TELESCOPIC JOINT WITH INTERCHANGEABLE INNER BARREL(S)

Abstract

Embodiments disclosed herein relate to an apparatus including a first inner barrel of a telescopic marine riser and a first locking mechanism to releasably lock an upper end of the first inner barrel to the telescopic marine riser or a second inner barrel. In another aspect, embodiments disclosed herein relate to a method including assembling a telescopic marine riser, replacing at least one inner barrel of a telescoping marine riser with a corresponding replacement inner barrel of a different length, and reassembling the telescoping marine riser with the replacement inner barrel.

Description

BACKGROUND

Drilling, production and completion of offshore wells from a floating platform, e.g., a vessel, tension leg platform, etc., is conducted through a riser assembly which extends from the platform to the wellhead on the sea floor. The riser assembly includes a series of pipe sections or barrels connected end to end. Marine drilling risers provide a conduit through which materials may flow between a platform and a wellbore. While the platform from which the wellbore activities are being conducted is maintained as nearly as possible in a fixed position above the wellhead, there is some variation in this relationship, such that there is relative lateral and vertical shifting between the platform and the wellbore. Accordingly, the riser assembly accommodates this relative movement between the platform and the wellhead as well as forces acting on the riser assembly from waves, currents and the like.

FIG. 1 shows a conventional marine drilling system having an outer barrel 16 of a telescoping riser section whose lower end is coupled to the top of a fixed length of riser (not shown) that extends to a subsea wellhead (not shown). The telescoping riser section is supported by a tension ring 20 coupled to the outer barrel 16. The tension ring 20 is a type of buoyancy component for supporting at least part of the weight of the telescoping riser once connected to a well head and to put tension on the riser. The tension ring 20 is coupled to the outer barrel 16 and includes cables (not shown) that extend to the floating drilling platform 11 in order to transfer some of the buoyancy thereof to the tension ring 20 to support at least part of the weight of the telescoping riser in the body of water. An inner barrel 14 slidably, sealingly engages the interior of the outer barrel 16. Specifically, a connector, for example a packing element 18 may be slidably engaged with the inner barrel 14. A lower end of the packing element 18 is permanently coupled to an upper end of the outer barrel 16. Thus, the length of the riser may be changed in order to compensate for heave of the drilling platform 11. The riser may also be moved laterally to compensate for lateral motion of the drilling platform 11. The upper end of the inner barrel 14 is permanently coupled to a flange 17. The flange 17 allows the telescoping riser section to easily connect to a flex joint 12 and a diverter 10, disposed at the top of the marine riser.

Currently, in the art, if the length of the telescopic riser is to be shortened, the inner barrel 14 is cut to remove from flange 17 and the cut section of the inner barrel 14 is removed to adjust the length. The remaining sections of the inner barrel are welded together to bring the length of the inner barrel to the desired length. If it is desired to lengthen the inner barrel, the inner barrel may be cut into two sections and a tubular section having the same characteristics (i.e. inner and outer diameters) as the inner barrel may be welded between the two sections of the cut inner barrel.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows an example embodiment of a marine drilling system using a riser;

FIG. 2 shows an example embodiment of a marine drilling system according to the present disclosure;

FIGS. 3-5 show example embodiments of locking mechanisms according to the present disclosure.

DETAILED DESCRIPTION

A riser assembly comprises a series of pipe sections or telescoping barrels connected end to end. In one aspect, embodiments disclosed herein relate to an apparatus and method for changing the length of a telescopic marine riser without physically damaging the barrels (e.g., cutting and/or welding). Specifically, embodiments disclosed herein provide a telescopic marine riser having interchangeable barrels.

In one aspect, embodiments disclosed herein relate to an apparatus having a first inner barrel of a telescopic marine riser and a first locking mechanism to releasably lock an upper end of the first inner barrel to the telescopic marine riser or a second inner barrel.

In another aspect, embodiments disclosed herein relate to an apparatus having an outer barrel of a telescopic marine riser, a first inner barrel slidingly engaged with the outer barrel, a first connector coupled to an upper end of the outer barrel, wherein the first inner barrel is slidingly engaged with the first connector, and a first locking mechanism coupled to a lower end of at least one of a first flange or a second connector, the first locking mechanism configured to receive an upper end of the first inner barrel and releasably lock the first inner barrel to a top portion of the marine riser or a second inner barrel.

In another aspect, embodiments disclosed herein relate to a method that includes coupling a first locking mechanism to a first connector or a marine riser; and releasably locking an upper end of a first inner barrel to the first locking mechanism. The method may further include coupling a lower flange to a lower end of an outer barrel of a marine riser, pre-assembling a first inner barrel by slidingly engaging the first inner barrel to a first connector to form a pre-assembled first inner barrel, coupling a lower end of the first connector to an upper end of the outer barrel, wherein the pre-assembled first inner barrel is slidingly engaged with the outer barrel, and locking an upper end of the first inner barrel to a first locking mechanism, wherein the first locking mechanism is coupled to a lower end of at least one of an upper flange coupled to a top portion of the marine riser, or a second connector slidingly engaged with a second inner barrel.

In another aspect, embodiments disclosed herein relate to a method, the method includes assembling a telescopic marine riser, replacing at least one inner barrel of a telescoping marine riser with a corresponding replacement inner barrel of a different length, and reassembling the telescoping marine riser with the replacement inner barrel.

A telescopic riser 100 section according to the present disclosure is shown schematically in FIG. 2. As used herein, the term “telescopic riser” and “telescopic marine riser” are used interchangeably to refer to a portion of a marine riser assembly having telescoping barrels. FIG. 2 does not show all components of the marine riser assembly, such as the drilling platform or the diverter for clarity of the illustration. The telescopic riser 100 includes an outer barrel 116, and two inner barrels 114-1 and 114-2. In other embodiments, the telescopic riser 100 may include one outer barrel and more than two inner barrels. Each inner barrel 114-1, 114-2 is slidingly engaged with a connector 118-1 and 118-2, such that first inner barrel 114-1 is slidingly engaged with first connector 118-1 and second inner barrel 114-2 is slidingly engaged with second connector 118-2, i.e. the position of the connectors 118 along the respective inner barrel may change. Connector 118-1 may be coupled to an upper end of second inner barrel 114-2 and connector 118-2 may be coupled to an upper end of outer barrel 116. As shown, the first and second connectors 118-1, 118-2 are positioned at a lower end of first and second inner barrels 114-1, 114-2, respectively. However, one of ordinary skill in the art will appreciate that because the connectors are slidingly engaged with the inner barrels, the connectors may be positioned at an upper end of the inner barrels in other configurations. According to some embodiments, the connector may be a packing element. Each of the outer barrel 116 and inner barrels 114-1, 114-2 are arranged end-to-end, such that the first inner barrel 114-1 is slidingly engaged with the second inner barrel 114-2 and the second inner barrel 114-2 is slidingly engaged with the outer barrel 116.

As seen in FIG. 2, first inner barrel 114-1 is coupled to a lower end of upper flange 117. The upper flange 117 allows a connection between the telescopic riser 100 and a top portion of the marine riser assembly (not shown) including, for example, a flex joint, a diverter, and a drilling platform. A first locking mechanism 121-1 may be coupled to a lower end of upper flange 117. The first locking mechanism 121-1 may be permanently coupled to the lower end of the upper flange 117 by, for example, welding or machining from a single integral piece. In some embodiments, the upper flange 117 may be integrally formed with the locking mechanism 121-1. The first inner barrel 114-1 may be releasably locked to the upper flange 117 with the first locking mechanism 121-1.

Still referring to FIG. 2, the first connector 118-1 may be slidingly engaged with the first inner barrel 114-1; in other words, the first connector 118-1 may slide along the length of first inner barrel 114-1. The first connector 118-1 includes a second locking mechanism 121-2 disposed at a lower end thereof. The second locking mechanism 121-2 may be permanently coupled to or integrally formed with the first connector 118-1. The second locking mechanism 121-2 may receive an upper end of the second inner barrel 114-2, such that the second inner barrel 114-2 is releasably locked to the second locking mechanism 121-2 of the first connector 118-1. Because the first connector 118-1 is releasably locked to an upper end of the second inner barrel 114-2, the first inner barrel 114-1 is also slidingly engaged with the second inner barrel 114-2. In other words, as first connector 118-1, second locking mechanism 121-2, and second inner barrel 114-2 slide along the length of the first inner barrel 114-1, the inner barrel 114-1 may fit within and stroke in and out of the second inner barrel 114-2.

The second inner barrel 114-2 may be slidingly engaged with a second connector 118-2. According to the embodiment shown in FIG. 2, a third locking mechanism 121-3 may be permanently coupled to or formed integrally with the second connector at a lower end thereof. The third locking mechanism 121-3 may receive an upper end of the outer barrel 116, such that the outer barrel 116 is releasably locked to the third locking mechanism of the second connector 118-2. Because the second connector 118-2 is releasably fixed to an upper end of the outer barrel 116, the second inner barrel 114-2 is also slidingly engaged with the outer barrel 116. In other words, as second connector 118-2, third locking mechanism 121-3, and outer barrel 116 slide along the length of the second inner barrel 114-2, the second inner barrel 114-2 may fit within and stroke in and out of the outer barrel 116. In some embodiments, the bottommost barrel, the outer barrel 116, may be coupled to a lower flange 115. The lower flange 115 is provided to allow a connection between the telescopic riser 100 and a bottom portion of the marine riser assembly, including for example, a fixed length riser, and the wellbore.

According to some embodiments, the telescopic marine riser may include any number of inner barrels. For example, the telescopic marine riser may include a first inner barrel slidingly engaged with the outer barrel, where an upper end of the first inner barrel is releasably locked to a first locking mechanism, where the first locking mechanism is coupled to a lower end of an upper flange, which is coupled to a top portion of the marine riser (not shown). According to other embodiments, three or four inner barrels may be included in the telescopic riser 100 and connected as described above with respect to FIG. 2, such that the uppermost inner barrel is engaged with the locking mechanism of the upper flange and the bottommost barrel or outer barrel is engaged with the lower flange. One having ordinary skill in the art will understand that more than four inner barrels may be included in the telescopic marine riser without departing from the scope of the present disclosure.

The locking mechanisms 121 of the telescopic riser 100 are substantially tubular members that may be coupled to a lower end of an upper flange 117 and/or a lower end of a packing element 118, for example, connectors 118-1 and 118-2. The locking mechanisms 121 may be permanently coupled, for example, welded or integrally formed, with a lower end of an upper flange 117 and/or a lower end of a packing element 118. Referring to FIGS. 3-5, each locking mechanism 121 includes a body 128 and a releasable mechanical fastener, for example internal threads (FIG. 3), a plurality of screw receiving apertures 122 (FIG. 4), or a plurality of slots 124 to provide a releasable locked connection (FIG. 5). The upper end of the corresponding inner barrel 114 or outer barrel 116 includes a complementing mating mechanical fastener, for example, external threads (FIG. 3), a plurality of screw receiving apertures 122 (FIG. 4), and a plurality of protrusions corresponding to the plurality of slots 124 of the locking mechanism 121 (FIG. 5). One having ordinary skill in the art will appreciate that the locking mechanism may use other mechanical fasteners without departing from the scope of this disclosure.

Referring to FIG. 3, the locking mechanism 121 may include internal threads 125 formed on the body 128 of the locking mechanism 121, and the upper end of the inner barrel 114 may have corresponding external threads 125 configured to engage the internal threads. In order to secure the inner barrel 114 to the upper flange 117 or connector 118, the inner barrel 114 may be inserted in the locking mechanism 121, and rotated to tighten the threaded connection. In order to release the connection, the inner barrel 114 may be rotated in the opposite direction relative to the locking mechanism 121 to loosen the threaded connection.

Referring to FIG. 4, the locking mechanism 121 may have a plurality of screw receiving apertures 122-1 in a wall of the body 128 of the locking mechanism 121, and the upper end of the inner barrel 114 may also have a plurality of screw receiving apertures 122-2 configured to align with the screw receiving apertures 122-1. In order to secure the inner barrel 114 to the locking mechanism 121 of the upper flange 117 or connector 118, each of the screw receiving apertures 122 of the inner barrel 114 and the locking mechanism 121 may be aligned and a screw (not shown) may then be inserted into each of the aligned screw receiving apertures 122 to lock the inner barrel 114 to the locking mechanism 121 of the upper flange 117 or connector 118. In order to release the connection, the screws may be removed from the screw receiving apertures 122. One of ordinary skill in the art will appreciate that other mechanical fasteners, such as bolts, pins, etc. may be used with the screw receiving apertures.

Referring to FIG. 5, the locking mechanism 121 may have a plurality of slots 124 disposed on a lower edge of the body 128 of the locking mechanism 121, and the upper end of the inner barrel 114 may have a plurality of protrusions 126 corresponding to the plurality of slots 124. The plurality of slots 124 may be disposed in a wall of the lower end of the body 128. According to some embodiments, the plurality of protrusions 126 may be spring loaded. In order to secure the inner barrel 114 to the locking mechanism 121 of the upper flange 117 or connector 118, the slots 124 of the locking mechanism 121 may be aligned with the protrusions 126 of the inner barrel 114. The protrusions 126 may then be inserted into the slots 124 and secured into place, thereby releasably locking the inner barrel 114 to the upper flange 117. According to some embodiments the inner barrel 114 may be rotated with respect to the locking mechanism 121 to release the spring loaded protrusions 126 and secure the locked connection. In order to release the connection, the inner barrel 114 may be rotated in the opposite direction, thereby compressing the spring loaded protrusions 126, and the inner barrel 114 may continue to be rotated following the path of slots 124 until the inner barrel 114 is disengaged from the locking mechanism 121.

Although the above examples are described with respect to the locking mechanism 121 and the inner barrel 114, one having ordinary skill in the art would understand that any of the above examples may be implemented with any combination of locking mechanisms and barrels.

Assembly of the telescopic marine riser as described with respect to FIG. 2 may include pre-assembly of the first inner barrel 114-1 to a first connector 118-1 to form a pre-assembled first inner barrel. Once the first inner barrel 114-1 is pre-assembled, the first connector 118-1 may be slidingly engaged with the first inner barrel 114-1. In other words, the first connector 118-1 may be able to slide along the length of the first inner barrel. In embodiments where the second locking mechanism 121-2 is permanently coupled to the first connector 118-1, the locking mechanism 121-2 may be permanently coupled to the first connector 118-1 prior to pre-assembly of the first inner barrel 114-1. In other words, the pre-assembled first inner barrel 114-1 may be slidingly engaged with the first connector 118-1 having a second locking mechanism 121-2 coupled thereto.

Pre-assembly may be repeated for the second inner barrel 114-2 and the second connector 118-2 to form a pre-assembled second inner barrel. One having ordinary skill in the art will understand that pre-assembly of the second inner barrel 114-2 (i.e. a barrel disposed lower on the telescopic marine riser than the first inner barrel 114-1) to the second connector 118-2 may be performed prior to assembly of the first inner barrel without departing from the scope of the present disclosure. According to embodiments having more than two inner barrels, pre-assembly may be completed for each inner barrel. For embodiments having a single inner barrel, pre-assembly may be completed for the first inner barrel.

Once pre-assembly of at least the bottommost inner barrel, for example, the second inner barrel 114-2 is completed, a lower end of the second connector 118-2 may be coupled to an upper end of the outer barrel 116. This allows the second inner barrel 114-2 to be slidably engaged within the outer barrel 116. According to some embodiments, a locking mechanism 121-3 may be disposed at a lower end of second connector 118-2, such that the second connector 118-2 is releasably locked to the outer barrel 116 according to the examples provided above with respect to FIGS. 3-5.

The upper end of the second inner barrel 114-2 may be coupled to the first connector 118-1 (which is pre-assembled to the inner barrel 114-1). This allows the first inner barrel 114-1 to be slidably engaged with the second inner barrel 114-2. As shown in FIG. 2, the second locking mechanism 121-2 is disposed at a lower end of the first connector 118-1. The upper end of the second inner barrel 114-2 may be releasably locked to the second locking mechanism 121-2 according to the examples provided above with respect to FIGS. 3-5.

The upper end of the first inner barrel 114-1 may be coupled to a lower end of the upper flange 117. As shown in FIG. 2, the first locking mechanism 121-1 is disposed at a lower end of the upper flange 117. The upper end of the first inner barrel 114-1 may be releasably locked to the first locking mechanism 121-1 according to the examples provided above. Although the above described method of assembly is presented in a particular order, one having ordinary skill in the art will understand that assembly of the telescopic riser 100 may be completed even if the steps are performed out of the order presented above.

Once a telescopic drilling riser has been assembled, the assembled telescopic drilling riser may be used at a drill site. According to some embodiments, it may be desirable to change the length of the outer barrel 116 and/or inner barrels 114-1, 114-2 of the telescopic drilling riser, for example, if the requirements of the drill site change or the telescopic marine riser is relocated to a new drill site. Thus, at least one inner barrel of the telescopic marine riser may be replaced with a corresponding replacement inner barrel of a different length. Then the telescopic marine riser may be reassembled with the replacement inner barrel.

In order to replace at least one inner barrel of the telescopic marine riser, the original telescopic marine riser may be disconnected from the marine riser assembly and pulled to the surface for disassembly. The number of original barrels to replace as well as the number and length of the replacement inner barrels to be included in the telescopic riser 100 may be determined based on the new requirements of, for example, a new drill site. The term “replacement inner barrel” as used herein describes an inner barrel that was not a part of the original telescopic marine riser assembly, in other words a replacement inner barrel is structurally similar to the inner barrels 114 described above but a replacement inner barrel may have a different length. For example, if the distance between the surface of the water and the wellhead of the wellbore is greater than the original drill site, longer replacement barrels may be selected, an additional inner barrel may be added or a combination of longer barrels and an additional inner barrel may be used. If the distance between the surface of the water and the wellhead of the wellbore is less than the original drill site, shorter replacement barrels may be selected or an inner barrel may be removed from the original telescopic marine riser assembly. Once the number of inner barrels to replace has been determined, said inner barrels may be unlocked from the locking mechanism and removed from the original telescopic marine riser assembly as described with respect to FIGS. 3-5 above.

The new telescopic marine riser may be assembled with the replacement inner barrels. Pre-assembly of the determined number of replacement barrels may be performed by slidingly engaging a first replacement barrel to a first connector to form a first pre-assembled replacement inner barrel. Once the determined number of replacement barrels has been pre-assembled, the first connector of the first pre-assembled replacement barrel may be coupled to the outer barrel of the existing telescopic marine riser assembly. According to some embodiments, not all of the inner barrels of the original telescopic riser 100 are replaced, therefore, the first pre-assembled replacement barrel may be coupled to an existing inner barrel of the original telescopic marine riser. The first connector may include a first locking mechanism at a lower end. Thus, the inner barrel or outer barrel of the original telescopic riser 100 may be removably locked to the first connector of the first replacement inner barrel. Coupling a connector to the telescopic riser 100 assembly and locking said connector to the telescopic riser 100 assembly may be repeated for the determined number of inner barrels. The uppermost pre-assembled replacement inner barrel may be coupled to an upper flange. Although the above described method of assembly has been described in a particular order, one having ordinary skill in the art will understand that assembly of the telescopic marine riser with the replacement inner barrels may be completed even if the steps are performed out of the order presented above.

Although the preceding description has been described herein with reference to particular means, materials and embodiments, it is not intended to be limited to the particulars disclosed herein. Rather, it extends to all functionally equivalent structures, methods and uses, such as are within the scope of the appended claims.

Claims

1. An apparatus comprising: a first inner barrel of a telescopic marine riser; anda first locking mechanism to releasably lock an upper end of the first inner barrel to the telescopic marine riser or a second inner barrel.

2. The apparatus of claim 1, wherein the first locking mechanism releasably locks the first inner barrel to a first flange coupled to the telescopic marine riser.

3. The apparatus of claim 1, wherein the first locking mechanism releasably locks the first inner barrel to a first connector, the first connector slidingly engaged with the second inner barrel.

4. The apparatus of claim 3, wherein the second inner barrel is slidingly engaged with the first inner barrel.

5. The apparatus of claim 3, further comprising a second locking mechanism, wherein the second locking mechanism releasably locks an upper end of the second inner barrel to a first flange coupled to the top portion of the telescopic marine riser.

6. The apparatus of claim 1, further comprising: an outer barrel slidingly engaged with the inner barrel; anda second connector coupled to an upper end of the outer barrel, wherein the first inner barrel is slidingly engaged with the second connector.

7. The apparatus of claim 1, wherein the first locking mechanism is a tubular member, wherein a lower end of the tubular member includes one selected from a group consisting of internal threads, a screw receiving apertures, and a plurality of slots.

8. The apparatus of claim 7, wherein the upper end of the first inner barrel includes one selected from a group consisting of external threads, a plurality of screw receiving apertures, and a plurality of protrusions corresponding to the plurality of slots of the first locking mechanism.

9. The apparatus of claim 1, further comprising a plurality of inner barrels each slidingly engaged to a corresponding connector, wherein the an upper end of an uppermost inner barrel is engaged with a first flange of the telescoping marine riser and an upper end of each remaining inner barrel is engaged with a connector disposed between each remaining inner barrel.

10. A method comprising: coupling a first locking mechanism to a first connector or a marine riser; andlocking releasably an upper end of a first inner barrel to the first locking mechanism.

11. The method of claim 10, wherein the locking comprises threadably engaging the upper end of the first barrel to the first locking mechanism.

12. The method of claim 10, wherein the locking comprises aligning a plurality of apertures disposed on the first locking mechanism with a plurality of apertures disposed on the upper end of the first inner barrel and securing the first locking mechanism to the first inner barrel by disposing a mechanical fastener in at least one of the aligned plurality of apertures.

13. The method of claim 10, wherein the locking comprises sliding a plurality of protrusions disposed on an outer diameter of the upper end of the first inner barrel into a corresponding plurality of slots disposed on the first locking mechanism.

14. The method of claim 10, further comprising: pre-assembling the first inner barrel by slidingly engaging the first inner barrel to a second connector to form a pre-assembled first inner barrel; andcoupling a lower end of the second connector to an upper end of an outer barrel, wherein the first inner barrel is slidingly engaged with the outer barrel.

15. The method of claim 10, wherein the first locking mechanism is coupled to the first connector, the method further comprising: pre-assembling a second inner barrel by slidingly engaging the second inner barrel to the first connector to form a pre-assembled second inner barrel; andlocking an upper end of the second inner barrel to a second locking mechanism, wherein the second locking mechanism is coupled to an upper flange of the marine riser.

16. A method comprising: assembling a telescopic marine riser;replacing at least one inner barrel of a telescoping marine riser with a corresponding replacement inner barrel of a different length; andreassembling the telescoping marine riser with the replacement inner barrel.

17. The method of claim 16, wherein the replacing comprises: determining a number of inner barrels to replace from the original marine riser assembly;unlocking a first inner barrel from an upper flange; andrepeating the unlocking for the determined number of inner barrels.

18. The method of 16, wherein the reassembling comprises: pre-assembling the determined number of replacement inner barrels by slidingly engaging a first replacement inner barrel to a first connector to form a first pre-assembled replacement inner barrel;coupling the first connector of the first pre-assembled replacement inner barrel to at least one of an upper end of an outer barrel or an upper end of a pre-assembled inner barrel;locking an upper end of the first pre-assembled replacement inner barrel to a first locking mechanism, wherein the first locking mechanism is coupled to a second connector of a second pre-assembled inner barrel; andrepeating the coupling and locking the upper end of a pre-assembled replacement inner barrel to a corresponding locking mechanism for the determined number of replacement inner barrels, wherein an uppermost pre-assembled replacement inner barrel is locked to a first flange.

19. The method of claim 16, wherein at least two inner barrels of the telescoping marine riser are replaced.

20. The method of claim 16, wherein a length of the replacement inner barrel is determined based on the requirements of a new drilling location.