Abstract:
A collapsible marine riser fairing that includes members configured to retract into a storage space and be deployed from the storage space when needed. The collapsible fairing is semi-permanently attached to the riser.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Application No. 61/496,631 filed Jun. 14, 2011. 
    
    
     TECHNICAL FIELD 
     A storage system for a marine riser fairing that would be semi-permanently attached to a slick joint or imbedded in a section of a buoyancy or encapsulation module in such a manner that it would eliminate the need to remove the fairing when pulling the riser out of the water and stowing it in the riser bay. 
     BACKGROUND OF THE INVENTION 
     This invention is meant to tackle the three primary problems with the use of marine riser fairings, the first being the time it takes to install/remove a fairing, the need to plan for a separate storage location for riser fairings aboard the drilling vessels, and the need to move the fairings from storage to the installation station. 
     This problem has been tackled in the past by trying to reduce the time it takes to install riser fairings. Several ways in which this has been achieved is by simplifying the steps needed to secure the connections/attachments to the buoyancy joints and reducing the fairing length/size for ease of handling. 
     BRIEF SUMMARY OF THE INVENTION 
     The invention is directed to a self contained collapsible/expandable marine riser fairing that would expand from and collapse int o a storage system strapped to a slick or buoyant or encapsulated joint of the riser. 
     The collapsible marine riser fairing comprises members configured to retract into a storage space and be deployed from the storage space when needed, wherein the collapsible fairing is semi-permanently attached to the riser. The storage space is a storage box that additionally comprises low friction attachment straps for attaching the box to the riser. The collapsible riser fairing can be stowed within a buoyancy joint or an encapsulated joint of the riser. 
     The members of the collapsible fairing comprises interlocking panels that are adapted to fold into the storage space and form a pyramid type shape when deployed. The interlocking panels include locking studs. Additional material is attached to the outside of the members in order to create a smooth foil when the members are deployed. 
     The members of the collapsible fairing comprise foldable sections in which the foldable sections are adapted to collapse to a map fold. The foldable sections are adapted to collapse to an accordion fold. 
     The fairing further comprises a deployment mechanism. The deployment mechanism is a scissor jack. 
     A member of the collapsible fairing comprises a wing section. The members comprise two wings sections that are spaced apart and attached to the riser. Malleable material is attached to and between the two wing sections and is adapted to form a smooth foil when the collapsible fairing is deployed. 
     The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. The novel features which are believed to be characteristic of the invention, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of the present invention, reference is now made to the following descriptions taken in conjunction with the accompanying drawing, in which: 
         FIG. 1  is a cross section of a riser showing an embodiment of the invention embedded therein; 
         FIG. 2  is a profile cross section of a riser showing a scissor jack that may be used to deploy collapsible fairings; 
         FIG. 3  is a plane view of the top of a collapsible fairing storage box; 
         FIG. 4  is a cross section of a collapsible fairing storage box illustrating a scissor jack with cross bars; 
         FIG. 5  is the profile view of a riser with a deployed collapsible fairing shown straight on; 
         FIG. 6  is a cross section of a riser showing a stowed collapsible fairing; 
         FIG. 7  is a cross section of a riser showing a deployed collapsible fairing; 
         FIG. 8  is an example of a push-pull locking mechanism for the collapsible fairing; 
         FIG. 9  is a cross section of a partially deployed collapsible fairing; 
         FIG. 10  is a cross section of the fully deployed collapsible fairing of  FIG. 9 ; 
         FIG. 11  is another view of the deployed collapsible fairing of  FIGS. 9 and 10 ; 
         FIG. 12  is a cross section of another embodiment of the collapsible fairing illustrating a stowed collapsible fairing; 
         FIG. 13  is the deployed collapsible fairing of  FIG. 12 ; 
         FIG. 14  is a profile view of a deployed collapsible fairing comprising rotatable wings; 
         FIG. 15  is the stowed collapsible fairing of  FIG. 14 . 
         FIG. 16  illustrates a buoyancy joint with a section removed and the removable section of the joint; 
         FIG. 17  is a buoyancy joint with a section removed. 
         FIG. 18  is a buoyancy joint with a collapsible fairing storage box attached; 
         FIG. 19  is a buoyancy joint with a collapsible fairing storage box attached and the collapsible fairing deployed; 
         FIG. 20  is a buoyancy joint with a collapsible fairing storage box attached with additional material around the box; 
         FIG. 21  is a buoyancy joint with a collapsible fairing storage box attached and the collapsible fairing deployed with additional material around the box. 
         FIG. 22  is a buoyancy joint with a collapsible fairing storage box attached and the collapsible fairing deployed and also illustrates the removable section of the buoyancy joint; 
         FIG. 23  is a collapsible fairing storage box with attachment straps; 
         FIG. 24  is a collapsible fairing storage box with attachment straps with a collapsible fairing partially deployed; 
         FIG. 25  is a collapsible fairing storage box with attachment straps with the collapsible fairing of  FIG. 24  fully deployed; 
         FIG. 26  is a collapsible fairing storage box with attachment straps and with an embodiment of the stowed collapsible fairing; 
         FIG. 27  is a collapsible fairing storage box with attachment straps and with the collapsible fairing of  FIG. 26  partially deployed; 
         FIG. 28  is a collapsible fairing storage box with attachment straps and with the collapsible fairing of  FIGS. 26 and 27  fully deployed; 
         FIG. 29  is a cross section of the collapsible fairing storage box of  FIGS. 26-28  with the fairing fully deployed with an additional cover section; 
         FIG. 30  is a profile view of a riser including a channel for securing an attachment strap; 
         FIG. 31  is another view of a channel for securing an attachment strap; 
         FIG. 32  is a profile view of a riser with a collapsible fairing comprising two rotatable stowed wings; 
         FIG. 33  is a profile view of a riser with a collapsible fairing comprising two rotatable wings partially deployed; 
         FIG. 34  is a profile view of a riser with a collapsible fairing comprising two rotatable wings fully deployed; and 
         FIG. 35  illustrates a duel layer buoyancy joint with a collapsible fairing attachment. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The invention is directed to a self contained collapsible/expandable marine riser fairing that would expand from and collapse into a storage system strapped to a slick, encapsulated or buoyant joint of a riser. This would be achieved by means of a mechanical system such as a rotational mechanism to activate a scissor jack that would then elevate the sections of the fairing, or a push/pull motion that would lock the sections in place via the use of locking studs or other securing methods. Once the fairing is deployed or retracted the riser would either be lowered into the water or lifted from the drill floor on its way to the riser bay with the faring storage system still attached. Self-contained fairing and collapsible fairing are used herein interchangeably. 
     The faring storage system would be semi-permanently attached to the riser by means of low friction straps and a special frame for either a buoyant or slick joint. This frame would allow the faring to rotate around the riser joint and keep its end always facing downstream from the current. 
     The shape of riser will determine what shape will be used for the containment area. It may be box shaped, or of a more efficient configuration. The shape will be dependent on the riser slick/buoyant joint design and the location of the choke and kill lines with respect to the largest outer diameter of the joint. 
     In the case of a buoyant or encapsulated joint, the fairing storage unit would be fitted in a special buoyancy or encapsulation module containing a series of removable sections, these would allow the installation of the fairing containment system in such a way that it would be free to rotate about the vertical axis of the riser joint while keeping some of the buoyancy characteristics of the module. The removable sections would be secured to the containment box in such a manner that would allow them to also change direction with the fairing and current. 
     The slick joint version of the storage unit would be designed in a manner where its placement would locate it above the choke and kill lines allowing for rotational movement about the vertical axis. A special frame would be used to strap the containment system to the slick joint and the straps would be made of a low friction material in order to allow the fairing to maintain its orientation downstream from the current. The frame would have its dimensions dictated by the location of the choke/kill lines and the maximum clearances between the joints while stored in the riser bay. The frame may be circular in nature with channels cut into the outer surface in order to guide the straps and holes cut through it to allow the choke/kill lines to pass. The faring would be deployed and recovered using a mechanical system, requiring the use of a drill or any other more appropriate mechanisms. 
     The deployment system could be similar but not limited to a system that expands or collapses a crossbar, similar to a scissor jack frame allowing for a simple turning motion to activate the mechanism. In the case where such a system is impractical the fairing would be pushed or pulled from its containment. A locking system for the fairing sections would then be utilized to keep them in place. The system could use a pulley connected to wires that would rotate pins allowing the sections to move in or out of the containment system. 
     The fairing could be stowed within the container in any number of ways. For example, a pyramid/accordion type system could be used where different sections would be lifted from the compartment until their internal guides reach a stopper at the correct height of each section. The length of the pyramid along the vertical will remain equal in all sections. Only the transverse width will vary with height. (See  FIGS. 6 ,  7 , and  26 - 29 ). Alternatively, a map type system could be used where the faring sides would fold upon themselves as the deployment mechanism is retracted. (See  FIGS. 9-11  and  23 - 25 ) Alternatively, a folded wing type configuration could be used that would form part of the riser curvature and be pulled out into position and secured with a snapping mechanism. (See  FIGS. 14 ,  15  and  32 - 34 ) Dimensions of the fairing will be optimized to fit riser storage and to reduce vortex induced vibration Depending on the riser other deployment solutions could be applied to the concept. 
     The invention keeps the riser fairing stowed within a container that is attached to the riser instead of separately on deck. In one embodiment, the person responsible for deployment will only need to use one tool or motion in order to deploy the fairing. 
     An embodiment of the invention is a collapsible fairing that fits into a storage system and is attached to the riser in a way that allows the riser to be stored with the fairing storage box still attached to it. This will eliminate the need to remove the fairings every time the riser is deployed or retrieved. 
     The invention also makes the deployment of the riser simpler and safer; since it only needs one tool or a simplified motion to deploy the fairing from its containment enclosure. Thus, eliminating the need to lift fairing sections into place while running the riser into or out of the water. 
       FIGS. 1-5  illustrate an example of the collapsible fairing  100  in a riser  102  which is deployed using a scissor jack  104 . The collapsible fairing  100  in these figures is fully contained within the boundaries of the riser  102 . A scissor jack  104  comprising crossbars  106  may be used to deploy the fairing  100  through a power tool access point  108  which may be connected to a long screw  110  as demonstrated in  FIGS. 2 and 4 . When the screw  110  is turned the cross bar will move in a scissor like motion and increase the height of the top section, thereby deploying the collapsible fairing  100 .  FIG. 5  illustrates a deployed collapsible fairing  100 . 
       FIGS. 6-15  illustrate example embodiments of the structure of the collapsible fairing  100 .  FIGS. 6-8  show one embodiment of the collapsible fairing  100  structure which uses interlocking fairing sections  600 . In  FIGS. 6 and 7  the structure of the collapsible fairing  100  is comprised of a fairing sections  600 , individually labeled  601 ,  602 ,  603 ,  604 ,  605 ,  606 ,  607 ,  608 , and an end section  609  that may be pulled out of the riser  104 . For example, when the top section  609  is pull away from the riser  102 , the top section  609  will extend away from the riser and lock into place in fairing sections  607  and  608 . With additional pulling, sections  607  and  608  will lock into place with sections  605  and  606 , and so forth.  FIG. 6  illustrates the stored collapsible fairing  100 , while  FIG. 7  illustrates the deployed collapsible fairing  100 . The fairing  100  may lock in place via the use of locking studs  800  as demonstrated in  FIG. 8  or other securing methods. 
       FIGS. 9-11  illustrate another example embodiment of the collapsible fairing  100  structure. In this embodiment, the collapsible fairing  100  is comprised of foldable sections  900 .  FIG. 9  illustrates a partially deployed fairing  100  while  FIGS. 10 and 11  illustrate two deployed views of this embodiment of the collapsible fairing  100 . 
       FIGS. 12 and 13  illustrate a further embodiment of the collapsible fairing  100  structure. In this embodiment the fairing  100  comprises two cut out sections  1100  and  1102  of the riser  102 . The two cut out sections  1100  and  1102  slide relative to the riser  102 , until the end of the slide when the cut out sections  1100  and  1102  are rotatable towards each other, such that the tips of the cut out sections  1100  and  1102  meet to form a fairing, as illustrated in  FIG. 13 . The sections are attached to the riser in the stored position by means of rail glides or slides (not shown). The two end sections of the cut out sections  1100  and  1102  are attached together and the opposing end sections are locked into place at the riser  102  when in a deployed position, thereby locking the cut out sections  1100  and  1102  in the deployed position. In this case the buoyancy module would be composed of two sections. An inner section that would contain the buoyant material along with some guide channels cut into it. The outer section would contain a rail that would either be made of a low friction material or be water lubricated. The outer section could also be neutral or buoyant depending on how the buoyancy impacts the rotation. It can be constructed of two half sections (one section would contain the fairing, while the other will be bare) that would be bolted together on top of the lower section. 
       FIGS. 14 and 15  illustrate another embodiment of the collapsible fairing  100 . In this embodiment two wing like sections  1401  and  1402  attached to each other at corners  1404  are laid flush against the riser  102  in the stored position as shown in  FIG. 15 . The wing like sections  1401  and  1402  are attached to the riser  102  at end  1406  by a means that allows the wing like sections  1401  and  1402  to pivot. The collapsible fairing  100  is deployed by rotating the wings away from the riser  102  and securing corners  1408  together. This embodiment may also be attached to the riser as described above for  FIGS. 12 and 13 . 
       FIGS. 16-21  illustrate an embodiment of the invention, where the collapsible fairing  100  is contained within a buoyancy joint  1600  of the riser.  FIG. 16  shows a removable section  1602  of the buoyancy joint  1600 .  FIG. 17  also shows the modified buoyancy joint  1600  without the removable section  1602 . In place of the removable section  1602 , a fairing storage box  1800  is attached to the buoyancy joint  1600 , as shown in  FIG. 18 . The fairing storage box may comprise six sides including a door or doors located on the top of the fairing storage box. The fairing storage box may also comprise only a base plate to which the sides of the collapsible fairing are attached. In stowed form, the collapsible fairing may form the sides and the top of the fairing storage box. The fairing storage box is attached to the buoyancy joint by means of low friction straps  1802  to allow for movement of the fairing around the circumference of the buoyancy joint  1600 .  FIG. 19  illustrates the collapsible fairing  100  after being deployed from the fairing storage box  1800 . The current C in  FIG. 19  is flowing in the direction of the arrow. Additional buoyancy or buoyancy neutral material  2000  maybe incorporated around the fairing storage box  1800  such that the circumference of the buoyancy joint  1600  is maintained through the section incorporating the fairing storage box  1800 , as shown in  FIG. 20 .  FIG. 21  illustrates the buoyancy joint with additional material  2000  and with the collapsible fairing  100  deployed.  FIG. 22  also shows the deployed collapsible fairing  100  without the removable section  1602 .  FIG. 23  shows an example of a closed fairing storage box  1800  with attachment straps  1802 .  FIG. 24  shows an example of a collapsible fairing  100  partially deployed from the fairing storage box  1800 .  FIG. 25  shows an example of the collapsible fairing  100  fully deployed from the fairing storage box  1800 . 
       FIGS. 26-28  illustrate another embodiment of the collapsible fairing  100  and fairing storage box  1800 .  FIG. 26  shows the fully collapsed fairing stowed in the fairing storage box  1800 . The collapsible fairing in this embodiment is made up of panels  105 . Each panel  105  is about the height of the fairing storage box  1800  ensuring a flush fit when stowed.  FIG. 27  illustrates the collapsible fairing  100  partially deployed.  FIG. 28  illustrates the fully deployed collapsible fairing  100 .  FIG. 29  shows the cross section of the fully deployed collapsible fairing of this embodiment. The collapsible fairing  100  may additionally include malleable material panels  2900  spanning the space between the tops of the fairing panels to allow for a smooth foil. 
       FIG. 30  illustrates an example of a collapsible fairing attachment. In this embodiment any of the fairing structures shown in  FIGS. 1-11  and  16 - 29  may be attached to the riser  102  by a securing strap channel  3000 . This securing strap channel  3000  is securely attached around the bare joint  3002 . Choke and kill lines  3004  extend through the securing strap channel through holes  3100  in the channel, as shown in  FIG. 31 . Attachment straps  1802  would be secured to the securing strap panel  3000  in such as way as to allow free movement of the fairing around the securing strap panel  3000 . In this way the fairing would rotate around the riser  102  with changing directions of current. 
       FIGS. 32-34  illustrate another embodiment of the collapsible fairing  100  structure. In this embodiment the collapsible fairing  100  is comprised of two wing like structures  3200  and  3202  spaced apart, as shown in  FIG. 32 .  FIG. 32  shows the wing like structures  3200  and  3202  in the stowed position. The wing like structures  3200  and  3202  are attached to the riser by a means that allows the wings to rotate away from the riser  102  as shown in elements  3208  and  3210 . The wing like structures  3200  and  3202  may additionally comprise latch knobs  3204  and  3206  that facilitate the rotation of the wing like panels, and lock the wing like structures into place when fully deployed or fully stowed.  FIG. 33  shows the collapsible fairing  100  in a partially deployed condition. The collapsible fairing may additionally comprise a folded sheet of material  3212  that unfolds to create the body of the deployed collapsible fairing.  FIG. 34  shows the collapsible fairing  100  in a fully deployed condition. In this embodiment, the collapsible fairing  100  hugs the riser  102  without having to store the fairing in an additional containment box. 
       FIGS. 35-38  illustrate another embodiment for attaching a collapsible riser fairing to a riser which is comprised of a buoyancy module made from two layers. The collapsible riser fairing embodiments of  FIGS. 12-15 , and  32 - 34  may be attached to the riser by the following attachment embodiment.  FIG. 35  shows a buoyancy modules that is composed of two layers, the inner layer  3500  and an outer layer  3502 . The layers be comprised of two separate sides which are attached around the riser  102  securely by mechanical attachments  3504 . The inner  3500  and outer  3502  layers of the buoyancy joint may be comprised of buoyant or buoyant neutral material. The outer layer  3502  houses the collapsible fairing  100 . 
     Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.