# Patent

## Title
Stage tool apparatus and components for same

## Abstract

A stage tool apparatus and components for same are described. In several exemplary embodiments, the stage tool apparatus is part of tubular string or casing positioned within a preexisting structure such as, for example, a wellbore.

## Background
CROSS-REFERENCE TO RELATED APPLICATION
This application claims the benefit of the filing date of, and priority to, U.S. Application No. 61/764,629, filed Feb. 14, 2013, the entire disclosure of which is incorporated herein by reference.


BACKGROUND
This disclosure relates in general to oil and gas exploration and production operations, and in particular to supporting a casing that extends within a wellbore, and isolating one or more formations through which the wellbore extends, to facilitate oil and gas exploration and production operations, including drill-out operations.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a stage tool apparatus according to an exemplary embodiment, the stage tool apparatus including a box sub, a body assembly and a pin sub.
FIG. 2 is a partially exploded view of the stage tool apparatus of FIG. 1 according to an exemplary embodiment.
FIG. 3 is a sectional view of the stage tool apparatus of FIG. 1 according to an exemplary embodiment.
FIG. 4 is a perspective view of the body assembly of FIG. 1 according to an exemplary embodiment, the body assembly including an outer sleeve and a plurality of components engaged therewith or disposed therein.
FIG. 5 is a perspective view of a section of the body assembly of FIG. 4 according to an exemplary embodiment, and depicts the outer sleeve and at least a portion of the plurality of components engaged therewith or disposed therein.
FIG. 6 is a perspective view of the plurality of components of FIGS. 4 and 5 according to an exemplary embodiment.
FIG. 7 is a perspective view of a section of a portion of the plurality of components of FIGS. 4-6 according to an exemplary embodiment.
FIG. 8 is an exploded view of a portion of the plurality of components of FIGS. 4-7 according to an exemplary embodiment.
FIG. 9 is a sectional view of the body assembly of FIGS. 4 and 5 according to an exemplary embodiment.
FIG. 10 is a perspective view of a shear screw according to an exemplary embodiment, the shear screw being one of the components shown in FIG. 6.
FIG. 11 is an enlarged view of a portion of FIG. 8 and illustrates a lock key and a spring according to respective exemplary embodiments.
FIG. 12 is a perspective view of the lock key and the spring of FIG. 11.
FIG. 13 is an enlarged view of a portion of FIG. 3.
FIG. 14 is a partial sectional view of the shear screw of FIG. 10 extending through the outer sleeve of the body assembly of FIG. 4, according to an exemplary embodiment.
FIG. 15 is a partial sectional view of the stage tool apparatus of FIG. 1 extending within a wellbore and placed in an operational mode, according to an exemplary embodiment.
FIG. 16 is a partial sectional view of the stage tool apparatus of FIG. 1 extending within a wellbore and placed in an operational mode similar to that of FIG. 15, but also including a dart seated within the apparatus, according to an exemplary embodiment.
FIG. 16a is a partial sectional view of a shear screw when the stage tool apparatus of FIG. 1 is in the operational mode of FIG. 16, according to an exemplary embodiment.
FIG. 17 is a partial sectional view of the stage tool apparatus of FIG. 1 extending within a wellbore and placed in an operational mode, according to an exemplary embodiment.
FIG. 18 is a partial sectional view of the stage tool apparatus of FIG. 1 extending within a wellbore and placed in an operational mode similar to that of FIG. 17, but also including a plug seated within the apparatus, according to an exemplary embodiment.
FIG. 18a is a view similar to that of FIG. 13, but depicting the portion shown in FIG. 13 when the stage tool apparatus of FIG. 1 is in the operational mode of FIG. 18, according to an exemplary embodiment.
FIG. 19 is a partial sectional view of the stage tool apparatus of FIG. 1 extending within a wellbore and placed in an operational mode, according to an exemplary embodiment.
FIG. 19a is a view similar to that of FIG. 18a, but depicting the portion shown in FIG. 18a when the stage tool apparatus of FIG. 1 is in the operational mode of FIG. 19, according to an exemplary embodiment.
FIG. 20 is a perspective view of a section of a portion of a stage tool apparatus, according to an exemplary embodiment, the stage tool including a dart, a lower seat, a plug, and an upper seat.
FIG. 21 is a perspective view of the dart of FIG. 20 according to an exemplary embodiment.
FIG. 21A is a side view of the dart of FIG. 20 according to an exemplary embodiment.
FIG. 21B is a sectional view of the dart of FIG. 20, taken along line 21B-21B of FIG. 21A, according to an exemplary embodiment.
FIG. 21C is a bottom plan view of the dart of FIG. 20 according to an exemplary embodiment.
FIG. 21D is another sectional view of the dart of FIG. 20, taken along line 21D-21D of FIG. 21C but inverted, according to an exemplary embodiment.
FIG. 22 is a perspective view of the lower seat of FIG. 20 according to an exemplary embodiment.
FIG. 22A is a top plan view of the lower seat of FIG. 20 according to an exemplary embodiment.
FIG. 23 is a perspective view of the plug of FIG. 20 according to an exemplary embodiment.
FIG. 23A is a side view of the plug of FIG. 20 according to an exemplary embodiment.
FIG. 23B is a sectional view of the plug of FIG. 20, taken along line 23B-23B of FIG. 23A, according to an exemplary embodiment.
FIG. 23C is a bottom plan view of the plug of FIG. 20 according to an exemplary embodiment.
FIG. 23D is another sectional view of the plug of FIG. 20, taken along line 23D-23D of FIG. 23C but inverted, according to an exemplary embodiment.
FIG. 24 is a perspective view of the upper seat of FIG. 20 according to an exemplary embodiment.
FIG. 24A is a top plan view of the upper seat of FIG. 20 according to an exemplary embodiment.
FIG. 25 is a partial sectional view of the stage tool apparatus of FIG. 20 extending within a wellbore and placed in an operational mode, according to an exemplary embodiment.
FIG. 26 is a partial sectional view of the stage tool apparatus of FIG. 20 extending within a wellbore and placed in an operational mode similar to that of FIG. 25, but also including the dart seated in the lower seat, according to an exemplary embodiment.
FIG. 26A is a sectional view, taken along line 26A-26A of FIG. 26, of the dart seated in the lower seat when the stage tool apparatus of FIG. 20 is in the operational mode of FIG. 26, according to an exemplary embodiment.
FIG. 26B is an enlarged view of a portion of FIG. 26.
FIG. 27 is a partial sectional view of the stage tool apparatus of FIG. 20 extending within a wellbore and placed in an operational mode, according to an exemplary embodiment.
FIG. 28 is a partial sectional view of the stage tool apparatus of FIG. 20 extending within a wellbore and placed in an operational mode similar to that of FIG. 27, but also including the plug seated within the upper seat, according to an exemplary embodiment.
FIG. 28A is a partial sectional view of the plug seated in the upper seat when the stage tool apparatus of FIG. 20 is in the operational mode of FIG. 28, according to an exemplary embodiment.
FIG. 29 is a partial sectional view of the stage tool apparatus of FIG. 20 extending within a wellbore and placed in an operational mode, according to an exemplary embodiment.
FIG. 30 is a view similar to that of FIG. 26 but depicting the apparatus of FIG. 20 placed in another operational mode, according to an exemplary embodiment.
FIG. 30A is a partial sectional view of the dart seated in the lower seat when the stage tool apparatus of FIG. 20 is in the operational mode of FIG. 30, according to an exemplary embodiment.
FIG. 30B is another partial sectional view of the dart seated in the lower seat when the stage tool apparatus of FIG. 20 is in the operational mode of FIG. 30, according to an exemplary embodiment.
FIG. 31 is a view similar to that of FIG. 28A but depicting the apparatus of FIG. 20 placed in another operational mode, according to an exemplary embodiment.



DETAILED DESCRIPTION
The foregoing disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. Further, spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper,” “uphole,” “downhole,” “upstream,” “downstream,” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the tool, or the apparatus, in use or operation in addition to the orientation depicted in the figures. For example, if the apparatus in the figures is turned over, elements described as being “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the exemplary term “below” can encompass both an orientation of above and below. The apparatus may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly.
In an exemplary embodiment, as illustrated in FIGS. 1-3, a downhole tool, and in particular a stage tool apparatus, is generally referred to by the reference numeral 10 and includes a box sub 12, a body assembly 14, and a pin sub 16. The box sub 12 includes an internal threaded connection 12a at one of its end portions, and an external threaded connection 12b that is axially spaced between the internal threaded connection 12a and the other of its end portions. The box sub 12 defines an internal passage 12c. 
Even though FIG. 3 depicts the stage tool apparatus 10 in a vertical orientation associated with vertical wellbores, it should be understood by those skilled in the art that the apparatus according to the present disclosure is equally well suited for use in wellbores having other orientations including slanted wellbores, horizontal wellbores, multilateral wellbores or the like. Accordingly, it should be understood by those skilled in the art that the use of directional terms such as “above,” “top,” “below,” “upper,” “lower,” “upward,” “bottom,” “downward,” “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 or top being toward the surface of the well, the downhole direction or bottom being toward the toe of the well.
The body assembly 14 includes an outer tubular member, such as an outer sleeve 18, and a plurality of components 20 engaged therewith or disposed therein, which components will be described in greater detail below. The outer sleeve 18 includes an internal threaded connection 18a at one of its end portions and an internal threaded connection 18b at the other of its end portions. The internal threaded connection 18a is coupled to the external threaded connection 12b of the box sub 12, thereby coupling the box sub 12 to the body assembly 14. The outer sleeve 18 defines an internal passage 18c. A sealing element, such as an o-ring 22, extends in an annular channel 12d formed in the outside surface of the box sub 12, the o-ring 22 sealingly engaging the inside surface of the outer sleeve 18.
The pin sub 16 includes an external threaded connection 16a at one end portion, which is coupled to the internal threaded connection 18b of the outer sleeve 18 of the body assembly 14, thereby coupling the pin sub 16 to the body assembly 14. The pin sub 16 further includes an external threaded connection 16b at the other end portion that is distal to the body assembly 14. The pin sub 16 defines an internal passage 16c. As shown in FIG. 3, a sealing element, such as an o-ring 24, extends in an annular channel 16d formed in the outside surface of the pin sub 16.
In an exemplary embodiment, as illustrated in FIGS. 4-9 with continuing reference to FIGS. 1-3, the outer sleeve 18 further includes a plurality of circumferentially-spaced flow ports 18d, each of which extends radially through the outer sleeve 18, and a plurality of circumferentially-spaced ports 18e spaced axially from the plurality of ports 18d, with each of the ports 18e also extending radially through the outer sleeve 18.
As noted above, the body assembly 14 includes a plurality of components 20 engaged with the outer sleeve 18 or disposed therein. The plurality of components 20 includes an upper tubular member such as an upper sleeve 26, a lower tubular member such as a lower sleeve 28, an upper seat 30, a lower seat 32, a plurality of components such as fasteners 34, a plurality of components such as fasteners 36, a plurality of shear screws 38, a plurality of shear screws 40, a plurality of springs 42, a plurality of lock keys 44, and sealing elements such as o-rings 46, 48, 50 and 52.
The upper sleeve 26 includes a plurality of axially-extending channels 26a formed in its outside surface, a circumferentially-extending shoulder 26b formed in its inside surface, and diametrically opposite arcuate notches 26c and 26d formed in one of its end portions. Each of the channels 26a includes an axially-extending channel or recess 26aa formed in a surface of the upper sleeve 26 defined by the channel 26a. The upper sleeve 26 defines an internal passage 26e. 
The lower sleeve 28 includes a plurality of axially-extending channels 28a formed in its outside surface, a circumferentially-extending shoulder 28b formed in its inside surface, an arcuate notch 28c formed in a first end portion of the lower sleeve 28, and an arcuate notch (not shown) formed in the first end portion of the lower sleeve 28 and diametrically opposite the arcuate notch 28c. The lower sleeve 28 defines an internal passage 28e. 
In an exemplary embodiment, as illustrated in FIG. 10 with continuing reference to FIGS. 1-9, each of the shear screws 38 includes a cylindrical body 38a, an external threaded connection 38b at one end portion of the cylindrical body 38a, a shoulder 38c formed in the cylindrical body 38a and adjacent the external threaded connection 38b, a generally cylindrical shear portion 38d extending from the other end portion of the cylindrical body 38a, and a shoulder 38e adjacent the proximal end of the generally cylindrical shear portion 38d, the shoulder 38e defining a flat 38f. One or more shear planes 38g extend through the generally cylindrical shear portion 38d, and are offset from, and generally parallel to, the flat 38f. Each of the one or more shear planes 38g is adapted to define the location at which at least a portion of the generally cylindrical shear portion 38d shears off from the remainder of the shear screw 38, under conditions to be described below.
The shear screws 40 are identical to the shear screws 38. Each of the shear screws 40 includes features that are identical to the features of each of the shear screws 38. Reference numerals used to refer to the features of the shear screws 40 that are identical to the features of the shear screws 38 will correspond to the reference numerals used to refer to the features of the shear screws 38 except that the prefix for the reference numerals used to refer to the features of the shear screws 38, that is, 38, will be replaced by the prefix of the shear screws 40, that is, 40.
In an exemplary embodiment, as illustrated in FIGS. 11 and 12 with continuing reference to FIGS. 1-10, each of the springs 42 includes opposing curved end portions 42a and 42b that define generally flat surfaces 42aa and 42ba, respectively, and a middle portion 42c. An arcuate portion 42d extends between the curved end portion 42a and the middle portion 42c. An arcuate portion 42e extends between the curved end portion 42b and the middle portion 42c. 
Each of the lock keys 44 includes a bar member 44a defining sides 44aa and 44ab spaced in a parallel relation, and having opposing curved end portions 44ac and 44ad. Protrusions 44b and 44c extend from the side 44ab and include curved outer surfaces 44ba and 44ca, respectively, which are flush with the extents of the curved end portions 44ac and 44ad, respectively. The protrusions 44b and 44c further include facing curved inner surfaces 44bb and 44cb, respectively. An axially-extending region 44d is defined by the side 44ab and the curved inner surfaces 44bb and 44cb. 
In an exemplary embodiment with continuing reference to FIGS. 1-12, when the stage tool apparatus 10 is in an assembled condition as illustrated in FIGS. 1 and 3, the external threaded connection 12b of the box sub 12 is threadably engaged with the internal threaded connection 18a of the outer sleeve 18, thereby coupling the box sub 12 to the outer sleeve 18. The o-ring 22 extends in the annular channel 12d formed in the outside surface of the box sub 12, and sealingly engages the inside surface of the outer sleeve 18. The external threaded connection 16a of the pin sub 16 is threadably engaged with the internal threaded connection 18b of the outer sleeve 18, thereby coupling the pin sub 16 to the outer sleeve 18. The o-ring 24 extends in the annular channel 16d formed in the outside surface of the pin sub 16, and sealingly engages an inside surface of the outer sleeve 18.
An annular region 54 (FIG. 3) is defined between the inside surface of the outer sleeve 18 and an outside surface of the end portion of the pin sub 16 that extends within the internal passage 18c of the outer sleeve 18. The annular region 54 is in fluid communication with the outside of the outer sleeve 18 and thus the apparatus 10 via the ports 18e. At least the lower end portion of the lower sleeve 28 extends within the annular region 54. A plurality of fasteners 56 extend through the outer sleeve 18 and into an annular channel formed in the outside surface of the box sub 12, thereby locking the box sub 12 to the outer sleeve 18. A plurality of fasteners 58 extend through the outer sleeve 18 and into an annular channel formed in the outside surface of the pin sub 16, thereby locking the pin sub 16 to the outer sleeve 18.
The upper sleeve 26 extends within the internal passage 18c of the outer sleeve 18. The lower sleeve 28 also extends within the internal passage 18c of the outer sleeve 18. Within the internal passage 18c, the upper sleeve 26 is engaged with the lower sleeve 28 so that lower end portions of the upper sleeve 26 defined by the arcuate notches 26c and 26d are interposed between upper end portions of the lower sleeve 28 defined in part by the arcuate notch 28c, as shown in FIGS. 6 and 7. In an exemplary embodiment, axial gaps are defined between axially-facing end surfaces defined by the interposed lower end portions of the upper sleeve 26 and corresponding axially-facing end surfaces defined by the interposed upper end portions of the lower sleeve 28; in an exemplary embodiment, grease is disposed in the axial gaps to eliminate any metal-to-metal surface seal.
The upper seat 30 is disposed within the upper sleeve 26, engaging the shoulder 26b of the upper sleeve 26. The o-ring 46 sealingly engages the inside surface of the outer sleeve 18, and the o-ring 48, which is axially spaced from the o-ring 46, also sealingly engages the inside surface of the outer sleeve 18. As a result, the channels 26a and thus the recesses 26aa are fluidically isolated from the internal passages 12c, 16c, 18c, 26e and 28e. The shear screws 38 extend through the outer sleeve 18 and into an opening, such as an annular channel 26f, formed in the outside surface of the upper sleeve 26, thereby generally preventing relative axial movement between the upper sleeve 26 and the outer sleeve 18.
The lower seat 32 is disposed within the lower sleeve 28, engaging the shoulder 28b of the lower sleeve 28. Each of the fasteners 36 is coupled to the outer sleeve 18 and extends radially from the outer sleeve 18 and into a respective one of the channels 28a of the lower sleeve 28, thereby preventing or at least resisting relative rotation between the lower sleeve 28 and the outer sleeve 18. As shown in FIG. 5, the lower sleeve 28 blocks the ports 18d, the o-ring 50 sealingly engages the inside surface of the outer sleeve 18, and the o-ring 52, which is axially spaced from the o-ring 50, sealingly engages the inside surface of the outer sleeve 18. As a result, the ports 18d are fluidically isolated from the internal passages 12c, 16c, 18c, 26e and 28e. The shear screws 40 extend through the outer sleeve 18 and into an opening, such as an annular channel 28d, formed in the outside surface of the lower sleeve 28, thereby generally preventing or at least resisting relative axial movement between the lower sleeve 28 and the outer sleeve 18.
In an exemplary embodiment, as illustrated in FIG. 13 with continuing reference to FIGS. 1-12, when the stage tool apparatus 10 is in an assembled condition as illustrated in FIGS. 1 and 3, each of the springs 42 is disposed in a respective one of the recesses 26aa of the upper sleeve 26. Each of the lock keys 44 is disposed in a respective one of the recesses 26aa so that the respective spring 42 is disposed radially between the upper sleeve 26 and the lock key 44, and is biased against the lock key 44 in an outwardly radial direction. At least one of the arcuate portions 42d and 42e of each spring 42 engages the vertically-extending surface of the sleeve 26 defined by the corresponding recess 26aa. For each of the springs 42 and its corresponding lock key 44, the opposing curved end portions 42a and 42b engage or nearly engage the curved inner surfaces 44bb and 44cb, respectively, the surfaces 42aa and 42ba engage the side 44ab, and the spring 42 extends within the region 44d of the corresponding lock key 44. Each of the fasteners 34 is coupled to the outer sleeve 18 and extends radially from the outer sleeve 18 and into a respective one of the channels 26a of the upper sleeve 26, thereby preventing or at least resisting relative rotation between the upper sleeve 26 and the outer sleeve 18. As shown in FIG. 13 and also in FIG. 5, each of the fasteners 34 engages at least the side 44aa of the corresponding lock key 44 at or proximate the curved end portion 44ac, thereby energizing the corresponding spring 42. More particularly, as a result of the engagements of the fasteners 34 with the sides 44aa of the respective lock keys 44, at least one of the arcuate portions 42d and 42e of each of the springs 42 is compressed between the vertically-extending surface of the sleeve 26 defined by the corresponding recess 26aa and the side 44ab of the corresponding lock key 44, thereby energizing the at least one of the arcuate portions 42d and 42e so that each of the springs 42 is energized and urges the corresponding lock key 44 radially outwards and out of the corresponding recess 26aa. However, the corresponding fastener 34 that is engaged with the side 44aa of the corresponding lock key 44 prevents or at least resists at least a portion of the lock key 44 from being pushed radially outwardly by the corresponding spring 42.
As noted above, the shear screws 38 extend through the outer sleeve 18 and into the annular channel 26f formed in the outside surface of the upper sleeve 26, thereby generally preventing or at least resisting relative axial movement between the upper sleeve 26 and the outer sleeve 18. In an exemplary embodiment, as illustrated in FIG. 14, each of the flats 38f engages a respective shoulder 18f of the outer sleeve 18 defined by, for example, a respective counterbore 18g in which the respective shear screw 38 is disposed, so that the shear screw 38 can be tightened up against the outer sleeve 18 for extra support, thereby preventing, or at least resisting, any twisting, slipping or stripping of the external threaded connection 38b. Each of the counterbores 18g includes an internal threaded connection 18h that is threadably engaged with the external threaded connection 38b of the respective shear screw 38. Likewise, as noted above, the shear screws 40 extend through the outer sleeve 18 and into the annular channel 28d formed in the outside surface of the lower sleeve 28, thereby generally preventing or at least resisting relative axial movement between the lower sleeve 28 and the outer sleeve 18. Each of the flats 40f engages a shoulder 18i (shown in FIG. 16a) of the outer sleeve 18 defined by, for example, a counterbore 18j (shown in FIG. 16a) in which the shear screw 40 is disposed, so that the shear screw 40 can be tightened up against the outer sleeve 18 for extra support, thereby preventing, or at least resisting, any twisting, slipping or stripping of the threaded connection 40b. Each of the counterbores 18j includes an internal threaded connection 18k (shown in FIG. 16a) that is threadably engaged with the external threaded connection 40b of the respective shear screw 40.
In several exemplary embodiments, the apparatus 10 or any component thereof includes, in whole or in part, one or more embodiments or portions thereof disclosed in U.S. patent application Ser. No. 12/898,444, filed Oct. 5, 2010, the entire disclosure of which is incorporated herein by reference.
In operation, in an exemplary embodiment, the apparatus 10 is initially in its assembled condition described above and is part of a tubular string or casing. A threaded end of a tubular support member (not shown) that defines an internal passage may be coupled to the internal threaded connection 12a of the box sub 12 so that the internal passage of the tubular support member is in fluid communication with the internal passage 12c of the box sub 12, the internal passage 18c of the outer sleeve 18, the internal passage 26e of the upper sleeve 26, the internal passage 28e of the lower sleeve 28, and the internal passage 16c of the pin sub 16. Similarly, a threaded end of another tubular member (not shown) that defines an internal passage may be coupled to the external threaded connection 16b of the pin sub 16 so that the internal passage of the other tubular support member is in fluid communication with the internal passage 12c of the box sub 12, the internal passage 18c of the outer sleeve 18, the internal passage 26e of the upper sleeve 26, the internal passage 28e of the lower sleeve 28, and the internal passage 16c of the pin sub 16.
As illustrated in FIG. 15, the tubular string or casing of which the apparatus 10 is a part is positioned within a preexisting structure such as, for example, a wellbore 60 that traverses one or more subterranean formations, thereby defining an annular region 62 between the inside wall of the wellbore and the outside surface of the outer sleeve 18. As shown in FIG. 15, the apparatus 10 is in a neutral configuration, which generally corresponds to the assembled condition described above in which, inter alia, the lower sleeve 28 blocks the ports 18d, which are fluidically isolated from the internal passages 12c, 16c, 18c, 26e and 28e. As a result, the annular region 62 is fluidically isolated from the internal passages 12c, 16c, 18c, 26e and 28e. 
In an exemplary embodiment, during or after the positioning of the apparatus 10 within the wellbore 60, fluidic materials 64 are injected into and circulated through the apparatus 10 via the internal passage 12c, the internal passage 18c, the internal passage 26e, the internal passage 28e, and the internal passage 16c. In an exemplary embodiment, the fluidic materials 64 may be circulated through and out of the tubular string or casing of which the apparatus 10 is a part and into the wellbore 60. In several exemplary embodiments, the fluidic materials 64 may include drilling fluids, drilling mud, water, other types of fluidic materials, or any combination thereof.
As illustrated in FIG. 16, a blocking element such as, for example, a dart 66, is injected into the apparatus 10 through at least the passage 12c and the internal passage 26e defined by the upper sleeve 26 until the dart 66 is seated in the lower seat 32. As a result, the flow of any fluidic materials, including the fluidic materials 64, through the lower sleeve 28 and therebelow is blocked.
Continued injection of the fluidic materials 64 into the apparatus 10, following the seating of the dart 66 in the lower seat 32, pressurizes the tubular string, of which the apparatus 10 is a part, above the dart 66. As a result, the dart 66, the lower seat 32 and the lower sleeve 28 are urged downward, relative to at least the outer sleeve 18 and the shear screws 40, so that a radially-extending surface 28f of the lower sleeve 28 that is defined by the annular channel 28d bears against the shear portions 40d of the respective shear screws 40. Continued injection of the fluidic materials 64 into the apparatus 10, following the surface 28f initially bearing against the shear portions 40d, causes the respective shear portions 40d of the shear screws 40 to shear, at which point the dart 66, the lower seat 32 and the lower sleeve 28 move downward, as viewed in FIG. 16, relative to the upper sleeve 26 and the outer sleeve 18 of the apparatus 10.
As illustrated in FIG. 16a, each of the shear portions 40d shears along the respective shear plane 40g. Since the shear plane 40g is offset from, and generally parallel to, the flat 40f that is tightened against and engages the surface 18i of the outer sleeve 18, or since the shear plane 40g extends through the shear portion 40d rather than through, for example, the external threaded connection 40b, a cleaner shear along the shear plane 40g is achieved.
During the downward movement of the dart 66, the lower seat 32 and the lower sleeve 28, the channels 28a of the lower sleeve 28 move relative to the fasteners 36. As a result of the extension of the fasteners 36 into the respective channels 28a, the fasteners 36 guide the lower sleeve 28 as it moves downward, continuing to prevent or at least resist any relative rotation between the lower sleeve 28 and the outer sleeve 18. During the downward movement of the dart 66, the lower seat 32 and the lower sleeve 28, the lower end of the lower sleeve 28 is further received by the annular region 54.
As illustrated in FIG. 17, the dart 66, the lower seat 32 and the lower sleeve 28 continue to move downward until the fasteners 36 engage the surfaces of the lower sleeve 28 defined by the upper ends of the respective channels 28a. As a result of these engagements, the lower sleeve 28 and thus the dart 66 and the lower seat 32 are prevented from moving any further downward. As a result of the downward movement of the dart 66, the lower seat 32 and the lower sleeve 28, the apparatus 10 is in an open configuration in which the ports 18d are not blocked by any of the upper sleeve 26 and the lower sleeve 28 and thus the annular region 62 is in fluid communication with at least the internal passage 12c, the internal passage 26e defined by the upper sleeve 26, and the internal passage 18c via the ports 18d. 
In an exemplary embodiment, instead of placing the apparatus 10 in the open configuration mechanically via the engagement between the dart 66 and the lower seat 32 and the subsequent downward movement of the dart 66, the lower seat 32 and the lower sleeve 28, the apparatus 10 is placed in the open configuration hydraulically by pressurizing the tubular string of which the apparatus 10 is a part, and controlling the respective pressures within one or more of the wellbore 60, the annular region 62, and the tubular string including the apparatus 10, so that a differential pressure is created between the pressure applied against, inter alia, at least the lower seat 32 and the upper portion of the lower sleeve 28, and the pressure within the annular region 54. This differential pressure is increased by, for example, increasing the pressure applied against, inter alia, at least the lower seat 32 and the upper portion of the lower sleeve 28, so that the shear screws 40 are sheared and thus the lower seat 32 and the lower sleeve 28 move downward, as viewed in FIG. 17. The lower sleeve 28 moves downward in the annular region 54 with hydraulic lock being prevented by the ports 18e, via which the annular region 54 is in fluid communication with the annular region 62. In several exemplary embodiments, the ports 18e are bleed holes that prevent hydraulic lock.
With continuing reference to FIG. 17, before, during or after the downward movement of the lower seat 32 and the lower sleeve 28 (and the dart 66 if the apparatus 10 is placed in the open configuration mechanically), a fluidic material, such as a hardenable fluidic material 68, is injected into the apparatus 10 via the tubular string of which the apparatus 10 is a part, and into the internal passage 12c, the internal passage defined by the upper sleeve 26, and the internal passage 18c. The hardenable fluidic material 68 flows out of the apparatus 10 through the ports 18d of the outer sleeve 18 and into the annular region 62. As a result, an annular body of the hardenable fluidic material 68 is formed within the annular region 62. After the curing of the annular body of the hardenable fluidic material 68 within the annular region 62, the apparatus 10 and the tubular string of which the apparatus 10 is a part is better supported within the wellbore 60, and the portion of the annular region 62 or any formation below the annular body of the hardenable fluidic material 68 is fluidically isolated from the portion of the annular region 62 or any formation above the annular body of the hardenable fluidic material 68. In several exemplary embodiments, the improved support of the apparatus 10 or the tubular string of which the apparatus 10 is a part, or the fluidic isolation of the portion of the annular region 62 or any formation above the annular body of the hardenable fluidic material 68 from the portion of the annular region 62 or the any formation below the annular body, facilitate oil and gas exploration or production operations subsequent to the operation of the apparatus 10, as described above and below. In an exemplary embodiment, the hardenable fluidic material 68 is, or includes, cement. In an exemplary embodiment, the hardenable fluidic material 68 is, or includes, cement, and the completion of forming (and subsequently curing) the annular body of the material 68 is the completion of one stage in the stage cementing of the tubular string or casing of which the apparatus 10 is a part in the wellbore 60.
As illustrated in FIG. 18, before, during or after the curing of the annular body of the hardenable fluidic material 68, a blocking element such as, for example, a plug 70, is injected into the apparatus 10 through at least the passage 12c, until the plug 70 is seated in the upper seat 30. As a result, the flow of any fluidic materials through the upper sleeve 26 and the remainder of the apparatus 10 therebelow is blocked. Fluidic materials 72 are injected into the apparatus 10, following the seating of the plug 70 in the upper seat 30, thereby pressurizing the tubular string of which the apparatus 10 is a part. Continued injection of the fluidic materials 72 causes the respective shear portions 38d of the shear screws 38 to shear, at which point the plug 70, the upper seat 30 and the upper sleeve 26 move downward, as viewed in FIG. 18, relative to the outer sleeve 18 and the lower sleeve 28 of the apparatus 10. Each of the shear portions 38d shears along the respective shear plane 38g. Since the shear plane 38g is offset from, and generally parallel to, the flat 38f that is tightened against and engages the surface 18f of the outer sleeve 18, or since the shear plane 38g extends through the shear portion 38d rather than through, for example, the external threaded connection 38b, a cleaner shear along the shear plane 38g is achieved. During the downward movement of the plug 70, the upper seat 30, and the upper sleeve 26, the channels 26a of the upper sleeve 26, the springs 42, and the lock keys 44 move relative to the fasteners 34. As a result of the extension of the fasteners 34 into the respective channels 26a, the fasteners 34 guide the upper sleeve 28 as it moves downward, continuing to prevent or at least resist any relative rotation between the upper sleeve 26 and the outer sleeve 18.
As illustrated in FIG. 18a, during the downward movement of the upper sleeve 26, each of the lock keys 44 slides against the corresponding fastener 34, and conversely each of the fasteners 34 continues to engage the side 44aa of the corresponding lock key 44, thereby continuing to energize the corresponding spring 42. Since each of the fasteners 34 initially engages the side 44aa of the corresponding lock key 44 (as shown in FIG. 13), the lock key 44 moves relative to, and slides against, the fastener 34, and conversely the fastener 34 continues to engage the side 44aa of the lock key 44 during this relative movement, as shown in FIG. 18a. 
As illustrated in FIGS. 19 and 19a, the plug 70, the upper seat 30 and the upper sleeve 26 continue to move downward until the fasteners 34 engage the surfaces of the upper sleeve 26 defined by the upper ends of the respective channels 26a (shown in FIG. 19a). As a result of these engagements, the upper sleeve 26 and thus the plug 70 and the upper seat 30 are prevented from moving any further downward. As a result of this downward movement of the plug 70, the upper seat 30 and the upper sleeve 26, the apparatus 10 is in a closed configuration in which the ports 18d are blocked by the upper sleeve 26 and thus the annular region 62 is fluidically isolated from at least the internal passage 26e defined by the upper sleeve 26. As another result of this downward movement of the plug 70, the upper seat 30 and the upper sleeve 26, each of the fasteners 34 is no longer engaging the side 44aa of the bar member 44a of the respective lock key 44. As a result, the springs 42 sufficiently relax to push the respective lock keys 44 radially outward within the respective channels 26a. 
As a result of the radially outward movement of the lock keys 44, the lock keys 44 are radially positioned so that each fastener 34 is axially disposed between a surface of the upper sleeve 26 defined by the upper end of the respective channel 26a and at least the end portion 44ad of the respective lock key 44, as shown in FIG. 19a. Moreover, each fastener 34 continues to be circumferentially disposed between the vertically-extending side walls of the upper sleeve 26 that are defined by the respective channel 26a. As a result, the upper sleeve 26 is jammed; the upper sleeve 26 cannot appreciably translate or rotate relative to the lower sleeve 28 or the outer sleeve 18.
The jammed upper sleeve 26 prevents any appreciable upward movement of the lower sleeve 28, as viewed in FIG. 19, and the respective engagements between the fasteners 36 and the surfaces of the lower sleeve 28 defined by the upper ends of the respective channels 28a prevent any downward movement of the lower sleeve 28, as viewed in FIG. 19. Moreover, each fastener 36 continues to be circumferentially disposed between the vertically-extending side walls of the lower sleeve 28 that are defined by the respective channel 28a. As a result, the lower sleeve 28 is jammed; the lower sleeve 28 is not permitted to appreciably translate or rotate relative to the upper sleeve 26 or the outer sleeve 18. Since neither the upper sleeve 26 nor the lower sleeve 28 is permitted to appreciably rotate or translate relative to each other or the outer sleeve 18, the apparatus 10 is thus locked in the closed configuration illustrated in FIG. 19. This locking of the upper sleeve 26 and the lower sleeve 28 facilitates any drill-out operation of the upper seat 30 and the lower seat 32.
As yet another result of the above-described downward movement of the upper sleeve 26, the upper sleeve 26 is engaged with the lower sleeve 28 so that lower end portions of the upper sleeve 26 defined by the arcuate notches 26c and 26d are again interposed between upper end portions of the lower sleeve 28 defined in part by the arcuate notch 28c; and axial gaps are defined between axially-facing end surfaces defined by the interposed lower end portions of the upper sleeve 26 and corresponding axially-facing end surfaces defined by the interposed upper end portions of the lower sleeve 28; in an exemplary embodiment, grease is disposed in the axial gaps to eliminate any metal-to-metal surface seal.
In an exemplary embodiment, after the apparatus 10 has been placed in the closed configuration illustrated in FIG. 19, a drill-out operation occurs during which at least the upper seat 30 and the lower seat 32 are drilled out. As noted above, the locking of the upper sleeve 26 and the lower sleeve 28 in the closed configuration illustrated in FIG. 19 assists in the drill-out operation by preventing the upper sleeve 26 and the lower sleeve 28 from appreciably translating or rotating within the outer sleeve 18 during the drill-out operation. In an exemplary embodiment, after the apparatus 10 has been placed in the closed configuration illustrated in FIG. 19, a drill-out operation occurs during which at least the plug 70, the upper seat 30, the dart 66 and the lower seat 32 are drilled out. As noted above, the locking of the upper sleeve 26 and the lower sleeve 28 in the closed configuration illustrated in FIG. 19 assists in the drill-out operation by preventing the upper sleeve 26 and the lower sleeve 28 from appreciably translating or rotating within the outer sleeve 18 during the drill-out operation.
In several exemplary embodiments, one or more additional stage tool apparatuses, each of which is substantially similar to the apparatus 10, are part of the tubular string or casing of which the apparatus 10 is a part.
In another embodiment, as illustrated in FIG. 20 with continuing reference to FIGS. 1-19a, the dart 66, the lower seat 32, the plug 70, and the upper seat 30 are omitted from the apparatus 10. Instead of the dart 66, the lower seat 32, the plug 70, and the upper seat 30, the exemplary embodiment of the apparatus 10 illustrated in FIG. 20 includes a dart 74, a lower seat 76, a plug 78, and an upper seat 80, respectively.
In an exemplary embodiment, as illustrated in FIGS. 21, 21A, 21B, 21C, and 21D with continuing reference to FIGS. 1-20, the dart 74 includes a top body member 74a coupled to a bottom body member 74b. The top body member 74a defines an outside surface 74c, and a plurality of circumferentially-spaced ribs 74d extending along the outside surface 74c. In an exemplary embodiment, the outside surface 74c is frusto-conical in shape. In an exemplary embodiment, the outside surface 74c and the ribs 74d extend downward at a 30 degree angle relative to longitudinal axis 74da of the dart 74. However, the outside surface 74c and the ribs 74d can extend downward at a variety of angles such as, for example, any angle between 20 degrees and 60 degrees.
As shown in FIG. 21D, the top body member 74a includes an internal threaded connection 74e that is formed through a bottom surface 74f. The lower body member 74b includes an external threaded connection 74g that extends from an upper surface 74h of the lower body member 74b. The internal threaded connection 74e is threadably engaged with the external threaded connection 74g, thereby coupling the top body member 74a to the lower body member 74b. The lower body member 74b defines an outside surface 74i. Proximate the upper surface 74h, the outside surface 74i is cylindrical in shape. As the lower body member 74b extends downward, the outside surface 74i tapers at a 30 degree angle, relative to the longitudinal axis 74da of the dart 74, towards a nose portion 74j of the lower body member 74b. However, the outside surface 74i may taper at a variety of angles such as, for example, any angle between 20 degrees and 60 degrees. An annular channel 74k is formed in the portion of the outside surface 74i that is cylindrical in shape (proximate the upper surface 74h). An annular sealing element, such as an o-ring 74l, is disposed in the annular channel 74k. A chamber 74m, having an opening 74n, is formed within the lower body member 74b. In an exemplary embodiment, the chamber 74m is formed in the distal axial end of the internal threaded connection 74g, and extends into the lower body member 74b and along the longitudinal axis 74m, terminating within the nose portion 74j. In an exemplary embodiment, lead shot or other weighted material is disposed within the chamber 74m to ballast the dart 74. In an exemplary embodiment, the coupling of the top body member 74a to the lower body member 74b prevents the lead shot that is disposed within the chamber 74m from exiting through the opening 74n. In an exemplary embodiment, the top body member 74a has a top surface 74o. 
In an exemplary embodiment, the dart 74 is composed of at least one or more non-metallic materials. In an exemplary embodiment, the top body member 74a and/or the bottom body member 74b is composed of at least one or more non-metallic materials. In an exemplary embodiment, the dart 74 is composed of plastic. In an exemplary embodiment, the dart 74 is composed of phenolic. In an exemplary embodiment, the dart 74 is composed of Durez® 118. In an exemplary embodiment, the dart 74 is composed of Durez® 118 and is filled with lead shot.
In an exemplary embodiment, as illustrated in FIGS. 22 and 22A with continuing reference to FIGS. 1-21D, the lower seat 76 includes an annular member 76a defining an inside surface 76b and an outside surface 76c. In an exemplary embodiment, the inside surface 76b is frusto-conical in shape. A plurality of circumferentially-spaced channels 76d are formed in the inside surface 76b. In an exemplary embodiment, each of the circumferentially-spaced channels 76d is sized to accommodate one of the circumferentially-spaced ribs 74d of the dart 74. In an exemplary embodiment, the inside surface 76b and the channels 76d taper at a 30 degree angle relative to longitudinal axis 76da of the lower seat 76. However, the inside surface 76b and the channels 76d may taper at a variety of angles such as, for example, any angle between 20 degrees and 60 degrees. The lower seat 76 further defines an inside surface 76e extending axially downward from the inside surface 76b. In an exemplary embodiment, the inside surface 76e is cylindrical in shape. In an exemplary embodiment, the outside surface 76c tapers inward to form an external shoulder 76f. The inwardly-tapered external shoulder 76f is spaced radially outwardly from the inside surface 76e. In an exemplary embodiment, the external shoulder 76f is configured to mate with the circumferentially-extending shoulder 28b to prevent downward movement of the lower seat 76 relative to the lower sleeve 28. The annular member 76a defines a seat passage 76g. Each of the inside surfaces 76b and 76e is adjacent the seat passage 76g. 
In an exemplary embodiment, the lower seat 76 is composed of at least one or more non-metallic materials. In an exemplary embodiment, the lower seat 76 is composed of plastic. In an exemplary embodiment, the lower seat 76 is composed of phenolic. In an exemplary embodiment, the lower seat 76 is composed of Durez® 118. As shown in FIG. 20, the lower seat 76 is disposed in the lower sleeve 28, with the shoulder 76f mating against the shoulder 28b. 
In an exemplary embodiment, as illustrated in FIGS. 23, 23A, 23B, 23C, and 23D with continuing reference to FIGS. 1-22A, the plug 78 includes a body member 78a defining an outside surface 78b, and a plurality of circumferentially-spaced ribs 78c extending along the outside surface 78b. In an exemplary embodiment, the outside surface 78b is frusto-conical in shape. In an exemplary embodiment, the outside surface 78b and the ribs 78c taper at a 30 degree angle relative to longitudinal axis 78ca of the plug 78. However, the outside surface 78b and the ribs 78c may taper at a variety of angles, such as for example, any angle between 20 degrees and 60 degrees.
As shown in FIG. 23D, an external threaded connection 78d extends from a top surface 78e of the body member 78a. A core element 78f defines a bottom surface 78g, and includes an internal threaded connection 78h formed in the bottom surface 78g. The internal threaded connection 78h is threadably engaged to with external threaded connection 78d, thereby coupling the core element 78f to the body element 78a. A wiper element 78i extends circumferentially around the core element 78f. In an exemplary embodiment, the wiper element 78i includes an inward flange 78j that extends between the top surface 78e of the body member 78a and the bottom surface 78g of the core element 78f. Thus, the coupling of the core element 78f to the body element 78a secures the wiper element 78i to each of the core element 78f and the body element 78. In several exemplary embodiments, one or more adhesives are used to further secure the wiper element 78i, the core element 78f, and the body element 78a together. The wiper element 78i includes a plurality of circumferentially-extending wipers or blades 78k, which are axially-spaced from one another along the longitudinal axis 78ca. 
In an exemplary embodiment, the body member 78a is composed of at least one or more non-metallic materials. In an exemplary embodiment, the body member 78a is composed of plastic. In an exemplary embodiment, the body member 78a is composed of phenolic. In an exemplary embodiment, the body member 78a is composed of Durez® 118. In an exemplary embodiment, the core element 78f is composed of phenolic.
In an exemplary embodiment, as illustrated in FIGS. 24 and 24A with continuing reference to FIGS. 1-23D, the upper seat 80 includes an annular member 80a defining an inside surface 80b and an outside surface 80c. In an exemplary embodiment, the inside surface 80b is frusto-conical in shape. A plurality of circumferentially-spaced channels 80d are formed in the inside surface 80b. In an exemplary embodiment, each of the circumferentially-spaced channels 80d is sized to accommodate one of the circumferentially-spaced ribs 78c. In an exemplary embodiment, the inside surface 80b and the channels 80d taper at a 30 degree angle relative to longitudinal axis 80da of the upper seat 80. However, the inside surface 80b and the channels 80d may taper at a variety of angles such as, for example, any angle between 20 degrees and 60 degrees. The upper seat 80 further defines an inside surface 80e, which extends axially downward from the inside surface 80b. In an exemplary embodiment, the inside surface 80e is cylindrical in shape. In an exemplary embodiment, the outside surface 80c tapers inward to form an external shoulder 80f. The inwardly-tapered external shoulder 80f is spaced radially outwardly from the inside surface 80e. In an exemplary embodiment, the external shoulder 80f is configured to mate with the circumferentially-extending shoulder 26b to prevent downward movement of the lower seat 76 relative to the upper sleeve 26. The annular member 80a defines a seat passage 80g. Each of the inside surfaces 80b and 80e is adjacent the seat passage 80g. 
In an exemplary embodiment, the upper seat 80 is composed of at least one or more non-metallic materials. In an exemplary embodiment, the upper seat 80 is composed of plastic. In an exemplary embodiment, the upper seat 80 is composed of phenolic. In an exemplary embodiment, the upper seat 80 is composed of Durez® 118. As shown in FIG. 20, the upper seat 80 is disposed in the upper sleeve 26, with the shoulder 80f mating against the shoulder 26b. 
In operation, the embodiment of the apparatus 10 illustrated in FIG. 20 is identical to the above-described operation of the embodiments of the apparatus 10 illustrated in FIGS. 1-19a, subject to operational aspects of the embodiment of the apparatus 10 illustrated in FIG. 20, which operational aspects are described below. Similarly to the apparatus 10 illustrated in FIGS. 1-19a, the apparatus 10 illustrated in FIG. 20 is coupled to the box sub 12 and the pin sub 16 while in the assembled position. Additionally, the apparatus 10 illustrated in FIG. 20 is positioned within the wellbore 60 to define the annular region 62. As illustrated in FIG. 25, the apparatus 10 is in the neutral configuration, in which the lower seat 76 is disposed within the lower sleeve 28, so that the shoulder 76f engages the shoulder 28b of the lower sleeve 28 and the upper seat 80 is disposed within the upper sleeve 26, so that the shoulder 80f engages the shoulder 26b of the upper sleeve 26. Additionally, the neutral configuration generally corresponds to the assembled condition previously described above in which, inter alia, the lower sleeve 28 blocks the ports 18d, which are fluidically isolated from the internal passages 12c, 16c, 18c, 26e and 28e. As a result, the annular region 62 is fluidically isolated from the internal passages 12c, 16c, 18c, 26e and 28e. 
In an exemplary embodiment, during or after the positioning of the apparatus 10 within the wellbore 60, the fluidic materials 64 are injected into and circulated through the apparatus 10 via the internal passage 12c, the internal passage 18c, the seat passage 80g, the internal passage 26e, the internal passage 28e, the seat passage 76g, and the internal passage 16c. In an exemplary embodiment, the fluidic materials 64 may be circulated through and out of the tubular string or casing of which the apparatus 10 is a part and into the wellbore 60.
As illustrated in FIG. 26, a blocking element such as, for example, the dart 74, is injected into the apparatus 10 through at least the passage 12c and the internal passage 26e defined by the upper sleeve 26 until the dart 74 is seated in the lower seat 76. As a result, the flow of any fluidic materials, including the fluidic materials 64, through the seat passage 76g and therebelow is prevented or at least partially blocked.
In an exemplary embodiment, during operation, as shown in FIG. 26A, the ribs 74d extend within the channels 76c, respectively, to prevent or at least resist relative rotation between the dart 74 and the lower seat 76. As shown in FIG. 26B, the dart 74 has an axial position 82, relative to the inside surface 76b of the lower seat 76. When the dart 74 is in the axial position 82, the ribs 74d extend within the channels 76c, respectively, and the o-ring 74l sealingly engages the inside surface 76e. As a result, the flow of any fluidic materials through the seat passage 76g is prevented or at least partially blocked. Additionally, the internal passages 12c and 26e are fluidically isolated from the internal passages 28c and 16c. 
Continued injection of the fluidic materials 64 into the apparatus 10, following the seating of the dart 74 in the lower seat 76, pressurizes the tubular string, of which the apparatus 10 is a part, above the dart 74. As a result, the fluidic materials 64 exerts a downward force on the top surface 74o of the top body 74a. As a result, the dart 74, the lower seat 76, and the lower sleeve 28 are urged downward, relative to at least the outer sleeve 18 and the shear screws 40 (and the wellbore 60), so that the radially-extending surface 28f of the lower sleeve 28 that is defined by the annular channel 28d bears against the shear portions 40d of the respective shear screws 40. Continued injection of the fluidic materials 64 into the apparatus 10, following the surface 28f initially bearing against the shear portions 40d, causes the respective shear portions 40d of the shear screws 40 to shear, at which point the dart 74, the lower seat 76, and the lower sleeve 28 move downward, as viewed in FIG. 27, relative to the upper sleeve 26 and the outer sleeve 18 of the apparatus 10 and relative to the wellbore 60.
During the downward movement of the dart 74, the lower seat 76, and the lower sleeve 28, the channels 28a of the lower sleeve 28 move relative to the fasteners 36. As a result of the extension of the fasteners 36 into the respective channels 28a, the fasteners 36 guide the lower sleeve 28 as it moves downward, continuing to prevent or at least resist any relative rotation between the lower sleeve 28 and the outer sleeve 18. During the downward movement of the dart 74, the lower seat 76, and the lower sleeve 28, the lower end of the lower sleeve 28 is further received by the annular region 54.
As illustrated in FIG. 27, the dart 74, the lower seat 76, and the lower sleeve 28 continue to move downward until the fasteners 36 engage the surfaces of the lower sleeve 28 defined by the upper ends of the respective channels 28a. As a result of these engagements, the lower sleeve 28 and thus the dart 74 and the lower seat 76 are prevented from moving any further downward. As a result of the downward movement of the dart 74, the lower seat 76, and the lower sleeve 28, the apparatus 10 is in an open configuration in which the ports 18d are not blocked by any of the upper sleeve 26 and the lower sleeve 28 and thus the annular region 62 is in fluid communication with at least the internal passage 12c, the internal passage 26e, and the internal passage 18c via the ports 18d. In an exemplary embodiment and while in the open configuration, the o-ring 74l continues to sealingly engage the inside surface 76e to fluidically isolate the internal passages 12c and 26e from internal passages 28c and 16c. In an exemplary embodiment and while in the open configuration, the dart 74 continues to prevent or at least partially block the flow of any fluidic materials through the seat passage 76g and into the internal passage 26e. 
With continuing reference to FIG. 27, during or after the downward movement of the lower seat 76 and the lower sleeve 28, a fluidic material, such as the hardenable fluidic material 68, is injected into the apparatus 10 via the tubular string of which the apparatus 10 is a part, and into the internal passage 12c. The hardenable fluidic material 68 flows out of the apparatus 10 through the ports 18d of the outer sleeve 18 and into the annular region 62. As a result, an annular body of the hardenable fluidic material 68 is formed within the annular region 62. In an exemplary embodiment and while the hardenable fluidic material 68 flows out of the apparatus 10 through the ports 18d, the o-ring 74l continues to sealingly engage the inside surface 76e to fluidically isolate the internal passages 12c and 26e from internal passages 28c and 16c. In an exemplary embodiment and while the hardenable fluidic material 68 flows out of the apparatus 10 through the ports 18d, the dart 74 continues to block the flow of any fluidic materials through the seat passage 76g and into the internal passage 26e. 
As illustrated in FIG. 28, before, during, or after the curing of the annular body of the hardenable fluidic material 68, a blocking element such as, for example, the plug 78, is injected into the apparatus 10 through at least the passage 12c, until the plug 78 is seated in the upper seat 80. As a result, the flow of any fluidic materials through the seat passage 80g, the upper sleeve 26, and the remainder of the apparatus 10 therebelow is blocked. Fluidic materials 72 are injected into the apparatus 10, following the seating of the plug 78 in the upper seat 80, thereby pressurizing the tubular string of which the apparatus 10 is a part. Continued injection of the fluidic materials 72 causes the respective shear portions 38d of the shear screws 38 to shear, at which point the plug 78, the upper seat 80, and the upper sleeve 26 move downward, as viewed in FIG. 18, relative to the outer sleeve 18 and the lower sleeve 28 of the apparatus 10 and relative to the wellbore 60. Each of the shear portions 38d shears along the respective shear plane 38g. During the downward movement of the plug 78, the upper seat 80, and the upper sleeve 26, the channels 26a of the upper sleeve 26, the springs 42, and the lock keys 44 move relative to the fasteners 34. As a result of the extension of the fasteners 34 into the respective channels 26a, the fasteners 34 guide the upper sleeve 28 as it moves downward, continuing to prevent or at least resist any relative rotation between the upper sleeve 26 and the outer sleeve 18. In an exemplary embodiment, during operation, as shown in FIG. 28A, the ribs 78c extend within the channels 80d, respectively, to prevent or at least resist relative rotation between the plug 78 and the upper seat 80.
As illustrated in FIG. 29, the plug 78, the upper seat 80, and the upper sleeve 26 continue to move downward until the fasteners 34 engage the surfaces of the upper sleeve 26 defined by the upper ends of the respective channels 26a (shown in FIG. 19a). As a result of these engagements, the upper sleeve 26 and thus the plug 78 and the upper seat 80 are prevented from moving any further downward. As a result of this downward movement of the plug 78, the upper seat 80, and the upper sleeve 26, the apparatus 10 is in the closed configuration in which the ports 18d are blocked by the upper sleeve 26 and thus the annular region 62 is fluidically isolated from at least the internal passage 26e defined by the upper sleeve 26. As another result of this downward movement of the plug 78, the upper seat 80, and the upper sleeve 26, each of the fasteners 34 is no longer engaging the side 44aa of the bar member 44a of the respective lock key 44 (shown in FIG. 19a). As a result, the springs 42 sufficiently relax to push the respective lock keys 44 radially outward within the respective channels 26a. 
As a result of the radially outward movement of the lock keys 44, the lock keys 44 are radially positioned so that each fastener 34 is axially disposed between a surface of the upper sleeve 26 defined by the upper end of the respective channel 26a and at least the end portion 44ad of the respective lock key 44, as shown in FIG. 19a. Moreover, each fastener 34 continues to be circumferentially disposed between the vertically-extending side walls of the upper sleeve 26 that are defined by the respective channel 26a. As a result, the upper sleeve 26 is jammed; the upper sleeve 26 cannot appreciably translate or rotate relative to the lower sleeve 28 or the outer sleeve 18.
The jammed upper sleeve 26 prevents any appreciable upward movement of the lower sleeve 28, as viewed in FIG. 29, and the respective engagements between the fasteners 36 and the surfaces of the lower sleeve 28 defined by the upper ends of the respective channels 28a prevent any downward movement of the lower sleeve 28, as viewed in FIG. 29. Moreover, each fastener 36 continues to be circumferentially disposed between the vertically-extending side walls of the lower sleeve 28 that are defined by the respective channel 28a. As a result, the lower sleeve 28 is jammed; the lower sleeve 28 is not permitted to appreciably translate or rotate relative to the upper sleeve 26 or the outer sleeve 18. Since neither the upper sleeve 26 nor the lower sleeve 28 is permitted to appreciably rotate or translate relative to each other or the outer sleeve 18, the apparatus 10 is thus locked in the closed configuration illustrated in FIG. 29. This locking of the upper sleeve 26 and the lower sleeve 28 facilitates any drill-out operation of the upper seat 80 and the lower seat 76.
As yet another result of the above-described downward movement of the upper sleeve 26, the upper sleeve 26 is engaged with the lower sleeve 28 so that lower end portions of the upper sleeve 26 defined by the arcuate notches 26c and 26d are again interposed between upper end portions of the lower sleeve 28 defined in part by the arcuate notch 28c; and axial gaps are defined between axially-facing end surfaces defined by the interposed lower end portions of the upper sleeve 26 and corresponding axially-facing end surfaces defined by the interposed upper end portions of the lower sleeve 28; in an exemplary embodiment, grease is disposed in the axial gaps to eliminate any metal-to-metal surface seal.
As a result of the ribs 78c extending within the channels 80d, as shown in FIG. 28A, relative rotation between the plug 78 and the upper seat 80 is prevented or at least resisted. In an exemplary embodiment, the resulting prevention or resistance of relative rotation between the plug 78 and the upper seat 80 facilitates any drill-out operation during which the plug 78, the upper seat 80, the dart 74, and the lower seat 76 are drilled out. Similarly, as a result of the ribs 74d extending within the channels 76c, as shown in FIG. 26A, the resulting prevention or resistance of relative rotation between the dart 74 and the lower seat 76 facilitates any drill-out operation during which the plug 78, the upper seat 80, the dart 74 and the lower seat 76 are drilled out.
In several exemplary embodiments, the non-metallic material(s) of which the lower seat 76 are composed facilitate the drill out of the lower seat 76. The non-metallic material(s), of which the dart 74 or at least the body member 74a thereof are composed, facilitate the drill out of the dart 74. The non-metallic material(s), of which at least the body member 78a of the plug 78 are composed, facilitate the drill out of the plug 78. The non-metallic material(s), of which the upper seat 80 are composed, facilitate the drill out of the upper seat 80. When compared with metallic materials, the non-metallic material(s) may be less resistant to drill-out operations, increasing the speed at which the apparatus 10 may be drilled out.
In another exemplary embodiment and as illustrated in FIGS. 30, 30A, and 30B, the ribs 74d of the dart 74 do not initially extend within the channels 76c of the lower seat 76, respectively, when the apparatus 10 is in the closed configuration. Instead, the ribs 74d engage the inside surface 76b. As a result, and as shown in FIG. 30B, the dart 74 has an axial position 84, relative to the inside surface 76b of the lower seat 76. When the dart 74 is in the axial position 84, the ribs 74d do not extend within the channels 76c, respectively, but the o-ring 74l still sealingly engages the inside surface 76e. Thus, the o-ring 74l sealingly engages the inside surface 76e when the dart 74 is in either the axial position 82 or the axial position 84. At the axial position 84, the o-ring 74l is closer to the lower ends of the channels 76c, than when the dart 74 is in the axial position 82, because the ribs 74d are contacting the inside surface 76b, rather than extending within the channels 76c. However, even if the ribs 74d do not initially extend within the channels 76c, respectively, in several exemplary embodiments, during a drill-out operation the dart 74 may undergo rotation, relative to the lower seat 76, which rotation may cause the ribs 74d to extend within the channels 76c, respectively. Such extensions may facilitate the remainder of the drill-out operation, increasing the speed at which the apparatus 10 may be drilled out.
In another exemplary embodiment and as illustrated in FIG. 31, the ribs 78c of the plug 78 do not initially extend within the channels 80d of the upper seat 80, respectively. Instead, the ribs 78c contact or are otherwise engaged with the inside surface 80b. However, even if the ribs 78c do not initially extend within the channels 80d, respectively, during a drill-out operation the plug 78 may undergo rotation, relative to the upper seat 80, which rotation may cause the ribs 78c to extend within the channels 80d, respectively. Such extensions may facilitate the remainder of the drill-out operation, increasing the speed at which the apparatus 10 may be drilled out.
In an exemplary embodiment, any two or more of the outside surfaces 74c and 78b and the inside surfaces 76b and 80b taper at equal angles to encourage the engagement of the outside surface 74c to the inside surface 76b and the engagement of the outside surface 78b to the inside surface 80b. However in another exemplary embodiment, two or more of the outside surfaces 74c and 78b and the inside surfaces 76b and 80b taper at different angles and the outside surface 74c still engages the inside surface 76b and the outside surface 78b still engages the inside surface 80b. In an exemplary embodiment, any two or more of the ribs 74d and 78c and the channels 76d and 80d taper at equal angles to encourage the engagement of the ribs 74d to the channels 78d, respectively, and the engagement of the ribs 78c to the channels 80d, respectively. However in another exemplary embodiment, any two or more of the ribs 74d and 78c and the channels 76d and 80d taper at different angles and the ribs 74d still engage the channels 76d, respectively, and the ribs 78c still engage the channels 80d, respectively.
In several exemplary embodiments, the apparatus 10 illustrated in FIGS. 20-31 or any component thereof includes, in whole or in part, one or more embodiments or portions thereof disclosed in U.S. patent application Ser. No. 12/898,444, filed Oct. 5, 2010, the entire disclosure of which is incorporated herein by reference.
A stage tool apparatus for forming an annular body of a fluidic material in an annular region that is partially defined by a preexisting structure has been described that includes a first seat, including: a first annular member defining a first seat passage and a first inside surface adjacent the first seat passage; and a plurality of circumferentially-spaced first channels formed in the first inside surface of the first annular member; and a first blocking element adapted to engage the first seat, the first blocking element including: a first body member defining a first outside surface; and a plurality of circumferentially-spaced first ribs extending along the first outside surface of the first body member; wherein the first blocking element engages the first seat so that the fluidic material is at least partially blocked from flowing through the first seat passage; and wherein the first ribs extend within the first channels, respectively, to resist relative rotation between the first seat and the first blocking element. In an exemplary embodiment, the preexisting structure is a wellbore that traverses a subterranean formation. In an exemplary embodiment, the first blocking element defines a second outside surface and further includes: an annular channel formed in the second outside surface; and an annular sealing element disposed in the annular channel and adapted to sealingly engage the first seat; wherein the first blocking element has: a first axial position, relative to the first seat, in which the first ribs do not extend within the first channels, respectively; and a second axial position, relative to the first seat, in which the first ribs do extend within the first channels, respectively; and wherein the annular sealing element sealing engages the first seat when the first blocking element is in either the first axial position or the second axial position. In an exemplary embodiment, each of the first inside surface and the first outside surface has a frusto-conical shape; wherein the second outside surface has a cylindrical shape; wherein the first seat further defines a second inside surface that extends axially from the first inside surface, the second inside surface having a cylindrical shape and being adjacent the first seat passage; and wherein the annular sealing element sealingly engages the second inside surface of the first seat when the first blocking element is in either the first axial position or the second axial position. In an exemplary embodiment, the stage tool apparatus includes a second seat spaced axially from the first seat, including: a second annular member defining a second seat passage and a third inside surface adjacent the second seat passage; and a plurality of circumferentially-spaced second channels formed in the third inside surface of the second annular member; and a second blocking element adapted to engage the second seat, the second blocking element including: a second body member defining a third outside surface; and a plurality of circumferentially-spaced second ribs extending along the third outside surface of the second body member; wherein the second blocking element engages the second seat so that the fluidic material is at least partially blocked from flowing through the second seat passage; and wherein the second ribs extend within the second channels, respectively, to resist relative rotation between the second seat and the second blocking element. In an exemplary embodiment, each of the first seat, the first body member, the second seat, and the second body member is composed of at least one or more non-metallic materials. In an exemplary embodiment, the first blocking element is a dart and the second blocking element is a plug. In an exemplary embodiment, the stage tool apparatus includes a first tubular member defining a first internal passage, wherein the outside surface of the first tubular member is adapted to partially define the annular region; a second tubular member defining a second internal passage, the second tubular member extending within the first internal passage; wherein the first seat is disposed in the second tubular member; wherein the second tubular member is movable, relative to the first tubular member, from a first position to a second position; wherein the first tubular member includes a flow port that is blocked by the second tubular member when the second tubular member is in the first position; and wherein the flow port is not blocked by the second tubular member when the second tubular member is in the second position. In an exemplary embodiment, the stage tool apparatus includes a third tubular member defining a third internal passage, the third tubular member extending within the first internal passage; wherein the second seat is disposed in the third tubular member; wherein the third tubular member is movable, relative to the first tubular member, from a third position to a fourth position; wherein the flow port is not blocked by the third tubular member when the third tubular member is in the third position; and wherein the flow port is blocked by the third tubular member when the third tubular member is in the fourth position.
A kit for a downhole tool has been described that includes a first seat adapted to be positioned in the downhole tool, the first seat including: a first annular member defining a first seat passage and a first inside surface adjacent the first seat passage; and a plurality of circumferentially-spaced first channels formed in the first inside surface of the first annular member; and a first blocking element adapted to engage the first seat when the first seat is positioned in the downhole tool, the first blocking element including: a first body member defining a first outside surface; and a plurality of circumferentially-spaced first ribs extending along the first outside surface of the first blocking element and adapted to extend within the first channels, respectively; wherein, when the first seat is positioned in the downhole tool, the first blocking element engages the first seat, and the first ribs extend within the first channels, respectively, relative rotation between the first seat and the first blocking element is resisted; and wherein, when the first seat is positioned in the downhole tool and the first blocking element engages the first seat, a fluidic material is at least partially blocked from flowing through the first seat passage. In an exemplary embodiment, the kit includes a second seat adapted to be positioned in the downhole tool and axially spaced from the first seat when the first and second seats are positioned in the downhole tool, the second seat including: a second annular member defining a second seat passage and a second inside surface adjacent the second seat passage; and a plurality of circumferentially-spaced second channels formed in the second inside surface of the second annular member; and a second blocking element adapted to engage the second seat when the second seat is positioned in the downhole tool, the second blocking element including: a second body member defining a second outside surface; and a plurality of circumferentially-spaced second ribs extending along the second outside surface of the second body member and adapted to extend within the second channels, respectively; wherein, when the second seat is positioned in the downhole tool, the second blocking element engages the second seat, and the second ribs extend within the second channels, respectively, relative rotation between the second seat and the second blocking element is resisted; and wherein, when the second seat is positioned in the downhole tool and the second blocking element engages the second seat, the fluidic material is at least partially blocked from flowing through the second seat passage. In an exemplary embodiment, the downhole tool is a stage tool apparatus for forming an annular body of the fluidic material in an annular region that is partially defined by a wellbore that traverses a subterranean formation; wherein the first blocking element is a dart; wherein the second blocking element is a plug; wherein, when the first and second seats are positioned in the stage tool apparatus and the dart engages the first seat, the first seat is adapted to move, relative to the second seat; and wherein, when the first and second seats are positioned in the stage tool apparatus and the plug engages the second seat, the second seat is adapted to move, relative to the first seat. In an exemplary embodiment, each of the first seat, the first body member, the second seat, and the second body member is composed of at least one or more non-metallic materials. In an exemplary embodiment, the first blocking element defines a third outside surface and further includes: an annular channel formed in the third outside surface; and an annular sealing element disposed in the annular channel and adapted to sealingly engage the first seat; wherein the first blocking element has: a first axial position, relative to the first seat, in which the first ribs do not extend within the first channels, respectively; and a second axial position, relative to the first seat, in which the first ribs do extend within the first channels, respectively; and wherein the annular sealing element sealing engages the first seat when the first blocking element is in either the first axial position or the second axial position. In an exemplary embodiment, each of the first inside surface and the first outside surface has a frusto-conical shape; wherein the third outside surface has a cylindrical shape; wherein the first seat further defines a third inside surface that extends axially from the first inside surface, the third inside surface having a cylindrical shape and being adjacent the first seat passage; and wherein the annular sealing element sealingly engages the third inside surface when the first blocking element is in either the first axial position or the second axial position.
A blocking element has been described wherein the blocking element is adapted to engage a seat positioned within a downhole tool, the seat including: an annular member defining a seat passage, a first inside surface having a frusto-conical shape, and a second inside surface extending axially from the first inside surface and having a cylindrical shape, the first and second inside surfaces being adjacent the seat passage, and a plurality of circumferentially-spaced channels formed in the first inside surface of the annular member. The blocking element includes: a body member defining a first outside surface, the first outside surface having a frusto-conical shape; and a plurality of circumferentially-spaced ribs extending along the first outside surface of the body member; wherein the blocking element is adapted to engage the seat so that a fluidic material is at least partially blocked from flowing through the seat passage; and wherein the ribs are adapted to extend within the channels, respectively, to resist relative rotation between the seat and the blocking element. In an exemplary embodiment, the blocking element defines a second outside surface, the second outside surface having a cylindrical shape; wherein the blocking element further includes: an annular channel formed in the second outside surface; and an annular sealing element disposed in the annular channel and adapted to sealingly engage the seat; wherein the blocking element is adapted to have: a first axial position, relative to the seat, in which the ribs do not extend within the channels, respectively; and a second axial position, relative to the seat, in which the ribs do extend within the channels, respectively; and wherein the annular sealing element is adapted to sealingly engage the second inside surface of the seat when the blocking element is in either the first axial position or the second axial position. In an exemplary embodiment, the downhole tool is a stage tool apparatus for forming an annular body of a fluidic material in an annular region that is partially defined by a wellbore that traverses a subterranean formation; wherein the blocking element is a plug and further includes a plurality of wiper elements connected to the body member; and wherein the body member is composed of at least one or more non-metallic materials.
A seat has been described wherein the seat is adapted to be positioned in a downhole tool and engage one of a dart and a plug when positioned in the downhole tool, the one of the dart and the plug including: a body member defining an outside surface, the outside surface having a frusto-conical shape, and a plurality of circumferentially-spaced ribs extending along the outside surface of the body member. The seat includes an annular member defining: a seat passage; a first inside surface adjacent the seat passage, the first inside surface having a frusto-conical shape; a second inside surface extending axially from the first inside surface, the second inside surface having a cylindrical shape and being adjacent the seat passage; and an inwardly-tapered external shoulder spaced radially outwardly from the second inside surface and adapted to engage another shoulder when positioned in the downhole tool; and a plurality of circumferentially-spaced channels formed in the first inside surface of the annular member; wherein the blocking element is adapted to engage the seat so that a fluidic material is at least partially blocked from flowing through the seat passage; and wherein the ribs are adapted to extend within the channels, respectively, to resist relative rotation between the seat and the one of the dart and the plug. In an exemplary embodiment, the downhole tool is a stage tool apparatus for forming an annular body of the fluidic material in an annular region that is partially defined by a wellbore that traverses a subterranean formation; and wherein the seat is composed of at least one or more non-metallic materials.
It is understood that variations may be made in the foregoing without departing from the scope of the disclosure.
In several exemplary embodiments, the elements and teachings of the various illustrative exemplary embodiments may be combined in whole or in part in some or all of the illustrative exemplary embodiments. In addition, one or more of the elements and teachings of the various illustrative exemplary embodiments may be omitted, at least in part, or combined, at least in part, with one or more of the other elements and teachings of the various illustrative embodiments.
Any spatial references such as, for example, “upper,” “lower,” “above,” “below,” “between,” “bottom,” “vertical,” “horizontal,” “angular,” “upwards,” “downwards,” “side-to-side,” “left-to-right,” “left,” “right,” “right-to-left,” “top-to-bottom,” “bottom-to-top,” “top,” “bottom,” “bottom-up,” “top-down,” etc., are for the purpose of illustration only and do not limit the specific orientation or location of the structure described above.
In several exemplary embodiments, while different steps, processes, and procedures are described as appearing as distinct acts, one or more of the steps, one or more of the processes, or one or more of the procedures may also be performed in different orders, simultaneously or sequentially. In several exemplary embodiments, the steps, processes or procedures may be merged into one or more steps, processes or procedures. In several exemplary embodiments, one or more of the operational steps in each embodiment may be omitted. Moreover, in some instances, some features of the present disclosure may be employed without a corresponding use of the other features. Moreover, one or more of the above-described embodiments or variations may be combined in whole or in part with any one or more of the other above-described embodiments or variations.
Although several exemplary embodiments have been disclosed in detail above, the embodiments disclosed are exemplary only and are not limiting, and those skilled in the art will readily appreciate that many other modifications, changes and/or substitutions are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of the present disclosure. Accordingly, all such modifications, changes and/or substitutions are intended to be included within the scope of this disclosure as defined in the following claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures.

## Claims

1. A stage tool apparatus for forming an annular body of a fluidic material in an annular region that is partially defined by a preexisting structure, the stage tool apparatus comprising:
a first seat, comprising:
a first annular member defining a first seat passage and a first inside surface adjacent the first seat passage; and
a plurality of circumferentially-spaced first channels formed in the first inside surface of the first annular member;

a first blocking element adapted to engage the first seat, the first blocking element defining a second outside surface, the first blocking element comprising:
a first body member defining a first outside surface;
a plurality of circumferentially-spaced first ribs extending along the first outside surface of the first body member, wherein the ribs are configured to extend within the first channels, respectively, to resist relative rotation between the first seat and the first blocking element;
an annular channel formed in the second outside surface; and
an annular scaling element disposed in the annular channel and adapted to sealingly engage the first seat;

a second seat spaced axially from the first seat, comprising:
a second annular member defining a second seat passage and a third inside surface adjacent the second seat passage; and
a plurality of circumferentially-spaced second channels formed in the third inside surface of the second annular member; and

a second blocking element adapted to engage the second seat, the second blocking element comprising:
a second body member defining a third outside surface; and
a plurality of circumferentially-spaced second ribs extending along the third outside surface of the second body member;

wherein the first blocking element is configured to engage the first seat so that the fluidic material is at least partially blocked from flowing through the first seat passage;
wherein the second blocking element engages the second seat so that the fluidic material is at least partially blocked from flowing through the second seat passage at a first pressure and at a second higher pressure the fluidic material flows through the second seat passage;
wherein the second ribs extend within the second channels, respectively, to resist relative rotation between the second seat and the second blocking element; and
wherein each of the first seat, the first body member, the second seat, and the second body member is composed at least in part of one or more non-metallic materials, selected from the group of plastics, plastic composites, phenolics, and mixtures thereof;
wherein the first blocking element has:
a first axial position, relative to the first seat, in which the first ribs do not extend substantially within the first channels, respectively; and
a second axial position, relative to the first seat, in which the first ribs do extend substantially within the first channels, respectively; and

wherein the annular sealing element sealing engages the first seat when the first blocking element is in either the first axial position or the second axial position.

2. The stage tool apparatus of claim 1, wherein the stage tool apparatus is configured for forming an annular body of a fluidic material in an annular region of a preexisting wellbore.

3. The stage tool apparatus of claim 1, wherein each of the first inside surface and the first outside surface has a frusto-conical shape and the second outside surface has a cylindrical shape;
wherein the first seat further defines a second inside surface that extends axially from the first inside surface, the second inside surface having a cylindrical shape and being adjacent the first seat passage; and
wherein the annular sealing element is adapted to sealingly engage the second inside surface of the first seat when the first blocking element is in either the first axial position or the second axial position.

4. The stage tool apparatus of claim 1, wherein the first blocking element is a dart and the second blocking element is a plug.

5. The stage tool apparatus of claim 4, further comprising:
a first tubular member having an outside surface and defining a first internal passage, the outside surface of the first tubular member adapted to partially define the annular region; and
a second tubular member defining a second internal passage, the second tubular member extending within the first internal passage the second tubular member movable relative to the first tubular member from a first position to a second position;
the first seat disposed in the second tubular member;
wherein the first tubular member comprises a flow port that is blocked by the second tubular member when the second tubular member is in the first position; and
wherein the flow port is not blocked by the second tubular member when the second tubular member is in the second position.

6. The stage tool apparatus of claim 5, further comprising:
a third tubular member defining a third internal passage, the third tubular member extending within the first internal passage;
wherein the second seat is disposed in the third tubular member, the third tubular member being movable relative to the first tubular member from a third position to a fourth position;
wherein the flow port is not blocked by the third tubular member when the third tubular member is in the third position; and
wherein the flow port is blocked by the third tubular member when the third tubular member is in the fourth position.

7. A kit for a downhole tool, the kit comprising:
a first seat adapted to be positioned in the downhole tool, the first seat comprising:
a first annular member defining a first seat passage and a first inside surface adjacent the first seat passage; and
said first inside surface including a plurality of circumferentially-spaced first channels; and

a first blocking element adapted to engage the first seat when the first seat is positioned in the downhole tool, the first blocking element defining a third outside surface, the first blocking element comprising:
a first body member defining a first outside surface;
a plurality of circumferentially-spaced first ribs extending along the first outside surface of the first blocking element and adapted to extend within the first channels, respectively;
an annular channel formed in the third outside surface; and
an annular sealing element disposed in the annular channel and adapted to sealingly engage the first seat;

a second seat adapted to be positioned in the downhole tool and axially spaced from the first seat when the first and second seats are positioned in the downhole tool, the second seat comprising:
a second annular member defining a second seat passage and a second inside surface adjacent the second seat passage; and
a plurality of circumferentially-spaced second channels formed in the second inside surface of the second annular member; and

a second blocking element adapted to engage the second seat when the second seat is positioned in the downhole tool, the second blocking element comprising:
a second body member defining a second outside surface; and
a plurality of circumferentially-spaced second ribs extending along the second outside surface of the second body member and adapted to extend within the second channels, respectively;

wherein, when the first seat is positioned in the downhole tool, the first blocking element engages the first seat, and the first ribs extend within the first channels, respectively, relative rotation between the first seat and the first blocking element is resisted;
wherein, when the first seat is positioned in the downhole tool and the first blocking element engages the first seat, a fluidic material is at least partially blocked from flowing through the first seat passage;
wherein, when the second seat is positioned in the downhole tool, the second blocking element engages the second seat, and the second ribs extend within the second channels, respectively, relative rotation between the second seat and the second blocking element is resisted;
wherein, when the second seat is positioned in the downhole tool and the second blocking element engages the second seat, the fluidic material is at least partially blocked from flowing through the second seat passage at the first pressure, and at a second higher pressure the fluidic material flows through the second seat passage; and
wherein each of the first seat, the first body member, the second seat, and the second body member is composed of at least one or more nonmetallic materials, selected from the group of plastics, plastic composites, phenolics, and mixtures thereof;
wherein the first blocking element has:
a first axial position, relative to the first seat, in which the first ribs do not extend within the first channels, respectively; and
a second axial position, relative to the first seat, in which the first ribs do extend within the first channels, respectively; and

wherein the annular sealing element sealing engages the first seat when the first blocking element is in either the first axial position or the second axial position.

8. The kit of claim 7, wherein the downhole tool is a stage tool apparatus for forming an annular body of the fluidic material in an annular region that is partially defined by a wellbore that traverses a subterranean formation;
wherein the first blocking element is a dart;
wherein the second blocking element is a plug;
wherein, when the first and second seats are positioned in the stage tool apparatus and the dart engages the first seat, the first seat is adapted to move, relative to the second seat; and
wherein, when the first and second seats are positioned in the stage tool apparatus and the plug engages the second seat, the second seat is adapted to move, relative to the first seat.

9. The kit of claim 7, wherein each of the first inside surface and the first outside surface has a frusto-conical shape;
wherein the third outside surface has a cylindrical shape;
wherein the first seat further defines a third inside surface that extends axially from the first inside surface, the third inside surface having a cylindrical shape and being adjacent the first seat passage; and
wherein the annular sealing element sealingly engages the third inside surface when the first blocking element is in either the first axial position or the second axial position.

10. A blocking element adapted to engage a seat positioned within a downhole tool, the seat comprising:
an annular member defining a seat passage, a first inside surface having a frusto-conical shape, and a second inside surface extending axially from the first inside surface and having a cylindrical shape, the first and second inside surfaces being adjacent the seat passage, and the first inside surface of the annular member defining a plurality of circumferentially-spaced channels, the blocking element defining a second outside surface, the second outside surface having a cylindrical shape, the blocking element comprising:
a body member defining a first outside surface, the first outside surface having a frusto-conical shape;
a plurality of circumferentially-spaced ribs extending along the first outside surface of the body member;
an annular channel formed in the second outside surface; and
an annular sealing element disposed in the annular channel and adapted to sealingly engage the seat;

wherein the blocking element is adapted to engage the seat so that a fluidic material is at least partially blocked from flowing through the seat passage;
wherein the ribs are adapted to extend within the channels, respectively, to resist relative rotation between the seat and the blocking element;
wherein the downhole tool is a stage tool apparatus for forming an annular body of a fluidic material in an annular region that is partially defined by a wellbore that traverses a subterranean formation;
wherein the blocking element is a plug and further comprises a plurality of wiper elements connected to the body member; and
wherein the body member is composed of at least one or more non-metallic materials, selected from the group of plastics, plastic composites, phenolics, and mixtures thereof;
wherein the blocking element is adapted to have:
a first axial position, relative to the seat, in which the ribs do not extend within the channels, respectively; and
a second axial position, relative to the seat, in which the ribs do extend within the channels, respectively;

wherein the annular sealing element is adapted to sealingly engage the second inside surface of the seat when the blocking element is in either the first axial position or the second axial position.

11. A seat adapted to be positioned in a downhole tool and engage one of a dart and a plug when positioned in the downhole tool, the one of the dart and the plug being a blocking element comprising:
a body member defining an outside surface, the outside surface having a frusto-conical shape, and the outside surface of the body member including a plurality of circumferentially spaced ribs, the seat comprising:
an annular member defining:
a seat passage;
a first inside surface adjacent the seat passage, the first inside surface having a frusto-conical shape;
a second inside surface extending axially from the first inside surface, the second inside surface having a cylindrical shape and being adjacent the seat passage; and
an inwardly-tapered external shoulder spaced radially outwardly from the second inside surface and adapted to engage another shoulder when positioned in the downhole tool;


the first inside surface of the annular member including a plurality of circumferentially spaced channels;
wherein the blocking element is adapted to engage the seat so that a fluidic material is at least partially blocked from flowing through the seat passage;
wherein the ribs are adapted to extend within the channels, respectively, to resist relative rotation between the seat and at least one of the dart and the plug; and
wherein the downhole tool is a stage tool apparatus for forming an annular body of the fluidic material in an annular region that is partially defined by a wellbore that traverses a subterranean formation; and wherein the seat is composed in part of at least one or more non-metallic materials, selected from the group of plastics, plastic composites, phenolics, and mixtures thereof;
wherein the second inside surface of the seat is configured to be sealingly engaged by an annular sealing element disposed in an annular channel of the blocking element when the blocking element is in either a first axial position, relative to the seat, in which the ribs do not extend within the channels, respectively, or a second axial position, relative to the seat, in which the ribs do extend within the channels, respectively.