Shear Ram Blowout Preventer with Engagement Feature

Abstract

A blowout preventer (“BOP”) includes a housing comprising a vertical bore extending through the housing, and a pair of opposing shear rams configured to move into the vertical bore. The shear rams comprise an engagement feature configured to engage with a corresponding engagement feature and urge the shear rams into axially towards each other with respect to an axis of the vertical bore when the shear rams are located in the vertical bore.

Description

BACKGROUND

This section is intended to provide background information to facilitate a better understanding of the various aspects of the described embodiments. Accordingly, it should be understood that these statements are to be read in this light and not as admissions of prior art.

Blowout preventers are used extensively throughout the oil and gas industry. Typical blowout preventers are used as a large specialized valve or similar mechanical device that seal, control, and monitor oil and gas wells. The two categories of blowout preventers that are most prevalent are ram blowout preventers and annular blowout preventers. Blowout preventer stacks frequently utilize both types, typically with at least one annular blowout preventer stacked above several ram blowout preventers. The ram units in ram blowout preventers allow for both the shearing of the drill pipe and the sealing of the blowout preventer. Typically, a blowout preventer stack may be secured to a wellhead and may provide a safe means for sealing the well in the event of a system failure.

A typical blowout preventer includes a main body with a vertical bore. Ram bonnet assemblies may be bolted to opposing sides of the main body using a number of high tensile bolts or studs. These bolts are required to hold the bonnet in position to enable the sealing arrangements to work effectively. Typically an elastomeric sealing element is used between the ram bonnet and the main body. There are several configurations, but essentially they are all directed to preventing a leakage bypass between the mating faces of the ram bonnet and the main body. Each bonnet assembly includes a piston which is laterally movable within a ram cavity of the bonnet assembly by pressurized hydraulic fluid acting on one side of the piston. The opposite side of each piston has a connecting rod attached thereto which in turn has a shear ram and corresponding blades mounted thereon.

These rams are designed to move laterally toward the vertical bore of the blowout preventer to shear or cut any object located therein. For instance, the rams can close in on and shear a tubular within the vertical bore of the blowout preventer, such as a section of drill pipe used during drilling operations. The opposing rams typically experience some axial separation after shearing, such as when shearing a larger object (e.g., a tool joint) or wireline. The axial separation results from shear forces encountered when shearing the object, leaving a vertical gap between the opposing shear blades. This vertical gap between the shear rams or blades may then make it difficult to seal or subsequently shear objects with the blowout preventer. Accordingly, a mechanism for enabling shear rams to more efficiently seal or shear in a blowout preventer bore may be desirable.

DESCRIPTION OF THE DRAWINGS

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

FIGS. 1A-1C depict multiple cross-sectional views of a blowout preventer for shearing a tubular, according to one or more embodiments;

FIG. 2 depicts a side perspective view of shear rams, according to one or more embodiments;

FIG. 3 depicts a top down view of the shear rams, according to one or more embodiments;

FIG. 4 depicts a cross-sectional view of the shear rams taken along line 4-4 in FIG. 2, according to one or more embodiments;

FIG. 5 depicts a detailed view of the engagement of the shear rams in FIG. 4, according to one or more embodiments;

FIG. 6 depicts a cross-sectional view of the shear rams taken along line 6-6 in FIG. 2, according to one or more embodiments; and

FIG. 7 depicts a detailed view of the engagement of the shear rams in FIG. 5, according to one or more embodiments.

DETAILED DESCRIPTION

Referring now to FIGS. 1A-1C, multiple views of a blowout preventer (“BOP”) 10 for shearing a tubular D in accordance with one or more embodiments of the present disclosure are shown. The BOP 10, which may be referred to as a ram BOP or shear ram BOP, includes a body 12 with a vertical bore 14 formed and/or extending through the body 12. As shown, the body 12 includes a lower flange 16 and/or an upper flange 18 to facilitate connecting the BOP 10 to other BOPs or other components, such as a wellhead connector on the flower flange 16 or to a lower marine riser package on the upper flange 18. Ram cavities 20 and 22 are formed within the body 12 of the BOP 10, with the cavities 20 and 22 intersecting and extending outwardly from the bore 14 on opposite sides of the BOP bore 14.

The BOP 10 includes one or more rams or ram assemblies, such as a first ram 24 and a second ram 26. The first ram 24 may be positioned and movable within the first cavity 20 and a second ram 26 positioned and movable within the second cavity 22. The first ram 24 and the second ram 26 are positioned to oppose each other (e.g., on opposite sides of the bore 14) and are movable towards and away from the tubular D. Actuators 28 are provided to move the first ram 24 and the second ram 26 into the BOP bore 14 to shear the portion of the tubular D extending through the BOP bore 14.

In this embodiment, a hydraulic actuator is shown, though any type of actuator (e.g., pneumatic, electrical, mechanical) may be used in accordance with the present disclosure. The actuators 28 shown in this embodiment include a piston 30 positioned within a cylinder 32 and a rod 34 connecting the piston 30 to each respective ram 24 and 26. Further, pressurized fluid is introduced and fluidly communicated on opposite sides of the piston 30 through ports 35, thereby enabling the actuator 28 to move the rams 24 and 26 in response to fluid pressure.

A first (e.g., upper) blade 36 is included with or connected to the first ram 24, and a second (e.g., lower) blade 38 is included with or connected to the second ram 26. The first and second blades 36 and 38 are formed and positioned such that a cutting edge of the second blade 38 passes below a cutting edge of the first blade 36 in shearing of a section of a tubular D. The shearing action of first and second blades 36 and 38 shear the tubular D. The lower portion of the tubular D may then drop into the well bore (not shown) below BOP 10, or the lower portion of tubular D may hung off a lower set of rams (not shown).

Accordingly, disclosed herein are a BOP apparatus and/or a ram for a BOP apparatus for shearing an object located therein. The object may be positioned within the bore extending through the BOP, in which the BOP is actuated to move one or more rams to engage and shear the object. A ram of a BOP in accordance with the present disclosure may be used for shearing one or more different types of objects that may have different shapes, sizes, thicknesses, and other dimensions and properties.

For example, an object may include a drill pipe joint, a casing joint, a tool joint, or a wireline, in which a BOP in accordance with the present disclosure may be used to shear each of these different types of objects. These objects may be sheared with or without replacement of any ram of the BOP, i.e., a single ram, or a pair of opposing rams, may be used to shear multiple objects in succession. To aid the ram in shearing multiple objects in succession, the present disclosure provides for an engagement feature to help urge the ram body (e.g., axially) to improve axial engagement with an opposing ram.

Referring now to FIGS. 2-7, multiple views of opposing shear rams 202 and 204 for a shear ram BOP in accordance with one or more embodiments of the present disclosure are shown. In particular, FIG. 2 provides a side perspective view of the shear rams 202 and 204, and FIG. 3 provides a top down view of the shear rams 202 and 204. Further, FIG. 4 shows a cross-sectional view of the shear rams 202 and 204 taken along line 4-4 in FIG. 2, FIG. 5 shows a detailed view of the engagement of the shear rams 202 and 204 in FIG. 4, FIG. 6 shows a cross-sectional view of the shear rams 202 and 204 taken along line 6-6 in FIG. 2, and FIG. 7 shows a detailed view of the engagement of the shear rams 202 and 204 in FIG. 5. The shear rams 202 and 204 may be similar to the rams 24 and 26 illustrated in FIGS. 1A-1C, in which the shear ram 202 may be the upper ram and the shear ram 204 may be the lower ram.

The shear rams 202 and 204 each include a ram body 206 and 208 that are defined by a ram back 210 and 212 and a ram front 214 and 216, respectively. The ram backs 210 and 212 are generally configured to receive a connector rod (not shown), such as the rod 34 shown in FIGS. 1A-1C, to move the shear rams 202 and 204 into and out of a BOP bore. The ram fronts 214 and 216 each include a cutting face or blade 218 and 220, respectively, configured to shear an object located in a BOP bore. The blade 218 of the upper shear ram 202 is best shown in FIG. 3, and the blades 218 and 220 of the shear rams 202 and 204 are also shown in FIG. 6.

The shear rams 202 and 204 may further include one or more seals to facilitate sealing the BOP bore. For example, the rams 202 and 204 may each include a top seal 222 and 224 and side seals 226 and 228, respectively. The seals 222-228 may be positioned within cavities or channels formed within the ram bodies 206 and 208 to maintain the seals 222-228 in position as the rams 202 and 204 move within the BOP body.

Further, a seal 250 (e.g., lateral seal), as best shown in FIGS. 4,6, and 7, may be positioned between the blades 218 and 220 of the shear rams 202 and 204. A recess 252 may be formed within one of the shear rams 202 and 204, with the seal 250 positioned within the recess 252.

One or both of the shear rams 202 and 204 may further include an engagement feature 230 and 232, such as located on an outer surface of the ram bodies 206 and 208, to urge one or both of the shear rams 202 and 204 axially when positioned within the bore of a BOP. In one or more embodiments, the engagement feature may refer to or include a tapered or angled portion that is used to engage with another component, surface, or corresponding engagement feature. The engagement of the tapered or angled portions upon closing of the shear rams 202 and 204 urges the shear rams axially (e.g., with respect to an axis of a bore of a BOP housing), such as towards and into engagement with each other. Engagement of the engagement features 230 and 232 also restricts separation of the shear rams 202 and 204 to facilitate sealing and/or shearing within the shear ram BOP.

As shown in FIGS. 2-7, both shear rams 202 and 204 may include engagement features 230 and 232. As the shear rams 202 and 204 move from an open position to a closed position, the engagement features 230 and 232 engage with each other. The engagement of the engagement features 230 and 232 with each other urges the shear rams 202 and 204 axially towards each other and into axial engagement with each other when the shear rams 202 and 204 are located in the BOP bore. The engagement features 230 and 232 may also not engage each other until after an object within the BOP bore has been sheared by the shear rams 202 and 204.

Accordingly, an engagement feature in accordance with the present disclosure may facilitate or increase the sealing capability within a shear ram BOP. As mentioned above, the seal 250 may be used to prevent fluid flow or debris from flow between the shear rams 202 and 204, particularly when the shear rams 202 and 204 are in the closed position after having sheared an object within the shear ram BOP. The engagement features 230 and 232 engage each other after the blades 218 and 220 of the shear rams 202 and 204 pass each other and the seal 250 when moving into the closed position. This engagement of the engagement features 230 and 232 urges the shear rams 202 and 204 into axial engagement with each other, which in turn then activates or further pressurizes the seal 250 with the shear rams 202 and 204. This axial engagement of the shear rams 202 and 204 may increase the sealing capability of the seal 250. Further, this delayed engagement of the engagement features 230 and 232 may help prevent damage to the seal 250, such as from the blades 218 and 220 potentially clipping or cutting the seal 250 when passing across each other and the seal 250.

In one or more embodiments in which the shear rams 202 and 204 include corresponding engagement features 230 and 232, one of the shear rams 202 and 204 may include a female engagement feature, and the other of the shear rams 202 and 204 may include a male engagement feature. For example, as shown best in FIGS. 4 and 5, the shear ram 202 includes the female engagement feature 230 and the shear ram 204 includes the male engagement feature 232. The engagement feature shown in FIGS. 4 and 5 includes a cone-shape (e.g., conical or frusto-conical shape) that forms a portion or surface of the engagement feature. Accordingly, in this embodiment, the female engagement feature 230 of the shear ram 202 is a conical shaped engagement feature that protrudes into a surface of the shear ram 202, and the male engagement feature 232 of the shear ram 204 is a conical shaped engagement feature that protrudes from a surface of the shear ram 204. The conical shaped engagement features then engage each other when the shear rams 202 and 204 are moving into the closed position to urge the shear rams 202 and 204 axially towards each other.

In one or more of the above embodiments, the engagement features are shown as conical shaped engagement features. However, the present disclosure is not so limited, as other shapes, sizes, and arrangements may be used for an engagement feature in one or more embodiments. For example, in another embodiment, the engagement feature may only include a tapered or angled surface, in which the tapered or angled surface engages with another surface (e.g., tapered or not-tapered) to urge the shear ram axially within the shear ram BOP.

Further, in one or more embodiments, to facilitate the engagement and urging of the shear rams 202 and 204 axially towards each other, the engagement features 230 and 232 may be offset from each other. For example, as shown in FIG. 5, an apex 234 of the conical shaped female engagement feature 230 is offset from an apex 236 of the conical shaped male engagement feature 232. The apex 234 of the conical shaped female engagement feature 230 may be offset by about 0.02 in (about 0.51 mm) from the apex 236 of the conical shaped male engagement feature 232. Accordingly, as the engagement features 230 and 232 are offset from each other, the offset facilitates engagement between the engagement features 230 and 232 as the shear rams 202 and 204 move axially towards and in proximity of each other, thereby urging the shear rams 202 and 204 axially towards each other.

The engagement features 230 and 232 may be formed on or coupled to the shear rams 202 and 204. As shown in FIGS. 4 and 5, the engagement features 230 and 232 are formed on the bodies 206 and 208 of the shear rams 202 and 204. However, in another embodiment, the engagement features 230 and 232 may be formed as separate components that are connected, attached, or otherwise coupled to the bodies 206 and 208 of the shear rams 202 and 204. This may facilitate replacing the engagement features 230 and 232, such as if the engagement features 230 and 232 become excessively worn or damaged. Further, the engagement features 230 and 232 may include or be formed from a hardened material. In one embodiment, the engagement features 230 and 232 may be heat-treated to harden and otherwise treat the material of the engagement features 230 and 232.

The shear rams 202 and 204 may each include more than one engagement feature. Further, as mentioned above, the engagement features 230 and 232 are located on an outer surface of the ram bodies 206 and 208 of the shear rams 202 and 204. Accordingly, in one or more embodiments, the engagement features 230 and 232 are formed or located on opposing (e.g., inner) faces of the shear rams 202 and 204. The shear rams 202 and 204 may each include an upper face 240 and 242 and a lower face 244 and 246, respectively, in which the upper faces 240 and 242 may oppose each other and the lower faces 244 and 246 may oppose each other. The upper faces 240 and 242 of the shear rams 202 and 204 then each include corresponding upper engagement features 230 and 232 that engage with each other, and the lower faces 244 and 246 include corresponding lower engagement features 230 and 232 that engage with each other.

The shear rams 202 and 204 may also include multiple engagement features on opposite lateral sides (e.g., left and ride sides) of the ram bodies 206 and 208. For example, the shear ram 202 may include engagement features 230 positioned on each side of the blade 218 such that the engagement features 230 are positioned adjacent each lateral side of the shear ram 202. Similarly, the shear ram 204 may include engagement features 232 positioned on each side of the blade 220 such that the engagement features 232 are positioned adjacent each lateral side of the shear ram 204. The engagement features 230 of the shear ram 202 may then engage with the engagement features 232 of the shear ram 204.

As mentioned above, the shear rams 202 and 204 are movable between an open position and a closed position, in which the shear rams 202 and 204 may then shear an object positioned between them or within a BOP bore when moving from the open positioned to the closed position. Accordingly, the engagement features 230 and 232 of the shear rams 202 and 204 may be used to urge the shear rams 202 and 204 into axial engagement with each other when in the closed position. For example, when in the open position, the engagement features 230 and 232 will not engage each other, and thus not urge the shear rams 202 and 204 into axial engagement with each other. However, when in the closed position, or closely approaching the closed position, the engagement features 230 and 232 engage each other to urge the shear rams 202 and 204 into axial engagement with each other. This urges the shear rams 202 and 204 into axial engagement with each other, particularly after shearing an object, and increases the sealing capability of the seal 250 between the shear rams 202 and 204.

In one or more of the above embodiments, the engagement features are shown as formed on each of the shear rams. However, in one or more embodiments, only one of the shear rams may include an engagement feature. For example, in such an embodiment, the BOP housing may include a corresponding engagement feature, such as formed internally within the BOP and adjacent the BOP bore. The shear ram engagement feature may then engage with the BOP engagement feature, such as when the shear ram moves towards the closed position within the BOP housing. This engagement may then urge the shear ram within the BOP housing, such as axially within the BOP housing to facilitate sealing or shearing within the BOP.

As discussed above, a ram and a BOP in accordance with the present disclosure may be used to shear one or more objects, including a casing joint, a drill pipe joint, a tool joint, and a wireline, with each having various shapes, sizes, and/or other dimensions. A casing joint may have one or more sizes, such as an outer diameter of about 16 inches (about 40.6 centimeters), about 14 inches (about 35.6 centimeters), about 12 inches (about 30.5 centimeters), and/or about 10.625 inches (about 26.99 centimeters). Further, a drill pipe joint may have one or more sizes, such as an outer diameter of about 6.625 inches (about 16.83 centimeters), about 5.5 inches (about 14.0 centimeters), and/or about 3.5 inches (about 8.9 centimeters). Moreover, wireline may have one or more sizes, such as an outer diameter of about 3/16 inches (about 0.47 centimeters), about 0.25 inches (about 0.64 centimeters), about 0.5 inches (about 1.28 centimeters), and so on. As such, rams and ram blades of different sizes may be selected to shear on a particular object. Inclusion of a biasing mechanism as discussed above may enhance sealing efficiency in a shear ram BOP, particularly after having sheared an object.

This discussion is directed to various embodiments of the invention. The drawing figures are not necessarily to scale. Certain features of the 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. Although one or more of these embodiments may be preferred, the embodiments disclosed should not be interpreted, or otherwise used, as limiting the scope of the disclosure, including the claims. It is to be fully recognized that the different teachings of the embodiments discussed may be employed separately or in any suitable combination to produce desired results. In addition, one skilled in the art will understand that the description has broad application, and the discussion of any embodiment is meant only to be exemplary of that embodiment, and not intended to suggest that the scope of the disclosure, including the claims, is limited to that embodiment.

Certain terms are used throughout the description and claims to refer to particular features or components. As one skilled in the art will appreciate, different persons may refer to the same feature or component by different names. This document does not intend to distinguish between components or features that differ in name but not function, unless specifically stated. In the 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 . . . .” Also, the term “couple” or “couples” is intended to mean either an indirect or direct connection. In addition, the terms “axial” and “axially” generally mean along or parallel to a central axis (e.g., central axis of a body or a port), while the terms “radial” and “radially” generally mean perpendicular to the central axis. The use of “top,” “bottom,” “above,” “below,” and variations of these terms is made for convenience, but does not require any particular orientation of the components.

Reference throughout this specification to “one embodiment,” “an embodiment,” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present disclosure. Thus, appearances of the phrases “in one embodiment,” “in an embodiment,” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.

Although the present invention has been described with respect to specific details, it is not intended that such details should be regarded as limitations on the scope of the invention, except to the extent that they are included in the accompanying claims.

Claims

1. A blowout preventer (“BOP”), comprising:

a housing comprising a vertical bore extending through the housing; and

a pair of opposing shear rams configured to move into the vertical bore, the shear rams comprising an engagement feature configured to engage with a corresponding engagement feature and urge the shear rams into axially towards each other with respect to an axis of the vertical bore when the shear rams are located in the vertical bore.

2. The BOP of claim 1, further comprising a seal positioned between the opposing rams and configured to prevent fluid flow therebetween.

3. The BOP of claim 2, wherein the axial movement of the shear rams towards each other increases the sealing capability of the seal.

4. The BOP of claim 2, wherein the seal comprises a lateral seal positioned between blades of the shear rams.

5. The BOP of claim 1, wherein:

the pair of opposing shear rams are movable between an open position and a closed position; and

the engagement features are configured to urge the shear rams axially towards each other when the shear rams are in the closed position.

6. The BOP of claim 1, wherein:

one of the shear rams comprises a male engagement feature; and

the other of the shear rams comprises a female engagement feature.

7. The BOP of claim 6, wherein:

the male engagement feature comprises a conical shaped male engagement feature protruding from a surface of the shear ram; and

the female engagement feature comprises a corresponding conical shaped female engagement feature protruding into a surface of the shear ram.

8. The BOP of claim 7, wherein an apex of the conical shaped male engagement feature is offset from an apex of the conical shaped female engagement feature.

9. The BOP of claim 8, wherein the engagement features each comprise a tapered engagement feature.

10. The BOP of claim 1, wherein the engagement features are formed on opposing inner faces of the shear rams.

11. The BOP of claim 1, wherein each shear ram comprises a plurality of engagement features.

12. The BOP of claim 11, wherein:

the shear rams comprise opposing upper faces and opposing lower faces;

one of the upper faces comprises an upper engagement feature and the other of the upper faces comprises a corresponding upper engagement feature; and

one of the lower faces comprises a lower engagement feature and the other of the lower faces comprises a corresponding lower engagement feature.

13. The BOP of claim 1, wherein the engagement features each comprise a hardened material compared to the shear rams.

14. A shear ram positionable in a blowout preventer (“BOP”) body to move into a vertical bore of the BOP body, the shear ram comprising:

a ram body including a shear blade configured to shear an object; and

an engagement feature configured to urge the ram body axially with respect to an axis of the vertical bore when positioned within the vertical bore of the BOP body.

15. The shear ram of claim 14, wherein the engagement feature is further configured to urge the shear ram axially towards an opposing shear ram.

16. The shear ram of claim 15, further comprising a seal positioned between the opposing rams to prevent fluid flow therebetween such that the axial movements of the shear rams towards each other increases the sealing capability of the seal.

17. The shear ram of claim 15, wherein the opposing shear ram comprises a corresponding engagement feature such that the engagement features are configured to engage with each other and urge the shear rams axially towards each other.

18. The shear ram of claim 17, wherein:

one of the shear rams comprises a male engagement feature; and

the other of the shear rams comprises a female engagement feature.

19. The shear ram of claim 17, wherein the engagement features of the shear rams are offset from each other.

20. The shear ram of claim 17, wherein the engagement features are formed on opposing inner faces of the shear rams.