RAPID MOBILIZATION AIR-FREIGHTABLE CAPPING STACK SYSTEM

Abstract

A method and apparatus for transporting a capping stack for use in a subsea structure includes a capping stack having a capping stack spool, a connector body connectable to the capping stack spool and at least one diverter leg connectable to the capping stack spool. A first skid receives the capping stack spool on a floor thereof. A second skid receives the connector body on a floor thereof. A third skid receives the diverter leg thereon. The first, second and third skids are adapted to be received within an interior of an aircraft. The skids and the connected components can then be flown by the aircraft to a desired location so as to be assembled at a location near a wellhead.

Claims

1. An apparatus comprising: a capping stack having a capping stack spool and a connector body connectable to said capping stack spool, said capping stack further having at least one diverter leg that is connectable to said capping stack spool; a first skid having a floor thereon, said floor receiving said capping stack spool thereon; a second skid having a floor thereon, said floor of said second skid receiving the connector body thereon; and a third skid having a floor thereon, said floor of said third skid receiving the diverter leg thereon, said first, second, and third skids adapted to be received with in an interior of an aircraft.

2. The apparatus of claim 1, wherein at least one of said first, second and third skids has a plurality of sidewalls extending upwardly from the floor of the skid.

3. The apparatus of claim 2, each of said plurality of sidewalls is positioned at respective corners of said floor of the skid.

4. The apparatus of claim 1, said capping stack spool being bolted at said floor of said first skid, said connector body being bolted to said floor of said second skid, the diverter leg being bolted to said floor of said third skid.

5. The apparatus of claim 1, the floors of at least one of said first, second and third skids having a pair of opposite ends and a pair of opposite sides extending between said pair of opposite ends, the skid having handles affixed to and extending upwardly from said pair of opposite ends and said pair of opposite sides.

6. The apparatus of claim 1, the skid having a top surface and a bottom surface in spaced parallel relation to each other, the skid having a pair of fork-receiving slots formed between said top surface and said bottom surface.

7. The apparatus of claim 1, said capping stack having a test stump connectable to a bottom of said connector body, the apparatus further comprising: a fourth skid having a floor thereon, said floor of said fourth skid receiving the test stump thereon.

8. The apparatus of claim 1, said at least one diverter leg comprising first, second and third diverter legs, said first skid comprising a plurality of skids having floors respectively receiving the first, second and third diverter legs.

9. The apparatus claim 1, further comprising: a first container receiving said first skid and said capping stack spool therein; a second container receiving said second skid and said at least one diverter leg therein; and a third container receiving said third skid and said connector body therein.

10. The apparatus of claim 9, further comprising: an aircraft having a cargo bay therein, said first, second and third containers being received in said cargo bay.

11. The apparatus of claim 1, said capping stack spool being removably affixed to said floor of said first skid, said at least one diverter leg being removably affixed to said floor of said second skid, said connector body being removably affixed to said floor of said third skid.

12. The apparatus of claim 1, said capping stack having a running tool, said running tool being removably affixed to said floor of said first skid.

13. A method for transporting a capping stack for use in a subsea structure, the capping stack having a capping stack spool, at least one diverter leg, and a connector body, the method comprising: affixing the capping stack spool onto a first skid; affixing the at least one diverter leg onto a second skid; affixing the connector body onto a third skid; moving the first, second and third skids with the affixed capping stack spool, the at least one diverter leg, and the connector body into a cargo bay of an aircraft; flying the aircraft to a desired location; removing the first, second and third skids and the affixed capping stack spool, the at least one diverter leg and the connector body from the cargo bay of the aircraft; transporting the first, second and third skids with the affixed capping stack spool, the at least one diverter leg, the connector body to a wellhead location; removing the capping stack spool, the at least one diverter leg and the connector body from the respective first, second and third skids; assembling the at least one diverter leg and the connector body to the capping stack spool so as to form the capping stack; and affixing the assembled capping stack to the subsea structure.

14. The method of claim 13, the capping stack having a test stump, the method further comprising: affixing the test stump to a fourth skid; and moving the fourth skid and the affixed test stump to the cargo bay of the aircraft.

15. The method of claim 13, the at least one diverter leg having a first diverter leg and a second diverter leg, said second skid comprising a pair of second skids, the method further comprising: affixing the first diverter leg to one of said pair of second skids; and affixing the second diverter leg to another of said pair of second skids.

16. The method of claim 13, the skids having a fork-receiving slot formed therein, the step of moving comprising: engaging forks of a forklift into the fork-receiving slots of the skid; and moving the forklift toward the cargo bay of the aircraft.

17. The method of claim 13, the step of transporting comprising: placing the first, second and third skids and the affixed capping stack spool, the diverter leg and the connector body onto a boat, the steps of removing and assembling occurring on the boat.

18. The method of claim 13, further comprising: positioning the first, second and third skids and the affixed capping stack spool, the diverter leg, and the connector body into respective first, second and third containers.

19. The method of claim 18, the step of moving comprising: moving the first, second and third containers into the cargo bay of an aircraft.

20. The method of claim 13, the step of moving comprising: positioning the first, second and third skids and the affixed capping stack spool, the diverter leg, and the connector body on respective trucks; and driving the trucks to the aircraft.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0048] FIG. 1 is a perspective view of the assembled capping stack in accordance with the teachings of the present invention.

[0049] FIG. 2 is a side elevational view showing the components of the capping stack of the present invention as modularized for transport.

[0050] FIG. 3 is a perspective view showing one of the diverter legs of capping stack of the present invention as placed on a skid.

[0051] FIG. 4 is a perspective view showing another of the diverter legs of the capping stack of the present invention as placed upon a skid.

[0052] FIG. 5 is a perspective view showing another of the diverter legs and the running tool of the capping stack of the present invention as placed upon a skid.

[0053] FIG. 6 is a perspective view showing the capping stack spool of the capping stack of the present invention as placed upon a skid.

[0054] FIG. 7 is a perspective view showing the connector body of the capping stack of the present invention as placed upon a skid.

[0055] FIG. 8 is a perspective view showing the test stump as used in the capping stack of the present invention.

[0056] FIG. 9 is a cross-sectional view of a Boeing 747-400 aircraft having the various components loaded therein.

[0057] FIG. 10 is a cross-sectional plan view showing the arrangement of the various skids within the cargo bay of the 747 aircraft.

DETAILED DESCRIPTION OF THE INVENTION

[0058] FIG. 1 shows a capping stack 10 in accordance with the teachings of the present invention. The capping stack 10 is similar to that described in prior U.S. Patent Application Publication Nos. 2012/0318520 and 2015/0060081 to the present applicant. In particular, the capping stack 10 includes a running tool 12, a plurality of diverter legs 14, 16 and 18, a capping stack spool 20, and a connector body 22. The running tool 10 is affixed to an outboard connector 24 of one of the diverter legs 16. A subsea retrievable isolation valve 26 is also connected to the diverter legs 16. The diverter legs 14 includes a choke 28 at the upper end thereof and a valve 30. The valve 30 is adapted to be manipulated by an ROV. The diverter legs 16 also include a choke 32 at an upper end thereof and an ROV-manipulatable valve 34 thereon. Each of the diverter legs 14, 16 and 18 has an interior passageway through which the flow of hydrocarbons can pass for the purposes of diversion.

[0059] The capping stack spool 20 includes a central passageway (not shown) that can be opened and closed by a valve 36. The closing of the valve 36 allows the hydrocarbons to flow outwardly through the diverter legs 14 and 18. Also, the opening of the valve 36 allows a pass through of the fluid flow through the diverter leg 16. As such, and was described in these prior U.S. Patent Application Publications, when the capping stack 10 is installed upon a blowout preventer or a wellhead, the central diverter leg 16 is open so as to allow a free flow of the hydrocarbons therethrough. Ultimately, once the connector 22 is properly installed on the wellhead or the blowout preventer, the valve 36 can be manipulated so as to diverge the flow of hydrocarbons through each of the diverter legs 14 and 18. The capping stack spool 20 also includes a ROV control panel 38 thereon. Ultimately, the capping stack spool 20 includes a lower connector 40 that is adapted to be connected to an upper connector 42 of connector body 22.

[0060] FIG. 2 shows each of the components of the capping stack 10 as isolated in the separate modules. In particular, there is a module 44 receiving the diverter leg 14, the diverter leg 16, and the diverter leg 18. The module 46 receives the capping stack spool 20 therein. The module 48 receives the connector body 22 therein. Ultimately, the module 50 includes a test stump 52 therein. Test stump 52 includes a portion that can be threadedly received within the connector body 22. The test stump 52 can be mounted upon a pad 54.

[0061] Within the concept of the present invention, it is important to separate the various components of the capping stack into an air-freightable and stackable arrangement. FIG. 3 shows, in particular, the diverter leg 14 as mounted upon a skid 60. The skid 60 includes a floor 62 and sidewalls 64. As such, the diverter leg 14 will be contained within the skid 60 and protected from damage by the sidewalls 64. In particular, the bottom connector 66 will be rigidly affixed to the floor 62 of the skid 60. FIG. 4 shows the diverter leg 80 as mounted upon a skid 70. Skid 70 includes a floor 72 and sidewalls 74. As will be described hereinafter, each of the skids described herein can include suitable slots for receiving the forks of a forklift. Other structures can be provided on each of the skid so as to allow the skids to be manipulated by a crane or by a scissor lift.

[0062] FIG. 5 shows the center diverter leg 16 as affixed onto a skid 76. Also, the running tool 12 is also mounted upon the floor 78 of the skid 76.

[0063] FIG. 6 shows the capping stack spool 20 mounted upon the skid 80. In particular, the lower connector 40 of the capping stack spool 20 is securely affixed onto the skid 80.

[0064] FIG. 7 shows the connector body 22 affixed to the skid 82. Although the walls associated with each of the skid 60, 70, 76, 80 and 82 is omitted for clarity, each of the walls will extend upwardly on each of the sides of the respective skids. If desired, a cover or roof can be provided over each of the components on the separate skids.

[0065] FIG. 8 shows the test stump 52 as mounted upon a test stand 84 and also mounted upon a transport skid 54. In particular, FIG. 8 shows that there are fork-receiving slots 86 formed in the transport skid 54. As such, a suitable forklift can easily transport the test stump 52. Additionally, handles 88 can extend upwardly from the transport skid 54. Handles 88 can be utilized in association with lines or other grasping devices so as to effectively lift the test stump 52.

[0066] FIG. 9 illustrates that the various containers 100, 102, 104 and 106 can be placed within the cargo bay 108 of a 747 aircraft 110. Doors 112 and 114 can open to the cargo bay 108 so as to allow the containers 100, 102, 104 and 106 to be introduced therein. In particular, door 114 can be open so as to allow the containers 104 and 106 to be introduced into the lower portion 120 of the cargo bay 108. Additionally, the door 112 can be open so as to allow containers 100 and 102 to be placed upon the floor 122 within the cargo bay 108 of the aircraft 110.

[0067] FIG. 10 shows the interior of the aircraft 110 in which a variety of containers are placed within the cargo bay 108. In particular, in FIG. 10, all of the components necessary for the assembly of the completed capping stack can be placed therein for the purposes of rapid deployment.

[0068] The capping stack system herein allows for rapid deployment to incident locations around the world. In particular, the capping stack system can be stored at a single location and delivered by suitable aircraft to the facilities in a period of less than 96 hours. As such, the capping stack system of the present invention is adapted to satisfy rapid response requirements.

[0069] The capping stack system described herein is suitable for the isolation of pressure to a maximum of 15,000 p.s.i. It can be installed in an incident well in water depths up to 10,000 feet. Additionally, it is suitable for installation on an incident well with a maximum discharge rate of up to 100,000 barrels of oil per day with a gas/oil ratio of 2000. The capping stack system provides primary well isolation (i.e. capping) and provides functionality to service the mechanical connection point for flow back (i.e. containment) operations if required for well integrity concerns. The capping stack system of the present invention adheres to the dual mechanical barrier philosophy for all functional barriers. The capping stack system of the present invention also provides center bore access for open water invention operations post-kill.

[0070] For ground transportation, the weight loads provided by the separate modules and skids of the present invention allows for DOT compliance for loads. The total weight transported by the various skids is designed to accommodate loading, transit and unloading on a Boeing 747-400 aircraft. The various components and/or the assembled capping stack are designed for lashing and marine transport to the incident site fully assembled by a marine deployment vessel.

[0071] In the present invention, the capping stack spool 20 provides two main functions. First it facilitates capping stack installation by providing a flow path for the hydrocarbon flow stream while the vertical flow is restricted or shut-off. Secondly, it provides multiple connection points for the containment/collection system should total capping/sealing of the flow not be possible. The individual gate valves are used to provide a barrier against flow on each of the diverter legs. Two gate valves are installed on each diverter leg for double isolation against flow. The chokes that are installed on each diverter leg are used to restrict flow in a shut-in situation to help gain control of a flowing well and minimize any hammer effects caused by restricting the flow too quickly. Once the flow has been restricted to a minimum, the gate valves are then employed to close the diverter leg and isolate the flow. Each of the chokes can be manually operated by way of a torque tool associated with a ROV. All of the subsea components are arranged to be visible for inspection and provided with suitable markings to aid in identification. The capping stack system is fitted with ROV grab handles to support alignment and installation. The grab panels are located so as to not to impede the connection of any of the components.

[0072] The capping stack system of the present invention is capable of being installed via conventional wireline rigging arrangements. The capping stack system contains all necessary handling and testing tools.

[0073] To be deployed to a drilling rig, the capping stack system will be compliant with various requirements: (1) to have a lifting frame or point to be handled by an offshore cranes; (2) to have a dedicated test stump; (3) to be handled modularly if the overall weight of the capping stack is heavier than thirty tons; and (4) to be capable of being re-connected and tested offshore by quick connectors. Each of the remaining equipment will have a lifting frame, a designated offshore storage container, or a point to be handled by an offshore crane.

[0074] The foregoing disclosure and description of the invention is illustrative and explanatory thereof. Various changes in the details of the illustrated construction or in the steps of the described method can be made within the scope of the present claims without departing from the true spirit of the present invention. The present invention should only be limited by the following claims and their legal equivalents.