(12) INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)
`(19) World Intellectual Property
`3‘
`Organization
`Intemationa] Bureau
`
`llllllllllllllllllllllllllllllll|l|||||l||||llllllllllllllllllllllllllllIllllllflllllllllllllll
`
`(10) International Publication Number
`
`
`
`& 1
`
`(43) International Publication Date
`8 May 2017 (18.05.2017)
`
`WO 2017/082865 A1
`WI P01 P C T
`
`
`(51)
`
`International Patent Classification:
`E218 33/12 (2006.01)
`E218 23/06 (2006.01)
`E213 33/128 (2006.01)
`
`(21)
`
`International Application Number:
`
`(72)
`
`Inventors: WALTON, Zachary William; 2204 Southern
`Ct., Carrollton, Texas 75006 (US). FRIPP, Michael Lin—
`ley; 3826 Cemetery Hill Rd., Carrollton, Texas 75007
`(US):
`
`(22)
`
`International Filing Date:
`
`(25) Filing Language:
`(26) Publication Language:
`
`PCT/USZOlS/059823
`
`(74)
`
`10 November 2015 (10.11.2015)
`
`English (81)
`English
`
`(71) Applicant: HALLIBURTON ENERGY SERVICES,
`INC. [US/US]; 3000 N. Sam Houston Parkway E, llous-
`ton, Texas 77032-3219 (US).
`
`Agents: KAISER, Iona et a1.; McDerinott Will & Emery
`LLP, 500 North Capitol Street, N.W., Washington, District
`ofColumbia 20001 (US).
`
`Designated States (unless otherwise indicated, for every
`kind ofnational protection available): AE, AG, AL, AM,
`AO, AT, AU, AZ, BA, BB, BG, BH, BN, BR, BW, BY,
`BZ, CA, CH, CL, CN, CO, CR, CU, CZ, DE, DK, DM,
`DO, DZ, EC, EE, EG, ES, FI, GB, GD, GE, GH, GM, GT,
`HN, HR, HU, ID, IL, IN, IR, IS, JP, KE, KG, KN, KP, KR,
`KZ, LA, LC, LK, LR, LS, LU, LY, MA, MD, ME, MG,
`MK, MN, MW, MX, MY, MZ, NA, NG, NI, NO, NZ, OM,
`e
`
`[Continued on next page]
`(54) Title: WELLBORE ISOLATION DEVICES WITH DEGRADABLE SLIPS AND SLIP BANDS
`
`
`
`230
`8on
`230
`NA N
`
`228
`
`
`3-{fix-a\
`
`
`
` ‘Z
`
`
`C\~‘.
`l
`
`215a kw
`
`217a «Hi-V '
`
`5.35;;
`2159
`1
`
`' ‘39:
`216a
`
`
`r M:
`218a
`
`(57) Abstract: A wellbore isolation device may include a mandrel; degradable slips dis—
`posed abont the mandrel and composed of a degradable metal alloy selected from the group
`consisting of a magnesium alloy, an aluminum alloy, and any combination thereof; and at
`least one packet element disposed along the mandrel. The degradable slips may be formed of
`a degradable metal material, Optionally, the wellborc isolation device may further include
`degradable slip bands formed of a degradable metal material or a degradable polymer,
`
`200
`/
`
`
`
`
`210
`2161)
`215b
`5 217b
`
`218D
`2161)
`2151)
`217b d
`
`236
`
`
`
`e2.amen:
`W'
`
` 222
`Willi/Illlllllllfll/A
`
`FIG. 2
`
`
`
`wo2017/082865A1Illllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllll
`
`

`

`WO 2017/082865 A1 llllllIllllllllilllllllllllIIIIIIIIIHIIIIllHIIIIIIIIIIIIIIIIIIIIIIlllllllllllllllllllllllllll
`PA, PE, PG, PH, PL, PT, QA, RO, RS, RU, RW, SA, SC,
`SD, SE, SG, SK, SL, SM, ST, SV, SY, TII, TJ, TM, TN,
`TR, TT, TZ, UA, UG, US, UZ, VC, VN, ZA, ZM, ZW.
`
`SI, SK, SM, TR), OAPI (BF, BJ, CF, CG, CI, CM, GA,
`GN, GQ, GW, KM, ML, MR, NE, SN, TD, TG).
`Declarations under Rule 4.17:
`
`(84)
`
`Designated States (unless otherwise indicated, jbr every
`kind Q/regionalprotection available): ARIPO (BW, GII,
`GM, KE, LR, LS, MW, MZ, NA, RW, SD, SL, ST, SZ,
`TZ, UG, ZM, ZW), Eurasian (AM, AZ, BY, KG, KZ, RU,
`TJ, TM), European (AL, AT, BE, BG, CH, CY, CZ, DE,
`DK, FE, ES, FI, FR, GB, GR, HR, HU, IE, IS, IT, LT,
`LU, LV, MC, MK, MT, NL, NO, PL, PT, RO, RS, SE,
`
`— as to applicant’s entitlement to apply fur and be granted
`apalem (Ru/e 4.l7(z'i))
`Published:
`
`—-
`
`with inlermnional search report (Art. 21(3))
`
`

`

`WO 2017/082865
`
`PCT/US2015/059823
`
`WELLBORE ISOLATION DEVICES WITH DEGRADABLE SLIPS
`AND SLIP BANDS
`
`5
`
`10
`
`15
`
`20
`
`25
`
`30
`
`BACKGROUND
`
`[0001]
`
`The present disclosure describes embodiments of wellbore
`
`isolation devices.
`
`[0002]
`
`In the drilling, completion, and stimulation of hydrocarbon~
`
`producing wells, a variety of downhole tools are used. For example,
`
`it
`
`is often
`
`desirable to seal portions of a wellbore, such as during fracturing operations when
`
`various fluids and slurries are pumped from the surface into a casing string that
`
`lines the wellbore, and forced out
`
`into a surrounding subterranean formation
`
`through the casing string.
`
`It thus becomes necessary to seal
`
`the wellbore and
`
`thereby provide zonal
`
`isolation at
`
`the location of
`
`the desired subterranean
`
`formation. Wellbore isolation devices, such as packers, bridge piugs, and fracturing
`
`plugs (i.e., “frac” plugs), are designed for these general purposes and are well
`
`known in the art of producing hydrocarbons, such as oil and gas. Such wellbore
`
`isolation devices may be used in direct contact with the formation face of the
`
`wellbore, with a casing string extended and secured within the weilbore, or with a
`screen or wire mesh.
`
`[0003]
`
`After
`
`the desired downhole operation is complete,
`
`the seal
`
`formed by the wellbore isolation device must be broken and the tool itself removed
`
`from the wellbore. Removing the wellbore isolation device may allow hydrocarbon
`
`production operations to commence without being hindered by the presence of the
`
`downhole tool. Removing wellbore isolation devices, however,
`
`is
`
`traditionally
`
`accomplished by a complex retrieval operation that involves milling or drilling out a
`
`portion of the wellbore isolation device, and subsequently mechanically retrieving
`
`its remaining portions. To accomplish this, a tool string having a mill or drill bit
`
`attached to its distal end is introduced into the wellbore and conveyed to the
`wellbore isolation device to mill or drill out the wellbore isolation device. After
`
`drilling out the wellbore isolation device,
`
`the remaining portions of the wellbore
`
`isolation device may be grasped onto and retrieved back to the surface with the
`
`tool string for disposal. As can be appreciated,
`
`this retrieval operation can be a
`
`costly and time—consuming process.
`
`

`

`WO 2017/082865
`
`PCT/USZOlS/059823
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`[0004]
`
`The following figures are included to illustrate certain aspects of
`
`the embodiments, and should not be viewed as exclusive embodiments. The subject
`
`matter disclosed is capable of considerable modifications, alterations, combinations,
`
`and equivalents in form and function, as will occur to those skilled in the art and
`
`having the benefit of this disclosure.
`
`[0005]
`
`FIG. 1 is a well system that can employ one or more principles of
`
`the present disclosure, according to one or more embodiments.
`
`[0006]
`
`FIG. 2 is a cross—sectional side view of a frac plug that can employ
`
`the principles of the present disclosure.
`
`[0007]
`
`FIG. 3 is a perspective view of the frac plug of FIG. 2.
`
`[0008]
`
`FIG. 4 is a perspective view of a frac plug that can employ the
`
`principles of the present disclosure.
`
`[0009]
`
`FIG. 5 is a
`
`cross—sectional view of a
`
`frac plug in operation,
`
`according to one or more embodiments of the present disclosure.
`
`DETAILED DESCRIPTION
`
`[0010]
`
`The present disclosure describes embodiments of wellbore
`
`isolation devices that are made of degrading materials, and their methods of use
`
`during a subterranean formation operation.
`
`In particular, the present disclosure
`
`describes wellbore isolation devices having slip bands composed of a degradable
`
`material (also referred to herein as “degradable slip bands") that degrade in a
`
`wellbore environment at a desired time during the performance of a subterranean
`
`formation operation (or simply “formation operation”). These degradable materials
`
`(also referred to collectively as “degradable substances”) are discussed in greater
`
`detail below. As used herein, the term “wellbore isolation device,” and grammatical
`
`variants thereof,
`
`is a device that is set in a wellbore to isolate a portion of the
`
`wellbore thereabove from a portion therebelow so that fluid can be forced into the
`
`surrounding subterranean formation above the device. As used herein, the term
`
`“sealing ball” and “frac ball,” and grammatical variants thereof, refer to a spherical
`
`or spheroidal element designed to seal a portion of a wellbore isolation device that
`
`is accepting fluids like the inner diameter of a mandrel, thereby diverting reservoir
`
`10
`
`15
`
`20
`
`25
`
`30
`
`

`

`WO 2017/082865
`
`PCT/U52015/059823
`
`treatments to other portions of a target zone in a subterranean formation. An
`
`example of a sealing ball
`
`is a frac ball
`
`in a frac plug wellbore isolation device. As
`
`used herein, the term “packer element,” and grammatical variants thereof, refers to
`
`inflatable, or swellable element that expands against a casing or
`an expandable,
`wellbore to seal the wellbore.
`
`[0011]
`
`One or more illustrative embodiments disclosed herein are
`
`presented below. Not all features of an actual
`
`implementation are described or
`
`shown in this application for the sake of clarity.
`
`It
`
`is understood that
`
`in the
`
`development of an actual embodiment incorporating the embodiments disclosed
`
`herein, numerous implementation—specific decisions must be made to achieve the
`
`developer's goals,
`
`such as compliance with system-related,
`
`lithology~related,
`
`business-related, government—related,
`
`and other constraints, which vary by
`
`implementation and over time. While a developer's efforts might be complex and
`
`time-consuming, such efforts would be, nevertheless, a routine undertaking for
`
`those of ordinary skill in the art having benefit of this disclosure.
`
`[0012]
`
`It should be noted that when “about” is provided herein at the
`
`beginning of a numerical list, the term modifies each number of the numerical list.
`
`In some numerical listings of ranges, some lower limits listed may be greater than
`
`some upper limits listed. One skilled in the art will recognize that the selected
`
`subset will require the selection of an upper limit
`
`in excess of the selected lower
`
`limit. Unless otherwise indicated, all numbers expressing quantities of ingredients,
`
`properties such as molecular weight, reaction conditions, and so forth used in the
`
`present specification and associated claims are to be understood as being modified
`
`in all instances by the term “about.” As used herein, the term “about” encompasses
`
`+/— 5% of each numerical value. For example,
`
`if the numerical value is “about
`
`80%,” then it can be 80% +/- 5%, equivalent to 76% to 84%. Accordingly, unless
`
`indicated to the contrary,
`
`the numerical parameters set forth in the following
`
`specification and attached claims are approximations that may vary depending
`
`upon the desired properties sought to be obtained by the exemplary embodiments
`
`described herein. At the very least, and not as an attempt to limit the application of
`
`the doctrine of equivalents to the scope of the claim, each numerical parameter
`
`10
`
`15
`
`20
`
`25
`
`30
`
`

`

`WO 2017/082865
`
`PCT/U52015/059823
`
`should at least be construed in light of the number of reported significant digits and
`
`by applying ordinary rounding techniques.
`
`[0013]
`
`While compositions and methods are described herein in terms
`
`of “comprising” various components or steps, the compositions and methods can
`
`also “consist essentially of” or “consist of" the various components and steps. When
`
`“comprising” is used in a claim, it is open-ended.
`
`[0014]
`
`As used herein, the term “substantially” means largely, but not
`
`necessarily wholly.
`
`10
`
`The use of directional terms such as above, below, upper, lower,
`[0015]
`upward, downward, left, right, uphole, downhole and the like are used in relation to
`
`the illustrative embodiments as they are depicted in the figures,
`
`the upward
`
`direction being toward the top of the corresponding figure and the downward
`
`direction being toward the bottom of the corresponding figure, the uphole direction
`
`being toward the surface of the well and the downhole direction being toward the
`toe of the well.
`
`15
`
`[0016]
`
`The embodiments of the present disclosure are directed toward
`
`degradable wellbore isolation devices (e.g., frac plugs, bridge plugs, and packers)
`
`comprising degradable slip bands. 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 result or reduced structural
`
`integrity results 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, or structural shape is
`
`lost.
`
`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
`
`20
`
`25
`
`30
`
`

`

`WO 2017/082865
`
`PCT/U82015/059823
`
`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, or an
`
`electrolyte may be introduced or naturally occurring to induce galvanic corrosion.
`
`The term “wellbore environment,” and grammatical variants thereof, includes both
`
`naturally occurring wellbore environments and materials or fluids introduced into
`
`the wellbore. The term “at least a portion,” and grammatical variants thereof, with
`
`reference to a component having at
`
`least a portion composed thereof of a
`
`degradable material or substance (e.g., “at
`
`least a portion of a component
`
`is
`
`degradable” or “at least a portion of the slips and/or slip bands is degradable,” and
`
`variants thereof) refers to at least about 80% of the volume of that part being
`
`formed of the degradable material or substance.
`
`[0017]
`
`The degradable materials of the degradable slip bands may
`
`allow for time between setting the wellbore isolation device and when a particular
`
`downhole operation is undertaken, such as a hydraulic fracturing operation).
`
`Moreover, degradable materials allow for acid treatments and acidified stimulation
`
`of a wellbore.
`
`In some embodiments,
`
`the degradable materials may require a
`
`greater
`
`flow area or
`
`flow capacity to enable production operations without
`
`unreasonably impeding or obstructing fluid flow while the wellbore isolation device
`
`degrades. As a result, production operations may be efficiently undertaken while
`
`the wellbore isolation device degrades and without creating significant pressure
`restrictions.
`
`[0018]
`
`Some embodiments of the present disclosure relate to methods
`
`of using a degradable wellbore isolation device, and in particular, a frac plug, during
`
`a hydraulic fracturing operation. For example, a frac plug may be introduced into a
`
`wellbore
`
`in
`
`a
`
`subterranean formation in accordance with the embodiments
`
`described herein. The wellbore may be an open—hole wellbore or have a casing
`
`string disposed therein. The frac plug comprises a plurality of components
`
`comprising at least a mandrel, degradable slips, optionally degradable slip bands,
`
`and a packer element. The degradable slip bands may be composed of a degradable
`
`metal material like a degradable metal alloy, wherein the degradable metal alloy is
`
`a magnesium alloy, and aluminum alloy, or a combination thereof. Optionally, the
`
`degradable slip bands may be composed of a degradable polymer, wherein the
`
`10
`
`15
`
`20
`
`25
`
`30
`
`

`

`WO 2017/082865
`
`PCT/U52015/059823
`
`degradable polymer is a polymer that degrades in water-based fluids or in an oil-
`
`based fluid, compositions for which are described further herein. Other components
`
`of the frac plug may additionally be comprised of a degradable material. For
`
`example, the mandrel, the degradable slips, the frac ball, or a combination thereof
`
`may be composed, at
`
`least
`
`in part, of a degradable metal material
`
`(e.g., a
`
`degradable metal alloy), a degradable polymer, or a combination thereof. Further,
`
`the packer elements, the frac ball, or a combination thereof may be composed, at
`
`least in part, of a degradable polymer, without departing from the scope of the
`
`present disclosure.
`
`[0019]
`
`The degradable slips or a component coupled thereto (e.g.,
`
`buttons coupled thereto) frictionally engage the wall of the wellbore or the casing
`
`string, depending on the configuration of
`
`the wellbore in
`
`the subterranean
`
`formation. As used herein, the term “wall,” and grammatical variants thereof (e.g.,
`
`wellbore wall), with reference to a wellbore refers to the outer rock face that
`
`bounds the drilled wellbore. The packer element of the frac plug is compressed
`
`against the wall of the wellbore or the casing string to set the frac plug within the
`
`wellbore,
`
`as described below. At
`
`least one perforation is created in
`
`the
`
`subterranean formation though the wall of the wellbore or the casing string (and
`
`any cement disposed between the wall of the wellbore and the casing string,
`
`if
`
`included). In some embodiments, a plurality of perforations, or a perforation cluster
`
`are created into the subterranean formation, without departing from the scope of
`
`the present disclosure. As used herein, the term “perforation,” and grammatical
`
`variants thereof, refers to a communication tunnel created through a wall of a
`
`wellbore, including through a casing string,
`
`into a subterranean formation through
`
`which production fluids may flow. Perforations may be formed by any means
`
`suitable in a subterranean formation including, but not limited to, shaped explosive
`
`charges, perforating guns, bullet perforating, abrasive jetting, or high—pressure fluid
`
`jetting, without departing from the scope of the present disclosure.
`
`[0020]
`
`The subterranean formation is hydraulically fractured through
`
`the at least one perforation. As used herein, the term “hydraulic fracturing," and
`
`grammatical variants thereof, refers to a stimulation treatment in which fluids are
`
`pumped at a high rate and pressure to overcome a fracture gradient within a
`
`10
`
`15
`
`20
`
`25
`
`30
`
`

`

`WO 2017/082865
`
`PCT/USZOIS/059823
`
`subterranean formation to cause fractures to be created or enhanced. The term
`
`“fracture gradient,” and grammatical variants thereof,
`
`refers to the pressure
`
`required to induce or enhance fractures in a subterranean formation at a given
`
`depth. That
`
`is,
`
`the fracture gradient may vary in a particular subterranean
`
`formation depending on the depth thereof.
`
`[0021]
`
`The degradable slip bands and other degradable components of
`
`the wellbore isolation device are degraded at
`
`least partially in the wellbore
`
`environment. As used herein,
`
`the term “at
`
`least partially degrading," and
`
`grammatical variants
`
`thereof
`
`(e.g.,
`
`“degrading at
`
`least partially,” “partially
`
`degrades,” and the like) with reference to degradation of a component thereof of a
`
`wellbore isolation device refers to the component degrading at least to the point
`
`wherein about 20% or more of the mass of the component degrades. For instance,
`
`the degradable metal alloy forming the degradable slip bands is at least partially
`
`degraded in the presence of an electrolyte in the wellbore environment. The
`
`production of a hydrocarbon (i.e., oil and/or gas) from the subterranean formation
`
`may proceed.
`
`In some instances, degradation of the degradable material and
`
`production of a hydrocarbon may occur simultaneously, or alternatively in series,
`
`without departing from the scope of the present disclosure. That is, the order,
`
`if
`
`any, of degradation and production may depend on selection of the particular
`
`degradable material (e.g., the degradable metal alloy or alloy combination), the
`
`degradation stimuli (e.g., the electrolyte or other stimulus), and the like, and any
`
`combination thereof.
`
`In some embodiments, accordingly, production may begin
`
`before degradation, or degradation may begin before production. Although
`
`degradation may begin and end before production begins,
`
`it is contemplated that
`
`both degradation and production will occur simultaneously during at least some
`
`point in time (or duration), regardless of which process is initiated first.
`
`[0022]
`
`FIG.
`
`1
`
`illustrates a well system 100 that may embody or
`
`otherwise employ one or more principles of the present disclosure, according to one
`
`or more embodiments. As illustrated, the well system 100 may include a service rig
`
`102 (also referred to as a “derrick") that is positioned on the earth’s surface 104
`
`and extends over and around a wellbore 106 that penetrates a subterranean
`
`formation 108. The service rig 102 may be a drilling rig, a completion rig, a
`
`10
`
`15
`
`20
`
`25
`
`30
`
`

`

`WO 2017/082865
`
`PCT/USZOIS/059823
`
`workover rig, or the like.
`
`In some embodiments,
`
`the service rig 102 may be
`
`omitted and replaced with a standard surface wellhead completion or installation,
`
`without departing from the scope of the disclosure. While the well system 100 is
`
`depicted as a landvbased operation, it will be appreciated that the principles of the
`
`present disclosure could equally be applied in any sea-based or sub~sea application
`
`where the service rig 102 may be a floating platform or sub-surface wellhead
`
`installation, as generally known in the art.
`
`[0023]
`
`The wellbore 106 may be drilled into the subterranean formation
`
`108 using any suitable drilling technique and may extend in a substantially vertical
`
`direction away from the earth’s surface 104 over a vertical wellbore portion 110. At
`
`some point in the wellbore 106, the vertical wellbore portion 110 may deviate from
`
`vertical
`
`relative to the earth’s surface 104 and transition into a substantially
`
`horizontal wellbore portion 112, although such deviation is not required. That is,
`
`the wellbore 106 may be vertical, horizontal, or deviated, without departing from
`
`the scope of the present disclosure. In some embodiments, the wellbore 106 may
`
`be completed by cementing a string of casing 114 within the wellbore 106 along all
`
`or a portion thereof. As used herein, the term “casing” refers not only to casing as
`
`generally known in the art, but also to borehole liner, which comprises tubular
`
`sections coupled end to end but not extending to a surface location.
`
`In other
`
`embodiments, however, the string of casing 114 may be omitted from all or a
`
`portion of the wellbore 106 and the principles of the present disclosure may equally
`
`apply to an “open~hole" environment.
`
`[0024]
`
`The well system 100 may further include a wellbore isolation
`
`device 116 that may be conveyed into the wellbore 106 on a conveyance 118 (also
`
`referred to as a “tool string”) that extends from the service rig 102. The wellbore
`
`isolation device 116 may include or otherwise comprise any type of casing or
`
`borehole isolation device known to those skilled in the art including, but not limited
`
`to, a frac plug, a bridge plug, a deployable baffle, a wellbore packer, a wiper plug, a
`
`cement plug, or any combination thereof.
`
`[0025]
`
`The conveyance 118 that delivers the wellbore isolation device
`
`116 downhole may be, but
`
`is not
`
`limited to, wireline, slickline, an electric line,
`
`coiled tubing, drill pipe, production tubing, or the like. The wellbore isolation device
`
`10
`
`15
`
`20
`
`25
`
`30
`
`

`

`WO 2017/082865
`
`PCT/U82015/059823
`
`116 may be conveyed downhole to a target
`
`location (not shown) within the
`
`wellbore 106. At the target location, the wellbore isolation device may be actuated
`
`or “set” to seal the wellbore 106 and otherwise provide a point of fluid isolation
`
`within the wellbore 106. In some embodiments, the wellbore isolation device 116 is
`
`pumped to the target location using hydraulic pressure applied from the service rig
`
`102 at the surface 104.
`
`In such embodiments,
`
`the conveyance 118 serves to
`
`maintain control of the wellbore isolation device 116 as it traverses the wellbore
`
`106 and provides the necessary power to actuate and set the wellbore isolation
`
`device 116 upon reaching the target location. In other embodiments, the wellbore
`
`isolation device 116 freely falls to the target location under the force of gravity to
`
`traverse all or part of the wellbore 106.
`
`[0026]
`
`It will be appreciated by those skilled in the art that even
`
`though FIG.
`
`1 depicts the wellbore isolation device 116 as being arranged and
`
`operating in the horizontal portion 112 of the wellbore 106,
`
`the embodiments
`
`described herein are equally applicable for use in portions of the wellbore 106 that
`
`are vertical, deviated, or otherwise slanted. It should also be noted that a plurality
`
`of wellbore isolation devices 116 may be placed in the wellbore 106.
`
`In some
`
`embodiments, for example, several (e.g., six or more) wellbore isolation devices
`
`116 may be arranged in the wellbore 106 to divide the wellbore 106 into smaller
`
`intervals or “zones” for hydraulic stimulation.
`
`[0027]
`
`FIGS. 2 and 3, with continued reference to FIG. 1, illustrate a
`
`cross-sectional view and a perspective view,
`
`respectively, of
`
`two different
`
`exemplary frac plug 200 that may employ one or more of the principles of the
`
`present disclosure. As used herein,
`
`the term “frac plug” (also referred to as a
`
`“fracturing plug”), and grammatical variants thereof, refers to a wellbore isolation
`
`device that isolates fluid flow in at least one direction relative to the plug, typically
`
`the isolation is from above the plug. While the present disclosure uses frac plugs to
`
`illustrate various embodiments of degradable slips and degradable slip bands, these
`
`embodiments may be applied to the slips and slip bands of the other foregoing
`
`wellbore isolation devices and are within the scope of the present application.
`
`[0028]
`
`The frac plug 200 may be similar to or the same as the wellbore
`
`isolation device 116 of FIG. 1. Accordingly, the frac plug 200 may be configured to
`
`10
`
`15
`
`20
`
`25
`
`30
`
`

`

`WO 2017/082865
`
`PCT/USZOIS/059823
`
`be extended into and seal
`
`the wellbore 106 at a target
`
`location, and thereby
`
`prevent fluid flow past the frac plug 200 for wellbore completion or stimulation
`
`operations. In some embodiments, as illustrated, the wellbore 106 may be lined
`
`with the casing 114 or another type of wellbore liner or tubing in which the frac
`
`plug 200 may suitably be set. In other embodiments, however, the casing 114 may
`
`be omitted and the frac plug 200 may instead be set or otherwise deployed in an
`
`uncompleted or “open-hole” environment.
`
`[0029]
`
`As illustrated, the frac plug 200 may include a ball cage 204
`
`extending from or otherwise coupled to the upper end of a mandrel 206. A sealing
`
`ball, frac ball 208,
`
`is disposed in the ball cage 204 and the mandrel 206 defines a
`
`longitudinal central flow passage 210. The mandrel 206 also defines a ball seat 212
`
`at its upper end. In other embodiments, the frac ball 208 may be dropped into the
`
`conveyance 118 (FIG. 1) to land on top of the frac plug 200 rather than being
`
`carried within the ball cage 204.
`
`[0030]
`
`One or more spacer rings 214 (one shown) may be secured to
`
`the mandrel 206 and otherwise extend thereabout. The spacer ring 214 provides an
`
`abutment, which axially retains a set of upper degradable slips 216a that are also
`
`positioned circumferentially about the mandrel 206. As illustrated, a set of lower
`
`degradable slips 216b may be arranged distally from the upper degradable slips
`
`216a. The upper degradable slips 216a constrain the degradable slip bands 215a;
`
`and the lower degradable slips 216b are constrained by the degradable slip bands
`
`215b. As used herein,
`
`the term “constrained" means at least partially enclosed
`
`within a supporting substance material. The degradable slip bands 215a, 215b may
`
`constrain the degradable slips 216a, 216b, respectively, by any known method.
`
`Examples of suitable methods may include, but are not limited to, via a press fit,
`
`via a thermal shrink fit, via an adhesive, interference fit, clearance fit, via a snap
`
`ring, and the like. For example, the degradable slips 216a, 216b, the degradable
`
`slip bands 215a, 215b, or a combination thereof may be machined from a
`
`degradable metal material. In another example, the degradable slips 216a, 216b,
`
`the degradable slip bands 215a, 215b, or a combination thereof may be cast from
`
`molten or otherwise liquid degradable metal material. In yet another example, the
`
`degradable slip bands 215a, 215b may be formed of a degradable polymer.
`
`10
`
`15
`
`20
`
`25
`
`30
`
`10
`
`

`

`WO 2017/082865
`
`PCT/U52015/059823
`
`[0031]
`
`The degradable slips 216a, 216b have buttons embedded
`
`therein. The buttons 217a, 217b, which may be composed of a degradable metal
`
`material, protrude from the degradable slips 216a, 216b respectively to penetrate
`
`or bite a downhole surface and frictionally engage the degradable slips 216a, 216b
`
`therewith downhole surface (e.g., a wellbore wall, a tubing string wall, such as
`
`casing string, and the like) when the frac plug 200 is actuated. Although each
`
`degradable slip 216a, 216b is shown having two degradable slip bands 215a, 215b
`
`and three or four buttons 217a, 217b embedded therein, respectfully,
`
`it will be
`
`appreciated that any number of degradable slip bands and buttons, including one or
`
`a plurality (two, three, four, five, six, eight, ten, twenty, and the like) of degradable
`
`slip bands and/or buttons may be embedded in each degradable slip, without
`
`departing from the scope of the present disclosure. Moreover,
`
`the number of
`
`degradable slip bands in the upper degradable slips 216a and lower degradable
`
`slips 216b, and any additional degradable slips included as part of the frac plug
`
`200, may have the same or different number of degradable slip bands, without
`
`departing from the scope of the present disclosure. Additionally, although the
`
`degradable slip bands 215a, 215b shown in FIG. 2 are depicted as rectangular or
`
`square in cross section, the degradable slip bands 215a, 215b may be any other
`
`shape, without departing from the scope of the present disclosure. For example, the
`
`shape of the degradable slips bands may be cylindrically shaped, frustrum shaped,
`
`conical shaped, spheroid shaped, pyramid shaped, polyhedron shaped, octahedron
`
`shaped,
`
`cube
`
`shaped,
`
`prism shaped,
`
`hemispheroid
`
`shaped,
`
`cone
`
`shaped,
`
`tetrahedron shaped, cuboid shaped, and the like, and any combination thereof,
`
`without departing from the scope of the present disclosure. That is, the degradable
`
`slip bands may be partially one shape and partially one or more other shapes.
`
`[0032]
`
`One or more slip wedges 218 (shown as upper and lower slip
`
`wedges 218a and 218b,
`
`respectively) may also be positioned circumferentially
`
`about the mandrel 206, as described in greater detail below. Collectively, the term
`
`“slip assembly” includes at least the degradable slips 216a, 216b, the degradable
`
`slip bands 215a, 215b, the buttons 217a, 217b, and slip wedges 218a, 218b. In
`
`some instances,
`
`the buttons and slip wedges may be composed of degradable
`
`materials. Accordingly,
`
`in
`
`some embodiments,
`
`the slip assembly may be a
`
`10
`
`15
`
`20
`
`25
`
`30
`
`11
`
`

`

`WO 2017/082865
`
`PCT/USZOIS/059823
`
`degradable slip assembly where all components thereof are at
`
`least partially
`
`degradable.
`
`[0033]
`
`Alternatively, FIG. 4, with continued reference to FIGS. 2 and 3,
`
`illustrates a perspective view of an upper portion of an exemplary frac plug 300
`
`that may employ one or more of the principles of the present disclosure. FIG. 4,
`
`specifically, illustrates an alternative slip assembly where the remaining portions of
`
`the frac plug 300 correspond to the frac plug 200 of FIGS. 2 and 3. Juxtaposing
`
`upper degradable slips 316a are connected by tabs 321. The slip wedges 318
`
`include fins 319 that are shaped to slide through a space 323 between the
`
`juxtaposing upper degradable slip 316a and break the tabs 321. The degradable
`
`slips 316a then extend outwardly, and the buttons 317a bite into, penetrate, or bite
`
`a downhole surface and frictionally engage the degradable slips 316a with the
`
`downhole surface when the frac plug 200 is actuated.
`
`In embodiments of FIG. 4
`
`and similar embodiments, the slip assembly includes at least the degradable slips
`
`316a with tabs 321 connecting juxtaposing degradable slips 316a,
`
`the buttons
`
`317a, and the slip wedges 318a with fins 319.
`
`In some embodiments,
`
`the slip
`
`assembly may be a degradable slip assembly where all components thereof are at
`
`least partially degradable.
`
`[0034]
`
`In some instances, a hybrid of the embodiment of FIGS. 2 and 3
`
`and the embodiment of FIG. 4 may be implemented where the upper slip assembly
`
`is configured as illustrated and described in FIGS. 2 and 3 and the lower slip
`
`assembly is

Accessing this document will incur an additional charge of $.

After purchase, you can access this document again without charge.

Accept $ Charge

This document could not be displayed.

We could not find this document within its docket. Please go back to the docket page and check the link. If that does not work, go back to the docket and refresh it to pull the newest information.

Your account does not support viewing this document.

You need a Paid Account to view this document. Click here to change your account type.

Your account does not support viewing this document.

Set your membership status to view this document.

With a Docket Alarm membership, you'll get a whole lot more, including:

  • Up-to-date information for this case.
  • Email alerts whenever there is an update.
  • Full text search for other cases.
  • Get email alerts whenever a new case matches your search.

Become a Member

One Moment Please

The filing “” is large (MB) and is being downloaded.

Please refresh this page in a few minutes to see if the filing has been downloaded. The filing will also be emailed to you when the download completes.

Your document is on its way!

If you do not receive the document in five minutes, contact support at support@docketalarm.com.

Sealed Document

We are unable to display this document, it may be under a court ordered seal.

If you have proper credentials to access the file, you may proceed directly to the court's system using your government issued username and password.


Access Government Site

We are redirecting you
to a mobile optimized page.

We are unable to display this document.

PTO Denying Access

Refresh this Document
Go to the Docket