US20200032607A1

US20200032607A1 - Well reentry

Info

Publication number: US20200032607A1
Application number: US16/518,209
Authority: US
Inventors: Christopher Scott Stewart; Thomas Strenger Proehl
Original assignee: Ensco International Inc
Current assignee: Ensco International Inc
Priority date: 2018-07-24
Filing date: 2019-07-22
Publication date: 2020-01-30
Also published as: WO2020023508A1

Abstract

A system includes a plug configured to restrict release of hydrocarbons from a terminal end of an offshore riser by accumulating the hydrocarbons at the plug when the plug is disposed in an internal portion of the offshore riser and at a first vertical location of the offshore riser. The system also includes a vent configured to be disposed at a second vertical location, wherein the vent is configured to provide a path for the hydrocarbons to be released from the offshore riser.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Non-Provisional application of U.S. Provisional Patent Application No. 62/702,467, entitled “Well Reentry” filed Jul. 24, 2018, which is herein incorporated by reference.

BACKGROUND

This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
When offshore wells (e.g., oil and/or gas wells) have reached their end-of-life they are to be decommissioned. Decommissioning of the wells involves, for example, plugging of the wellbore and disposal of the equipment used in offshore oil production. To finalize a decommissioning of a well, the well may be adequately plugged and abandoned. In order to plug and abandon the well, a drilling contractor reenters the well. However, wells that are not yet decommissioned may leak hydrocarbons (e.g., natural gas), which can present problems for reentry of the well, thus complicating the decommissioning of the wells.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates a first example of an offshore platform;

FIG. 1A illustrates a second example of an offshore platform;

FIG. 2 illustrates a prospective side view the well of FIGS. 1 and 1A;

FIG. 3 illustrates a prospective side view of a reentry system in conjunction with the well of FIGS. 1 and 1A;

FIG. 4 illustrates a method of reentering a well using the reentry system of FIG. 3;

FIG. 5 illustrates a prospective side view of a second reentry system in conjunction with the well of FIGS. 1 and 1A; and

FIG. 6 illustrates a method of reentering a well using the reentry system of FIG. 5.

DETAILED DESCRIPTION

One or more specific embodiments will be described below. In an effort to provide a concise description of these embodiments, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.
When introducing elements of various embodiments, the articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.
Offshore oil and/or gas well decommissioning involves, in part, well plugging and abandonment as well as subsequent conductor removal. The well plugging and abandonment operation may include, for example, steps to seal the well (e.g., using cement or other sealant materials) as well as removal of the conductor casing to a particular distance below the seafloor (e.g., to a distance that conforms with local regulations). To plug and abandon the well, a drilling contractor will reenter the well, for example, by running casing into the well. However, in many instances, wells (e.g., previously abandoned wells) may be leaking hydrocarbons (e.g., natural gas), which increases the difficulty of tieback of the well for reentry from a drilling rig. For example, gas or other hydrocarbons leaking from an annulus of an offshore well may impede rigging up a blowout preventer (BOP) atop a tieback casing string. Accordingly, devices and methods to evacuate gas from a casing to allow for well plugging and abandonment to proceed are described herein.
With the foregoing in mind, FIG. 1 illustrates an offshore platform 10 as a self-elevating unit 2. Although the presently illustrated embodiment of an offshore platform 10 is of a particular offshore self-elevating unit 2, other offshore platforms may be substituted for the self-elevating unit 2. The techniques and systems described below are described in conjunction with self-elevating unit 2 and are intended to cover at least jackups, liftboats, jackup barges, mobile offshore drilling units (MODUs), mobile offshore production units (MOPUs), mat rigs, or the like.
The present self-elevating unit 2 includes one or more legs 4 and the self-elevating unit 2 is capable of floating on a hull 6 (e.g., a buoyant hull), which may also operate to support the legs 4 of the self-elevating unit 2. As illustrated in FIG. 1, the self-elevating unit 2 is operating in an elevated mode as its mode of operation, whereby the self-elevating unit 2 has its legs 4 lowered onto the seafloor 14 so that the self-elevating unit 2 (e.g., the hull 6) may be raised above the surface 8 relative to the seafloor 14. While in the elevated mode, footings 9 (e.g., spudcans or the like) at the bottom of the legs 4, provide a bearing surface for transmitting loads between the self-elevating unit 2 and the seafloor 14. This may allow the self-elevating unit 2 to operate as a stable platform. Additionally, it should be appreciated that the self-elevating unit 2 may transition to an afloat mode in which the legs 4 of the self-elevating unit 2 are raised from the seafloor 14, for example, to allow for transit of the self-elevating unit 2.
As further illustrated in FIG. 1, the offshore platform 10 as the self-elevating unit 2 may be positioned above a well 12 along the seafloor 14 that is to be decommissioned. As illustrated, the well 12 may include a conductor 16 (e.g., a conductor pipe or other pipe) set into the seafloor 14 that may operate to provide an initial structural foundation for a borehole of the well 12 as well as casing 18 (e.g., pipe or pipes disposed in sections of the borehole of the well 12). Also illustrated is a riser 20, e.g., an offshore riser, which may be a pipe or series of pipes, that connects self-elevating unit 2 to the well 12. The riser 20 may be, for example, a tie-back riser string or a tie-back casing string that extends from the self-elevating unit 2 at the surface 8 (i.e., at or above a waterline) to the seafloor 14 and the riser 20 may be coupled to the conductor 16 and/or the casing 18 of the well 12. The riser 20 may pass through an opening (e.g., a moonpool) in the self-elevating unit 2 and may be positioned in a vertical orientation between the well 12 and the self-elevating unit 2.
To finalize reentry of the well 12, the riser 20 may be cut or otherwise severed at the surface 8 (e.g., at the end of the riser 20 located at the offshore platform 10, here, the self-elevating unit 2, at or above a waterline) to properly size the riser 20 to extend a distance (e.g., a predetermined distance) from the self-elevating unit 2 to the well 12. A connector (e.g., a starter wellhead or another connector) may be welded or otherwise affixed to the riser 20 at the surface 8 (e.g., at the self-elevating unit 2) to operate as a connection point for attachment of a BOP to the riser 20 at the surface 8. The BOP may include at least one valve with a sealing element to control wellbore fluid flows. Other embodiments of the offshore platform 10 that operate in a similar manner as that discussed above are additionally contemplated.
For example, FIG. 1A illustrates an offshore platform 10 as a drillship 13. Although the presently illustrated embodiment of an offshore platform 10 is a drillship 13 (e.g., a ship equipped with a drilling system and engaged in offshore oil and gas exploration and/or well maintenance or completion work including, but not limited to, casing and tubing installation, subsea tree installations, and well capping), other offshore platforms 10 such as a semi-submersible platform, a jack-up platform (e.g., self-elevating unit 2), a spar platform, a floating production system, or the like may be substituted for the drillship 13. Indeed, while the techniques and systems described below are described in conjunction with a drillship 13, the techniques and systems are intended to cover at least the additional offshore platforms 10 described above, for example, the self-elevating unit 2.
As illustrated in FIG. 1A, the offshore platform 10 as drillship 13 may be positioned above a well 12 along the seafloor 14 that is to be decommissioned. As illustrated, the well 12 may include a conductor 16 (e.g., a conductor pipe or other pipe) set into the seafloor 14 that may operate to provide an initial structural foundation for a borehole of the well 12 as well as casing 18 (e.g., pipe or pipes disposed in sections of the borehole of the well 12). Also illustrated is a riser 20, e.g., an offshore riser that includes a pipe or series of pipes, that connects the offshore platform 10 to the well 12. The riser 20 may be, for example, a tie-back riser string or a tie-back casing string that extends from the offshore platform 10 at the surface 8 to the seafloor 14 and the riser 20 may be coupled to the conductor 16 and/or the casing 18 of the well 12. The riser 20 may pass through an opening (e.g., a moonpool) in the offshore platform 10 and may be positioned in a vertical orientation between the well 12 and the offshore platform 10.
To finalize reentry of the well 12, the riser 20 may be cut or otherwise severed at the surface 8 (e.g., at the end of the riser 20 located at the offshore platform 10) to properly size the riser 20 to extend a distance (e.g., a predetermined distance) from the offshore platform 10 to the well 12. A connector (e.g., a starter wellhead or another connector) may be welded or otherwise affixed to the riser 20 at the surface 8 (e.g., at the offshore platform 10) to operate as a connection point for attachment of a BOP to the riser 20 at the surface 8. The BOP may include at least one valve with a sealing element to control wellbore fluid flows.
FIGS. 1 and 1A illustrate the offshore platform 10 (as self-elevating unit 2 and drillship 13, respectively) coupled to the well 12, thus illustrating completed reentry of the well 12 to allow for decommissioning of the well 12. However, if the well 12 is leaking hydrocarbons, completing tieback of the well 12 (i.e., coupling the riser 20 to the well 12) may be problematic, since cutting or otherwise severing the riser 20 and/or welding or otherwise affixing the connector to the riser 20 for attachment of a BOP may be difficult to complete, for example, if the riser 20 is conducting the leaking hydrocarbons from the well 12 to the offshore platform 10. FIG. 2 illustrates an example the well 12 leaking hydrocarbons that may complicate the reentry of the well 12.
As illustrated in FIG. 2, the well 12 includes the conductor 16 set into and extending from the seafloor 14. Also illustrated is the casing 18 (e.g., mudline suspension system) of the well 12. The casing 18 may include casing threads 24 or other connectors that may operate to couple the riser 20 to the well 12. Further illustrated is an example of hydrocarbons 26 (e.g., natural gas) that may be leaking through the casing 18. Reentry of the well 12 may include coupling the riser 20 to the well 12, for example, utilizing the casing threads 24. However, this coupling of the riser 20 to the well 12 operates to provide a channel or pathway that may conduct or otherwise transmit the hydrocarbons 26 (e.g., via the coupled riser 20) to the surface 8.
FIG. 3 illustrates a reentry system 28 that may be utilized to facilitate reentry of the well 12. The reentry system 28 may include, for example, a plug 30. The plug 30 may be, for example, a packer, such as an hydraulically inflatable packer, a cap, or another fixed or expandable sealing mechanism. The plug 30 may operate to fluidly seal the riser 20 so as to contain any hydrocarbons 26 therein. Additionally, the reentry system 28 may include a vent 32 to allow for the removal of hydrocarbons 26 from the riser 20. The vent 32 may be a valve controlled aperture in the packer and/or in the riser 12. For example, as illustrated, the vent 32 in the riser 20 may be coupled to a valve 34 (e.g., an isolation valve) which may include or otherwise be coupled to a connector 36, such as a stab connector. In operation, the valve 34 may be opened to provide a path for accumulated hydrocarbons 26 through the vent 32.
Also illustrated in FIG. 3 is a connector 38, which may be, for example, a starter wellhead, a flange, or another connector to allow for connection of the BOP to the riser 20. As illustrated, the connector 38 may be coupled to the riser 20 at connection point 40. Thus, connection point 40 may represent the location at which the riser 20 is severed and/or the connector 38 is coupled (e.g., welded or otherwise affixed) to the riser 20. Placement of the plug 30 and the vent 32 below the connection point 40, may allow for hydrocarbons 26 to be kept in a region 42 of the riser 20 (e.g., approximately 5 feet, 6 feet, 7 feet, 8 feet, 9 feet, 10 feet, or more below the connection point 40) to allow for work to be completed at the connection point 40 with minimal, reduced, or no interference from the hydrocarbons 26. A line 44 (e.g., a hose, a tube, etc.) may be coupled to the vent 32, the valve 34, or the connector 36 (e.g., via a connector 46, such as a stab connector) and, for example, a vacuum 48 may be coupled to the line 44 (either as part of the connector 46 or at a separate end of the line 44 opposite the connector 46) to aid in the evacuation of the hydrocarbons 26 from the riser 20.
Thus, as illustrated in FIG. 3, a plug 30 may be internal to the riser 20 and may seal hydrocarbons 26 from release from a terminal end of the riser 20 (e.g., the terminal end of the riser at the surface 8 adjacent to connection point 40). The plug 30 may be disposed in an internal portion of (e.g., along an inner circumference of) the riser 20 and the plug 30 may be disposed at a first vertical location of the riser 20 (e.g., below the connection point 40 relative to the seafloor 14). Additionally, the vent 32 may be disposed in the riser 20 (e.g., as an aperture passing through the riser 20) and the vent 32 may be disposed at a second vertical location below the first vertical location relative to the seafloor 14 (e.g., at a second location of the riser 20 below the connection point 40 and below the vertical location of plug 30 relative to the seafloor 14).
FIG. 4 illustrates a method for reentry of a well 12 that includes the reentry system 28. In step 50, the riser 20 (which may have a tool, such as a running tool coupled thereto) may be run to a depth below the surface 8. This depth may be a distance above the well (e.g., a predetermined distance above one or more of the conductor 16 and/or the casing 18). In step 51, the reentry system 28 may be installed. This installation in step 51 may include drilling or otherwise forming a vent 32 in region 42 of the riser 20. This vent 32 may be positioned approximately 1 foot, 2 feet, 3 feet, 4 feet, five feet, or more below the location where the plug 30 will be disposed in the riser 20. The valve 34 may be welded or otherwise affixed to the vent 32 and any connector 36 (if external to the valve 34 and not included in a common housing or a common device with the valve 34) may be affixed to the valve 34. The line 44 may be coupled to the valve 34 (e.g., via coupling the connector 46 to the connector 36) and the vacuum 48 (if not present in the connector 46) may be coupled to the line 44 in step 51.
Additionally in step 51, the plug 30 may be placed into the riser 20, for example, at a distance of approximately 1 foot, 2 feet, 3 feet, 4 feet, 5 feet or another distance below a location of the connection point 40. If the plug 30 is expandable, it may be expanded once disposed in the riser 20. Placing the plug 30 into the reentry system 28 may operate to seal hydrocarbons 26 in the body 58. Alternatively, the plug 30 may be actuated (e.g., expanded) to seal hydrocarbons 26 in the body 58.
In step 52, the riser may be landed and engaged with (coupled to) the well 12, for example, using casing threads 24 or other connectors in the conductor 16 and/or the casing 18 to couple the riser 20 to the well 12. As part of step 52, the riser 20 may be made up to a mudline suspension system of the well 12, which may incorporate one or more tieback tools to reconnect the mudline hanger to the surface 8 to facilitate reentry of the well 12. In step 53, evacuation of the hydrocarbons 26 may be undertaken (if any are present in region 42). This step 53 may include attachment of the line 44 (if not already completed), activation of the vacuum 48, and opening of the valve 34 to begin evacuation of the hydrocarbons 26. In step 54, the connector 38 may be attached to the riser 20. Attachment of the connector 38 may include, for example, cuts to the riser 20 at the connection point 40 (e.g., to properly size the riser 20 to a length, such as a predetermined length) as well as affixing of the connector 38 (e.g., welding or other affixing techniques) to the riser 20 at the connection point 40 and in step 55, the BOP may be attached to the connector 38, to be used in ongoing program of work (i.e., decommission of the well 12).
FIG. 5 illustrates a reentry system 56. Reentry system 56 is similar to reentry system 28 of FIG. 3 in that it includes a plug 30 and a vent 32. Additionally, the reentry system 56 includes a body 58 that can house the plug 30 and through which the vent 32 is an aperture such that the plug 30, vent 32, and body 58 of the reentry system 56 together make up a reentry device that may be coupled to a riser 20. The body 58 may also include a connector 60 (e.g., a thread, a stab connector, etc.) that may operate to engage with the riser 20 directly to couple the reentry system 56 to the riser 20. Alternatively, the connector 60 may be coupled to a crossover (or other adapter) to affix the reentry system 56 to the riser 20. The use of a dedicated reentry system 56 that may be coupled to various sized risers 20 (e.g., via associated crossovers) allows the reentry system 56 to be used in multiple environments. Additionally, as no modifications are made to the riser 20 itself when used in conjunction with the reentry system 56.
As illustrated, the vent 32 may be coupled to a valve 34 (e.g., an isolation valve) which may include or otherwise be coupled to a connector 36, such as a stab connector. In operation, the valve 34 may be opened to provide a path for accumulated hydrocarbons 26 through the vent 32. Also illustrated in FIG. 5 is the connector 38, which may be, for example, a starter wellhead, a flange, or another connector to allow for connection of the BOP to the riser 20 via the reentry system 56. As illustrated, the connector 38 may be coupled to the reentry system 56 at connection point 40. Thus, connection point 40 may represent the location at which the reentry system 56 is severed and/or the connector 38 is coupled (e.g., welded or otherwise affixed) to the reentry system 56. Placement of the plug 30 and the vent 32 below the connection point 40, may allow for hydrocarbons 26 to be kept in a region 62 of the reentry system 56 (e.g., approximately 5 feet, 6 feet, 7 feet, 8 feet, 9 feet, 10 feet, or more below the connection point 40) to allow for work to be completed at the connection point 40 with minimal, reduced, or no interference from the hydrocarbons 26. A line 44 (e.g., a hose, a tube, etc.) may be coupled to the vent 32, the valve 34, or the connector 36 (e.g., via a connector 46, such as a stab connector) and, for example, a vacuum 48 may be coupled to the line 44 (either as part of the connector 46 or at a separate end of the line 44 opposite the connector 46) to aid in the evacuation of the hydrocarbons 26 from the reentry system 56 and the riser 20.
Thus, as illustrated in FIG. 5, the reentry system 56 may include a body 58 comprising a terminal end (e.g., a terminal end of the reentry system 56 at the surface 8 adjacent to connection point 40). The body 58 of the reentry system 56 may also include a second end (e.g., adjacent to the connector 60) wherein the second end of the body 58 can be coupled to the riser 20 (e.g., either directly or via an adapter). The reentry system may also include a plug 30 that seals hydrocarbons 26 from release from the terminal end of the body 58 when the plug 30 is disposed in an internal portion of (e.g., along an inner circumference of) the body 58 and the plug 30 may be disposed at a first vertical location of the body 58 (e.g., below the connection point 40 relative to the seafloor 14). Additionally, the vent 32 may be disposed in the reentry system 56 (e.g., as an aperture passing through the body 58 of the reentry system 56) and the vent 32 may be disposed at a second vertical location below the first vertical location relative to the seafloor 14 (e.g., at a second location of the body 58 below the connection point 40 and below the vertical location of plug 30 relative to the seafloor 14).
FIG. 6 illustrates a method for reentry of a well 12 that includes the reentry system 56. In step 50, the riser 20 (which may have a tool, such as a running tool coupled thereto) may be run to a depth below the surface 8. This depth may be a distance above the well (e.g., a predetermined distance above one or more of the conductor 16 and/or the casing 18). In step 64 the reentry system 56 may be installed by coupling the reentry system 56 directly to the riser 20 or may include coupling the reentry system 56 to the riser 20 via a crossover (or other adapter). The vent 32 of the reentry system be located approximately 1 foot, 2 feet, 3 feet, 4 feet, five feet, or more below the location where the plug 30 will be disposed in the reentry system 56. Any connector 36 (if external to the valve 34 and not included in a common housing or a common device with the valve 34) may be affixed to the valve 34. The line 44 may be coupled to the valve 34 (e.g., via coupling the connector 46 to the connector 38) and the vacuum 48 (if not present in the connector 46) may be coupled to the line 44 as part of step 64.
Additionally in step 64, the plug 30 may be placed into the reentry system 56, for example, at a distance of approximately 1 foot, 2 feet, 3 feet, 4 feet, 5 feet or another distance below a location of the connection point 40. If the plug 30 is expandable, it may be expanded once disposed in the reentry system 56. Placing the plug 30 into the reentry system 56 may operate to seal hydrocarbons 26 in the body 58. Alternatively, the plug 30 may be actuated (e.g., expanded) to seal hydrocarbons 26 in the body 58.
In step 52, the riser may be landed and engaged with (coupled to) the well 12, for example, using casing threads 24 or other connectors in the conductor 16 and/or the casing 18 to couple the riser 20 to the well 12. As part of step 52, the riser 20 may be made up to a mudline suspension system of the well 12, which may incorporate one or more tieback tools to reconnect the mudline hanger to the surface 8 to facilitate reentry of the well 12. In step 53, evacuation of the hydrocarbons 26 may be undertaken (if any are present in region 42). This step 53 may include attachment of the line 44 (if not already completed), activation of the vacuum 48, and opening of the valve 34 to begin evacuation of the hydrocarbons 26. In step 66, the connector 38 may be attached to the reentry system 56. Attachment of the connector 38 may include, for example, casing cuts of the reentry system 56 at the connection point 40 (e.g., to properly size the combined riser 20 and reentry system 56 to a length, such as a predetermined length) as well as affixing of the connector 38 (e.g., welding or other affixing techniques) to the reentry system 56 at the connection point 40 and in step 55, the BOP may be attached to the connector 38, to be used in ongoing program of work (i.e., decommission of the well 12).
This written description uses examples to disclose the above description to enable any person skilled in the art to practice the disclosure, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims. Accordingly, while the above disclosed embodiments may be susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and have been described in detail herein. However, it should be understood that the embodiments are not intended to be limited to the particular forms disclosed. Rather, the disclosed embodiment are to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the embodiments as defined by the following appended claims.

Claims

What is claimed is:

1. A system, comprising:

a plug configured to restrict release of hydrocarbons from a terminal end of an offshore riser by accumulating the hydrocarbons at the plug when the plug is disposed in an internal portion of the offshore riser and at a first vertical location of the offshore riser; and

a vent configured to be disposed at a second vertical location, wherein the vent is configured to provide a path for the hydrocarbons to be released from the offshore riser.

2. The system of claim 1, comprising a valve configured to control a flow of the hydrocarbons passing though the vent.

3. The system of claim 2, comprising a vacuum configured to evacuate the hydrocarbons from the offshore riser via the vent.

4. The system of claim 3, comprising a connector configured to couple the vacuum to the vent.

5. The system of claim 4, wherein the connector comprises a stab connector.

6. The system of claim 1, comprising a connector coupled to the offshore riser at a connection point at a third vertical location of the offshore riser.

7. The system of claim 6, wherein the third vertical location is disposed above the first vertical location relative to a seafloor.

8. The system of claim 6, wherein the connector is configured to be coupled to a blowout preventer.

9. The system of claim 1, wherein the vent is disposed in the offshore riser below the first vertical location relative to a seafloor as the second vertical location.

10. The system of claim 1, wherein the vent is disposed in the plug as the second vertical location.

11. A system, comprising:

a body comprising a terminal end and a second end, wherein the second end of the body is configured to be coupled to an offshore riser;

a plug configured to restrict release of hydrocarbons from the terminal end of the body by accumulating hydrocarbons at the plug when the plug is disposed in an internal portion of the body and at a first vertical location of the body; and

a vent configured to be disposed in the body at a second vertical location, wherein the vent is configured to provide a path for the hydrocarbons to be released from the offshore riser.

12. The system of claim 11, wherein the body comprises a connector disposed at the second end of the body.

13. The system of claim 12, wherein the connector is configured to engage with the offshore riser to couple the body to the offshore riser.

14. The system of claim 11, comprising a valve configured to control a flow of the hydrocarbons passing though the vent.

15. The system of claim 14, comprising a connector coupled to the terminal end of the body, wherein the connector is configured to be coupled to a blowout preventer.

16. The system of claim 11, wherein the vent is disposed in the body below the first vertical location relative to a seafloor as the second vertical location.

17. The system of claim 11, wherein the vent is disposed in the plug as the second vertical location.

18. A system, comprising:

a plug configured to restrict release of hydrocarbons from a terminal end of an offshore riser by accumulating the hydrocarbons at the plug when the plug is disposed adjacent to the offshore riser and at a first vertical location; and

a vent configured to be disposed at a second vertical location, wherein the vent is configured to provide a path for the hydrocarbons to be released.

19. The system of claim 18, wherein the plug is configured to be disposed directly adjacent to the offshore riser as the first vertical location.

20. The system of claim 18, wherein the plug is configured to be disposed directly adjacent a body, wherein the body comprises a terminal end and a second end, wherein the second end of the body is configured to be coupled to the offshore riser.

21. A method, comprising:

disposing a plug adjacent to an offshore riser at a first vertical location to restrict release of hydrocarbons from a terminal end of the offshore riser by accumulating the hydrocarbons at the plug; and

venting the hydrocarbons via a vent disposed at a second vertical location, wherein the vent is configured to provide a path for the accumulated hydrocarbons to be released.