Patent Grant
11306554
The present application is a U.S. National Stage Application of International Application No. PCT/US2018/019986 filed Feb. 27, 2018, which is incorporated herein by reference in its entirety for all purposes.
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. Zonal isolation devices, such as frac plugs, bridge plugs, packers, and other suitable tools, may be used to isolate wellbore sections.
Frac plugs and other zonal isolation devices are commonly run into the wellbore on a conveyance such as a wireline, work string or production tubing. Such tools typically 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. Upon reaching a desired location within the wellbore, the downhole tool is actuated by hydraulic, mechanical, electrical, or electromechanical means to seal off the flow of liquid around the downhole tool. After a treatment operation, zonal isolation devices may be removed from the wellbore by various methods, including dissolution and/or drilling. Certain zonal isolation devices may have numerous constituent parts, complicating removal. Some zonal isolation devices may include a ratchet or similar mechanism to retain the device in a set configuration. Ratchets may allow shifting or “free play” within each ratchet increment.
These drawings illustrate certain aspects of some of the embodiments of the present disclosure, and should not be used to limit or define the claims.
While embodiments of this disclosure have been depicted, such embodiments do not imply a limitation on the disclosure, and no such limitation should be inferred. The subject matter disclosed is capable of considerable modification, alteration, and equivalents in form and function, as will occur to those skilled in the pertinent art and having the benefit of this disclosure. The depicted and described embodiments of this disclosure are examples only, and not exhaustive of the scope of the disclosure.
Illustrative embodiments of the present disclosure are described in detail herein. In the interest of clarity, not all features of an actual implementation may be described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions may be made to achieve the specific implementation goals, which may vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of the present disclosure.
As used herein, the terms “casing,” “casing string,” “casing joint,” and similar terms refer to a substantially tubular protective lining for a wellbore. Casing can be made of any material, and can include tubulars known to those skilled in the art as casing, liner, and tubing. In certain embodiments, casing may be constructed out of steel. Casing can be expanded downhole, interconnected downhole and/or formed downhole in some cases.
As used herein, the term “downhole surface” and similar terms refer to any surface in the wellbore or subterranean formation. For example, downhole surfaces may include, but are not limited to a wellbore wall, an inner tubing string wall such as a casing wall, a wall of an open-hole wellbore, and the like.
As used herein, the term “degradable” and all of its grammatical variants (e.g., “degrade,” “degradation,” “degrading,” “dissolve,” dissolving,” and the like), refers to the dissolution or chemical conversion of solid materials such that reduced-mass solid end products are formed by at least one of solubilization, hydrolytic degradation, biologically formed entities (e.g., bacteria or enzymes), chemical reactions (including electrochemical and galvanic reactions), thermal reactions, reactions induced by radiation, or combinations thereof. In complete degradation, no solid end products result. In some instances, the degradation of the material may be sufficient for the mechanical properties of the material to be reduced to a point that the material no longer maintains its integrity and, in essence, falls apart or sloughs off into its surroundings. The conditions for degradation are generally wellbore conditions where an external stimulus may be used to initiate or effect the rate of degradation, where the external stimulus is naturally occurring in the wellbore (e.g., pressure, temperature) or introduced into the wellbore (e.g., fluids, chemicals). For example, the pH of the fluid that interacts with the material may be changed by introduction of an acid or a base. The term “wellbore environment” includes both naturally occurring wellbore environments and materials or fluids introduced into the wellbore.
Directional terms, such as “above”, “below”, “upper”, “lower”, etc., are used for convenience in the present disclosure in referring to the accompanying figures. In general, “above”, “upper”, “upward” and similar terms refer to a direction toward the earth's surface along a wellbore, and “below”, “lower”, “downward” and similar terms refer to a direction away from the earth's surface along the wellbore.
As used herein, the term “coupled” and its grammatical variants refer to two or more components, pieces, or portions that may be used operatively together, that are joined together, that are linked together. For example, coupled components may include, but are not limited to components that are detachably coupled, shearably coupled, coupled by compression fit, coupled by interference fit, joined, linked, connected, coupled by a bonding agent, or the like.
The present disclosure relates to downhole tools used in the oil and gas industry. Particularly, the present disclosure relates to an apparatus for isolating zones in a wellbore and methods of use.
More specifically, the present disclosure relates to a zonal isolation device, comprising: a tubular body having a fluid communication pathway formed along a longitudinal axis comprising: a sealing element comprising a deformable material and an inner bore forming at least a portion of the fluid communication pathway; an expansion ring disposed within the bore of the sealing element; a wedge engaged with a downhole end of the sealing element; and an anchoring assembly engaged with the wedge. In certain embodiments, the tubular body further comprises an end element adjacent the anchoring assembly.
In some embodiments, the present disclosure relates to a method comprising: inserting into a wellbore a zonal isolation device disposed on a setting tool adapter kit comprising a mandrel, wherein the zonal isolation device comprises: a sealing element comprising a deformable material and an inner bore; an expansion ring movably disposed within the inner bore of the sealing element; a wedge engaged with a downhole end of the sealing element; an anchoring assembly engaged with the wedge; and an end element adjacent the anchoring assembly and detachably coupled to the mandrel; and actuating to pull upwardly on the mandrel, wherein the upward movement of the mandrel longitudinally compresses the zonal isolation device, causing the expansion ring to axially move relative to the sealing element and radially expand the sealing element into a sealing engagement with a downhole surface.
In some embodiments, the present disclosure relates to a zonal isolation system, comprising: a setting tool adapter kit comprising a mandrel; a sealing element disposed on the mandrel for sealing engagement with a downhole surface; an expansion ring movably disposed on the mandrel and engaged with the sealing element; a wedge disposed on the mandrel; and an anchoring assembly disposed around the mandrel for locking engagement with a downhole surface.
Among the many potential advantages of the apparatus and methods of the present disclosure, only some of which are alluded to herein, the zonal isolation device of the present disclosure may be provided with fewer component parts. Further, a zonal isolation device according to certain embodiments of the present disclosure may include a large inner diameter than other devices, which may prove advantageous for increasing flow rates during production operations. Further, a zonal isolation device according to certain embodiments of the present disclosure may be provided with more controlled dissolution characteristics due to, for example, fewer components parts. In some embodiments, the zonal isolation device of the present disclosure may retain a set configuration without a ratchet or similar mechanism, which may result in a lower cost tool with better dissolution characteristics and/or may eliminate the shifting that may occur in devices with a ratchet. In some embodiments, the zonal isolation device of the present disclosure may provide a more stable set frac plug, as the sealing element may provide additional stability.
The zonal isolation device is generally depicted and described herein as a hydraulic fracturing plug or “frac” plug. It will be appreciated by those skilled in the art, however, that the principles of this disclosure may equally apply to any of the other aforementioned types of casing or borehole isolation devices, without departing from the scope of the disclosure. Indeed, the zonal isolation device may be any of a frac plug, a wellbore packer, a deployable baffle, a bridge plug, or any combination thereof in keeping with the principles of the present disclosure.
Embodiments of the present disclosure and their advantages are best understood by references to
Representatively illustrated in
The zonal isolation device 200 of
In some embodiments, the anchoring assembly 215 and sealing element 100 are sufficient to hold the zonal isolation device 200 in a set configuration, when in locking engagement and sealing engagement with a downhole surface, respectively. In certain embodiments, the zonal isolation device 200 may retain a set configuration without a ratchet or similar component.
The sealing element 100 may comprise an inner bore 105 that forms at least a part of the fluid communication pathway 206. In certain embodiments, a wedge 180 may be adjacent to the downhole end 101 of the sealing element 100. The wedge 180 and the sealing element 100 may be coupled or uncoupled. In some embodiments, wedge 180 and sealing element 100 may engage each other with interlocking tapered surfaces at an interface 102. In certain embodiments, wedge 180 and sealing element 100 may be coupled together by a compression fit or an interference fit. For example, wedge 180 and sealing element 100 may be longitudinally compressed together after the zonal isolation device 200 is set.
The sealing element 100 may be elastically or plastically deformable, and may be composed of any suitable elastically or plastically deformable material including, but not limited to, elastomers (including but not limited to rubber), polymers (including but limited to plastics), or metal. One of ordinary skill in the art will understand that the material selected and the deformable nature (elastic or plastic) is an understood design choice generally dictated by the application of the system and method described herein. Furthermore, one of ordinary skill in the art will understand that the material may be further selected to ease the removal of zonal isolation device 200 by, for example, choosing a material that easily broken up if drilled out or a material that is dissolvable.
With reference to
In some embodiments, the expansion ring 190 may also act be configured to receive a sealing device (e.g., a frac ball, frac dart, or the like). As shown in
The wedge 180 may have a frustoconical shape and be disposed between the sealing element 100 and the anchoring assembly 215. In certain embodiments, the anchoring assembly 215 is engaged with the wedge 180. In some embodiments, the wedge may be engaged with a downhole end 101 of the sealing element 100. some embodiments, the wedge 180 may comprise a single frustoconical surface 182 (e.g., as depicted in
In certain embodiments, the anchoring assembly 215 allows the zonal isolation device to hold its position within the wellbore. As depicted in
The plurality of slip segments 216 may be fully interconnected (e.g., as depicted in
The slip segments 216 may comprise slip inserts 218 embedded therein. Slip inserts 218 may be wear buttons, wickers, wedges, or any other element for reducing wear of the slip segments 216. Slip inserts 218 may protrude from the slip segments 216 to penetrate or bite a downhole surface. Although each slip segment 216 is shown having four slip inserts 218 respectfully, it will be appreciated that any number of slip inserts, including one or a plurality (three, four, five, ten, twenty, and the like) of slip inserts may be embedded in each slip, without departing from the scope of the present disclosure. The slip segments 216 may have the same or a different number of slip inserts 218, without departing from the scope of the present disclosure. The slip inserts 218 in
In some embodiments, the slip inserts 218 may include hardened metals, ceramics, and any combination thereof. The material forming the slip inserts 218 may be an oxide or a non-oxide material. In certain embodiments, the thickness of a material may be increased in order to achieve the desired compressive strength. For example, in some embodiments the material forming the slip insert 218 may include, but is not limited to, iron (e.g., cast iron), steel, titanium, zircon, a carbide (e.g., tungsten carbide, a tungsten carbide alloy (e.g., alloyed with cobalt), silicon carbide, titanium carbide, boron carbide, tantalum carbide), a boride (e.g., osmium diboride, rhenium boride, tungsten boride, zirconium boride, iron tetraboride), a nitride (e.g., silicon nitride, titanium nitride, boron nitride, cubic boron nitride, boron carbon nitride, beta carbon nitride), diamond, synthetic diamond, silica (e.g., amorphous silica), an oxide (e.g., aluminum oxide, fused aluminum oxide, zirconium oxide, beryllium oxide, alumina-chrome oxide), corundite, topaz, synthetic topaz, garnet, synthetic garnet, lonsdaleite, and any combination thereof.
An end element 170 may be positioned at or secured at the downhole end of the zonal isolation device 200. As will be appreciated, the end element 170 of the wellbore isolation device 200 could be a mule shoe, or any other type of section that serves to terminate the structure of the wellbore isolation device 200, or otherwise serves as a connector for connecting the wellbore isolation device 200 to other tools, such as a valve, tubing, or other downhole equipment. The end element 170 may comprise end element inserts 171 embedded therein. End element inserts 171 may be wear buttons, wickers, wedges, or any other element for reducing wear of the end element 170. End element inserts 171 may be any shape or material discussed above with respect to slip inserts 218. In certain embodiments, the end element 170 may be adjacent, engaged with, and/or coupled to the anchoring assembly 215. For example, as shown in
With reference to
As depicted in
In some embodiments, one or more components of the setting tool adapter kit 160 or a setting tool coupled to the adapter kit 160 may be actuated to force the end element 170 upward by drawing the mandrel 161 upward. Drawing the end element 170 upward may force the anchoring assembly 215 upward such that the slip segments 216 engage with the wedge 180. For example, drawing the end element 170 upward may force the slip segments 216 up a surface of the wedge 180, causing the slip segments 216 to radially expand into locking engagement with a downhole surface.
In some embodiments, one or more portions of the setting tool adapter kit 160 may hold the expansion ring 190 stationary relative to the sealing element 100 and/or other elements of the zonal isolation device 200. In certain embodiments, the setting sleeve 167 may restrict upward movement of the expansion ring 190 during upward movement of the mandrel 161. For example, the setting tool 160 may comprise one or more retention elements shaped to restrict the upward movement of the expansion ring 190 during upward movement of the mandrel 161 and other components of the zonal isolation device 200. In certain embodiments, the retention element may include a ridge, flange, tab, pin, sleeve, or other element suitable to restrict upward movement of the expansion ring 190 during upward movement of the mandrel 161. Actuating the setting tool 160 may cause the sealing element 100 to move upward relative to the expansion ring 190, forcing the expansion ring 190 towards the downhole end 101 of the sealing element 100. Shifting of the expansion ring 190 towards the downhole end 101 of the sealing element 100 may radially expand the sealing element 100 into sealing engagement with a downhole surface. For example, a tapered surface of the expansion ring 190 may engage with a tapered inner bore 105 of the sealing element 100.
In certain embodiments, the zonal isolation device 200 may be made up in the form depicted in
In certain embodiments, the mandrel 161 may be shearably coupled to one or more components of the zonal isolation device 200 by one or more shear devices, including, but not limited to shear threads, shear pins, a shear ring, shear screws, shearable ridges, and the like, or any other shearable device. In embodiments where the mandrel 161 is shearably coupled to one or more components of the zonal isolation device 200, the mandrel 161 may overcome a shear force provided by the shear device. For example, during or after setting, enough upward force may be applied to the mandrel 161 to shear one or more shear devices and decouple the mandrel from one or more components of the zonal isolation device 200. In some embodiments, the mandrel 161 may be shearably coupled to the end element 170 by a shear device. In some embodiments, the shear force necessary to overcome one or more shear devices of the zonal isolation device 200 is from about 10,000 lbf to 50,000 lbf.
As discussed above, the end element 170 may be coupled or uncoupled to the anchoring assembly 215. As depicted in
In some embodiments, the zonal isolation device 200 may be run into a wellbore 120 via conveyance 140 in a sealed configuration. For example, as depicted in
As shown in
For example, in certain embodiments, one or more components of the zonal isolation device 200 may include a pump-down ring. A pump-down ring may, in certain embodiments, be a portion of a component of the zonal isolation device 200 or the setting tool adapter kit 160 with an increased outer diameter relative to at least one other portion of the component. For example, as depicted in
With reference to
One or more scarf cuts 233 may extend between the first end 234 and second end 235 at an angle 236 relative to one of the first end 234 and the second end 235 or any other suitable plane extending normal to a longitudinal axis of the expandable collar 220. In the illustrated embodiment in
The one or more scarf cuts 233 may permit diametrical expansion of the expandable collar 220 to an expanded state and into locking engagement with a downhole surface. In certain embodiments, due to the construction of the expandable collar 220, a large flow area can be provided through an inner diameter 237 of the body 230. During expansion of the expandable collar 220, the expandable collar 220 may radially expand into locking engagement with a downhole surface (e.g., with a casing). In the expanded state, a gap 238 may be formed between opposing angled surfaces 239a,b of the scarf cut 233. The angle 236 of the scarf cut 233 may be calculated such that when the expandable collar 220 moves to the expanded state, the opposing angled surfaces 239a,b of the scarf cut 233 axially overlap to at least a small degree such that no axial gaps are created in the body 230. Accordingly, the one or more scarf cuts 233 may enable the expandable collar 220 to separate at the opposing angled surfaces 239a,b and thereby enable a degree of freedom that permits expansion and contraction of the expandable collar 220 during operation. In certain embodiments, the first end 234 is movable relative to the second end 235 as the expandable collar 220 expands. In certain embodiments, the first end portion 234 rotates or otherwise moves circumferentially relative to the second end 235 during expansion. In certain embodiments, the first end 234 converges and/or diverges circumferentially relative to the second end 235 during expansion.
One or more components of the zonal isolation device 200 such as the wedge 180, expansion ring 190, anchoring assembly 215, end element 170, and/or lower mandrel 163 may comprise a variety of materials including, but not limited to, a metal, a polymer, a composite material, and any combination thereof. Suitable metals that may be used include, but are not limited to, steel, brass, aluminum, magnesium, iron, cast iron, tungsten, tin, and any alloys thereof. Suitable composite materials that may be used include, but are not limited to, materials including fibers (chopped, woven, etc.) dispersed in a phenolic resin, such as fiberglass and carbon fiber materials.
In some embodiments, one or more components of the zonal isolation device 200 such as the sealing element 100, wedge 180, expansion ring 190, anchoring assembly 215, end element 170, or lower mandrel 163 may be made of a degradable or dissolvable material. The degradable materials described herein may allow for time between setting a downhole tool (e.g., a zonal isolation device) and when a particular downhole operation is undertaken, such as a hydraulic fracturing treatment operation. In certain embodiments, degradable metal materials may allow for acid treatments and acidified stimulation of a wellbore. In some embodiments, the degradable metal materials may require a large flow area or flow capacity to enable production operations without unreasonably impeding or obstructing fluid flow while the zonal isolation device 200 degrades. As a result, production operations may be efficiently undertaken while the zonal isolation device 200 degrades and without creating significant pressure restrictions.
Degradable materials suitable for certain embodiments of the present disclosure include, but are not limited to borate glass, polyglycolic acid (PGA), polylactic acid (PLA), a degradable rubber, a degradable polymer, a galvanically-corrodible metal, a dissolvable metal, a dehydrated salt, and any combination thereof. The degradable materials may be configured to degrade by a number of mechanisms including, but not limited to, swelling, dissolving, undergoing a chemical change, electrochemical reactions, undergoing thermal degradation, or any combination of the foregoing.
Degradation by swelling may involve the absorption by the degradable material of aqueous fluids or hydrocarbon fluids present within the wellbore environment such that the mechanical properties of the degradable material degrade or fail. Hydrocarbon fluids that may swell and degrade the degradable material include, but are not limited to, crude oil, a fractional distillate of crude oil, a saturated hydrocarbon, an unsaturated hydrocarbon, a branched hydrocarbon, a cyclic hydrocarbon, and any combination thereof. Exemplary aqueous fluids that may swell to degrade the degradable material include, but are not limited to, fresh water, saltwater (e.g., water containing one or more salts dissolved therein), brine (e.g., saturated salt water), seawater, acid, bases, or combinations thereof. In degradation by swelling, the degradable material may continue to absorb the aqueous and/or hydrocarbon fluid until its mechanical properties are no longer capable of maintaining the integrity of the degradable material and it at least partially falls apart. In some embodiments, the degradable material may be designed to only partially degrade by swelling in order to ensure that the mechanical properties of a component of the zonal isolation device 200 formed from the degradable material is sufficiently capable of lasting for the duration of the specific operation in which it is utilized.
Degradation by dissolving may involve a degradable material that is soluble or otherwise susceptible to an aqueous fluid or a hydrocarbon fluid, such that the aqueous or hydrocarbon fluid is not necessarily incorporated into the degradable material (as is the case with degradation by swelling), but becomes soluble upon contact with the aqueous or hydrocarbon fluid. Degradation by undergoing a chemical change may involve breaking the bonds of the backbone of the degradable material (e.g., a polymer backbone) or causing the bonds of the degradable material to crosslink, such that the degradable material becomes brittle and breaks into small pieces upon contact with even small forces expected in the wellbore environment. Thermal degradation of the degradable material may involve a chemical decomposition due to heat, such as the heat present in a wellbore environment. Thermal degradation of some degradable materials mentioned or contemplated herein may occur at wellbore environment temperatures that exceed about 93° C. (or about 200° F.).
With respect to degradable polymers used as a degradable material, a polymer may be considered “degradable” if the degradation is due to, in situ, a chemical and/or radical process such as hydrolysis, oxidation, or UV radiation. Degradable polymers, which may be either natural or synthetic polymers, include, but are not limited to, polyacrylics, polyamides, and polyolefins such as polyethylene, polypropylene, polyisobutylene, and polystyrene. Suitable examples of degradable polymers that may be used in accordance with the embodiments include polysaccharides such as dextran or cellulose, chitins, chitosans, proteins, aliphatic polyesters, poly(lactides), poly(glycolides), poly(ε-caprolactones), poly(hydroxybutyrates), poly(anhydrides), aliphatic or aromatic polycarbonates, poly(orthoesters), poly(amino acids), poly(ethylene oxides), polyphosphazenes, poly(phenyllactides), polyepichlorohydrins, copolymers of ethylene oxide/polyepichlorohydrin, terpolymers of epichlorohydrin/ethylene oxide/allyl glycidyl ether, and any combination thereof. In certain embodiments, the degradable material is polyglycolic acid or polylactic acid. In some embodiments, the degradable material is a polyanhydride. Polyanhydride hydrolysis may proceeds, in situ, via free carboxylic acid chain-ends to yield carboxylic acids as final degradation products. The erosion time may be varied over a broad range of changes in the polymer backbone. Examples of polyanhydrides suitable for certain embodiments of the present disclosure include, but are not limited to poly(adipic anhydride), poly(suberic anhydride), poly(sebacic anhydride), and poly(dodecanedioic anhydride). Other examples suitable for certain embodiments of the present disclosure include, but are not limited to poly(maleic anhydride) and poly(benzoic anhydride).
Degradable rubbers suitable for certain embodiments of the present disclosure include, but are not limited to degradable natural rubbers (i.e., cis-1,4-polyisoprene) and degradable synthetic rubbers, which may include, but are not limited to, ethylene propylene diene M-class rubber, isoprene rubber, isobutylene rubber, polyisobutene rubber, styrene-butadiene rubber, silicone rubber, ethylene propylene rubber, butyl rubber, norbornene rubber, polynorbornene rubber, a block polymer of styrene, a block polymer of styrene and butadiene, a block polymer of styrene and isoprene, and any combination thereof. Other degradable polymers suitable for certain embodiments of the present disclosure include those that have a melting point that is such that it will dissolve at the temperature of the subterranean formation in which it is placed.
In some embodiments, the degradable material may have a thermoplastic polymer embedded therein. The thermoplastic polymer may modify the strength, resiliency, or modulus of a portion of the zonal isolation device 200 and may also control the degradation rate. Thermoplastic polymers suitable for certain embodiments of the present disclosure include, but are not limited to an acrylate (e.g., polymethylmethacrylate, polyoxymethylene, a polyamide, a polyolefin, an aliphatic polyamide, polybutylene terephthalate, polyethylene terephthalate, polycarbonate, polyester, polyethylene, polyetheretherketone, polypropylene, polystyrene, polyvinylidene chloride, styrene-acrylonitrile), polyurethane prepolymer, polystyrene, poly(o-methylstyrene), poly(m-methylstyrene), poly(p-methylstyrene), poly(2,4-dimethylstyrene), poly(2,5-dimethylstyrene), poly(p-tert-butylstyrene), poly(p-chlorostyrene), poly(α-methylstyrene), co- and ter-polymers of polystyrene, acrylic resin, cellulosic resin, polyvinyl toluene, and any combination thereof. Each of the foregoing may further comprise acrylonitrile, vinyl toluene, or methyl methacrylate. The amount of thermoplastic polymer that may be embedded in a degradable material may be any amount that confers a desirable elasticity without affecting the desired amount of degradation. In some embodiments, the thermoplastic polymer may be included in an amount in the range of a lower limit of about 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, and 45% to an upper limit of about 91%, 85%, 80%, 75%, 70%, 65%, 60%, 55%, 50%, and 45% by weight of the degradable material, encompassing any value or subset therebetween.
In certain embodiments, galvanically-corrodible metals may be used as a degradable material and may be configured to degrade via an electrochemical process in which the galvanically-corrodible metal corrodes in the presence of an electrolyte (e.g., brine or other salt-containing fluids present within the wellbore). Galvanically-corrodible metals suitable for certain embodiments of the present disclosure include, but are not limited to gold, gold-platinum alloys, silver, nickel, nickel-copper alloys, nickel-chromium alloys, copper, copper alloys (e.g., brass, bronze, etc.), chromium, tin, aluminum, iron, zinc, magnesium, and beryllium. Galvanically-corrodible metals may include a nano-structured matrix. One example of a nano-structured matrix micro-galvanic material is a magnesium alloy with iron-coated inclusions. Galvanically-corrodible metals suitable for certain embodiments of the present disclosure include micro-galvanic metals or materials, such as a solution-structured galvanic material. An example of a solution-structured galvanic material is zirconium (Zr) containing a magnesium (Mg) alloy, where different domains within the alloy contain different percentages of Zr. This may lead to a galvanic coupling between these different domains, which causes micro-galvanic corrosion and degradation. Micro-galvanically corrodible magnesium alloys could also be solution-structured with other elements such as zinc, aluminum, nickel, iron, carbon, tin, silver, copper, titanium, rare earth elements, et cetera. Micro-galvanically corrodible aluminum alloys could be in solution with elements such as nickel, iron, carbon, tin, silver, copper, titanium, gallium, et cetera.
In some embodiments, blends of certain degradable materials may also be suitable as the degradable material for at least a portion of the zonal isolation device 200. One example of a suitable blend of degradable materials is a mixture of PLA and sodium borate. Another example may include a blend of PLA and boric oxide. The choice of blended degradable materials may depend, at least in part, on the conditions of the well (e.g., wellbore temperature). For instance, lactides have been found to be suitable for lower temperature wells, including those within the range of 60° F. to 150° F., and PLAs have been found to be suitable for wellbore temperatures above this range. In addition, PLA may be suitable for higher temperature wells. Some stereoisomers of poly(lactide) or mixtures of such stereoisomers may be suitable for even higher temperature applications. Dehydrated salts may also be suitable for higher temperature wells. Other blends of degradable materials may include materials that include different alloys including using the same elements but in different ratios or with a different arrangement of the same elements.
In some embodiments, a degradable material may include a material that has undergone different heat treatments and exhibits varying grain structures or precipitation structures. As an example, in some magnesium alloys, the beta phase can cause accelerated corrosion if it occurs in isolated particles. Homogenization annealing for various times and temperatures causes the beta phase to occur in isolated particles or in a continuous network. In this way, the corrosion behavior may be different for the same alloy with different heat treatments.
In some embodiments, all or a portion of the outer surface of at least a portion of the zonal isolation device 200 may be treated to impede degradation. For example, a surface of the zonal isolation device 200 may undergo a treatment that aids in preventing the degradable material (e.g., a galvanically-corrodible metal) from galvanically-corroding. Treatments suitable for certain embodiments of the present disclosure include, but are not limited to, an anodizing treatment, an oxidation treatment, a chromate conversion treatment, a dichromate treatment, a fluoride anodizing treatment, a hard anodizing treatment, and any combination thereof. Some anodizing treatments may result in an anodized layer of material being deposited on the surface. The anodized layer may comprise materials such as, but not limited to, ceramics, metals, polymers, epoxies, elastomers, or any combination thereof and may be applied using any suitable processes known to those of skill in the art. Examples of suitable processes that result in an anodized layer include, but are not limited to, soft anodize coating, anodized coating, electroless nickel plating, hard anodized coating, ceramic coatings, carbide beads coating, plastic coating, thermal spray coating, high velocity oxygen fuel (HVOF) coating, a nano HVOF coating, a metallic coating, and any combination thereof.
In some embodiments, all or a portion of an outer surface of the zonal isolation device 200 may be treated or coated with a substance configured to enhance degradation of the degradable material. For example, such a treatment or coating may be configured to remove a protective coating or treatment or otherwise accelerate the degradation of the degradable material of the zonal isolation device 200. In some embodiments, a galvanically-corroding metal material is coated with a layer of PGA. In this example, the PGA may undergo hydrolysis and cause the surrounding fluid to become more acidic, which may accelerate the degradation of the underlying metal.
In some embodiments, the degradable material may be made of dissimilar metals that generate a galvanic coupling that either accelerates or decelerates the degradation rate of the zonal isolation device 200. As will be appreciated, such embodiments may depend on where the dissimilar metals lie on the galvanic potential. In at least one embodiment, a galvanic coupling may be generated by embedding a cathodic substance or piece of material into an anodic structural element. For instance, the galvanic coupling may be generated by dissolving aluminum in gallium. A galvanic coupling may also be generated by using a sacrificial anode coupled to the degradable material. In such embodiments, the degradation rate of the degradable material may be decelerated until the sacrificial anode is dissolved or otherwise corroded away.
An embodiment of the present disclosure is a zonal isolation device, comprising: a tubular body having a fluid communication pathway formed along a longitudinal axis comprising: a sealing element comprising a deformable material and an inner bore forming at least a portion of the fluid communication pathway; an expansion ring disposed within the bore of the sealing element; a wedge engaged with a downhole end of the sealing element; and an anchoring assembly engaged with the wedge.
In one or more embodiments described in the preceding paragraph, the tubular body further comprises an end element adjacent the anchoring assembly. In one or more embodiments described above, the sealing element is radially expandable into sealing engagement with a downhole surface. In one or more embodiments described above, the anchoring assembly comprises a plurality of arcuate-shaped slip segments for locking engagement with a downhole surface. In one or more embodiments described above, at least two of the plurality of arcuate-shaped slip segments are interconnected by a shearable link. In one or more embodiments described above, the shearable link shears upon axial expansion. In one or more embodiments described above, longitudinal compression of the tubular body radially expands the sealing element and radially expands the anchoring assembly. In one or more embodiments described above, the sealing element is coupled to the wedge and the wedge is coupled to the anchoring assembly. In one or more embodiments described above, the wedge is coupled to the sealing element by a compression fit, an interference fit, or a bonding agent.
Another embodiment of the present disclosure is a method comprising: inserting into a wellbore a zonal isolation device disposed on a setting tool adapter kit comprising a mandrel, wherein the zonal isolation device comprises: a sealing element comprising a deformable material and an inner bore; an expansion ring movably disposed within the inner bore of the sealing element; a wedge engaged with a downhole end of the sealing element; an anchoring assembly engaged with the wedge; and an end element adjacent the anchoring assembly and detachably coupled to the mandrel; and actuating to pull upwardly on the mandrel, wherein the upward movement of the mandrel longitudinally compresses the zonal isolation device, causing the expansion ring to axially move relative to the sealing element and radially expand the sealing element into a sealing engagement with a downhole surface.
In one or more embodiments described in the preceding paragraph, the upward movement of the mandrel engages the anchoring assembly with the wedge, radially expanding the anchoring assembly into a locking engagement with the downhole surface. In one or more embodiments described above, the method further comprises shearing a shear device coupling the mandrel to the end element. In one or more embodiments described above, the method further comprises removing the setting tool adapter kit and the mandrel from the wellbore. In one or more embodiments described above, one or more components of the zonal isolation device comprises a pump-down ring. In one or more embodiments described above, the method further comprises seating a sealing ball on the expansion ring. In one or more embodiments described above, the anchoring assembly comprises a plurality of arcuate-shaped slip segments for locking engagement with the downhole surface. In one or more embodiments described above, upon sufficient movement of the wedge relative to the plurality of arcuate-shaped slip segments, at least two of the plurality of arcuate-shaped slip segments slip segments are separated from each other by shearing a shearable link joining the at least two slip segments.
Another embodiment of the present disclosure is a zonal isolation system, comprising: a setting tool adapter kit comprising a mandrel; a sealing element disposed on the mandrel for sealing engagement with a downhole surface; an expansion ring movably disposed on the mandrel and engaged with the sealing element; a wedge disposed on the mandrel; and an anchoring assembly disposed around the mandrel for locking engagement with a downhole surface.
In one or more embodiments described in the preceding paragraph, the system further comprises an end element coupled to the mandrel. In one or more embodiments described in the preceding sentence, the end element is detachably coupled to the mandrel by a shearing element.
Therefore, the present disclosure is well adapted to attain the ends and advantages mentioned as well as those that are inherent therein. The particular embodiments disclosed above are illustrative only, as the present disclosure may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. While numerous changes may be made by those skilled in the art, such changes are encompassed within the spirit of the subject matter defined by the appended claims. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular illustrative embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the present disclosure. In particular, every range of values (e.g., “from about a to about b,” or, equivalently, “from approximately a to b,” or, equivalently, “from approximately a-b”) disclosed herein is to be understood as referring to the power set (the set of all subsets) of the respective range of values. The terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2018/019986 | 2/27/2018 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2019/168502 | 9/6/2019 | WO | A |
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| Number | Date | Country | |
|---|---|---|---|
| 20210054704 A1 | Feb 2021 | US |
