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Patent application title:

APPARATUS AND METHOD FOR ENHANCING BUOYANCY CAPACITY OF A SPAR

Publication number:

US20250249980A1

Publication date:

2025-08-07

Application number:

19/045,399

Filed date:

2025-02-04

Smart Summary: A new system improves the floating ability of a spar, which is a platform used in deep water. It uses a special modular can made up of several compartments that can be connected together easily. The spar has a deck on top and a hull with a central well that has walls creating slots. One of these slots is empty and has a flexible guide attached to the walls. The modular can is placed into this empty slot and lowered down, helping to support the spar effectively. 🚀 TL;DR

Abstract:

The buoyancy capacity of a spar (i.e., a floating platform in deep waters) is enhanced using a modular can. The modular can includes a plurality of compartments releasably connectable (e.g., via bolts) to one another. The spar includes a spar deck and a hull surrounding a center well. The center well is partitioned by walls that form slots inside the hull. One of the slots is vacant. The vacant slot includes a compliant guide mounted to the walls. The modular can is assembled inside the vacant slot and progressively lowered into it so that the buoyancy can interfaces with the spar at the compliant guide. In use, the modular can supports the spar at the spar deck, the compliant guide, and/or a soft can coupled below the hull via a truss.

Inventors:

James Maher 7 🇺🇸 Houston, TX, United States

Applicant:

Trendsetter Vulcan Offshore, Inc. 🇺🇸 Houston, TX, United States

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Classification:

B63B1/107 » CPC main

Hydrodynamic or hydrostatic features of hulls or of hydrofoils deriving lift mainly from water displacement with multiple hulls Semi-submersibles; Small waterline area multiple hull vessels and the like, e.g. SWATH

B63B1/10 IPC

Hydrodynamic or hydrostatic features of hulls or of hydrofoils deriving lift mainly from water displacement with multiple hulls

B63B43/06 » CPC further

Improving safety of vessels, e.g. damage control, not otherwise provided for reducing risk of capsizing or sinking by improving stability using ballast tanks

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to U.S. provisional application Ser. No. 63/549,978, filed on Feb. 5, 2024, which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

Spars, also referred to as spar platforms, are commonly used in offshore oil extraction, specifically as a type of floating platform designed for deepwater oil production. A spar, which stands for “Single Point Anchor Reservoir,” is essentially a large vertical structure anchored to the seabed, used to drill and process oil in very deep waters.

Spars have a center well that is partitioned in riser slots. Some of these slots are occupied by equipment, such as pumps, or filters, which were attached to the spar before the spar was towed to sea and used. Most of these slots are occupied by buoyancy cans to support vertical dry tree risers. The buoyancy cans are installed after the spar is upended. In addition, some of these slots are either planned to be spares for future expansion or become available because the wells associated with the initial risers have been decommissioned.

Atop the spar hull sits the topsides, which can be comprised of drilling equipment, production facilities, and living quarters. The drilling equipment and/or production facilities is/are often modified and enhanced during service. The production facilities often grow to meet or exceed the capacity that was originally intended. In these cases, one or more center well slots that are vacant could be used to install additional buoyancy cans to enhance the overall capacity of the production facilities. These additional buoyancy cans would act in similar fashion to a “blister” that is built onto the side of a semi-submersible, but these additional buoyancy cans could provide buoyancy through the center well.

The original buoyancy cans are very long (usually 100-200 ft) and were usually installed using a derrick barge, often before the topsides process facilities were installed. Thus, the design of the original buoyancy cans and the initial installation method of the original buoyancy cans cannot be used to enhance the buoyancy capacity of the spar.

So, there is a need for a method to be able to install the buoyancy cans modularly using the platform crane and some additional installation equipment.

SUMMARY

In general, the disclosure describes apparatus and methods for enhancing the buoyancy capacity of a spar by adding a purpose-built buoyancy cans into its center well.

In some particular aspects, the disclosure describes a buoyancy can that is modular, made of compartments connectable to one another. The buoyancy can includes means for coupling the buoyancy can to the spar.

In some particular aspects, the disclosure describes a method of assembling compartments to construct a buoyancy can in a center well of a spar and coupling the buoyancy can to the spar.

In some particular aspects, the disclosure describes a system including a spar and a buoyancy can coupled thereto.

The invention is susceptible to various modifications and alternative forms, and specific embodiments thereof are shown by way of example in the drawings and description. It should be understood, however, that the drawings and description are not intended to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives available to a person having ordinary skill in the art.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more detailed description of the embodiments of the disclosure, reference will now be made to the accompanying drawings, wherein:

FIG. 1 is an elevation view of three embodiments of a buoyancy can coupled to a spar, in each embodiment, the buoyancy can is located in a vacant slot of the center well of the spar;

FIG. 2 is a perspective view of the center well of the spar shown in FIG. 1, with and without the hull of the center well. The center well encloses compliant guides mounted to walls that define a four-by-four array of slots in this example;

FIG. 3 shows three views illustrating the buoyancy can of the left most embodiment in FIG. 1, wherein the buoyancy can is segmented with, in this example, two void compartments on top and four air-over-water compartments at the bottom;

FIG. 4 shows a perspective view and a sectional view of a void compartment, and, in the top left corner, the way the buoyancy can is coupled to the stopper flange of the deck of the spar, or, in the bottom left corner, the way the void compartment can be coupled to the next compartment (not shown);

FIG. 5 shows a sectional view of an air-over-water compartment, wherein, in this example, two, but not all four, of the compartments include a structural layer configured to fit into the compliant guide of the middle or the bottom levels shown in FIG. 2; and

FIGS. 6A-6D illustrate a method of assembling the buoyancy can shown in FIG. 3 and coupling it to the spar.

DETAILED DESCRIPTION

The spar 10 shown in FIG. 1 includes a deck 12, on top of tanks surrounding a center well 14, on top of a truss 16, on top of a soft tank 18. In the example shown, the truss 16 includes three heave plates. The buoyancy can 20 is shown schematically in dotted pattern. At least three ways of coupling the buoyancy can 20 to the spar 10 are illustrated.

The guides 22 coupled to the spar 10 inside the center well 14 formed inside the tanks are not visible in FIG. 1, but are shown in FIG. 2. Inside the hull of the center well 14, usually at top, middle and bottom levels, the center well 14 is partitioned in slots 24 by walls 26. The compliant guides 22 are mounted to the walls 26, for example, inside each of the slots 24. As mentioned previously, some of these slots 24 are occupied by buoyancy cans, not shown in FIG. 2, which are attached to the spar 10. Some of these slots 24 are vacant.

FIG. 3 shows that the buoyancy can 20 is segmented into compartments 28a, 28b. The compartments 28a, 28b can be bolted head to toe at top and/or bottom flanges.

FIG. 4 shows the structure of a void compartment 28a. Also, the flange of the top compartment is clamped to the flange of the deck stopper 30, and an elastomer layer 32 is provided between the flange of the top compartment and the flange of the deck stopper 30.

FIG. 5 shows the structure of an air-over-water compartment 28b. In this example, the air-over-water compartment 28b has one watertight deck 34 and two flooding holes 36. Some air-over-water compartments include an outer structural layer 38 that provides strength to interface with the spar 10 at the guide 22.

FIG. 6A shows that compartments 28a, 28b of a buoyancy can 20 be towed on a barge to a spar 10 at sea. A crane provided on the spar 10 can pick up the compartments 28a, 28b.

FIG. 6B shows that a first compartment (e.g. 28b) can be lowered in a vacant slot and retained using locking dogs 40 which may be compliant (e.g., involving elastomers or similar).

FIG. 6C shows that a second compartment (e.g., 28a) can be picked by the crane and lowered on top of the first compartment. The two compartments (e.g., 28a, 28b) are bolted.

FIG. 6D shows the first and second compartments (e.g., 28a, 28b) can be picked up and lowered in the slot using a winch on the work over deck.

The sequence may repeat as shown in FIG. 6B, and a next compartment (e.g., 28a) may be added as shown in FIG. 6C, as many times as necessary.

Then, the structural layers 38 align with the guides 22 as shown in the middle view of FIG. 4, and the top compartment is coupled to the flange of the deck stopper 30 as shown in FIG. 4.

Claims

What is claimed is:

1. A modular can for enhancing the buoyancy capacity of a spar, the modular can comprising:

a plurality of compartments releasably connected to one another; and

means for coupling the buoyancy can to the spar.

2. The modular can of claim 1, wherein the plurality of compartments comprise:

at least one void compartment directly or indirectly connected to at least one an air-over-water compartment;

wherein the at least one void compartment comprises a top deck, a cylindrical inner shell connected below the top deck, and a bottom deck connected below the cylindrical inner shell;

wherein the top deck, the cylindrical inner shell, and the bottom deck form a close compartment that encloses a void space; and

wherein the at least one an air-over-water compartment comprises a top deck, a cylindrical inner shell connected below the top deck, a bottom deck connected below the cylindrical inner shell, and a watertight deck connected inside the cylindrical inner shell between the top deck and the bottom deck;

wherein the top deck comprises a top outer flange that extends beyond an outermost perimeter of the cylindrical inner shell, wherein the bottom deck comprises a bottom outer flange that extends beyond the outermost perimeter of the cylindrical inner shell, wherein the watertight deck has a diameter that fits inside an innermost perimeter of the cylindrical inner shell;

wherein the top deck, the cylindrical inner shell, and the bottom deck form an open compartment that includes at least one top flooding hole located above the watertight deck and at least one bottom flooding hole located below the watertight deck, wherein the top flooding hole and the bottom flooding hole are configured to allow water to flow inside and air to flow outside of the at least one an air-over-water compartment to form a variable ballast.

3. The modular can of claim 2, wherein the means for coupling the buoyancy can to the spar comprise a structural layer that surrounds the cylindrical inner shell of the at least one an air-over-water compartment and extends above and below the watertight deck of the at least one an air-over-water compartment.

4. The modular can of claim 2, further comprising:

an elastomer layer sized to fit between the top outer flange of the at least one void compartment and a stopper flange of a deck of the spar; and

a clamp configured to fasten the stopper flange of the deck of the spar, the elastomer layer, and the top outer flange of the at least one void compartment, together.

5. The modular can of claim 1, wherein the plurality of compartments are bolted head to toe.

6. A spar for use as a floating platform in deep waters, comprising:

a spar deck;

a hull surrounding a center well, wherein the center well is partitioned by walls that form a plurality of slots, wherein at least one of the slots include a compliant guide mounted to some of the walls;

tanks surrounding the hull below the spar deck;

a truss located below the tanks and coupled to the tanks;

a soft tank located below the truss and coupled to the truss;

a modular can located in the at least one of the slots, the modular can including:

a plurality of compartments releasably connected to one another; and

means for coupling the buoyancy can to the spar;

wherein the means for coupling the buoyancy can to the spar interface with the spar at the compliant guide; and

wherein, in use, the spar is supported by the modular can at one or more of the spar deck, the compliant guide, and the soft can, so that the buoyancy capacity of the spar is enhanced.

7. The spar of claim 6, wherein the plurality of compartments comprise:

at least one void compartment directly or indirectly connected to at least one an air-over-water compartment;

wherein the at least one void compartment comprises a top deck, a cylindrical inner shell connected below the top deck, and a bottom deck connected below the cylindrical inner shell;

wherein the top deck, the cylindrical inner shell, and the bottom deck form a close compartment that encloses a void space; and

8. The spar of claim 7, wherein the means for coupling the buoyancy can to the spar comprise a structural layer that surrounds the cylindrical inner shell of the at least one an air-over-water compartment and extends above and below the watertight deck of the at least one an air-over-water compartment.

9. The spar of claim 7, further comprising:

an elastomer layer sized to fit between the top outer flange of the at least one void compartment and a stopper flange of the spar deck; and

a clamp configured to fasten the stopper flange of the spar deck, the elastomer layer, and the top outer flange of the at least one void compartment, together.

10. The spar of claim 6, wherein the plurality of compartments are bolted head to toe.

11. The spar of claim 10, further comprising locking dogs located on the spar deck around the at least one slot, the locking dock having an extended configuration wherein the locking dogs are capable of retaining the modular can in or above the at least one slot, and a retracted configuration wherein the locking dogs allow the modular can to be lowered into the at least one slot.

12. A method of enhancing a buoyancy capacity of a spar, the spar including a spar deck, a hull surrounding a center well, wherein the center well is partitioned by walls that form a plurality of slots inside the hull, wherein at least one of the slots include a compliant guide mounted to some of the walls, the spar further including tanks surrounding the hull below the spar deck, a truss located below the tanks and coupled to the tanks, and a soft tank located below the truss and coupled to the truss, the method comprising:

providing a modular can, the modular can including:

a plurality of compartments releasably connected to one another; and

means for coupling the buoyancy can to the spar;

placing the modular can in the at least one of the slots;

interfacing the means for coupling the buoyancy can to the spar with the spar at the compliant guide; and

using the modular can to support the spar at one or more of the spar deck, the compliant guide, and the soft can.

13. The method of claim 12, wherein the plurality of compartments comprise:

at least one void compartment directly or indirectly connected to at least one an air-over-water compartment;

wherein the at least one void compartment comprises a top deck, a cylindrical inner shell connected below the top deck, and a bottom deck connected below the cylindrical inner shell;

wherein the top deck, the cylindrical inner shell, and the bottom deck form a close compartment that encloses a void space; and

14. The method of claim 13, wherein the means for coupling the buoyancy can to the spar comprise a structural layer that surrounds the cylindrical inner shell of the at least one an air-over-water compartment and extends above and below the watertight deck of the at least one an air-over-water compartment.

15. The method of claim 13, further comprising:

providing an elastomer layer sized to fit between the top outer flange of the at least one void compartment and a stopper flange of the spar deck; and

providing a clamp; and

fastening the stopper flange of the spar deck, the elastomer layer, and the top outer flange of the at least one void compartment, together.

16. The method of claim 12, comprising bolting the plurality of compartments head to toe.

17. The method of claim 16, further comprising:

hoisting a first of the plurality of compartments in or above the at least one of the slots;

extending locking dogs located on the spar deck around the at least one slot to retain the first of the plurality of compartments in or above the at least one of the slots;

hoisting a second of the plurality of compartments on top of the first of the plurality of compartments;

bolting the second of the plurality of compartments to the first of the plurality of compartments;

retracting locking dogs the locking dogs to allow the first of the plurality of compartments and the second of the plurality of compartments to be lowered into the at least one slot.

Resources

Images & Drawings included:

Fig. 01 - APPARATUS AND METHOD FOR ENHANCING BUOYANCY CAPACITY OF A SPAR — Fig. 01

Fig. 02 - APPARATUS AND METHOD FOR ENHANCING BUOYANCY CAPACITY OF A SPAR — Fig. 02

Fig. 03 - APPARATUS AND METHOD FOR ENHANCING BUOYANCY CAPACITY OF A SPAR — Fig. 03

Fig. 04 - APPARATUS AND METHOD FOR ENHANCING BUOYANCY CAPACITY OF A SPAR — Fig. 04

Fig. 05 - APPARATUS AND METHOD FOR ENHANCING BUOYANCY CAPACITY OF A SPAR — Fig. 05

Fig. 06 - APPARATUS AND METHOD FOR ENHANCING BUOYANCY CAPACITY OF A SPAR — Fig. 06

Fig. 07 - APPARATUS AND METHOD FOR ENHANCING BUOYANCY CAPACITY OF A SPAR — Fig. 07

Fig. 08 - APPARATUS AND METHOD FOR ENHANCING BUOYANCY CAPACITY OF A SPAR — Fig. 08

Fig. 09 - APPARATUS AND METHOD FOR ENHANCING BUOYANCY CAPACITY OF A SPAR — Fig. 09

Fig. 10 - APPARATUS AND METHOD FOR ENHANCING BUOYANCY CAPACITY OF A SPAR — Fig. 10

Sources:

United States Patent and Trademark Office - verify current appl. status at the USPTO↗

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