Containment unit and method of using same

Abstract

The present invention generally relates to containment and control of an oil spill caused by a damaged or broken riser in deepwater. More specifically, the present invention relates to a reusable unit that will contain oil spills to a specific location and will also allow oil to be harvested as it flows to the top of the unit while minimizing or even eliminating any environmental clean-up cost. The unit of the present invention is dropped over a damaged or broken riser in a closed position, the unit is released and stabilized in sections until the surface is reached and the containment unit is completely erected.

Claims

1. A containment unit for containing a leak of a material into an ambient fluid, the containment unit comprising: a weighted base for being disposed around the leak wherein the weighted base is rectangular and comprises first and second end pieces and braces connecting the first and second end pieces to one another, the first and second end pieces being spaced apart from one another to provide an opening configured to allow the ambient fluid to enter the containment unit, flow through the containment unit, and comingle with the material; a flotation unit attachable to the weighted base, the flotation unit comprising a flotation device and a barrier wall; and one or more additional flotation units attachable to and stackable on the flotation unit, the additional flotation units comprising additional flotation devices and additional barrier walls configured to contain the material; wherein the flotation device and the additional flotation devices comprise coated foam supported by a brace and have identical rectangular shape as the weighted base.

2. The containment unit of claim 1, wherein the containment unit is reusable.

3. The containment unit of claim 1, wherein the base comprises reinforced concrete supported by a brace.

4. The containment unit of claim 3, wherein the brace is metal.

5. The containment unit of claim 4, wherein the metal is aluminum.

6. The containment unit of claim 3, wherein the brace is PVC filled with concrete.

7. The containment unit of claim 1, wherein the brace is metal.

8. The containment unit of claim 7, wherein the metal is aluminum.

9. The containment unit of claim 1, wherein the brace is PVC filled with concrete.

10. The containment unit of claim 1, wherein the coated foam is Styrofoam coated with plastic or rubber.

11. The containment unit of claim 1, wherein the barrier walls and the additional barrier walls are flexible.

12. The containment unit of claim 1, wherein the barrier walls and the additional barrier walls comprise Kevlar or rubber.

13. The containment unit of claim 1, wherein the barrier walls and the additional barrier walls are reinforced.

14. The containment unit of claim 13, wherein the barrier walls and the additional barrier walls are reinforced with rubber coated cables or solid PVC piping.

15. The containment unit of claim 1, further comprising a storm cap.

16. The containment unit of claim 1, wherein the containment unit is a transfer tank.

17. The containment unit of claim 16, wherein the base is open.

18. The containment unit of claim 17, wherein a top of the containment unit is enclosed.

19. A method of using the containment unit of claim 1, the method comprising: deploying the containment unit to an ocean floor over a broken riser while the flotation unit and the additional flotation units are in a first, compressed position; releasing the flotation unit; releasing the additional flotation units sequentially until an ocean surface is reached; and anchoring the flotation unit and the additional flotation units as necessary before releasing a subsequent one of the additional flotation units.

20. A method of using the containment unit of claim 1, the method comprising: providing the weighted base around the leak; assembling the flotation unit and enough of the additional flotation units together to account for a depth of the ambient fluid; and anchoring the flotation unit and additional flotation units to the base.

21. The containment unit of claim 1, wherein the flotation unit and the additional flotation units have identical configurations to one another.

22. The containment unit of claim 1, wherein the flotation unit and the additional flotation units are sequentially releasable from compressed states into erected states at different respective depths of the ambient fluid.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIGS. 1-6 are schematics depicting the method of using the containment unit of a first preferred embodiment.

(2) FIGS. 7A-7D together form a schematic representation of a flotation device or weighted base according to the first preferred embodiment.

(3) FIGS. 8A and 8B together form a schematic representation of an erected containment unit according to the first preferred embodiment.

(4) FIG. 9 shows a containment unit according to a second preferred embodiment with a ship in a body of water.

(5) FIGS. 10A-10C are close-up views of variations of the containment unit according to the second preferred embodiment.

(6) FIG. 11 shows the containment unit according to the second preferred embodiment in position.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(7) Preferred embodiments of the invention will be set forth in detail with reference to the drawings, in which like reference numerals refer to like elements throughout.

(8) The containment unit of the first preferred embodiment is used by having a Remotely Operated Vehicle (ROV) deploy a compressed containment unit to the ocean floor over a broken riser. A first flotation unit is released, and subsequent flotation units are then sequentially released at about 1,000-foot increments until the ocean surface is reached. Each flotation unit is anchored to the ocean floor (preferably up to 3,000 feet from the ocean floor) or to tug boats/barges (preferably over 3,000 feet from the ocean floor) as necessary to stabilize each flotation unit before releasing a subsequent flotation unit.

(9) The result is an erected containment unit comprising multiple flotation units (depending on the depth needed) with flotation devices and Kevlar or rubber walls reinforced with cables, rubber coated cables or solid PVC piping, which keeps the spilled oil in one specific location and does not allow the oil to spread and contaminate the environment. The containment unit of the present invention also allows ships or tankers to draw the oil from the top of the unit.

(10) The process will now be described in greater detail. The specifics of the process are illustrative rather than limiting and can vary as determined by specific needs or conditions.

(11) As shown in FIG. 1, a compressed containment unit 102 containing multiple flotation units, preferably five flotation units (depending on the depth of the water, i.e., 5,000 feet), is placed around a broken or damaged riser 104 on the floor 106 of an ocean, gulf, or other body of salt water 108 having a surface 110.

(12) As shown in FIG. 2, the first flotation unit 202 is released. As shown, the base unit 204 is formed from concrete 206 with coated foam flotation devices on top. The first flotation unit 202 also has barrier walls 210 of Kevlar or rubber, reinforced by cables 212 connected by connectors 214. The flotation devices of the flotation unit 202 are made of coated foam braced with metal crossbars, in a manner to be explained below. Second through fourth flotation units 202 are compressed on top of the first flotation unit 202. The flotation unit 202 is 1,000 feet high and has an inner diameter sufficient to accommodate the riser.

(13) FIG. 3 shows the second flotation unit 202 released. FIG. 4 shows the third flotation unit 202 released. FIG. 5 shows the fourth flotation unit 202 released. A fifth flotation unit (not shown) is then deployed to reach 5,000 feet.

(14) FIG. 6 shows the erected containment unit 102. Each flotation unit 202 is anchored by cables 602 to anchors 604 as necessary before the next flotation unit 202 is released. Flotation units up to 3,000 feet from the ocean floor 106 can be anchored to the ocean floor 106. Flotation units above 3,000 feet from the ocean floor 106 can be anchored to tugboats or barges. A barrier 606 such as an oil boom is placed around the top of the containment unit 102 on the ocean's surface 110.

(15) FIGS. 7A-7D are top, perspective, first side, and second side views of a base unit or a flotation device. The two end pieces 702, which are formed of concrete for the base unit and of coated foam for the flotation devices, are connected by metal braces 704. Preferably, the metal is aluminum. Alternatively, the brace 704 is PVC filled with concrete. The coated foam is preferably about 8 feet thick and Styrofoam coated with plastic or rubber.

(16) FIGS. 8A and 8B are two side views of a fully extended containment unit 102, showing the flotation units 202, the base unit 204, the reinforcing cables 602, and the concrete anchors 604 anchored to the ocean floor 106. The base unit 204 provides an opening 802 to allow sea water to enter the containment unit 102 to prevent freezing of the oil.

(17) The containment unit is preferably made of flotation units 202 with barrier walls 210 comprising a synthetic fiber, preferably an aramid fiber material such as Kevlar or Twaron, reinforced with cable 212, with flotation units 202 at about 1,000-foot increments to form a stack or tower. Both the dimensions and the material are illustrative rather than limiting and can be determined by the circumstances. Alternatively, the walls 210 may be made of rubber. The flotation devices of the flotation units 202 are preferably braced with metal bars. The containment unit is preferably large enough to allow equipment to be deployed from the surface of the unit. More preferably, it can be used as a drafting tank, while protecting the environment.

(18) The containment unit of the first embodiment is preferably made up of 4 flotation units and 1 anchor unit. Each flotation unit preferably has an inside diameter of 3030 feet to accommodate a broken/damaged riser and Kevlar walls reinforced with rubber coated iron cables for frame support. The base unit is 2 to 4 tons and 20 feet high depending on the water depth. The containment unit may also be square, rectangle, oval or round.

(19) The walls are preferably made of a layer of Kevlar with a rubber coated cable frame and then another coat of Kevlar for added strength. When attached to the flotation units that will become the containment unit, the cables comprise 20,000 feet of Kevlar and cable frame. Each flotation unit will rise 1,000 feet. While Kevlar is given as an illustrative example, any other suitable material can be used, as long as it is impermeable to oil, flexible, and not broken down by oil or salt water. Kevlar is considered a good choice because it can withstand salt water for long-term deployments.

(20) The base unit serves as a platform and housing for the flotation units. All flotation units are stacked on top of the base unit and lowered to the ocean floor. Packing straps are released from the base unit to the top flotation unit, one at a time. Each section must be stabilized before moving to the next section at 1,000-foot increments. Preferably, all units are not released at once to avoid ripping of material and loss of control of the stacking process. The containment unit should be raised as straight as possible, but the pliable materials (Kevlar/cables) allow it to shift and sway with the movement of the ocean. Alternatively, the base unit could be made of clump weights and preinstalled.

(21) An ROV is utilized to release each flotation unit starting from base unit. Drop anchor blocks with attached cables at strategic points are used for structural support. As the first flotation unit is released, it will rise up 1,000 feet from the base, with or without the additional use of lift bags or air bags. The first flotation unit may or may not need anchor lines for support. If so, anchors are attached before the second flotation unit is released. Then the second unit is released and the containment unit is raised another 1,000 feet, i.e., 2,000 feet total, and anchor blocks are attached with cables to the flotation unit. ROVs are used to anchor all 4 sides every 1,000 feet. Then the ROV releases the third flotation unit and anchors it at 3,000 feet on 4 sides. This method is used up to 3,000 feet. Barges or tug boats are used once the containment unit is 4,000 to 5,000 feet high.

(22) At approximately 4,000 feet, anchor lines may be attached to barges or tug boats for additional support and stabilization of the units. At the surface of ocean, additional flotation units can be added to increase the height of the containment unit. An additional perimeter barrier such as an oil boom can be used around the surface containment section to capture any oil that may escape from the containment unit. As the riser loses pressure and oil flows to the surface, ships can draw oil from the surface inside the containment area.

(23) The completed structure is high enough to contain the oil while necessary repairs are done without allowing oil to reach the shoreline. On that note, the unit is a containment unit and not a tank; i.e., sea water will flow into the unit through an opening in the concrete base, and the oil, via pressure, will push upwards to the surface for capture by barges/ships on the surface. Sea water is necessary in order to avoid freezing of the oil at such depths.

(24) Preferably, the containment unit of the present invention is compressed for storage, such as by means of straps, preferably rubber or nylon straps. The packaging for deployment can include pulleys and other devices to prevent tangling of the cables. The cables themselves can be made out of metal, nylon, or any other material capable of withstanding the environment.

(25) The second preferred embodiment is constructed and used like the first preferred embodiment, with the flotation unit lowered in the closed position over the riser or other equipment and the anchor unit, and opened up from the bottom to the top. The second preferred embodiment uses a storm cap and buoy to contain oil (or gas, etc.) in a Kevlar (or other suitable material) column to direct flow to a production vessel/tanker. More specifically, as shown in FIG. 9, in the containment unit 900, the base 902 is attached with rigging or attachment cables 904 to a column 906 topped by a flotation device 908. Oil reaching the top of the column 906 enters an oil collection unit or storm cap 910 and is taken via a hose 912, preferably a large diameter hose, to a capture/containment vessel or transfer ship 914 on the surface 916 of the body of water 918. The second preferred embodiment provides a safer environment for capture vessels to operate at a safer distance from possible gas collection above the well. The hose 912 provides the link between the containment unit 900 and the capture/containment vessels 914. Additional options include the ability to inject hydrate inhibitors or dispersants to ensure flow.

(26) The storm cap 910 is a transfer tank that retains oil while allowing gas to escape. The containment unit 900 can be topped initially with a metal plate, which is then replaced with the storm cap 910 as necessary.

(27) One advantage of the present invention over conventional techniques is that only three ships are required: a transfer ship 914, which separates oil from water; a tanker 920, which carries the oil to shore, and a deployment ship 922, which deploys the unit 900. The containment unit 900 can be conveyed in a closed position by the deployment ship 922 and then opened and installed from bottom to top. Another is that the storm cap 910 can be used at various locations depending on local conditions, including storms. For example, the storm cap 910 can be located at the least pressure point. The gap between the storm cap 910 and the water's surface 916, in combination with the use of the hose 912, will protect ships from explosions.

(28) The second preferred embodiment provides for the containment and control of an oil spill caused by a damaged or faulty piece of subsea equipment in deepwater situations. The containment unit of the present invention is a cost-effective way to contain oil spills to a specific location and also allows the oil to be harvested as it flows to the top at the water surface, minimizing impact on the environment.

(29) The unit 900 itself is comprised of two major components. The first is a weighted base 902 measuring approximately 30 feet in diameter, preferably circular. The unit can also have different shapes to best suit the need of a specific situation. The base is made of concrete and embedded structural beams. Its purpose is to provide an anchor for the rest of the components to function properly. The unit 900 is deployed over a leaking structure 1002, such as a blowout preventer (BOP), on or near the seabed 1004 as shown in FIG. 10A.

(30) The second piece of the unit is a section of barrier composed of a flotation device 908 at the top of an encompassing perimeter 906 made of Kevlar or other such material which extends down from the flotation unit 1,000 feet. The sections are connected topside before deployment. The number of sections needed depends on the water depth on location, one section per 1,000 feet water depth. There are numerous ways to install and customize the above components to facilitate installation in adverse conditions such as high currents and well pressure. A guide by wire system may be used to attach barrier components to the concrete base. Provisions can also be made to supply enough mooring points to the overall unit to withstand currents and vibrations. This can be done with clump weights, a partial ring or other available methods to obtain stability.

(31) The Kevlar or other material provides an insulating column that acts as a barrier to keep the environment safe. The material is preferably light-weight to maintain stability during deployment and recovery. As seen in FIG. 10A, wire rope runners 1006, used as reinforcements, are attached from the top of the unit to the base concrete ring or a series of clump weights. The concrete ring or series of clump weights provides the needed weight to keep the containment unit in place, withstanding ocean currents and other forces. Adjustable, heavy-duty rigging 904 anchors the column 906 to the base 902. The rigging is adjustable, allowing greater flexibility in terms of ROV access to the BOP and maximizing containment.

(32) FIG. 10B shows a smaller diameter structure 900 used for a leaking riser (small diameter leak) with clump weights or a partial ring 1008. FIG. 10C shows a containment column 906 being lowered onto a BOP. FIG. 11 shows the containment unit 900 in position.

(33) The structure of the second embodiment provides: A sturdy concrete base that can be preinstalled before disaster strikes; A quick response deep sea containment structure; A safe solution to containment and control of an oil spill caused by a damaged or faulty piece of subsea equipment in deepwater situations; A cost-effective method to contain oil spills to a specific location; and The ability to harvest the oil as it flows to the top at the water surface, minimizing impact on the environment.

(34) In either of the preferred embodiments, or in any other embodiment, variations on the flotation device are possible. For example, lift bags can be used for quick erection, and the flotation devices are then used to keep the containment unit upright and erected. Although foam is preferred for the flotation devices because of its stability for long-term deployment in various environments, other suitable materials as would be known to one of skill in the art may also be used. Preferably, the foam should be able to provide sufficient lift, e.g., 1,000 lbs, to keep the containment unit upright. In addition to the flotation devices that are permanently mounted to the inside of the barrier at 1,000-foot increments, additional flotation devices may be added to the exterior of the barrier, i.e., flotation donuts. These flotation donuts may be fixed to the outside of the barrier or may be movable, i.e., they can be fixed to the exterior of the barrier during manufacture or during deployment. Also, the spacing can be varied; for example, the external (donut) flotation devices can be placed every 500 or 800 feet as the conditions warrant. In addition, the weighted base can be replaced by, or supplemented with, an anchoring scheme in which pins are shot into the mud at the sea floor.

(35) Having now described a few embodiments of the invention, it should be apparent to those skilled in the art that the foregoing is merely illustrative and not limiting, having been presented by way of example only. Numerous modifications and other embodiments are within the scope of the invention and any equivalent thereto. It can be appreciated that variations to the present invention would be readily apparent to those skilled in the art, and the present invention is intended to include those alternatives.

(36) Further, since numerous modifications will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to as falling within the scope of the invention. For example, numerical limitations are illustrative rather than limiting, as are recitations of particular materials. Also, the invention can be used to contain any leak of a material into an ambient fluid, in which the ambient fluid can be water, air for land-based uses, or the like. Therefore, the present invention should be construed as limited only by the appended claims.