Abstract:
Apparatus and methods for insulating a connector that connects a first tubular member having a first flange with a second tubular member having a second flange. The apparatus comprises a generally tubular body forming a generally tubular cavity therein adapted to enclose the connector. The body has a longitudinal opening adapted to receive the first tubular member and a closure member for closing said opening. The body and the closure member are lined with insulation and include first and second seals for sealing with the first and second flanges so as to seal around the connector.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     Not Applicable.  
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
       [0002]     Not Applicable.  
       BACKGROUND  
       [0003]     The present invention relates generally to apparatus for insulating hydrocarbon production equipment in a subsea environment. More specifically, the present invention relates to apparatus for insulating subsea connectors for flowlines, jumpers, umbilicals, and other tubular members.  
         [0004]     Production equipment, such as manifolds and trees, that are used in producing oil and gas in a subsea environment are usually interconnected by flowlines, or other tubulars. The flowlines provide fluid communication to support the flow of production fluids, control fluids, and other fluids. In the subsea environment, the equipment is often exposed to temperature at or only slightly above the freezing point of water.  
         [0005]     Although the fluids extracted from subsea wells are often at an elevated temperature when leaving the well, the fluids can cool as they move through the production equipment and flowlines. This cooling is especially problematic during an interruption in flow where temperatures can decrease to a point where flow will be impeded, such as by the formation of hydrates. In order to decrease the rate at which the fluid cools, thermal insulation is often installed on and around the production equipment and flowlines.  
         [0006]     One area of difficulty in providing thermal insulation is at the connections between the production equipment and the flowlines. The flowlines are typically installed after the production equipment is on the seabed, with the connections between the flowlines and the production equipment made by remotely operated vehicles (ROV) or some other remotely operated device. Therefore, any thermal insulation must allow for remotely controlled installation of the connector or be able to be installed after the connection is made.  
         [0007]     Insulation used in subsea environments must be able to withstand the high hydrostatic pressures found in deep water applications. Conventional insulation used for subsea systems provides very little compressibility so as to better withstand hydrostatic pressure. When installing insulating systems subsea, water often becomes trapped by the insulation. When this water is heated it expands and may tend to damage the insulation or create circulation paths for cold water to seep under the insulation.  
         [0008]     Thus, there remains a need to develop methods and apparatus for thermally insulating flowline connectors, which overcome some of the foregoing difficulties while providing more advantageous overall results.  
       SUMMARY OF THE PREFERRED EMBODIMENTS  
       [0009]     The embodiments of the present invention are directed toward methods and apparatus for insulating a connector that connects a first tubular member having a first flange with a second tubular member having a second flange. The apparatus comprises a generally tubular body forming a generally tubular cavity therein adapted to enclose the connector. The body has a longitudinal opening adapted to receive the first tubular member and a closure member for closing said opening. The body and the closure member are lined with insulation and include first and second seals for sealing with the first and second flanges so as to seal around the connector.  
         [0010]     A method of insulating a connector comprises receiving a flow line through a longitudinal opening in a insulating shroud. The insulating shroud is lowered around the connector and sealingly engaging flanges on each side of the connector to seal around the connector. A closure member closes the opening is latched closed. Insulation on the insulating shroud is compressed as water that is trapped around the connector in a cavity in the insulating shroud is heated and expands.  
         [0011]     Thus, the present invention comprises a combination of features and advantages that enable it to overcome various problems of prior devices. The various characteristics described above, as well as other features, will be readily apparent to those skilled in the art upon reading the following detailed description of the preferred embodiments of the invention, and by referring to the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]     For a more detailed description of the preferred embodiment of the present invention, reference will now be made to the accompanying drawings, wherein:  
         [0013]      FIG. 1  is cross-sectional view of a flowline jumper connector with an insulation assembly installed thereon;  
         [0014]      FIG. 2  is a top view of an insulating shroud assembly being installed on a connector;  
         [0015]      FIG. 3  is a top view of an insulating shroud assembly installed on a connector;  
         [0016]      FIG. 4  is a partial cross-sectional view of an upper seal arrangement;  
         [0017]      FIG. 5  is a partial cross-sectional view of a lower seal arrangement;  
         [0018]      FIG. 6  is a partial cross-sectional seal of a door seal;  
         [0019]      FIG. 7  is a top view of a drive mechanism;  
         [0020]      FIG. 8  is a cross-sectional view of the drive mechanism of  FIG. 7 ;  
         [0021]      FIG. 9  is a cross-sectional view of a flowline jumper connector with an insulating shroud assembly installed thereon; and  
         [0022]      FIG. 10  is a top view of a latching mechanism for use with an insulating shroud. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0023]     Referring now to  FIG. 1 , a flowline jumper connector  10  joins a flowline jumper  12  to a manifold  14 . Insulating shroud assembly  16  surrounds and extends above and below connector  10 . Insulating shroud assembly  16  comprises outer shell  17 , insulation  18 , upper seal  20 , and lower seal  22 . Upper seal  20  sealingly engages flange  24  on flowline jumper  12 . Lower seal  22  sealingly engages flange  26  of the connector support structure on manifold  14 . Thus, seals  20  and  22  form an insulated volume  28  that surrounds connector  10 .  
         [0024]     Outer shell  17  is generally tubular forming a cavity therewithin. Outer shell  17  is formed from a hard plastic material or some other non-compliant, corrosion-proof material. Insulation  18  is a flexible insulation molded onto the inner surface of outer shell  17 . Insulation  18  may be held in place by a plurality of plastic pins that are connected to outer shell  17  and molded into insulation  18 . In certain embodiments, outer shell may be approximately 0.5 inches thick and insulation  18  is preferably at least 1.5 inches thick. When insulating shroud assembly  16  is installed, water is trapped within insulated volume  28 . This water will expand, by approximately 10% by volume, when heated by the fluid flowing through connector  10 . Insulation  18  preferably has a volume at least equal to the volume of water that will be trapped within volume  28 .  
         [0025]     Insulation  18  is sufficiently compressible so as to absorb the expansion of the water without damaging outer shell  17 . Thus, insulation  18  is formed from a material that can support compression both from hydrostatic pressure and from expansion of the water trapped within insulated volume  28  while maintaining sufficient insulating properties. In certain embodiments, insulation  18  is formed from a material that will compress approximately 1% at a water depth of 7,200 feet and still have approximately 2.5-3% compressibility remaining and available to absorb the expansion of the trapped water. Thus, the insulation material provides sufficient compressibility so as to allow the expansion of trapped water without breaking the outer shell and sufficient elasticity to provide reliable sealing engagement with the connector.  
         [0026]     To facilitate installation of insulating shroud assembly  16  onto connector  10 , which is shown in  FIGS. 2 and 3 , insulating shroud assembly  16  further comprises body  30  and door  32  that are hingeably connected by drive mechanism  34 . Assembly  16  also comprises locking mechanism  36  that holds door  32  closed and door face seals  38  that provide sealing engagement between a closure member, i.e. door  32 , and body  30  when the door is closed. Door  32  provides sufficient opening for insulating shroud assembly  16  to be installed around flowline jumper  12  above connector  10 , then slid onto and around the connector. As shown, door  32  forms less than one-half of insulating shroud assembly  16 . The particular angular dimension of door  32  will depend on the size of the tubular member, i.e. flowline jumper  12 , that is received within body  30 . In certain embodiments, door  32  provides an approximately 135 degree longitudinal opening into body  30 .  
         [0027]     Referring now to  FIG. 2 , door  32  is opened such that insulating shroud assembly  16  can be slid onto flowline jumper  12  above connector  10  and moved downward to the position shown in  FIG. 1 . An ROV pushes insulating shroud assembly  16  into place on flowline jumper  12  and then moves the assembly downward over connector  10  so as to set the seals on body  30 . Once insulating shroud assembly  16  is in position, door  32  is rotated by drive mechanism  34  until the door is in the closed position, as shown in  FIG. 3 . In the closed position, face seals  38  seal door  32  against body  30 . Drive mechanism  34  provides sufficient force to close door  32  and energize seals  20 ,  22 , and  38  by compressing insulation  18 . The interface between the insulation at seals  20  and  22  also maintains the vertical position of insulating shroud assembly  16  on connector  10 . Door  32  is maintained in the closed and sealed position by locking mechanism  36 , which may be a ratchet-type mechanism, spring latch mechanism, or some other system for maintaining the closed position of door  32  relative to body  30 . Locking mechanism  36  may also include an ROV-operable release to facilitate removal of insulating shroud assembly  16 .  
         [0028]     Once in the closed position, body  30  and door  32  are sealed against jumper  12  by upper seal  20 , against manifold  14  by lower seal  24 , and against each other by face seals  38 . The interactions of these seals are more clearly seen in  FIGS. 4-6 . Referring now to  FIG. 4 , the engagement of upper seal  20  and flange  24  of flowline jumper  12  is shown. Upper seal  20  preferably comprises three annular protrusions  40  of insulation  18 . Annular protrusions  40  project radially inward so that the protrusions are compressed when assembly  16  is installed on connector  10 . The plurality of annular protrusions  40  are arranged vertically so as to take into account dimensional tolerances that may effect the position of flange  24  when connector  10  is engaged. Thus, protrusions  40  are arranged such that at least two of the protrusions is compressed against flange  26  to form an annular seal.  
         [0029]     The engagement of lower seal  22  and manifold  14  is detailed in  FIG. 5 . Lower seal  22  comprises two annular protrusions  42  of insulation  18 . Annular protrusions  42  project radially inward from insulation  18  so that the protrusions are compressed when assembly  16  is installed on connector  10 . Annular protrusions  42  are arranged vertically so as to take into account dimensional tolerances that may effect the position of flange  26  when connector  10  is engaged. Thus, protrusions  42  are arranged such that at least one of the protrusions is compressed against flange  26  to form an annular seal.  
         [0030]     Referring now to  FIG. 6 , the engagement of face seals  38  are shown. Face seal  38  comprises male sealing face  44  disposed on each side of door  32  with a corresponding female sealing face  46  disposed on the sides of the longitudinal opening in body  30 . Male sealing face  44  comprises wedged protrusion  48  sized so as to sealingly interface with wedged receptacle  50  on female sealing face  46 .  
         [0031]     Drive mechanism  34  is shown in  FIGS. 7 and 8 , where  FIG. 8  is a cross-section taken along section line A-A of  FIG. 7 . Drive mechanism  34  comprises gear assembly  52  connected to shell arms  54  and shell brackets  56 . Shell arms  54  are connected to body  30  of insulating shroud assembly  16  and shell brackets  56  are connected to door  32 .  
         [0032]     Gear assembly  52  comprises planetary gears  58 , ring gear  60 , and sun gear  62 . Sun gear  62  is mounted on shaft  64  and rotated via paddle  66 , such as by an ROV. Planetary gears  58  are each mounted to a shaft  68 . Sun gear shaft  64  and planetary gear shafts  68  are mounted to shell arms  54 . Ring gear  60  is connected to housing  72  that is rotatably supported on torsion plug  70  and held in place by retainer ring  74 . Shafts  64  and  68  extend the height of door  32 .  
         [0033]     In operation, an ROV, or other rotatable actuator, engages paddle  66  so as to rotate shaft  64  and sun gear  62 . The rotation of sun gear  62  causes corresponding rotation in planetary gears  58  and ring gear  60 . Planetary gears  58  rotate about shafts  68  but maintain their relative positions to sun gear  62 . Thus, the rotation of planetary gears  58  causes ring gear  60  to rotates about its central axis, which is coaxial with shaft  64 . The rotation of ring gear  60  causes housing  72  to rotate and thus rotates shell brackets  56  and door  32  relative to shell arms  54  and body  30 . Gears  58 ,  60 , and  62  also act to provide a mechanical advantage in closing door  32  by increasing the torque that is applied by the ROV to rotate paddle  66 . For example, if the ROV can apply 100 ft-lbs. of torque, 600 ft.-lbs. of torque can be applied to door  32 . In certain embodiments, other rotatable actuators may take the place of geared drive mechanism  34 .  
         [0034]     Insulating assemblies can be constructed in any number of configurations and arrangements to support insulating different sizes and types of connectors. For example, referring now to  FIG. 9 , a flowline jumper connector  80  joins a flowline jumper  82  to a manifold  84 . Insulating shroud assembly  86  surrounds connector  80  and comprises outer shell  87 , insulation  88 , upper seal  90 , and lower seal  92 . Upper seal  90  sealingly engages flange  94  on flowline jumper  82 . Lower seal  92  sealingly engages flange  96  of the connector support structure on manifold  84 . Thus, seals  90  and  92  form an insulated volume  98  that surrounds connector  80 .  
         [0035]      FIG. 10  illustrates one embodiment of a latching system  100  for use in securing door  102  to body  104  of an insulating shroud assembly  106 . Latching system  100  comprises latch assembly  108  and receptacle  110 . Latch assembly  108  is mounted to body  104  and further comprises latch  112 , spring  114 , axle  116 , and bracket  118 . Receptacle  110  is disposed on door  102  and further comprises cam surface  120  and notch  122 . Axle  116  pivotally connects latch  112  to bracket  118 , which is fixably connected to body  104 . Spring  114  is received within slot  124  on latch  112  and biases the latch to the engaged position shown in  FIG. 10 .  
         [0036]     In the engaged position, latch  112  is received within notch  122  so as to maintain the position of door  102  relative to body  104 . Latch system  100  is disengaged by rotating latch  112  counterclockwise about axle  116  and rotating door  102  to an open position. As door  102  is rotated back to the closed position, as shown in  FIG. 10 , cam surface  120  will engage latch  112 . Cam surface  120  causes latch  112  to rotate counterclockwise about axle  116  and allows door  102  to move past the open latch  124  to the closed position. As door  102  fully closes, spring  114  rotates latch  112  clockwise about axle  116  and pushes latch  112  into notch  122 . The engagement of latch  112  with notch  122  and the force generated by spring  114  maintains door  102  in the closed position and generates sufficient force to maintain the seals formed between insulating shroud assembly  106  and the connector on which it is installed.  
         [0037]     While preferred embodiments of this invention have been shown and described, modifications thereof can be made by one skilled in the art without departing from the scope or teaching of this invention. The embodiments described herein are exemplary only and are not limiting. Many variations and modifications of the system and apparatus are possible and are within the scope of the invention. For example, the relative dimensions of various parts, the materials from which the various parts are made, and other parameters can be varied, so long as the insulating apparatus retain the advantages discussed herein. Accordingly, the scope of protection is not limited to the embodiments described herein, but is only limited by the claims that follow, the scope of which shall include all equivalents of the subject matter of the claims.