Abstract:
A connector is lowered onto and secured to a subsea member, effecting a seal between subsea member and the connector. The connector includes an outer body defining a cavity, and an inner body defining a bore, wherein the lower end of the inner body resides within the cavity. The connector also includes an engaging member coupled to the outer body and adapted to engage the subsea device, the engaging member radially movable between a disengaged position and an engaged position. The connector includes a seal carried by the inner body and adapted to form a seal between the bore and the subsea device. Finally, the connector includes a pre-loading member coupled to the outer body, operable to urge the inner body and seal against the subsea device to exert a pre-loading force on the seal. A differential pressure between the bore and a subsea environment energizes the seal.

Description:
[0001]    This application claims the benefit of U.S. Provisional Application No. 61/362,960, filed on Jul. 9, 2010, entitled “Made-Up Flange Locking Cap,” which application is hereby incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention relates in general to a connector for deploying subsea to connect to a subsea device. 
       BACKGROUND OF THE INVENTION 
       [0003]    In subsea drilling operations, drilling operators generally use subsea connectors to join risers or other devices to the wellhead. Typically, these devices rely on an externally applied mechanical force to energize a seal between the connector and the joined device. While these mechanically set seals initially hold quite well, during the course of operation differential pressures between an internal bore shared by the devices and the subsea environment can stress or strain the seal, causing the seal to fail. 
         [0004]    In addition, during energization, the differential pressure may cause movement of the connector relative to the subsea device that the connector connects to. When this occurs, the seal may not set properly, allowing leakage into or out of the connector. This leakage can further stress or strain the seal causing it to fail earlier than anticipated. Application of additional external mechanical force to further energize the seal may overcome this problem, but it is impractical to continually apply an external mechanical force to the connector to maintain the seal. 
         [0005]    Therefore, there is a need for a connector that can be used in subsea environments that overcomes the problems sealing in subsea differential pressure environments. 
       SUMMARY OF THE INVENTION 
       [0006]    These and other problems are generally solved or circumvented, and technical advantages are generally achieved, by preferred embodiments of the present invention that provide a subsea locking cap, and a method for using the same. 
         [0007]    In accordance with an embodiment of the present invention, a connector for connecting to a subsea device having an axis comprises an outer body defining a cavity, and an inner body defining a bore, wherein the lower end of the inner body resides within the cavity. The connector further comprises an engaging member coupled to the outer body and adapted to engage a first surface of the subsea device, the engaging member being radially movable between an outward, disengaged position and an inward, engaged position. A seal is carried by the inner body and adapted to form a seal between the bore and the subsea device. Finally, the connector comprises a pre-loading member coupled to the outer body, the pre-loading member being operable to engage a second surface of the subsea device and urge the inner body and seal against the subsea device to exert a pre-loading force on the seal. A substance pressure within the bore energizes the seal. 
         [0008]    In accordance with an another embodiment of the present invention, an apparatus for connecting to a subsea member comprises a body defining a bore having an axis. The apparatus also comprises a seal carried by the body. The seal comprises a coupler ring coupled to a lower rim of the body and a sealing ring coupled to the body by the coupler ring. The sealing ring moves along the axis relative to the body in response to a pressure in the bore, thereby energizing the seal. 
         [0009]    In accordance with still another embodiment of the present invention, a method for connecting to a subsea device comprises providing a connector with an outer body defining a cavity, and an inner body defining a bore, wherein the lower end of the inner body resides within the cavity. The connector has an engaging member coupled to the outer body and a seal carried by the inner body. Finally, the connector has a pre-loading member coupled to the outer body. The method also comprises lowering the connector toward the subsea member and inserting an end of the subsea member into the cavity. Then the method continues with the step of energizing the engaging member to engage the subsea member. The method concludes with the steps of energizing the pre-loading member to engage the inner body, exerting a preload force on the seal and pressure energizing the seal throughout the life of the connector. 
         [0010]    An advantage of a preferred embodiment of the present invention is that the apparatus connects to a subsea member and uses a differential pressure to energize the seal, thereby maintaining the energiziation of the seal. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    So that the manner in which the features, advantages, and objects of the invention, as well as others which will become apparent, are attained and can be understood in more detail, more particular description of the invention briefly summarized above may be had by reference to the embodiments thereof that are illustrated in the appended drawings that form a part of this specification. It is to be noted, however, that the drawings illustrate only certain preferred embodiments of the invention and are therefore not to be considered limiting of the invention&#39;s scope as the invention may admit to other equally effective embodiments. 
           [0012]      FIG. 1  is a vertical sectional view of a connector in accordance with this invention, shown being lowered onto a vertically-oriented made-up flange. 
           [0013]      FIGS. 2A-2E  are sectional views of alternate embodiments of a seal of the connector of  FIG. 1 . 
           [0014]      FIG. 3  is a perspective view illustrating the connector of  FIG. 1 . 
           [0015]      FIG. 4  is perspective View of a lower portion of the connector as shown in  FIG. 3 , but illustrating the guide pins and stop pin re-positioned for installation on a made-up flange that has an upper asymmetrical portion. 
           [0016]      FIG. 5  is a bottom view of the connector as shown in  FIG. 3 . 
           [0017]      FIG. 6  is a bottom view of the connector as shown in  FIG. 4 . 
           [0018]      FIG. 7  is a perspective view of the connector configured as in  FIG. 6 , shown during a first step in engaging a made-up flange, which involves lowering a long guide pin through one of the holes in the made-up flange. 
           [0019]      FIG. 8  is a perspective view similar to  FIG. 7 , illustrating a second step, which involves rotating the connector. 
           [0020]      FIG. 9  is a sectional view of the connector and made-up flange of  FIG. 7 , illustrating a third step, which involves lowering both guide pins through holes in the made-up flange. 
           [0021]      FIG. 10  is a sectional view similar to  FIG. 9 , illustrating a fourth step, which involves stroking the outer body of the connector downward relative to the inner body and stroking the lower dogs. 
           [0022]      FIG. 11  is a sectional view similar to  FIG. 10 , illustrating a fifth step, which involves moving upper dogs inward. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0023]    The present invention will now be described more fully hereinafter with reference to the accompanying drawings that illustrate embodiments of the invention. This invention may be embodied in many different forms and should not be construed as limited to the illustrated embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout, and the prime notation, if used, indicates similar elements in alternative embodiments. 
         [0024]    In the following discussion, numerous specific details are set forth to provide a thorough understanding of the present invention. However, it will be obvious to those skilled in the art that the present invention may be practiced without such specific details. Additionally, for the most part, details concerning drilling unit operation, materials, and the like have been omitted inasmuch as such details are not considered necessary to obtain a complete understanding of the present invention, and are considered to be within the skills of persons skilled in the relevant art. 
         [0025]    Referring to  FIG. 1 , connector assembly  11  is shown positioned over a made-up flange, which in this example comprises a lower riser connector  13 . Lower riser connector  13  is a lower portion of a drilling riser (not shown) that normally would extend to a floating vessel at surface. The riser has been damaged and severed from lower riser connector  13  by a cut  15  on the upper end of the lower riser connector  13 . Lower riser connector  13  has a curved surface  18  that tapers in a downward direction to a riser flange  17  having a flat upper surface. Curved surface  18  is a curved frusto-conical surface. 
         [0026]    In this example, lower riser connector  13  mounts on top of a blowout preventer  21  (BOP), the upper end of which is shown. BOP  21  has a BOP flange  19 , and riser flange  17  bolts to BOP flange  19  by a series of bolts (not shown in  FIG. 1 ). BOP  21  and lower riser connector  13  have a mating central passage  23  for drilling fluids and tools to pass through. The mating flanges  17  and  19  preferably have at least two holes  25  that do not contain bolts. The bolts from holes  25  may have been removed, or holes  25  may have originally been left open for another purpose, such as allowing fluid lines to pass through. In this example, holes  25  are spaced 180 degrees apart from each other, but other circumferential spacings between holes  25  may be employed. A person skilled in the art will understand that lower riser connector  13  and BOP  21  could alternatively be another type of connection point. Connector assembly  11  can then connect using a seal as described below with respect to  FIG. 2E . 
         [0027]    Connector assembly  11  includes an inner body  27  and an outer body  29 , both being cylindrical, tubular members. A plurality of lifting devices, such as hydraulic cylinders  31 , extend between outer body  29  and a bracket  33  attached to an upper end of inner body  27 . When energized, hydraulic cylinders  31  will stroke inner body  27  and outer body  29  relative to each other from a contracted position to an extended position. Outer body  29  is in its upper position relative to inner body  27  in  FIG. 1 . A person skilled in the art will understand that other devices and methods, such as remotely operated screw lifts, for moving inner body  27  and outer body  29  relative to each other are contemplated and included in this invention. Likewise, methods that do not require motion between inner body  27  and outer body  29  may be used, for example, inner body  27  and outer body  29  may comprise a single unit. 
         [0028]    Inner body  27  has a lower portion that locates within a cavity  43  of outer body  29 . The lower portion of inner body  27  includes a flange  45  that extends radially outward from the exterior of inner body  27 . Flange  45  has an upward facing shoulder  47 . Upward facing shoulder  47  may be beveled as illustrated in  FIG. 1  or, alternatively, a horizontal surface. A bushing or guide member  49  may be mounted to the outer diameter of flange  45  for sliding along the inner diameter of cavity  43 . In the example shown, the lower rim of inner body  27  is still recessed within outer body  29  when outer body  29  is in its upper position. A stop member  35  mounted on the upper end of outer body  29  serves to limit the axial movement of inner and outer bodies  27 ,  29  between the extended and retracted positions. Stop member  35  may be a portion of a ring that engages a recess  37  formed in the exterior of inner body  27 , or it may be other devices. 
         [0029]    Inner body  27  has a bore  39  with a seal  41  mounted at the lower end. Seal  41  has a curved lower portion for sealing against curved portion  18  of lower riser connector  13 . Seal  41  may be a variety of configurations and materials.  FIGS. 2A-2D  show four embodiments for seal  41 . Each embodiment includes a metal body  32 , such as of steel, defining one or more recesses  42 , a flange  34  for securing to inner body  27 , and one or more inner body seal members  44  for sealing seal  41  against inner body  27 . A person skilled in the art will understand that alternative embodiments contemplate and include seal  41  without recesses  42  and inner body seal members  44 . Likewise, a person skilled in the art will understand that alternative embodiments contemplate and include use of elastomerics, soft metals, and the like, to construct inner body seal members  44  Inner body seal members  44  may also comprise taper sealing surfaces, flat sealing surfaces, or the like rather than curved sealing surfaces. 
         [0030]    In  FIG. 2A , an elastomeric seal member  36 , formed of a material such as rubber, is located in a groove in the lower portion of body  32  for sealing against curved surface  18 . In  FIG. 2B , seal  41  has an inlay  38  of a soft metal on the lower portion for metal-to-metal sealing. In  FIG. 2C , the entire lower portion is of the same steel material as body  32  for forming a metal-to-metal seal. In  FIG. 2D , seal  41  has an elastomeric layer  40  bonded to its lower portion for forming a seal. Other variations may include an inflatable seal  41 . 
         [0031]    Preferably, flange  34  loosely couples to inner body  27 . As illustrated in  FIG. 2A , elastomeric seal member  36  defines an annular member substantially filling the groove in the lower portion of body  32 . When placed within the groove of body  32 , elastomeric seal member  36  provides a different inner diameter of body  32  than that of body  32  without the groove. Preferably, the inner diameter of the combined elastomeric seal member  36  and body  32  is less than that of body  32  at that location without the groove. Similarly, inner body seal members  44  define annular members substantially filling recesses  42 . When placed within recesses  42 , inner body seal members  44  provide a different outer diameter of body  32  than that of body  32  without recesses  42 . Preferably, the combined outer diameter of the combined inner body seal members  44  and body  32  is greater than the outer diameter of body  32  without recesses  42  at the location of recesses  42 . 
         [0032]    Following placement and engagement of connector assembly  11 , described in more detail below, an initial seal is created between the curved surface of body  32 , elastomeric seal member  36 , inlay  38 , or elastomeric layer  40 , and the curved surface  18  of lower riser connector  13 . As fluid passes through mating central passage  23  and into bore  39 , the fluid pressure within mating central passage  23  and bore  39  cause axial movement of connector assembly  11 , generally axially away from lower riser connector  13 . As connector assembly  11  moves, loosely coupled seal  41  will float axially relative to connector assembly  11 . As connector assembly  11  pulls axially away from lower riser connector  13 , seal  41  will remain in contact with lower riser connector  13  and curved surface  18  of lower riser connector  13 . Inner body seal members  44  maintain a seal with inner body  27 , while allowing a small gap to develop between the portion of body  32  axially above the upper inner body seal  44  and inner body  27 . The fluid pressure then fills the small gap and pushes body  32  radially inward and further against lower riser connector  13  and curved surface  18  of lower riser connector  13 . In this manner, the fluid pressure within bore  39  further sets seal  41 , increasing the ability to seal during operational use of connector assembly  11 . 
         [0033]    Referring now to  FIG. 2E , there is shown an alternative embodiment of seal  41  for connecting to lower riser connector  13  that does not have riser flange  17  awl thus curved surface  18  secured to it. As shown in  FIG. 2E , a lower riser connector  113  is a lower portion of a drilling riser (not shown) that normally would extend to a floating vessel at surface. In this example, lower riser connector  113  mounts on top of a blowout preventer  121  (BOP), the upper end of which is shown. BOP  121  has a BOP flange  119 . BOP  121  and lower riser connector  113  have a mating central passage for drilling fluids and tools to pass through similar to that of mating central passage  23  and central bore  39  of BOP  21  and lower riser connector  13  of  FIG. 1 . BOP flange  119  preferably has at least two holes  125  that do not contain bolts, only one of which is shown in  FIG. 2E . 
         [0034]    In the illustrated embodiment of  FIG. 2E , a seal  141  couples to an inner body  127  of a connector assembly. The connector assembly comprises an alternative embodiment of connector assembly  11  having a seal  141  configured to connect to lower riser connector  113  and BOP flange  119 . The connector assembly lands on, seals, and energizes as described below with respect to connector assembly  11  of  FIGS. 3-11 . 
         [0035]    Seal  141  has a metal body  132 , such as of steel, and a retainer ring  152 . Metal body  132  has an inner diameter surface configured to fit flush against an exterior surface of lower riser connector  113 . Metal body  132  also defines one or more recesses  142 , an outer flange  148 , and one or more inner body seal members  144  for sealing seal  141  against inner body  127 . A person skilled in the art will understand that alternative embodiments contemplate and include seal  141  without recesses  142  and inner body seal members  144 . Likewise, a person skilled in the art will understand that alternative embodiments contemplate and include use of elastomerics, soft metals, and the like, to construct inner body seal members  144 . Inner body seal members  144  may also comprise tapered sealing surfaces, flat sealing surfaces, or the like rather than curved sealing surfaces. An elastomeric seal member  146 , formed of a material such as rubber, is located in a groove in the lower portion of body  132  for sealing against an upper surface of BOP flange  119 . 
         [0036]    Seal retainer ring  152  comprises a U-shaped ring defining an inner flange  154  near a lower end of seal retainer ring  152  proximate to metal body  132 . Seal retainer ring  152  couples to a lower rim of inner body  127  by bolt  158 . Interposed between seal retainer ring  152  and the lower rim of inner body  127  is a spacing washer  156  of a thickness such that a gap  150  will exist between inner flange  154  and outer flange  148 . Preferably, gap  150  allows seal  141  of  FIG. 2E  to float similar to seal  41  of  FIGS. 2A-2D . Also coupled to inner body  127  is a deflection spacer  160  configured to limit the compression of seal  141  to a predetermined amount. During placement and engagement, described with respect to connector assembly  11  in more detail below, seal  141  is placed under axial compression by a pre-loading force, deflection spacer  160  limits the total axial compression of seal  141  during pre-loading to a predetermined amount selected for the particular application. 
         [0037]    As illustrated in  FIG. 2E , elastomeric seal member  136  defines an annular member substantially filling the groove in the lower portion of body  132 . When placed within the groove of body  132 , elastomeric seal member  136  extends the axial length of body  132  over that of body  132  without the groove. Similarly, inner body seal members  144  define annular members substantially filling recesses  142 . When placed within recesses  142 , inner body seal members  144  provide a different outer diameter of body  132  than that of body  132  without recesses  142  at the location of recesses  142 . Preferably, the combined outer diameter of the combined inner body seal members  144  and body  132  is greater than the outer diameter of body  132  without recesses  142  at the location of recesses  142 . 
         [0038]    Following placement and engagement of the connector assembly, described with respect to connector assembly  11  in more detail below, an initial seal is created between the surface of body  132 , elastomeric seal member  136  and an upper surface of BOP flange  119 . As fluid passes through the mating central passage and into the bore, the fluid pressure within the mating central passage and the bore cause axial movement of the connector assembly, generally axially away from lower riser connector  113 . As the connector assembly moves, gap  150  allows seal  141  to float axially relative to the connector assembly. That is, inner body  127  can move axially relative to seal body  132  an amount equal to the axial dimension of gap  150 . As the connector assembly pulls axially away from lower riser connector  113 , seal  141  will remain in contact with lower riser connector  113  and BOP flange  119 . Inner body seal members  144  maintain a seal with inner body  127 , while allowing a small gap to develop between the portion of body  132  axially above the upper inner body seal  144  and inner body  127 . The fluid pressure then fills the small gap and pushes body  132  radially inward and downward, further against lower riser connector  113  and BOP flange  119 . In this manner, the fluid pressure within the bore further sets seal  141 , increasing the strength of the seal during operational use of connector assembly  111 . In this manner, connector assembly  111  may seal to a subsea member having a bore without an attached flange using the internal pressure within bore  139 . 
         [0039]    Referring again to  FIG. 1 , outer body  29  has a lower engaging member that may be a plurality of lower dogs  51  or alternately segments of a ring, a collet, or some other device. In the illustrated embodiment, the lower engaging member has an engaged state configured to hold connector assembly  11  to BOP flange  19 , and a disengaged state configured to not inhibit connector assembly  11  from movement onto and off of the lower riser connector  13  and BOP  21 . Lower dogs  51  may be energized from the retracted position shown in  FIG. 1  to an inward engaged position shown in  FIGS. 10 and 11 . In this example, lower dogs  51  are energized by a remote operated vehicle (ROV) that engages an ROV interface  53 . The ROV may move lower dogs  51  inward by rotating a shaft or some other type of mechanism in ROV interface  53 , such as supplying fluid pressure to a piston located within ROV interface  53 . Alternately, lower dogs  51  could be spring-biased to the inward position. Furthermore, they could be controlled by hydraulic fluid pressure delivered from a surface vessel to connector assembly  11  via an umbilical or line (not shown). 
         [0040]    Outer body  29  also has an upper engaging member that, in this example, comprises a set of upper dogs  55  located above lower dogs  51 . In the illustrated embodiment, the upper engaging member is configured to alternately apply a load to or remove a load from inner body  27 . Upper dogs  55  may alternately be segments of a ring, a collet, or some other device. Upper dogs  55  are located at the upper end of cavity  43  and will move from the retracted position shown in  FIG. 1  to the inward engaging position shown in  FIG. 11 . Upper dogs  55  may be moved inward by an ROV engaging an ROV interface  59 . ROV interface  59  may comprise a device that moves upper dogs  55  inward by rotating a screw mechanism. Alternately, the ROV could move upper dogs  55  inward by supplying hydraulic fluid to move them inward. In another embodiment, upper dogs  55  could be energized by a hydraulic fluid supply from a surface vessel. In yet another embodiment, upper dogs  55  could be spring-biased to the inward position. 
         [0041]    A long guide pin  61  extends downward from a lower edge or rim  60  of inner body  27 . Long guide pin  61  is a cylindrical member in this embodiment that may have a lower entry portion  62  of smaller diameter. Long guide pin  61  has its upper end fixed to inner body  27 , such as by threads. Long guide pin  61  extends below outer body  29  even when outer body  29  is in its lower position. 
         [0042]    A short guide pin  63  also secures to lower rim  60  of inner body  27 . Short guide pin  63  is also a cylindrical member. It optionally may have a slightly larger diameter than long guide pin  61 . Short guide pin  63  has a shorter length than long guide pin  63 , but also protrudes below outer body  29  when outer body  29  is in the lower position. Short guide pin  63  may have a tapered nose. Short guide pin  63  is spaced for engaging one of the holes  25  in flange  17  after long guide pin  61  has engaged the other of the empty holes  25 . In this example, the empty holes  25  are spaced 180° apart, thus guide pins  61  and  63  are 180° apart from each other relative to a longitudinal axis  65  of connector assembly  11 . Guide pins  61  and  63  are parallel to a longitudinal axis  65  of connector assembly  11 . A person skilled in the art will understand that alternative embodiments may not include guide pins  61  and  63 . 
         [0043]    A stop pin  67  is mounted to a lower edge or rim  69  of outer body  29 . Stop pin  67  extends downward parallel to axis  65 . Stop pin  67  is spaced farther from axis  65  than guide pins  61 ,  63  so that when guide pins  61 ,  63  are in flange holes  25 , the side surface of stop pin  67  will be touching an outer diameter portion of flanges  17 ,  19 . Stop pin  67  may have a length that is approximately the same as long guide pin  61  or it may differ. Stop pin  67  may be spaced circumferentially from both guide pins  61 ,  63 , as in this example. A person skilled in the art will understand that alternative embodiments may not include stop pin  67 . 
         [0044]    An annular tapered surface or bevel  70  extends upward from an inner edge of rim  70  of outer body  29  and joins the cylindrical wall defining cavity  43 . Stop pin  67  secures to a threaded hole in rim  69  radially outward from bevel  70 . 
         [0045]    Bracket  33  has a series of bolts  73  that extend upward for connecting connector assembly  11  to additional equipment. That equipment may include a valve block containing valves or a lower end of another riser. Further, the additional equipment may comprise a running tool for lowering connector assembly  11  on drill pipe or on a lift line. 
         [0046]    In  FIG. 1 , axis  71  of riser connector  13  is oriented vertical. However, it may be tilted as shown  FIGS. 7-8 , which illustrate a tilt of approximately 4.6° from vertical. The tilting may be a result of damage to BOP  21  or to a subsea wellhead housing onto which BOP  21  is connected. Also, curved surface  18  of lower riser connector  13  leading from flange  17  to cut  15  may be generally symmetrical or it may be asymmetrical about axis  71 . Damage may have occurred, causing the portion at cut  15  to be asymmetrical about axis  71 . The center point at cut  15  may be offset laterally in one direction from axis  71 . If the portion at cut  15  is symmetrical about axis  71 , connector assembly  11  may be lowered onto lower riser connector  13  with its axis  65  generally aligned with riser connector axis  71 . Preferably, whether or not the upper portion of riser connector  13  is symmetrical or asymmetrical, connector assembly  11  is oriented with its axis  65  vertical while being lowered onto riser connector  13 . If lower riser connector axis  71  is vertical, connector axis  65  and riser connector axis  71  would coincide with each other while connector assembly  11  is only a short distance above riser connector  13 . Even if lower riser connector axis  71  is tilted slightly, if cut  15  is generally symmetrical about axis  71 , it may be possible to lower connector assembly  11  with its axis  65  generally centered on riser connector axis  71 . 
         [0047]    For a riser connector  13  with a symmetrical portion at cut  15  relative to axis  71 , guide pins  61 ,  63  are spaced concentrically relative to axis  65 , as shown in  FIGS. 3 and 5 . Referring to  FIG. 5 , the radius from guide pin  61  to axis  65  is the same as the radius from guide pin  63  to axis  65 . Stop pin  67  serves as a guide in the embodiment of  FIGS. 3 and 5  by contacting the outer diameter of flanges  17 ,  19 . Stop pin  67  is shown in  FIG. 5  about 30 degrees from long guide pin  61  and 150 degrees from short guide pin  63 , but other angles are possible. Preferably, guide pins  61 ,  63  are substantially aligned with their respective holes  25  before lowering guide pins  61 ,  63  into their respective holes  25 . Long guide pin  61  first enters one of the holes  25 , then continued lowering causes short guide pin  63  to enter its hole  25 . Some rotation of connector assembly  11  may be required for this alignment to occur. 
         [0048]    If the portion of riser connector  13  adjacent cut  15  is asymmetrical, it may not be possible for guide pins  61 ,  63  to be aligned then lowered straight into holes  25 .  FIGS. 4 and 6  show an arrangement of guide pins  61 ,  63  and stop pin  67  that may be employed if riser connector  13  is asymmetrical relative to flange axis  71 . Preferably, inner body  27  has a plurality of threaded holes  64  on its rim  60  for securing guide pins  61 ,  63 . Some individual threaded holes  64  are at different radial distances from axis  65  than others. In  FIG. 6 , guide pins  61 ,  63  have been secured to different threaded holes  64  in rim  60  from  FIG. 5 , so that a point equidistant between guide pins  61 ,  63  will not coincide with connector assembly axis  65 . Rather, a center point between guide pins  61 ,  63  will be slightly offset from axis  65 . Long guide pin  61  is at a greater distance r 1  to axis  65  than distance r 2  of short guide pin  63  to axis  65 . The distance r 1  plus r 2  between guide pins  61 ,  63  is still the same distance as between holes  25  ( FIG. 1 ). The distance r 2  is less than the distance from short pin  63  to axis  65  in  FIG. 5 . The distance r 1  is greater than the distance from long pin  61  to axis  65  in  FIG. 5 . Stop pin  67  is about 70 degrees from short pin  63  and 110 degrees from long pin  61  in this example, but these angles could differ. 
         [0049]      FIG. 7  illustrates a first step in installing connector assembly  11  on a tilted lower riser connector  13  with an asymmetrical upper portion. Connector assembly  11  has its axis  65  oriented vertically while being lowered subsea. Outer body  29  will be in its upper position relative to inner body  27 , with guide pins  61 ,  63  protruding below the lower end of outer body  29 . Long guide pin  61  is first stabbed a short distance into one of the holes  25 . When this occurs, connector assembly  11  will be oriented so that its axis  65  is spaced laterally or outboard from flanges  17 ,  19 . Short guide pin  63  will also be laterally spaced or outboard from flanges  17 ,  19 , far out of alignment with its respective hole  25 . Long guide pin  61  will only enter an upper portion of its hole  25  so that the lower end of short guide pin  63  is at a higher elevation than the upper flat surface of riser flange  17 . The lower end of short guide pin  63  need not be at an elevation higher than severed upper end  15  ( FIG. 1 ) because it will swing around the asymmetrical portion of lower riser connector  13  during the next step. Preferably, an ROV with a video camera will be in assistance. A paint mark (not shown) on long guide pin  61  will indicate to the ROV operator in a surface vessel when the proper amount of penetration in hole  25  has occurred. 
         [0050]    Referring to  FIG. 8 , the operator then rotates connector assembly  11  about long guide pin  61 . In this example, the rotation is counterclockwise while looking down on connector assembly  11 . The rotation will be around the hole  25  receiving long guide pin  61 , not around connector assembly axis  65 . The degree of rotation is the amount that is required to swing stop pin  67  around until it bumps against the outer diameter of flanges  17  and  19 . The amount of rotation will be less than 360 degrees and will depend on the position of stop pin  67  when long guide pin  61  enters hole  25 . Stop pin  67  is positioned relative to guide pins  61 ,  63  so that when stop pin  67  bumps against the outer diameter of flanges  17 ,  19 , short guide pin  63  will be aligned above the other hole  25  (not shown).  FIG. 8  illustrates stop pin  67  bumping against flanges  17 ,  19 , and short guide pin  63  aligned with the other of the holes  25 . The offset positions of guide pins  61 ,  63  relative to axis  65  will position connector axis  65  offset from lower riser connector axis  71  at this point. 
         [0051]    The operator then lowers connector assembly  11 , which causes guide pins  61 ,  63  to move downward in their respective holes  25 . Lowering connector assembly  11  also causes axis  65  of connector assembly  11  to tilt and align with the tilted inclination of lower riser connector  13 . As connector assembly  11  moves downward, the offset in axis  65  relative to axis  71  allows seal  41  ( FIG. 1 ) to clear the laterally protruding upper portion of lower riser connector  13 .  FIG. 9  shows seal  41  in close proximity, but not yet landed on lower riser connector  13 . Bevel  70  on lower rim  69  of outer body  29  will be engaging riser flange  17  before seal  41  touches riser connector  13  (not shown in  FIG. 9 ). Outer body  29  will still be in the upper position relative to inner body  27 . The inner diameter of outer body  29  at bevel  70  is only slightly larger in diameter than riser flange  17 , thus bevel  70  will cause connector assembly  11  to move slightly laterally from the offset position to an aligned position wherein axis  65  coincides with axis  71 . Guide pins  61 ,  63  are slightly smaller than their respective guide holes  25  to allow this lateral shifting to occur. Once axes  65 ,  71  are aligned, seal  41  will land on curved surface  18 . Another paint line (not shown) on long guide pin  61  will indicate when seal  41  has properly landed on curved surface  18 . When seal  41  has properly landed, each guide pin  61 ,  63  will be slightly offset in its respective flange hole  25 . 
         [0052]    Referring to  FIG. 10 , the operator then applies fluid pressure to hydraulic cylinders  31  to stroke outer body  29  downward relative to inner body  27 , which is now aligned and resting on lower riser connector  13 . While outer body  29  is in its lowest position relative to inner body  27 , lower dogs  51  will be located at a lower elevation than the lower side of BOP flange  19 . The operator then strokes lower dogs  51  inward by engaging ROV interfaces  53 . Preferably, lower dogs  51  will be spaced a short distance below the lower side of BOP flange  19  once in the inward positions. 
         [0053]    Then, the operator will employ hydraulic cylinders  31  to lift outer body  29  relative to inner body  27  a short distance until lower dogs  51  abut the lower side of BOP flange  19 . The operator will then stroke upper dogs  55  inward as shown in  FIG. 11 . The lower surfaces  57  of upper dogs  55  will engage upward facing shoulder  47 , pushing downward on flange  45  and inner body  27  and pulling upward on outer body  29 . The engagement of upper dogs  55  with upward facing shoulder  47  causes a preload force to occur that lower dogs  51  react to by engaging the lower sides of BOP flange  19 . The application of the preload force forms a tight seal between seal  41  and curved surface  18 . Guide pins  61 ,  63  aren&#39;t shown in  FIGS. 10 and 11 , but will remain in their respective holes  25 . If needed, a sealant can be injected through a port (not shown) in connector assembly  11  between curved surface  18  and the area around seal  41 . Any fluid flowing up through lower riser connector  13  will thus flow into inner body bore  39  where it may be delivered to the surface or otherwise contained. 
         [0054]    As fluid flows up through lower riser connector  13  into bore  39 , the internal pressure created by the movement of the fluid may cause movement of connector assembly  11  relative to lower riser connector  13 . As described above with respect to  FIGS. 2A-2E , seal  41  will float relative to connector assembly  11  and move axially such that the inner body seal members  44  and the elastomeric seal members  36 ,  46  will maintain the tight seal between inner body  29  and lower riser connector  13 . In this manner, the fluid flow through bore  39  pressure energizes seal  41 . 
         [0055]    It may be possible to disconnect lower riser flange  17  from BOP flange  19  before running connector assembly  11  as illustrated in  FIG. 2E . If so, connector assembly  11  could land on and connect to BOP flange  119  employing lower dogs  51  and upper dogs  55  as described above with respect to  FIGS. 3-11 . Seal  141  then seals against the upper surface of BOP flange  119  and an exterior surface of lower riser connector  113  as described above with respect to  FIG. 2E . Cap assembly  11  will operate to energize the seal as described above with respect to  FIGS. 9-11 . In this embodiment, seal  141  has an axial length sufficient to extend from a lower surface of inner body  127  to BOP flange  119 . The concentric arrangement of guide pins  61 ,  63  shown in  FIG. 5  could be employed or alternatively not used at all. 
         [0056]    While described in connection with a blowout preventer and lower riser connector, the invention is also applicable to connecting to other types of made-up flanges or connection points. 
         [0057]    By the use of the present invention, a subsea device may be connected to and sealed using the internal pressure of the device. Thus, the seal disclosed herein is energized in a manner that overcomes the differential pressure problems of prior art connectors by using the differential pressure to energize and maintain the seal. 
         [0058]    It is understood that the present invention may take many forms and embodiments. Accordingly, several variations may be made in the foregoing without departing from the spirit or scope of the invention. Having thus described the present invention by reference to certain of its preferred embodiments, it is noted that the embodiments disclosed are illustrative rather than limiting in nature and that a wide range of variations, modifications, changes, and substitutions are contemplated in the foregoing disclosure and, in some instances, some features of the present invention may be employed without a corresponding use of the other features. Many such variations and modifications may be considered obvious and desirable by those skilled in the art based upon a review of the foregoing description of preferred embodiments. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention.