Patent Description:
<CIT> discloses a blowout preventer and seal assembly for sealing a wellbore penetrating a subsurface formation. The blowout preventer includes a housing having a flow path therethrough in fluid communication with the wellbore and a sealing assembly positionable in the housing about the flow path. The sealing assembly includes a piston slidably positionable in the housing and a packer element. The packer element includes a plurality of fingers and a packer seal. The fingers include a housing portion and a piston portion. The housing portion is slidably movable along the housing and the piston portion is slidingly movable along the piston. The fingers are engageable by the piston and movable to a sealed position about the flow path whereby the packer seal is energized to form a seal about the blowout preventer.

<CIT>, <CIT> and <CIT> disclose similar known blowout preventers.

An embodiment of an annular elastomeric packer for a blowout preventer comprise a plurality of circumferentially spaced inserts, wherein at least one of the plurality of inserts comprises a rib, and a foot pivotally coupled to the rib, and an elastomeric body coupled to the plurality of inserts and comprising an inner surface, wherein the foot is configured to resist deformation of the elastomeric body in response to the blowout preventer actuating from a first position to a second position. In some embodiments, each insert comprises a rib coupled between a web and a heel, wherein the web comprises an interlock configured to overlap a mating surface of a web of an adjacently positioned insert in response to the blowout preventer actuating from a first position to a second position. In some embodiments, each insert comprises a rib coupled between a web and a heel, wherein at least one of the heel and the web comprise an interlock configured to circumferentially overlap a mating surface of at least one of the heel and the web of an adjacently positioned insert in response to the elastomeric packer actuating from a first position to a second position. In certain embodiments, the foot of each insert an interlock configured to circumferentially overlap a mating surface of the foot of an adjacently positioned insert in response to the elastomeric packer actuating from a first position to a second position. In certain embodiments, each insert comprises a biasing assembly configured to retract the foot towards a rib of the insert. In some embodiments, each insert further comprises a link pivotally coupled to the foot. In some embodiments, the link comprises a groove that receives an annular seal configured to sealingly engage a piston of the blowout preventer.

An embodiment of an annular blowout preventer comprises an outer housing, an elastomeric packer disposed in the housing, comprising a plurality of circumferentially spaced inserts, wherein at least one of the plurality of inserts comprises a rib coupled between a web and a heel, wherein the insert comprises an interlock configured to circumferentially overlap a mating surface of an adjacently positioned insert in response to the elastomeric packer actuating from a first position to a second position, and an elastomeric body coupled to the plurality of inserts and comprising an inner surface, and a piston slidably disposed in the housing and configured to actuate the elastomeric packer from the first position to the second position. In some embodiments, the piston is configured to actuate the elastomeric packer into sealing engagement against a tubular member. In some embodiments, the piston comprises an annular seal configured to sealingly engage the elastomeric body of the packer. In certain embodiments, the interlock of each insert slidably engages the mating surface of the adjacently positioned insert in response to the elastomeric packer actuating from the first position to the second position. In certain embodiments, the web of the insert comprises the interlock positioned at a first lateral side of the web and the mating surface positioned at a second lateral side of the web opposite the first lateral side. In some embodiments, the interlock of the insert is circumferentially spaced from the mating surface of the adjacently positioned insert when the elastomeric packer is in the first position. In some embodiments, each insert comprises a pivotally coupled foot that is configured to resist deformation of the elastomeric body in response to the blowout preventer actuating from a first position to a second position. In certain embodiments, the piston comprises an annular seal configured to sealingly engage the foot of each insert.

An embodiment of an annular elastomeric packer for a blowout preventer comprises a plurality of circumferentially spaced inserts, wherein at least one of the plurality of inserts comprises a rib coupled between a web and a heel and an interlock configured to overlap a mating surface of a web of an adjacently positioned insert in response to the elastomeric packer actuating from a first position to a second position, and an elastomeric body coupled to the plurality of inserts and comprising an inner surface. In some embodiments, the web of the insert comprises the interlock positioned at a first lateral side of the web and the mating surface positioned at a second lateral side of the web opposite the first lateral side. In some embodiments, the heel of the insert comprises the interlock positioned at a first lateral side of the heel and the mating surface positioned at a second lateral side of the heel opposite the first lateral side. In certain embodiments, the interlock of each insert slidably engages the mating surface of the adjacently positioned insert in response to the elastomeric packer actuating from the first position to the second position. In certain embodiments, each insert comprises a pivotally coupled foot that is configured to resist deformation of the elastomeric body in response to the blowout preventer actuating from a first position to a second position.

For a detailed description of exemplary embodiments, reference will now be made to the accompanying drawings in which:.

In the drawings and description that follow, like parts are typically marked throughout the specification and drawings with the same reference numerals. The drawing figures are not necessarily to scale. Certain features of the disclosed embodiments may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in the interest of clarity and conciseness. The present disclosure is susceptible to embodiments of different forms. Specific embodiments are described in detail and are shown in the drawings, with the understanding that the present disclosure is to be considered an exemplification of the principles of the disclosure, and is not intended to limit the disclosure to that illustrated and described herein. It is to be fully recognized that the different teachings of the embodiments discussed below may be employed separately or in any suitable combination to produce desired results.

Unless otherwise specified, in the following discussion and in the claims, the terms "including" and "comprising" are used in an open-ended fashion, and thus should be interpreted to mean "including, but not limited to. Any use of any form of the terms "connect", "engage", "couple", "attach", or any other term describing an interaction between elements is not meant to limit the interaction to direct interaction between the elements and may also include indirect interaction between the elements described. The various characteristics mentioned above, as well as other features and characteristics described in more detail below, will be readily apparent to those skilled in the art upon reading the following detailed description of the embodiments, and by referring to the accompanying drawings.

Referring to <FIG>, an embodiment of a well or drilling system <NUM> for drilling and/or producing a well is shown. In the embodiment of <FIG>, drilling system <NUM> includes a derrick <NUM> supported by a drilling platform <NUM>. Platform <NUM> has a drill deck or rig floor <NUM> supporting a rotary table <NUM> selectively rotated by a prime mover (not shown) such as an electric motor controlled by a motor controller. In this embodiment, derrick <NUM> includes a traveling block <NUM> controlled by a drawworks <NUM> for raising and lowering a drill string <NUM> suspended from traveling block <NUM>. Drill string <NUM> of drilling system <NUM> extends downward through the rotary table <NUM>, a BOP stack <NUM> including an annular BOP <NUM>, and into a borehole <NUM> that extends into a subterranean earthen formation <NUM> from the surface <NUM>. Drill string <NUM> is formed from a plurality of drill pipe joints <NUM> connected end-to-end. In this embodiment, a bottom-hole-assembly (BHA) <NUM> is attached to the lowermost joint <NUM> and a drill bit <NUM> is attached to the lower end of BHA <NUM> for drilling borehole <NUM>. BHA <NUM> includes, as examples, a drill collar, a mud motor, as well as other sensors or tools. Drilling system <NUM> comprises a land-based drilling system in this embodiment; however, in other embodiments, drilling system <NUM> may comprise an offshore drilling system.

In this embodiment, drill bit <NUM> is rotated with rotary table <NUM> via drill string <NUM> and BHA <NUM>. By rotating drill bit <NUM> with weight-on-bit (WOB) applied, the drill bit <NUM> disintegrates the earthen formation <NUM> to drill borehole <NUM>, which may also be referred to as a wellbore. In some embodiments, a top-drive may be used to rotate the drill string <NUM> rather than rotation by the rotary table <NUM>. In some embodiments, a downhole motor (mud motor) is disposed in the drilling string <NUM> to rotate the drill bit <NUM> in lieu of or in addition to rotating the drill string <NUM> from the surface <NUM>. For example, the mud motor may rotate the drill bit <NUM> when a drilling fluid passes through the mud motor under pressure. In this embodiment, a casing or casing string <NUM> is installed and extends downward generally from the surface <NUM> into at least a portion of borehole <NUM>. In some embodiments, casing <NUM> is cemented within the borehole <NUM> to isolate various vertically-separated earthen zones, preventing fluid transfer between the zones. BOP stack <NUM> is secured to the upper end of casing <NUM>. In this embodiment, casing <NUM> comprises multiple tubular members, such as pieces of threaded pipe, joined end-to end to form liquid-tight or gas-tight connections, to prevent fluid and pressure exchange between the inner surface of casing <NUM> and a surrounding earthen zone.

An annular space or annulus <NUM> is formed between both the sidewall of borehole <NUM> and drill string <NUM> and between casing <NUM> and drill string <NUM>. In other words, annulus <NUM> extends through borehole <NUM> and casing <NUM>. BOP stack <NUM> includes an annular space or flow path <NUM> in fluid communication with annulus <NUM>. Annular BOP <NUM> of the BOP stack <NUM> is generally configured to selectively seal the annular flow path <NUM> from annulus <NUM>, and hence selectively seal annulus <NUM> at the surface <NUM> to thereby inhibit fluid contained in annulus <NUM> from discharging upward and out of borehole <NUM>. As will be described further herein, annular BOP <NUM> includes an annular elastomeric sealing element configured to squeeze radially inward to sealingly engage an outer surface of a tubular (e.g., drill string <NUM>, casing, drill pipe, drill collar, etc.) extending through annular BOP <NUM>. In certain embodiments, an operator and/or drilling control system of drilling system <NUM> selectively and controllably opens and closes annular BOP <NUM> to allow, to restrict, or to inhibit the flow of drilling fluid or another fluid through flow path <NUM> and annulus <NUM>. In this embodiment, drilling system <NUM> includes a drilling fluid circulation system to circulate drilling fluid or mud <NUM> down drill string <NUM> and back up annulus <NUM>. Drilling fluid <NUM> generally functions to cool drill bit <NUM>, remove cuttings from the bottom of borehole <NUM>, and maintain a desired pressure or pressure profile in borehole <NUM> during drilling operations. The drilling fluid circulation system of drilling system <NUM> includes a drilling fluid reservoir or mud tank <NUM>, a supply pump <NUM>, a supply line <NUM> connected to the outlet of supply pump <NUM>, and a kelly <NUM> for supplying drilling fluid <NUM> to the drill string <NUM>.

Referring to <FIG>, an embodiment of the annular BOP <NUM> of drilling system <NUM> is shown. While annular BOP <NUM> is shown as part of drilling system <NUM>, annular BOP <NUM> may be utilized in other well systems, including offshore well systems. In the embodiment of <FIG>, annular BOP <NUM> has a central or longitudinal axis <NUM> and generally includes a first or lower housing <NUM>, a second or upper housing <NUM>, a piston <NUM> slidably disposed in lower housing <NUM>, an adapter ring <NUM> coupled to lower housing <NUM>, and an annular, elastomeric packer <NUM> received in upper housing <NUM>. Lower housing <NUM> of annular BOP <NUM> has a central bore or passage <NUM> extending between upper and lower ends of lower housing <NUM>, where central passage <NUM> is defined by an inner surface <NUM>. Lower housing <NUM> includes an annular shoulder <NUM>, a first or upper port <NUM>, and a second or lower port <NUM>, where both ports <NUM>, <NUM> extend radially between an outer surface of lower housing <NUM> and the inner surface <NUM>. Additionally, the inner surface <NUM> of lower housing <NUM> includes an annular second or upper shoulder <NUM> against which adapter ring <NUM> is seated. Further, a pair of annular seals <NUM> are disposed on inner surface <NUM> of lower housing <NUM> where annular seals <NUM> sealingly engage piston <NUM>.

In this embodiment, upper housing <NUM> of annular BOP <NUM> releasably couples to lower housing <NUM> via a connector assembly <NUM> disposed radially between lower housing <NUM> and upper housing <NUM>. Upper housing <NUM> includes a central bore or passage <NUM> extending between upper and lower ends of the upper housing <NUM>, where central passage <NUM> is defined by an inner surface <NUM>. In this embodiment, a portion of the inner surface <NUM> of upper housing <NUM> comprises a concave or hemispherical surface <NUM> that guides the movement of elastomeric packer <NUM> during the actuation of annular BOP <NUM> and elastomeric packer <NUM> between a first or open position (shown in <FIG>) and a second or closed position (shown in <FIG>). Adapter ring <NUM> of annular BOP <NUM> is generally configured to retain piston <NUM> within the central passage <NUM> of lower housing <NUM>. In this embodiment, adapter ring <NUM> includes an outer surface <NUM> that receives an annular first or outer seal <NUM> that sealingly engages the inner surface <NUM> of lower housing <NUM> and a pair of annular second or inner seals <NUM> that sealingly engage piston <NUM>.

Piston <NUM> of annular BOP <NUM> is slidably disposed within the central passage <NUM> of lower housing <NUM> and is configured to actuate annular BOP <NUM> and elastomeric packer <NUM> between the open and closed positions in response to the communication of fluid pressure to central passage <NUM> from a hydraulic pressure source (e.g., a hydraulic accumulator, bottle, etc.). In this embodiment, piston <NUM> has an outer surface <NUM> extending between upper and lower ends of piston <NUM> and a central bore or passage <NUM>. The outer surface <NUM> of piston <NUM> includes a pair of annular outer seals <NUM> disposed thereon that sealingly engage the inner surface <NUM> of lower housing <NUM>. Additionally, the outer surface <NUM> of piston <NUM> includes an annular first or outer engagement surface <NUM> and an annular second or inner engagement surface <NUM>.

Outer engagement surface <NUM> of piston <NUM> is positioned at the upper end of piston <NUM> while inner engagement surface <NUM> comprises a frustoconical surface extending radially inwards from outer engagement surface <NUM>. As shown particularly in <FIG>, in this embodiment, an annular first packer seal <NUM> is disposed on outer engagement surface <NUM> while an annular second packer seal <NUM> is disposed on inner engagement surface <NUM>. As will be described further herein, packer seals <NUM>, <NUM> sealingly engage components of elastomeric packer <NUM>. Although in this embodiment piston <NUM> includes a single annular seal <NUM> disposed on outer engagement surface <NUM> and a single annular seal <NUM> disposed on inner engagement surface <NUM>, in other embodiments, engagement surfaces <NUM>, <NUM> may include zero annular seals or more than one annular seals. For example, referring briefly to <FIG>, another embodiment of a piston <NUM> of annular BOP <NUM> includes a plurality of annular seals <NUM> disposed on inner engagement surface <NUM> and no annular seals disposed on outer engagement surface <NUM>.

Referring again to <FIG>, the sealing engagement provided by the seals <NUM> of lower housing <NUM> and the outer seals <NUM> of piston <NUM> define an annular first or closing chamber <NUM> (shown in <FIG>) within central passage <NUM> of lower housing <NUM>. Additionally, sealing engagement by outer annular seals <NUM> of piston <NUM> and the seals <NUM>, <NUM> of adapter ring <NUM> define an annular second or opening chamber <NUM> (shown in <FIG>) within central passage <NUM> of lower housing <NUM>. Annular BOP <NUM> and elastomeric packer <NUM> are shown in the open position in <FIG>, where fluid communication is allowed or provided through central passage <NUM> of lower housing <NUM> and central passage <NUM> of upper housing <NUM>, thereby permitting the circulation of fluid along annular flowpath <NUM>. Annular BOP <NUM> and elastomeric packer <NUM> may be actuated from the open position to the closed position where fluid flow along annular flowpath <NUM> is restricted via sealing engagement between packer <NUM> and the outer surface of drill string <NUM>.

In this embodiment, to actuate annular BOP <NUM> and elastomeric packer <NUM> from the open position shown in <FIG> to the closed position shown in <FIG>, closing chamber <NUM> of central passage <NUM> is hydraulically pressurized while hydraulic pressure within opening chamber <NUM> is concurrently reduced, thereby providing a hydraulic pressure closing force against piston <NUM> (shown schematically by arrow <NUM> in <FIG>). Closing force <NUM> is axially directed towards the upper end of upper housing <NUM>, causing piston <NUM> to be displaced axially upwards within central passage <NUM> until annular BOP <NUM> and elastomeric packer <NUM> are disposed in the closed position shown in <FIG>. Conversely, annular BOP <NUM> and elastomeric packer <NUM> may be actuated from the closed position shown in <FIG> to the open position shown in <FIG> by hydraulically pressurizing opening chamber <NUM> while concurrently depressurizing closing chamber <NUM>. The pressurization of opening chamber <NUM> and depressurization of closing chamber <NUM> provides an axially directed opening force against piston <NUM>, causing piston <NUM> to be displaced through central passage <NUM> of lower housing <NUM> until annular BOP <NUM> and elastomeric packer <NUM> are disposed in the open position with the lower end of piston <NUM> in physical engagement with or disposed directly adjacent the inner surface <NUM> of lower housing <NUM>. Fluid pressure may be communicated to chambers <NUM>, <NUM> via ports extending radially through lower housing <NUM>, where each port is in fluid communication with a hydraulic pressure source.

The elastomeric packer <NUM> of annular BOP <NUM> is configured to sealingly engage the outer surface of drill string <NUM> when annular BOP <NUM> and elastomeric packer <NUM> are actuated into the closed position. In certain embodiments, packer <NUM> is configured to seal central passage <NUM> of upper housing <NUM> and central passage <NUM> of lower housing <NUM> when there is no tubular member (e.g. drill string <NUM>) extending through annular BOP <NUM> and BOP <NUM> and elastomeric packer <NUM> are actuated into the closed position. In other words, in at least some embodiments, when drill string <NUM> (or any other tubular member) does not extend through annular BOP <NUM>, elastomeric packer <NUM> is configured to seal against itself to thereby restrict fluid flow along flowpath <NUM>.

In this embodiment, elastomeric packer <NUM> of annular BOP <NUM> has a central or longitudinal axis and a central passage <NUM> extending between upper and lower ends thereof. Packer <NUM> generally includes a plurality of circumferentially spaced inserts <NUM> coupled to an annular elastomeric body <NUM>. In certain embodiments, inserts <NUM> comprise a metallic material and are circumferentially arranged in a mold such that elastomeric body <NUM> may be molded thereto to form elastomeric packer <NUM>. In this embodiment, elastomeric body <NUM> includes an annular inner surface <NUM> (shown in <FIG>), an annular outer surface <NUM> (shown in <FIG>), and an annular lower surface <NUM> (shown in <FIG>). In the closed position of annular BOP <NUM> and elastomeric packer <NUM>, inner surface <NUM> of elastomeric body <NUM> sealingly engages the outer surface of drill string <NUM> while outer surface <NUM> sealingly engages the hemispherical surface <NUM> of upper housing <NUM> while lower surface <NUM> sealingly engages the outer surface <NUM> of piston <NUM> to thereby restrict fluid flow along annular flowpath <NUM>. When annular BOP <NUM> and elastomeric packer <NUM> are in the closed position and no tubular member extends through annular BOP <NUM>, the inner surface <NUM> of elastomeric body <NUM> seals against itself to restrict fluid flow through annular BOP <NUM>. In this embodiment, first packer seal <NUM> of piston <NUM> sealingly engages the lower surface <NUM> of elastomeric body <NUM> to augment the sealing integrity between elastomeric body <NUM> and piston <NUM>; however, in other embodiments, piston <NUM> may not include first packer seal <NUM>. For clarity, the elastomeric body <NUM> of elastomeric packer <NUM> is hidden in <FIG>.

As shown particularly in <FIG>, each insert <NUM> of elastomeric packer <NUM> includes a first or upper end comprising an upper member or web <NUM>, a second or lower end comprising a lower member or heel <NUM>, and a link or rib <NUM> extending between the web <NUM> and heel <NUM>. In this embodiment, an upper end of the web <NUM> of each inert <NUM> includes an extension <NUM> extending therefrom. Although in this embodiment each insert <NUM> includes an extension <NUM>, in other embodiments, inserts <NUM> may not include extensions <NUM>. Additionally, each web <NUM> includes a laterally extending (relative a longitudinal axis of the insert <NUM>) first or upper interlock <NUM> positioned at a first lateral side of web <NUM> and a first or upper mating surface <NUM> disposed laterally opposite the upper interlock <NUM> at a second lateral side of web <NUM> opposite the first lateral side. Similarly, in this embodiment, the heel <NUM> of each insert <NUM> includes a laterally extending second or lower interlock <NUM> positioned at a first lateral side of heel <NUM> and a second or lower mating surface <NUM> disposed laterally opposite the lower interlock <NUM> at a second lateral side of heel <NUM> opposite the first lateral side.

In this embodiment, each insert <NUM> of elastomeric packer <NUM> also includes a first or intermediate link <NUM> pivotally coupled to a lower end of rib <NUM> and a second link or foot <NUM> pivotally coupled to intermediate link <NUM>. Particularly, the intermediate link <NUM> of each insert <NUM> has a first or outer end that receives a first pin <NUM> that extends through rib <NUM>, thereby pivotally coupling the outer end of intermediate link <NUM> with the rib <NUM>. Additionally, the intermediate link <NUM> of each insert <NUM> has a second or inner end that receives a second pin <NUM> that extends through a first or inner end of the foot <NUM>, thereby pivotally coupling the inner end of intermediate link <NUM> with the outer end of the foot <NUM>. The pivotable foot <NUM> of each insert <NUM> includes a laterally extending third or foot interlock <NUM> positioned at a first lateral side of foot <NUM> and a third or foot mating surface <NUM> disposed laterally opposite the foot interlock <NUM> at a second lateral side of foot <NUM> opposite the first lateral side.

Upper interlocks <NUM> and corresponding mating surfaces <NUM> may be referred to as upper interlocks <NUM>, <NUM> of elastomeric packer <NUM> while lower interlocks <NUM> and corresponding mating surfaces <NUM> may be referred to as lower interlocks <NUM>, <NUM>, and feet interlocks <NUM> and corresponding mating surfaces <NUM> may be referred to as feet interlocks <NUM>, <NUM>. In this embodiment, interlock <NUM> of the foot <NUM> arcuately or circumferentially overlaps the mating surface <NUM> of the foot <NUM> of an adjacently positioned insert <NUM> such that no arcuate gap is formed between adjacently positioned feet <NUM>, irrespective of whether annular BOP <NUM> is in the open or closed positions. In this embodiment, interlocks <NUM>, <NUM>, and <NUM> of each insert <NUM> comprise substantially planar surfaces configured to slidably engage mating surfaces <NUM>, <NUM>, and <NUM>, respectively; however, in other embodiments, the geometry of interlocks <NUM>, <NUM>, and <NUM>, and mating surfaces <NUM>, <NUM>, and <NUM> may vary.

Although in this embodiment each insert <NUM> includes a foot <NUM> with a foot interlock <NUM> and a corresponding mating surface <NUM>, in other embodiments, each foot <NUM> may not include an interlock <NUM> and/or a mating surface <NUM>. For example, referring briefly to <FIG>, <FIG>, another embodiment of an elastomeric packer <NUM> of annular BOP <NUM> is shown. Elastomeric packer <NUM> includes features in common with elastomeric packer <NUM> shown in <FIG>, and shared features are labeled similarly. Particularly, in the embodiment of <FIG>, <FIG>, elastomeric packer <NUM> generally includes elastomeric body <NUM> and a plurality of circumferentially spaced inserts <NUM> coupled thereto. Each insert <NUM> of elastomeric packer <NUM> includes a foot <NUM> pivotally coupled to the rib <NUM> of the insert <NUM> via intermediate link <NUM>. In this embodiment, the foot <NUM> of each insert <NUM> does not include either an interlock or a corresponding mating surface. Thus, in this embodiment, an arcuate gap (shown schematically in <FIG> by arrows <NUM>) extends between the foot <NUM> of each adjacently positioned insert <NUM> of elastomeric packer <NUM> when annular BOP <NUM> is in the open position.

Referring again to <FIG>, when annular BOP <NUM> is in the open position shown in <FIG>, the feet <NUM> of elastomeric packer <NUM> are each positioned at an incline relative central axis <NUM> that is parallel to the incline of the inner engagement surface <NUM> of piston <NUM>. In this arrangement, the second packer seal <NUM> of piston <NUM> sealingly engages an outer surface of each foot <NUM> of elastomeric packer <NUM> while the first packer seal <NUM> sealingly engages the lower surface <NUM> of elastomeric body <NUM> which is located radially between each foot <NUM> and the heel <NUM> of the insert <NUM> to which it is pivotally coupled. Thus, packer seals <NUM>, <NUM> provide a dual seal barrier at the interface formed between piston <NUM> and elastomeric packer <NUM>. Additionally, in this embodiment, a minimum inner diameter of the central passage <NUM> of piston <NUM> is the same or greater in size than a minimum inner diameter of the central passage <NUM> of elastomeric packer <NUM> when annular BOP <NUM> is in the open position. In this embodiment, some or all of the interlocks <NUM>, <NUM> of each insert <NUM> may be circumferentially spaced from the mating surfaces <NUM>, <NUM> of an adjacently positioned insert <NUM> when the annular BOP <NUM> and elastomeric packer <NUM> are in the open position. For example, the upper interlock <NUM> of each insert <NUM> is circumferentially spaced from the upper mating surface <NUM> of an adjacently positioned insert <NUM> when annular BOP <NUM> and elastomeric packer <NUM> are in the open position.

When annular BOP <NUM> is actuated from the open position shown in <FIG> to the closed position shown in <FIG>, the hemispherical surface <NUM> of upper housing <NUM> compresses the elastomeric body <NUM> of elastomeric packer <NUM> radially inwards towards central axis <NUM> to force the inner surface <NUM> of elastomeric body <NUM> into sealing engagement with the outer surface of the drill string <NUM>. In some applications, including applications where the drilling fluid flowing along annular flowpath <NUM> is at an elevated temperature, the elastomeric body <NUM> of packer <NUM> may deform in response to the actuation of annular BOP <NUM> from the open position to the closed position. Inserts <NUM> of elastomeric packer <NUM> are configured to prevent portions of elastomeric body <NUM> from extruding axially past (e.g., above or below) or radially between inserts <NUM> such that elastomeric body <NUM> is trapped radially between the circumferentially spaced inserts <NUM> and the outer surface of drill string <NUM> to maintain sealing integrity between elastomeric body <NUM> and the outer surface of drill string <NUM>.

Particularly, extensions <NUM> of inserts <NUM>, which are also displaced radially inwards towards central axis <NUM> in response to the actuation of annular BOP <NUM> to the closed position, restrict elastomeric body <NUM> from extruding upwards and axially past extensions <NUM> of inserts <NUM>, thereby trapping the upper end of the elastomeric body <NUM> against the outer surface of drill string <NUM>. Additionally, when annular BOP <NUM> is in the closed position, there is no arcuate gap extending between adjacently disposed upper interlocks <NUM> and <NUM>, lower interlocks <NUM> and <NUM>, and feet interlocks <NUM>, <NUM>, respectively. In other words, when annular BOP <NUM> is in the closed position: each upper interlock <NUM> circumferentially overlaps with, and matingly engages, a corresponding mating surface <NUM>, each lower interlock <NUM> overlaps with, and matingly engages, a corresponding mating surface <NUM>, and each foot interlock <NUM> overlaps with, and matingly engages, a corresponding mating surface <NUM>. With interlocks <NUM>, <NUM>, and <NUM> in overlapping arrangements with mating surfaces <NUM>, <NUM>, and <NUM>, respectively, elastomeric body <NUM> is at least substantially prevented from extruding radially between adjacent inserts <NUM> of elastomeric packer <NUM>, thereby maximizing the sealing integrity formed between elastomeric body <NUM> and the outer surface of drill string <NUM>. Further, when annular BOP <NUM> is in the closed position, feet <NUM> of inserts <NUM> cradle the lower end of elastomeric body <NUM> to prevent body <NUM> from extruding or flowing axially below feet <NUM>, thereby trapping the lower end of elastomeric body against the outer surface of drill string <NUM> to maximize sealing integrity between elastomeric body <NUM> and the outer surface of drill string <NUM>. Thus, extensions <NUM> of inserts <NUM> prevent the upper end of elastomeric body <NUM> from escaping the annular space surrounded by inserts <NUM> while feet <NUM> of inserts <NUM> prevent the lower end of elastomeric body <NUM> from escaping the annular space surrounded by inserts <NUM>. Moreover, as described above, packer seals <NUM>, <NUM> increase the integrity of the seal formed at the interface between piston <NUM> and elastomeric packer <NUM>.

Referring to <FIG>, another embodiment of an elastomeric packer <NUM> of annular BOP <NUM> is shown. Elastomeric packer <NUM> includes features in common with packer <NUM> described above, and shared features are labeled similarly. Elastomeric packer <NUM> generally includes elastomeric body <NUM> and a plurality of circumferentially spaced inserts <NUM> coupled thereto. In the embodiment of <FIG>, each insert <NUM> of packer <NUM> includes both intermediate link <NUM> (referred to as first link <NUM> in this embodiment) and a second link <NUM> pivotally coupled to first link <NUM> via second pin <NUM>. Additionally, each insert <NUM> includes a foot <NUM> pivotally coupled to second link <NUM> via a third pin <NUM>. Thus, the foot <NUM> of each insert <NUM> is pivotable about each of pins <NUM>, <NUM>, and <NUM>. In this embodiment, the foot <NUM> of each insert <NUM> is disposed at an angle relative to the inner engagement surface <NUM> of piston <NUM>, cradling the lower end of elastomeric body <NUM>. In this embodiment, a circumference defined by the radially inner ends of circumferentially spaced feet <NUM> has a minimum diameter the same size or greater than the minimum diameter <NUM> of piston <NUM> when annular BOP <NUM> is in the open position. In this embodiment, an upper surface of each foot <NUM> is adhered or frictionally coupled to the inner surface <NUM> of elastomeric body <NUM> via the adhesive or frictional quality of the elastomeric material comprising body <NUM>. In this manner, feet <NUM> may pivot in response to deformation if elastomeric body <NUM> such that feet <NUM> remain attached to inner surface <NUM> of elastomeric body <NUM> during the actuation of annular BOP <NUM> between the open and closed positions.

Referring to <FIG>, another embodiment of an elastomeric packer <NUM> of annular BOP <NUM> is partially shown in <FIG>. Elastomeric packer <NUM> includes features in common with packers <NUM>, <NUM> described above, and shared features are labeled similarly. Elastomeric packer <NUM> generally includes elastomeric body <NUM> and a plurality of circumferentially spaced inserts <NUM> coupled thereto. In the embodiment of <FIG>, each insert <NUM> includes a second link <NUM> pivotally coupled between first link <NUM> and foot <NUM>. In the embodiment of <FIG>, each second link <NUM> includes a groove that receives at least a portion of an annular seal <NUM> extending about the central passage <NUM> of elastomeric packer <NUM>. Second link <NUM> is supported on outer engagement surface <NUM> of piston <NUM> with seal <NUM> in sealing engagement therewith when annular BOP <NUM> is in the open position. Thus, instead of placing seals in grooves formed in piston <NUM> (e.g., packer seals <NUM>, <NUM>), elastomeric packer <NUM> includes annular seal <NUM> for increasing the sealing integrity formed between piston <NUM> and packer <NUM>.

Referring to <FIG>, another embodiment of an insert <NUM> for an elastomeric packer of the annular BOP <NUM> is shown. Insert <NUM> includes features in common with inserts <NUM>, <NUM>, and <NUM> described above, and shared features are labeled similarly. Insert <NUM> is similar to insert <NUM> shown in <FIG>, <FIG> except that insert <NUM> includes a biasing assembly <NUM> configured to bias foot <NUM> radially outwards in the direction of the inner surface <NUM> of elastomeric body <NUM> (not shown in <FIG>) in the event that foot <NUM> becomes unattached therefrom. In the embodiment of <FIG>, biasing assembly <NUM> includes a cylinder <NUM> pivotally coupled to the rib <NUM> of insert <NUM> via a first pin <NUM>, a piston or mandrel <NUM> pivotally coupled to foot <NUM> via a second pin <NUM>, and a biasing member <NUM> (e.g., a spring) disposed in cylinder <NUM> radially between an outer surface of mandrel <NUM> and an inner surface of cylinder <NUM>. In this configuration, biasing member <NUM> of each insert <NUM> applies a biasing force against foot <NUM> in the radially outwards direction towards the inner surface <NUM> of elastomeric body <NUM>.

Referring to <FIG>, another embodiment of an elastomeric packer <NUM> of the annular BOP <NUM> is shown. Elastomeric packer <NUM> includes features in common with packers <NUM>, <NUM>, and <NUM> described above, and shared features are labeled similarly. Elastomeric packer <NUM> generally includes a plurality of circumferentially spaced inserts <NUM> that are coupled or molded to an elastomeric body <NUM>. In the embodiment of <FIG>, each insert <NUM> includes a rib <NUM> and a foot <NUM> directly coupled to rib <NUM> via a rotatable pin or pivot joint <NUM>. In this embodiment, elastomeric body <NUM> includes an outer sealing surface <NUM> and a frustoconical lower surface <NUM> configured to sealingly engage the inner engagement surface <NUM> of the piston <NUM> of annular BOP <NUM>. In some embodiments, a lower surface of each foot <NUM> may be curved to sealingly engage a curved (e.g., concave) surface of piston <NUM>.

Referring to <FIG>, another embodiment of an elastomeric packer <NUM> of the annular BOP <NUM> is shown. Elastomeric packer <NUM> includes features in common with packers <NUM>, <NUM>, <NUM>, and <NUM> described above, and shared features are labeled similarly. Particularly, elastomeric packer <NUM> generally includes circumferentially spaced inserts <NUM> that are coupled or molded to an elastomeric body <NUM>. In the embodiment of <FIG>, elastomeric body <NUM> includes a lower surface that includes an annular outer engagement surface <NUM> and an annular inner or frustoconical engagement surface <NUM> that extends at an angle relative to outer engagement surface <NUM>. In this embodiment, outer engagement surface <NUM> of elastomeric body <NUM> is configured to sealingly engage outer engagement surface <NUM> of piston <NUM> while inner engagement surface <NUM> is configured to sealingly engage the inner engagement surface <NUM> of piston <NUM>. Referring briefly to <FIG>, another embodiment of an elastomeric packer <NUM> of the annular BOP <NUM> is shown. In the embodiment of <FIG>, elastomeric packer <NUM> generally includes circumferentially spaced inserts <NUM> that are coupled or molded to elastomeric body <NUM>.

Referring to <FIG>, another embodiment of an insert <NUM> for an elastomeric packer of the annular BOP <NUM> is shown. Insert <NUM> includes a web <NUM>, a rib <NUM> coupled to web <NUM>, and a heel <NUM> coupled to rib <NUM>. In the embodiment of <FIG>, insert <NUM> does not include an extension (e.g., extension <NUM> of insert <NUM>) and the heel <NUM> of insert <NUM> does not include an interlock and corresponding mating surface. However, web <NUM> of insert <NUM> includes an upper interlock <NUM> and an upper mating surface <NUM> disposed laterally opposite the upper interlock <NUM> for preventing an upper end of an elastomeric body (to which insert <NUM> is coupled) from being extruded axially between web <NUM> and the outer surface of drill string <NUM>, thereby maintaining the sealing integrity between the elastomeric body and the outer surface of drill string <NUM> to thereby seal annular flowpath <NUM>.

Claim 1:
An annular elastomeric packer (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) for a blowout preventer (<NUM>), comprising:
a plurality of circumferentially spaced inserts (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>), wherein each of the plurality of inserts comprises a rib (<NUM>, <NUM>, <NUM>), and a foot (<NUM>, <NUM>, <NUM>) pivotably coupled to the rib (<NUM>, <NUM>, <NUM>), and wherein each insert (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) further comprises a link (<NUM>, <NUM>)) having a first end pivotably coupled to the rib (<NUM>, <NUM>, <NUM>) and a second end, opposite the first <NUM> end, pivotably coupled to the foot (<NUM>, <NUM>, <NUM>) whereby the foot (<NUM>, <NUM>, <NUM>) is pivotably coupled to the rib (<NUM>, <NUM>, and <NUM>) through the link (<NUM>, <NUM>); and
an elastomeric body (<NUM>, <NUM>, <NUM>) coupled to the plurality of inserts (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) and comprising an inner surface (<NUM>); wherein the foot (<NUM>, <NUM>, <NUM>) is configured to resist deformation of the elastomeric body (<NUM>, <NUM>, <NUM>) in <NUM> response to the blowout preventer (<NUM>) actuating from a first position to a second position.