Abstract:
A subsea fluid collector is provided, comprising a container having a fluid inlet and a fluid outlet, and a vessel positioning device which is attachable to a submerged vessel leaking oil or other fluids. The container is positioned by the vessel positioning device to receive, through the fluid inlet, a leaking fluid (such as crude oil, gasoline, diesel, or the like) exiting from a fluid leak source on the vessel, and the water residing within the container is displaced as leaking fluid enters the container. The vessel positioning device may be attached or detached from the vessel by divers or remotely using a remotely operated vehicle (ROV). In one embodiment, the container may be guided into position above the leak by a guide cable. Once the container is filled by the leaking fluid, it ascends to the surface of the sea for retrieval and removal of the contents.

Description:
RELATION TO PRIOR APPLICATIONS  
       [0001]     This nonprovisional application is based on prior provisional applications, U.S. Ser. No. 60/436,119 filed on Dec. 23, 2002, and U.S. Ser. No. 60/444,028 filed on Jan. 31, 2003. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     I. Field of the Invention  
         [0003]     The present invention relates generally to devices and methods used to contain leaks of oil and other liquids having a specific gravity less than that of water from vessels or other fluid-containing structures below the surface of the ocean or any other body of water.  
         [0004]     II. Background and Prior Art  
         [0005]     It is well known that oil tankers, barges, and other oil-containing vessels occasionally sustain damage and release the contents of their cargo into the surrounding water. The cargo is typically oil, although other combustible fuels having a specific gravity less than water, such as gasoline, diesel, and kerosene, are often transported in this manner. Because the most common cargo is oil, however, that term will be used exclusively herein with the understanding that it is representative of all fluids having specific gravities less than 1.0. Such leaks sometimes occur when the vessel is still afloat, and in other cases, the vessel sinks to the bottom of the ocean and remains their permanently. In those instances when a vessel sinks, the oil may still be contained within the vessel, but may slowly leak out through the damaged hull or other opening. By virtue of its lower density, the oil will rise to the surface of the water. This accumulation of oil, sometimes referred to as an “oil slick”, is particularly difficult to collect, prompting tremendous efforts over the last several decades to devise equipment and methods to remove the oil from the surface.  
         [0006]     Consequently, there is a great need for a system which can be employed to retrieve oil leaking from sunken vessels in a manner which prevents the oil from reaching the surface. Even if the oil-containing vessel is not leaking, the gradual effects of corrosion and ocean currents over the course of time will eventually cause the oil to escape from the vessel. Therefore, it is desirable to have an oil collection system which can also be positioned above a release hole formed into the penetrated hull of the vessel to remove the oil.  
       SUMMARY OF THE INVENTION  
       [0007]     Therefore, one object of the present invention is to provide a subsea oil collector which collects oil from below the surface of the water.  
         [0008]     It is also an object of the present invention to provide a subsea oil collector which can be positioned on the hull of a vessel at a select location.  
         [0009]     A further object of the present invention is to provide a subsea oil collector which can be retrieved onto surface vessels or emptied in accordance with acceptable methods.  
         [0010]     Another object of the present invention is to provide a subsea oil collector which can be guided into place by a remotely operated vehicle (ROV).  
         [0011]     Accordingly, a subsea fluid collector is provided, comprising a container having a fluid inlet and a fluid outlet; a vessel positioning device operatively connected to the container; a closure mechanism to close the fluid inlet; and a closure mechanism to close the fluid outlet; wherein the container is positioned by the vessel positioning device to receive, through the fluid inlet, a leaking fluid (such as crude oil, gasoline, diesel, or the like) exiting from a fluid leak source on the vessel, and wherein water, if any, residing within the container is displaced as leaking fluid enters the container. Preferably, the vessel positioning device includes means for attaching to and detaching from the vessel, and is optionally controlled remotely. Also, it is preferable that both the inlet aclosure mechanism and outlet closure mechanism are controlled remotely, or by the volume of fluid collected within the container. In a preferred embodiment, the container has negative buoyancy prior to being filled with the leaked fluid.  
         [0012]     In an alternate embodiment, the collector further includes a buoy residing at or near the surface of the water; and a guide cable having a first end operatively attached to the buoy, and a second end operatively attached at or near the fluid leak source; and wherein the container is slidably attached to the guide cable for ascent and descent. Optionally, a speed control means for controlling the speed at which the container slides along the cable is also present. In a further arrangement, the collector further inclues a fluid conduit operatively connected between the fluid outlet on the container and the buoy, wherein the conduit permits transfer of fluid from the container to the buoy.  
         [0013]     In another alternate embodiment, the collector further includes a ballast chain and handling wire wherein the container is attached to ballast chain which is in turn attached to a lighter, high tensile, handling wire. The chain provides negative buoyancy to assist the container on its descent. Once the container reaches the ocean bottom, and the ballast chain lays on the ocean bottom, the container can be more easily maneuvered by an ROV with the assistance of the handling wire. The handling wire can be retrieved onto a reel type mechanism to assist the collector with a controlled ascent after it has been filled with fluids.  
         [0014]     A method for collecting fluids below the sea is also disclosed, comprising the steps of providing a fluid collection container having a positioning mechanism, a fluid inlet, and a fluid outlet; mounting the container using the positioning device to a submerged vessel having a fluid leak source and positioning the fluid inlet above the leak source; permitting the leaking fluid to enter the container until the container is filled with fluid; closing the fluid inlet; and moving the container to the sea surface where it can be retrieved onto a surface vessel or the fluids can be transferred to a surface vessel. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]      FIG. 1  is an elevation view of a preferred embodiment of the present invention, depicting the subsea oil collector in an operating configuration.  
         [0016]      FIG. 2  is another view of the embodiment of  FIG. 1  offloading the contents of the collector to a barge.  
         [0017]      FIG. 3  is an elevation view of an alternative embodiment of the present invention depicting the subsea oil collector in an operating configuration, while offloading fluids into a barge at the ocean surface, and attached to a guide cable extending between a submerged vessel and a surface ship.  
         [0018]      FIG. 4  is an elevation view of a third embodiment of the present invention depicting the subsea oil collector as including a ballast chain and handling wire device.  
         [0019]      FIG. 5  is yet another embodiment employing features common to those in  FIGS. 1-4 .  
         [0020]      FIG. 6  is another view of the embodiment of  FIG. 3  depicting the subsea oil collector in an operating configuration near the ocean bottom, while collecting fluids from the leaking source.  
         [0021]      FIG. 7  is an elevation view of an alternative embodiment depicting the subsea oil collector attached to a guide cable extending between a submerged vessel and a buoy.  
         [0022]      FIG. 8  is an elevation view of a basic alternative embodiment depicting the subsea oil colletor in an operating configuration without the attachment of any cables or wires. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0023]     Unless otherwise noted herein, all construction materials are fluid impervious, and all attachments between such components are structurally sound. Materials and methods are intended to impart a maximum level of strength and structural rigidity, while keeping the invention as lightweight and easy to use as possible. Certain features which are used in assembling or operating the invention, but which are known to those of ordinary skill in the art and not bearing upon points of novelty, such as screws, bolts, nuts, welds, and other common fasteners, may not be shown for clarity.  
         [0024]     In preparation for use of the invention to be described below, a large release hole  11  is cut into one of the tanks on the submerged tanker or other vessel  10  using an ROV (in deep water) or by divers (at depths enabling diver operations). Immediately after the release hole  11  is formed, a closure mechanism is immediately installed on the vessel  10 , such as a magnetic cap, valve, or other suitable device capable of substantially sealing the release hole  11 , to prevent the premature release of fluids  12  through hole  11 .  
         [0025]     Turning now to the figures, a preferred embodiment of a subsea oil collector  1  is illustrated in an elevation view in  FIG. 1 . The collector  1  is shown in an operating configuration below the surface of the sea  6 , and includes a container  2 , which can be either a rigid structure or of flexible material, having a fluid inlet  3  and a fluid outlet  4 . The holding volume of the container  2  may be approximately 100,000 gallons, although this size may vary depending on the circumstances. The container  2  includes a positioning device  5 , which can simply be one or more link chains, cables or a mechanical latching device, which operates to position the container  2  above a vessel  10  which has a leak source  11 . Fluid  12  leaking from the leak source  11  is typically oil, gasoline or some other hydrocarbon-based fluid which has a positive buoyancy, e.g. a specific gravity less than that of the surrounding water. In the absence of the present invention, such fluid  12  would simply float to the surface  6  and form a “slick,” which is exceedingly difficult and expensive to contain and remove. Preferably, the collector  1  has a “negative” buoyancy upon entering the water, such that its weight and density will enable it to sink toward the vessel  10  relatively unassisted.  
         [0026]     In the embodiment of  FIG. 1 , the container  2  is suspended from a tethered cable  40  which is attached to the top of container  2  and originating from some other structure, typically a ship, barge, or other first surface vessel  41 , located on the sea surface  6 . Most conveniently, the cable  40  is attached to a cable storage reel  42  on the first surface vessel  41 , such that unwinding of the reel  42  permits the container  2  to sink toward the submerged vessel  10 , and winding of the reel  42  raises the container  2  for further handling.  
         [0027]     With specific reference to the container  2 , inlet  3  may include a closure device or valve  7  which seals the container  2  at that location when closed, and which permits fluid  12  to enter container  2  when open. In typical applications, inlet  3  may range from  24  inches to  36  inches in diameter to accommodate the flow of fluids  12  released from hole  11 , although the specific size may vary depending upon the precise needs of the situation. Similarly, outlet  4  also includes a closure device or valve  8  which remains closed as the container  2  is filled with fluid  12 , but which can be opened to release the contents of the container  2  when it is retrieved. Both of closure devices  7 ,  8  may be opened and closed manually by divers or by an ROV, depending upon the depth of the water. Alternatively, either or both of closure devices  7 ,  8  can be opened or closed responsive to operating conditions or a fill condition of the container  2 . For example, inlet closure device  7  may be caused to close by a motor or other common solenoid device upon an electronic signal generated from buoyancy sensors indicating that the container  2  is becoming completely filled with fluid  12 .  
         [0028]     Once the container  2  is positioned directly above the hole  11  or other leak source, the positioning device  5  is preferably attached to the vessel  10 . This task would be performed either by divers at the site or by an ROV depending on the depth. The outlet closure device  8  is closed to seal outlet  4 , and fluid  12  rises into the inlet  3  and displaces any water, if any, residing within the container  2 . As the volume of fluid  12  increases within the container  2 , water is continuously expelled through the inlet  3  until the container  2  is completely filled with fluid  12 . Since the density of the oil is less than the density of the water, the oil will float to the top of container  2  while displacing the water to the bottom of container  2  and then out through inlet  3 . When the container  2  is filled with fluid  12 , the inlet  3  is closed. Next, the positioning device  5  is detached from the vessel  10  in preparation for retrieval of the fluid-filled container  2 .  
         [0029]     Preferably, the materials of construction of the container  2  and the positioning device  5  are such that the filled container  2  will ascend without assistance due to its increased buoyancy. If desired, additional flotation devices, such as buoyant materials commonly used for deep water marine applications, may also be installed onto the container  2 .  
         [0030]     With respect to the attachment and detachment of the positioning device  5 , the positioning device  5  may also comprise mechanical devices or additional ropes or cables with anchors to ensure that the collector  1  is securely in place over the release hole  11 . Alternatively, the positioning device  5  may be detached in response to some other condition, such as by the closing of inlet closure device  7  or by reaching a predetermined volume of fluid  12  within container  2 . In either case, it is essential that the anchoring or attachment of the positioning device  5  be sufficiently secure to prevent the premature ascendence of the container  2  due to the increased buoyancy during collection of the fluid  12 .  
         [0031]     Although not required, the container  2  may be constructed from a tightly woven scrim that is permeable by water but not by the leaking fluid, e.g. crude oil. In this configuration, water can simply be passed through the sides of the container  2  as fluid  12  fills the container  2 . Preferably, the top of the container  2  may be formed in the shape of an inverted cone, because the buoyancy forces applied to the top of the container  2  when filled will impart significant stresses to the fabricated container  2 . Constructing the top of the container  2  in this manner should serve to minimize such stress and avoid possible tearing.  
         [0032]      FIG. 2  illustrates a preferred manner in which the contents of the collector  1  are offloaded. Upon closure of the inlet closure device  7  and release of the positioning devices  5  from the vessel  10 , a magnetic cover or other closure for the release hole  11  is reapplied as explained earlier. Since the container  2  is filled with oil, it should then naturally rise due to its positive buoyancy. As the container  2  approaches the surface  6 , an ROV or divers maneuver the container  2  toward the underside of a barge  43  or other containment vessel. The barge  43  includes an underside inlet  44  which is sized and shaped to interface with the outlet  4  of container  2 . Once the outlet  4  is connected to the barge inlet  44 , positioning devices  45  in the form of chains, cables, or other suitable means, are used to secure the container  2  to the barge  43 . Next, outlet closure device  8  is opened to allow the buoyant fluid  12  to enter the barge  43 . Generally, the buoyancy of the fluid  12  will be sufficient to convey the contents of container  2  directly into barge  43 , although assisted emptying of container  2  may be accomplished by pumps or vacuum methods known to those of ordinary skill in this field. Finally, when the container  2  is substantially empty, the outlet  4  is closed, and the positioning devices  45  are released, causing the empty collector  1 , due to its negative buoyancy, to sink back down toward the vessel  10  for another collection cycle. It should also be noted that although a second surface vessel in the form of barge  43  is described in this embodiment, it is also possible for the first surface vessel  41  to serve as the offloading location if it includes suitable storage compartments similar to those of barge  43 .  
         [0033]     In  FIGS. 3 and 6 , an alternative embodiment of the invention is shown, and further includes a barge  43  or other containment vessel residing at or near the surface  6  of the water and a guide cable  21 . The guide cable  21  includes a first end  22  operatively attached to the barge  43 , and a second end  23  operatively attached in close proximity to the fluid leak source, such as to a mechanical fastener which has been installed in or near the release hole  11 . Alternatively, the second end  23  can be attached to anchors adjacent to the release hole  11 . In this embodiment, the second end  23  of the guide cable  21  is attached either by divers or by an ROV depending upon the depth. The guide cable  21  serves as a guide for the container  2 , and is passed through a guide tube  24  extending within the center of the container  2 , thus making the container  2  slidably attached to the guide cable  21 . Optionally, the guide tube  24  may be attached to the outside of the container  2  with substantially the same effect. Also, while it is believed that a single guide cable  21  may be sufficient for most purposes, two or more such guide cables  21  may be employed to maintain the orientation of the container  2 . Thus, as container  2  is introduced into the water and descends toward the vessel  10 , it is guided and positioned above the release hole  11  with minimal assistance. Optionally, the collector  1  may include speed control means for controlling the speed at which the container  2  slides along the guide cable  21  during descent to the vessel  10 . For example, one such speed control means may comprise a friction-type lock which slows the rate of descent, but which also locks against the guide cable  21  once the container  2  reaches the vessel  10 . In this manner, the speed control device contributes to the secure placement of the container  2  and prevents its premature ascendance. Once the container  2  is properly in place, the positioning devices  5  are applied and the closure device or cover for the release hole  11  is opened by divers or by ROV, and the fluid  12  commences to fill the container  2 , as shown in  FIG. 6 . When the container  2  is filled, the inlet  3  is closed as with the previous embodiment, and the closure device over the release hole  11  is replaced. Next, the locking mechanism is released by the divers or ROV, along with the positioning devices  5 , and the container  2  should rise due to its positive buoyancy. Offloading of the container  2  is essentially identical to the procedure described for the previous embodiment, except for the ease with which the container  2  may be guided toward the barge  43  by the guide cable  21 .  
         [0034]      FIG. 4  illustrates a third embodiment of the present invention, depicting a variation on the first embodiment described above. Although the prior embodiments may be employed at a variety of depths, this embodiment is particularly suited to extreme depths, i.e. greater than about 5,000 feet. Specifically, the tethered cable  51  originates from a reel  42  similar to that described earlier, and it is attached at its opposite end  53  to the terminal end  54  of a ballast chain  55  or other suitably heavy and flexible device which can be used as will be explained below. Preferably, the cable  51  is constructed from a light, high tensile strength material whose weight at extreme depths will not significantly hinder the maneauverability of the container  2 , and which can be easily spooled and unspooled for frequent collection cycles over extended periods of time. In this embodiment, assuming that the ballast chain  55  is attached to the top of the container  2 , the ballast chain  55  is at least as long as the height and width of the container  2 , such that a portion of the ballast chain  55  may come to rest upon the surrounding surfaces. For example, as the container  2  comes into contact with the vessel  10 , the ballast chain  55  continues to sink and rest upon the surrounding surfaces or the ocean bottom. This effectively temporarily anchors the container  2  at the vessel  10 , but still permits the ROV to move the container  2  from side to side with much less power required than without the presence of the ballast chain  55 .  
         [0035]      FIG. 5  is another embodiment which depicts an elongated container  2  slidably attached to a guide cable  21 , but which also includes a ballast chain  55  connected to a handling wire or cable  51  as described earlier. In this embodiment, the guide cable  21  would be attached between the vessel  10  and the offloading barge  43 , which the handling wire  51  originates from a reel  42  either on the same barge  43  or on another support vessel  41 . Note that in this embodiment, the ballast chain  55  is attached roughly midway along the container  2 , such that the only length requirement of the ballast chain  55  is that there be at least some portion of its length that will rest upon the surrounding surfaces when the container  2  is secured to the leaking vessel  10 .  
         [0036]      FIG. 7  illustrates another embodiment of the invention in which the container  2 , as described previously herein with respect to  FIGS. 3 and 6 , is slidably attached to a cable having a first end  22  attached to a buoy floating at or near the surface of the water. Optionally, the buoy may comprise a floating fluid vessel, and an additional conduit fluidically connected between the top of container  2  and the buoy or floating fluid vessel. In this manner, fluids collected within container  2  may rise through the conduit and into the floating fluid vessel, which can then be removed or emptied as described earlier herein.  
         [0037]     Finally,  FIG. 8  depicts the simplest embodiment in which the container  2  is maneuvered to its submerged position and retrieved for removal or emptying entirely by ROV or divers. Although both of these embodiments require the greatest amount of manual handling, their relatively inexpensive costs, in terms of both labor and equipment, may make them suitable for a variety of applications, such as in shallow water.  
         [0038]     In all of the above described embodiments, an offloading pump on board surface vessels  43  may be used to connect to the outlet  4  to pump out fluids  12  within the container  2 . The fluids  12  may be pumped into towable bladders or into other barges on site. If necessary, a steam collar may be affixed to the outlet  4  to heat and facilitate offloading of highly viscous fluids  12 . Also, the filled container  2  may be towed to land for offloading or transported on a vessel to port for offloading at another site.  
         [0039]     Although exemplary embodiments of the present invention have been shown and described, many changes, modifications, and substitutions may be made by one having ordinary skill in the art without necessarily departing from the spirit and scope of the invention. For example, the invention could be adapted to capture oil that rises from naturally occurring oil seeps in the ocean floor, by modifying the mounting device as necessary to attach to sea floor structures.