downhole. The electric linemay also deliver power (e.g., voltage) to accelerate the chemical reaction of the one or more downhole packers. The power (e.g., voltage) can be through a direct connection to the wire or through an inductive coupling or a capacitive coupling. In another embodiment, the power (e.g., voltage) is delivered from a chemical battery, such as a lithium battery or an alkaline battery. In another embodiment, the power (e.g., voltage) is delivered from a fluid-flow driven power generator, such as a turbine power generator.

An experiment was conducted, wherein the reaction time of the expandable metal was compared between an applied voltage and no voltage. The mass of the unreacted metal is shown in. As illustrated, applying just a 5 volt signal greatly accelerated the reaction rate.

In an alternative embodiment, the opposite voltage is used to delay the initiation of the chemical reaction. Thus, while applying a positive voltage accelerates the chemical reaction, applying a negative voltage to the expandable metal will inhibit the reaction. This can ensure that the expandable metal does not react (e.g., expand) until the desired time. Additionally, the negative voltage can protect the metal from acid based corrosion.

A Pourbaix diagram for Mg, Al, and Zn are shown in. Aluminum, magnesium, and zinc will normally dissolve when exposed to acid (pH=0). If a negative voltage is applied to the expandable metal, then the expandable metal will be immune from corrosion. As shown in, applying −2.8V will protect Mg. Applying −1.8V will protect Al. Applying −1V will protect Zn. In one embodiment, a negative voltage is used to delay the reaction of the expandable metal for one period of time and then a positive voltage is used to accelerate the reaction of the expandable metal for a second period of time.

Turning to, illustrated is a downhole tool(e.g., packer, plug, anchor, etc.) positioned within a wellbore. The downhole toolincludes a downhole tubularhaving expandable metalon a surface (e.g., radial surface) thereof. In the illustrated embodiment, the downhole tubularis a downhole conveyance and the expandable metalis one or more expandable metal members positioned on an exterior surface thereof. Nevertheless, it should be understood that any downhole application and use of an expandable metal is within the scope of the present disclosure.

In the illustrated embodiment of, a power sourceis positioned proximate the expandable metal. In accordance with at least one embodiment, a first electrodecouples a first connection of the power sourcewith the expandable metal, wherein a second electrodecouples a second connection of the power sourcewith the downhole tubular. In at least one embodiment, the first connection is a positive terminal of the power source, thereby causing the expandable metalto function as an anode, and the second connection is a negative terminal of the power source, thereby causing the downhole tubularto function as a cathode. For example, a direct current (DC) power source could be coupled to the expandable metaland the downhole tubular.

Further to this embodiment, an electrical insulatorphysically separates the expandable metaland the downhole tubularfrom one another. This electrical insulatorhelps to ensure that the electrical current passes through the fluid rather than through direct electrical contact (e.g., by way of a physical connection between the expandable metaland the downhole tubular). The electrical insulator, thus, reduces the power requirements. As illustrated in, the electrical insulatoris a Teflon coating on the downhole tubular, but other insulators are within the scope of the disclosure. The electrical insulatoris optional but may be useful in reducing the power consumption. The power source can be connected to the electrodes in one, two, or multiple locations.

Turning to, illustrated is an alternative embodiment of a downhole tool. The downhole toolshares many of the same features as the downhole tool. Accordingly, like reference numbers have been used to illustrate similar, if not identical, features. In the illustrated embodiment of, expandable metalandare used as both conductive features, for example positioned radially about the downhole tubular. In accordance with at least one embodiment, a first electrodecouples a first connection of the power sourcewith the expandable metal, wherein a second electrodecouples a second connection of the power sourcewith the expandable metal. Electrical power may then be applied to expandable metaland expandable metal. In the illustrated embodiment, an insulatoris applied to the expandable metaland expandable metal. In some cases, the insulatorcould just be applied to one of the expandable metalor expandable metal(e.g., like the anode). In another embodiment, a non-expandable metal, such as a plate or a mesh of stainless steel, titanium, or copper, could couple to the second electrode.

In one embodiment, the power is created from a DC voltage. As shown in, one of expandable metalor expandable metalis the anode and would more rapidly react, while the other of the expandable metalor expandable metalis the cathode and would have a delayed reaction. In another embodiment, the power is created from an alternating current (AC) voltage. In this configuration, such as that shown in the embodiment of, both sections of the expandable metaland expandable metalwould alternate between being the anode and the cathode, and thus alternate between having a rapid reaction and a delayed reaction.

Turning to, illustrated is an alternative embodiment of a downhole tool. The downhole toolshares many of the same features as the downhole tool. Accordingly, like reference numbers have been used to illustrate similar, if not identical, features. In the illustrated embodiment of, a power sourceis positioned within the downhole tubularwithin the wellbore. In accordance with at least one embodiment, a first electrodecouples a first connection of the power sourcewith a conductive platecoupled to a slurry of expandable metal particles, and a second electrodecouples a second connection of the power sourcewith a downhole conductive feature.

In the illustrated embodiment of, the slurry of expandable metal particlesmay be flowed into the downhole tubularin the wellbore. The slurry of expandable metal particleslands on the conductive plate, which at some point (e.g., either after, before, or substantially simultaneously with the slurry of expandable metal particleslanding on the conductive plate) receives a positive voltage accelerating the expansion thereof. The downhole conductive featurecan be in the fluid (as shown) or can be electrically connected with an oilfield tubular (casing).

Turning to, illustrated is yet another alternative embodiment of a downhole tooldesigned, manufactured and operated according to one aspect of the disclosure. The downhole toolmay be an expandable metal wellbore anchor or an expandable metal packer or seal, among other downhole tools. In accordance with one embodiment of the disclosure, the downhole toolincludes one or more expandable metal memberspositioned on a downhole tubular. While the downhole tubularillustrated inis API pipe, other embodiments may exist wherein another type conveyance is used.

The one or more expandable metal members, in accordance with the disclosure, comprise a metal configured to expand in response to hydrolysis, as discussed in detail above. Furthermore, a combined volume of the one or more expandable metal members should be sufficient to expand to anchor one or more downhole tools within the wellbore in response to the hydrolysis. In one embodiment, the combined volume of the one or more expandable metal membersis sufficient to expand to anchor at least about 100,000 Newtons (e.g., about 25,000 lbs.) of weight within the wellbore. In yet another embodiment, the combined volume of the one or more expandable metal membersis sufficient to expand to anchor at least about 200,000 Newtons (e.g., about 50,000 lbs.) of weight within the wellbore, and in yet another embodiment sufficient to expand to anchor at least about 300,000 Newtons (e.g., about 70,000 lbs.) of weight within the wellbore. In one embodiment, for example where the one or more expandable metal membersare seals, they may be capable of holding pressures up to about 1000 psi. In another embodiment, the one or more expandable metal members are capable of holding pressures up to about 10,000 psi, and in even yet another embodiment up to about 20,000 psi, or more.

In the illustrated embodiment of, two or more expandable metal members(e.g., four expandable metal members in the embodiment shown) are axially positioned along and substantially equally radially spaced about the downhole tubular. In the illustrated embodiment, the two or more expandable metal membersinclude openings extending entirely through a wall thickness thereof for accepting a fastener(e.g., a set screw in one embodiment) for fixing to the downhole tubular. As those skilled in the art now appreciate, the two or more expandable metal memberswill expand to engage with the wellbore (e.g., cased region of the wellbore or open hole region of the wellbore) when subjected to a suitable fluid, including a brine based fluid, and thus act as a wellbore anchor and/or wellbore packer.

In the illustrated embodiment of, the downhole toolincludes a power source. In accordance with the disclosure, a first electrodeis coupled between the one or more expandable metal membersand a first connection of the power source, and a second electrodeis coupled between the downhole tubularand a second connection of the power source. The power source, and the connections between the power sourceand the one or more expandable metal members, may be similar in many respects to the power sourcediscussed above, and thus may be used to accelerate the expansion of the one or more expandable metal members.

Turning to, illustrated is yet another alternative embodiment of a downhole tooldesigned, manufactured and operated according to one aspect of the disclosure. The downhole toolis similar in many respects to the downhole tool. Accordingly, like reference numerals have been used to reference similar, if not identical, features. The downhole tooldiffers from the downhole toolprimarily in that it includes two or more spacersradially interleaving the two or more expandable metal members. The two or more spacersmay comprise a variety of different materials and remain within the scope of the disclosure. In the embodiment of, the two or more spacersdo not comprise the metal configured to expand in response to hydrolysis, and thus do not expand. For example, the two or more spacerscould comprise steel.

Turning to, illustrated is yet another alternative embodiment of a downhole tooldesigned, manufactured and operated according to one aspect of the disclosure. The downhole toolis similar in certain respects to the downhole tool. Accordingly, like reference numerals have been used to reference similar, if not identical, features. The downhole toolincludes a single elongate toroidal expandable metal memberpositioned around the downhole tubular. The single elongate toroidal expandable metal membermay comprise one or more of the expandable metals discussed above. Moreover, the single elongate toroidal expandable metal memberneed not have a circular opening or circular exterior, and thus could comprise a rectangle, another polygon, or any other suitable shape.

In the particular embodiment of, the single elongate toroidal expandable metal memberis held in place on the downhole conveyanceusing a pair of retaining rings, for example positioned adjacent a proximal end and a distal end of the single elongate toroidal expandable metal member. In accordance with one embodiment of the disclosure, the pair of retaining ringsdoes not comprise the metal configured to expand in response to hydrolysis, and moreover include one or more fastenersfor holding the single elongate toroidal expandable metal memberin place.