Abstract:
The method of providing an accessible outlet on a subsea pipeline which has an unknown rotational orientation comprising connecting a first end of a flexible hose to the subsea pipeline, providing a multiplicity of connected bend restrictor sections around the flexible hose to restrict the bending of the hose, and providing buoyancy to the end of the hose such that the second end of the hose will remain accessible for future operations.

Description:
TECHNICAL FIELD 
       [0001]    This invention relates to the general subject of providing outlets for fluid connection to subsea pipelines. 
       CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0002]    Not applicable. 
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0003]    Not applicable 
       REFERENCE TO A “MICROFICHE APPENDIX” 
       [0004]    Not applicable 
       BACKGROUND OF THE INVENTION 
       [0005]    The field of this invention is that of pipelines in deep water where the process of laying the pipeline involves substantial stresses in the pipeline which can leave the exact orientation of the pipeline unknown. In the worst case scenario, the outlets on the pipeline can be oriented straight down and be completely inaccessible. Any orientation other than straight to the side or straight up typically involve substantial complications to any future tie-ins. 
         [0006]    Outlets are needed for a variety of reasons. The first is simply the immediate connection of another pipeline. The potential for future tie-ins also exists as when a pipeline is laid, the full extent of future tie-ins is not known. In some cases the original supply of gas planned for the pipeline can be depleted and other reservoir locations can be found to tie in to the pipeline, if appropriate connection points are available. 
         [0007]    In relatively deep water, water can accumulate in gas pipelines, slowing and sometimes completely stopping the flow. Frequently the production of natural gas also produces some water. When this water accumulates at the low point in the pipeline, it blocks the flow of water until the gas pushes the water in the upstream side down to the lowest point, with all the water pushed up the downstream side. The historic solution for this is to install a “pig” in the pipeline which seals on the internal bore of the pipeline and pumping it through the pipeline. As the pig sweeps through the pipeline, it will push the water out the other end. If the gas pressure is not sufficient, it will simply not be able to push the water up the other side. 
         [0008]    Another problem which exists is the tendency for gas pipelines to form hydrates when water is present. At the pressures and temperatures of deepwater subsea pipelines, hydrates can form and block pipelines for months. Hydrates are something similar to crushed ice which are a mixture of water and natural gas. 
         [0009]    There has long been a need for a more flexible way to make connections to subsea pipelines and a way to remove water from the pipelines, to remove other liquids from the pipeline, or to inject flow into the pipeline. Due to the probability that a contemporary pipeline will have an unpredictable orientation when it is laid on the sea floor, connection points are rarely added to pipelines or when they are they are provided with a large stabilizing skid to force them into a specific orientation. 
       BRIEF SUMMARY OF THE INVENTION 
       [0010]    The object of this invention is to provide a method of allowing pipelines to land in an unknown orientation when laid on the seafloor and still providing an outlet with a desired orientation. 
         [0011]    A second object of this invention is to provide an outlet in a subsea pipeline capable of removing unwanted liquids from the pipeline. 
         [0012]    A third object of this invention is to provide a method to allow the flow of gas or liquids from another subsea pipeline. 
         [0013]    Another object of the present invention is to provide a method of flowing gases and/or liquids into a subsea pipeline from another pipeline. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  is a view of a pipeline being laid with the outlet of this invention. 
           [0015]      FIG. 2 . Is a view of the pipeline of  FIG. 1  completely laid and being used to remove unwanted liquids from the pipeline. 
           [0016]      FIG. 3  is a view of a pipeline outlet being connected for an auxiliary pipeline. 
           [0017]      FIG. 4  is a perspective view of a portion of  FIG. 1  showing the outlet exiting the pipeline as it is being laid from the vessel. 
           [0018]      FIG. 5  is a partial section of the outlet showing the flexible hose and the surrounding bend restrictor. 
           [0019]      FIG. 6  is a closer view of a bend restrictor section showing an anti-rotation key. 
           [0020]      FIG. 7  is a perspective view of the outlet as would be seen if the subsea pipeline did not rotate during laying. 
           [0021]      FIG. 8  is a side view of the view of  FIG. 7 . 
           [0022]      FIG. 9  is an end view of  FIG. 8  as seen along lines “ 9 - 9 ” of  FIG. 8 . 
           [0023]      FIG. 10  is a view similar to  FIG. 9 , but with the subsea pipeline rotated 360 degrees. 
           [0024]      FIG. 11  is a view similar to  FIG. 10 , but with the subsea pipeline rotated only 180 degrees. 
           [0025]      FIG. 12  is a perspective view of  FIG. 11 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0026]    Referring now to  FIG. 1 , a subsea pipeline  10  is shown being laid on the seafloor  12  from an offshore structure  14  towards the shore  16 . A pipeline outlet  18  is connected into subsea pipeline  10  in a position such that it will land in a low point or subsea valley  20  in the pipeline path along the seafloor  12 . 
         [0027]    The pipelay vessel  22  is shown with the pipeline end  24  and buoy  26  which is connected to hose  28  which in turn is connected to pipeline outlet  18 . By attaching the hose  28  to the pipeline outlet  18  and in turn attaching the buoy  26  to the hose at the appropriate position, a single pipelay vessel  22  is able to both deploy the subsea pipeline  10  and the buoy  26 . 
         [0028]    Referring now to  FIG. 2 , the subsea pipeline  10  is fully laid on the ocean floor  12  with end  30  arriving at a shore facility (not shown). The pipeline outlet  18  is laid in the valley  20  with hose  28  going up to buoy  26  near the surface of the ocean. Water  32  is shown collected in the low portion of the subsea pipeline  10  in the valley  20 . Sufficient accumulations of water in the valley of the pipeline will stop the flow of gas in the pipeline. The outlet  18 , hose  28  and buoy  26  are utilized to remove the unwanted water from the subsea pipeline  10  by a surface vessel  34 . In the embodiment shown a remotely operated vehicle (ROV)  36  is deployed from the surface vessel  34 , engages the buoy  26  and operates a pump to pump the water out of the pipeline and to the surface. One method for doing this is to have a first hose with seawater flowing down to a motor proximate the pipeline outlet  18  to drive a pump to pump the pipeline water back up to the surface. 
         [0029]    Referring now to  FIG. 3 , the hose  40  is shorter than hose  28  of  FIG. 2  and buoy  42  provides a connection mandrel  44  facing upwardly. Pipeline  46  is lowered from vessel  48  with a connector  50  on the lower end for sealingly engaging with connection mandrel  44 . At this time the pipeline  46  can be laid along the ocean floor to other facilities as required. A characteristic of subsea pipelines as they are laid from deepwater vessels is that they frequently twist slightly. When a steel pipeline such as  46  twists 180 degrees, the rigidity of the pipeline tends to prevent it from being twisted and will cause the flexible hose at the end to absorb all the twist. If the hose  40  is short, i.e. 50 feet long, and is twisted 180 degrees it will frequently give the hose spiral failure. As will be seen in  FIG. 6 , the hose can be reinforced against spiral failure without limiting its flexibility. 
         [0030]    Referring now to  FIG. 4 , subsea pipeline  10  is shown with an outlet hose  28  protected at its lower end by a multiplicity of bend restrictor sections  60  and attached a control package  62 . Control package section  62  can comprise shut-off valves, check valves, and/or pumps as are required for the particular purpose of the pipeline outlet. The control package section is in turn connected to elbow  64  into the subsea pipeline  10 . On each side of the control package section, protective gussets  66  are shown. This is as it would be seen when being laid from the vessel before the buoy  26  is launched. 
         [0031]    Referring now to  FIG. 5 , a closer partial view of the outlet  18  is seen showing the hose  28  inside the multiplicity of bend restrictor sections  60 . 
         [0032]    Referring now to  FIG. 6 , a single half section of bend restrictor is shown with an orientation key  68  which allows the bend restrictor sections to sustain torque and protect the hose  28  from being damaged by torsion. 
         [0033]    Referring now to  FIG. 7 , a perspective view of an outlet for attaching a pipeline is seen with the bend restrictor sections  60  going all the way up to the buoy  70  in order to protect the hose within from torque. As shown, the pipe did not rotate during the laying process, and the bend restrictors allow a simple 90 degree curve upwards toward the buoyancy. 
         [0034]    Referring now to  FIG. 8 , a side view of  FIG. 7  is seen. 
         [0035]    Referring now to  FIG. 9 , an end view of the arrangement of view  7  is seen. 
         [0036]    Referring now to  FIG. 10 , the view of  FIG. 9  is shown with the subsea pipeline  10  rotated a full 360 degrees showing what happens when the pipe is rotated in the laying process. The pipe is rotated, but the connection  44  is still available for connection. 
         [0037]    Referring now to  FIG. 11 , the view of  FIG. 9  is shown with the subsea pipeline  10  rotated 180 degrees in the laying process. 
         [0038]    Referring now to  FIG. 12 , a perspective view of  FIG. 11  is shown. 
         [0039]    The particular embodiments disclosed above are illustrative only, as the invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the invention. Accordingly, the protection sought herein is as set forth in the claims below.