Abstract:
A connector for severed pipes in a wellbore has an elongated tubular mandrel, a sealing pack-off ring mounted on the mandrel, an activator ring for pressing against the pack-off ring and causing the pack-off ring to seal an interior of a casing above a shut-off valve. A grapple member is slidable mounted on the mandrel above the activator ring; the grapple member has an enlarged diameter plate, which rests on an upper edge of a severed casing. A production pipe, control lines abd production casing can be lowered through the large opening in the mandrel and re-establish connection with the severed casing and production pipes.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     This invention relates to connection of underwater flow lines and other tubular members without the use of divers.  
         [0002]     Oil and gas industries develop production lines in deep-sea locations, with the tubular members extending hundreds of feet below the water surface. When a catastrophic event occurs, such as a hurricane, the tubular members become bent, damaged and sometimes broken. The depth of the location where the tubular members are broken off is often determined by either the bottom structure, the depth of the water, the height of the waves during the storm, the type of platform supporting the production and other variables that cannot be fully predicted and estimated.  
         [0003]     Conventionally, when a well falls over the divers are engaged to either repair and reconnect the well or plug and abandon the well. The operations involving divers are relatively expensive and time consuming. In most instances, the production tubing, as well as the casings is cut off close to the mudline at a level above the surface controlled sub surface safety valve (SCSSV). When the well is shut up at the evacuation of the personnel due to the approaching storm, the pressure is bled off and the failsafe valve that is set at about 6,500 feet below the mudline is closed. Conventionally, the shut off production tubing and the immediately surrounding casing is no longer useful for reconnecting to the production facilities. In such a case, a new well has to be drilled, with associated work of installing production tubing, casings, cementing, etc.  
         [0004]     The present invention contemplates provision of an apparatus and method for connecting severed underwater tubular members for reestablishing production through the original production tubing.  
       SUMMARY OF THE INVENTION  
       [0005]     It is, therefore, an object of the present invention to provide an apparatus for connecting underwater tubular members.  
         [0006]     It is another object of the present invention to provide an apparatus and method for connecting underwater tubular members, such as production tubing and casing, thus repairing storm damaged production lines.  
         [0007]     It is a further object of the present invention to provide an apparatus for connecting underwater tubular members that can be installed and made operational without the use of divers.  
         [0008]     These and other objects of the present invention are achieved through a provision of an apparatus for connecting tubular members in a wellbore, which comprises an elongated tubular mandrel configured for positioning inside of a tubular member in the wellbore. The tubular member may be a casing, a production pipe, or a combination thereof. An activator ring member is slidably mounted on the mandrel, the activator ring member being provided with a lower generally cylindrical portion and an upper frustoconical portion.  
         [0009]     A grapple member is slidably mounted on the mandrel above the activator ring, the grapple member comprising an enlarged diameter plate configured for resting on a top edge of the tubular member inside the wellbore. The grapple member has a plurality of downwardly extending tensioned hooks that have lower parts carrying exterior teeth and inner serrations formed on outwardly inner slanting surfaces. The inner serrations mesh with matching teeth formed on the frustoconical surface of the activator ring when the tool is in a set position in the wellbore. The outer teeth of the grapple hooks are oriented upwardly; they engage the inner surface of the tubular member and resist an upward movement of the mandrel.  
         [0010]     A flexible resilient pack-off ring is mounted below the activator ring and rests on a lower stop ring, which fixedly attached to the mandrel. When a downward force is applied to the activator ring, the force is transferred to the pack-off ring and causes the pack-off ring to expand laterally and seal the interior of the tubular member.  
         [0011]     A connector is detachably secured to an upper end of the mandrel. An extension tubular member is secured to the free end of the connector, thus moving into the wellbore when the connector apparatus is lowered into the wellbore.  
         [0012]     The method of connecting the tubular members of the present invention allows a severed mineral production pipe to be connected with an extension pipe that is lowered from the surface through the extension tubular member and wide central opening extending through the mandrel of the connector apparatus. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]     Reference will now be made to the drawings, wherein like parts are designated by like numerals and wherein  
         [0014]      FIG. 1  is a schematic view illustrating the storm damaged tubular members of a tubular production line.  
         [0015]      FIG. 2  is a schematic illustration of the tubular members severed below the damaged portion with a new drive pipe positioned over the existing casing.  
         [0016]      FIG. 3  is a schematic view illustrating positioning of the apparatus of the present invention resting on a casing stub.  
         [0017]      FIG. 4  is a schematic view illustrating position of the connector apparatus of the present invention with the production tubing tied back.  
         [0018]      FIG. 5  is a schematic view illustrating new casing strings cemented in place around the connector apparatus of the present invention.  
         [0019]      FIG. 6  is a perspective view of the apparatus of the present invention illustrating the connector apparatus in a run-in position.  
         [0020]      FIG. 7  is a perspective view of the apparatus of the present invention with the connector apparatus in a set position.  
         [0021]      FIG. 8  is a perspective view of the apparatus of the present invention, with the connector apparatus in a release position with the pack off element engaged.  
         [0022]      FIG. 9  is a plan view illustrating the apparatus of the present invention in a set position, with the pack off element expanded.  
         [0023]      FIG. 10  is a detail view illustrating the mandrel of the connector apparatus of the present invention.  
         [0024]      FIG. 11  is a detail view illustrating the mandrel of the connector apparatus of the present invention, with the grapple activator ring in place.  
         [0025]      FIG. 12  is a detail view illustrating one embodiment of the activator ring.  
         [0026]      FIG. 13  is a front view illustrating an optional activator ring design.  
         [0027]      FIG. 14  is a top view of the top connector body showing a large internal diameter opening.  
         [0028]      FIG. 15  is a detail view illustrating a grapple of the connector apparatus of the present invention.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0029]     Turning now to the drawings in more detail,  FIG. 1  schematically illustrates the condition of tubular members following a major storm. As can be seen in the drawing, the larger outside casing  12 , the intermediate casing  14 , the inner casing  16 , as well as the production casing  18  are all bent at a level designated by numeral  20  in  FIG. 1 . At that time, the surface control sub surface safety valve  22  had shut off the flow of fluid through the production tubing  24 . The production tubing  24  is also bent and out of shape, potentially damaged above the surface control sub surface safety valve  22  and cannot be used in such condition to re-establish mineral production. The control line  26  is also out of shape and cannot be used to control operation of the valve  22 .  
         [0030]     The operator of the production facility has a choice of either cutting the exterior casings in a “wedding cake” manner, with the staggered height of the outer cemented casings to allow access to the undamaged portion of the inner casing or to sever all the casings and the production tubing along the same line by using a cutting device, such as a guillotine saw. The latter method is less expensive and therefore more frequently used by the well operators. The present invention is believed to be particularly useful in re-establishing the wells, where the tubular members have been cut at the generally similar horizontal level below the water line.  
         [0031]     Following the severing of the tubing method, the casings  12 ,  14 ,  16 , and  18  are cut at about the same level as schematically shown in  FIG. 2 . The operator then establishes a new control line  28  using a control line tieback  30 . A new outer casing  32  is driven into the soil of the sub sea location, with the new drive pipe  32  having an internal diameter at least slightly greater than the diameter of the existing outer casing  12 . Once the new drive pipe  32  is positioned in place, the connector apparatus of the present invention can be positioned within the space defined by the new outer casing  32 .  
         [0032]     As can be seen in  FIG. 6-15 , the connector apparatus of the present invention comprises an elongated tubular mandrel  42  having a top sub  44 , which serves as a connector member between the mandrel  42  and a new casing  46 , which is lowered from the surface into the underwater location. The mandrel body  42  is provided with a plurality of hinged J-shaped latch lugs  48 , which assist in alignment of the grapple hooks, which are described below. The J-lugs  48  are caught behind the hooks of the grapple member. The lugs  48  can be used for an optional retrieval of the grapple member by twisting the mandrel  42  and causing the lugs  48  to fall into the apex of the grapple hooks, thereby allowing the grapple hooks to be pulled from the wedged position, and hence remove the entire connector apparatus  40  from the well bore.  
         [0033]     A lower stop ring  50  is welded to the mandrel  42 . The ring  50  has an exterior diameter greater than the exterior diameter of the mandrel  42 . The bottom of the mandrel  42  may be cut at an angle, with the bottom surface  52  assisting in guiding the connector apparatus into the tubular casing. If desired, the slanted edge  52  can be provided with serrations or teeth  53  to further assist in guiding of the mandrel  42  into the casing  16 . A flexible, resilient sealing means, or pack off element  54  is slidably positioned on the mandrel  42 . The bottom of the pack off element  54  rests on the ring  50 , which prevents downward movement of the pack off element  54  along the mandrel body  42 .  
         [0034]     An activator ring  56  is positioned above the pack off element  54 . The activator ring  56  has a cylindrical bottom portion  58  and a frustoconical upper portion  60 . The frustoconical portion  60  can be made comprising spaced prongs  61  having a wedge-shaped cross-section, as shown in  FIG. 12 , or a solid surface conical member  63 , as shown in FIG.  13 . An exterior surface of the prongs  61  and member  63  is provided with a plurality of spaced teeth  62  which are adapted to mesh with the inner teeth  68  of the grapple hooks  70 .  
         [0035]     Secured between a bottom surface  72  of the portion  60  or member  63  and the top of the cylindrical portion  58  is an annular flange  64 , which has a diameter greater than the exterior diameter of the cylindrical portion  58 . The flange  64  has an exterior diameter substantially equal to or slightly smaller than the diameter of the bottom surface  72  of the portion  60  or  63 . The flange  64  defines an annular shoulder  74 , which contacts an upper surface  76  of the pack off element  54 . The cylindrical portion  58  fits inside the ring shaped flexible pack off element  54  as shown in  FIG. 6 . In the run in position, illustrated in  FIG. 6 , the flange  64  is located above the top surface  76 , while the grapple hooks  70  are located above the portion  60 . In this position, the grapple hooks  70  and the activator ring  56  are not engaged.  
         [0036]     As shown in more detail  FIG. 15 , the grapple member  80  is provided with a plurality of tensioned grapple hooks  70  secured to a ring shaped plate  82 . The grapple hooks  70  extend downwardly from the plate  82  in an equidistant relationship to each other; the grapple hooks  70  have outwardly extending lower parts  71  that may have narrow angularly-shaped bottom edges  73 . The grapple member  80  can have three or more grapple hooks  70 . In the embodiment shown in  FIG. 3-15 , four grapple hooks  70  are used, with three of them shown in the drawings.  
         [0037]     Each grapple hook  70  has an elongated body  86  which is provided with a plurality of spaced exterior teeth  88  in the lower part thereof. Each of the lower parts  71  have slanted inner surfaces  75 , slanted away from the center of the grapple member  80 . The inclined surfaces  75  match the angle of the inclined surfaces  60 ,  63  of the activator ring  56 . The inner teeth  68  are formed on the inclined surfaces  75 .  
         [0038]     The teeth  88  are oriented in an upward direction so as not to resist downward movement of the connector apparatus  40 , while resisting upward movement of the connector apparatus  40 . When the mandrel  42  is pulled upwardly, the teeth  88  engage the inner wall of the casing  16 . In the run-in position shown in  FIG. 6 , the grapple member  80  moves through the casing  18  without contacting the wall of the casing to enable the grapple hooks  70  to slide into the casing  18 , while frictionally engaging the wall of the casing  16 . At such time, the pack off element  54  is in a retracted position.  
         [0039]     In a set position shown in  FIGS. 3 and 7 , the connector apparatus  40  is moved into the casing  16  with the flange  82  resting on top of the stub formed by the cut off casing  16 . The pack off element  54  is pressed by the flange  64  of the activator ring  56 , causing the pack-off element  54  to expand laterally and fill the space within the casing  16 . In this position, the pack-off element  54  seals the interior of the casing  16  while the stop ring  50  prevents downward movement of the pack off element  54  along the mandrel  42 .  
         [0040]     As can be further seen in  FIG. 3 , the teeth  88  of the hooks  70  engage the inner wall of the casing  16 , with the teeth  68  of the grapple member  80  engaging the teeth  62  of the activator ring  56 . The new casing  46 , which has been lowered with the connector apparatus  40  is positioned around the new control line  28 , allowing the operator to re-establish control of the safety valve  22 .  
         [0041]     When an upwardly-directed force is applied to the connector apparatus  40 , the grapple member  80  slides upwardly away from the activator ring  56  while the teeth  88  still engage the interior of the casing  16 . The pack off element  54  is laterally expanded under the force created by the activator ring  56 . The plate  82  contacts the bottom of the connector member  44 , as shown in  FIG. 8 , allowing the large diameter openings  43  in the mandrel  42  and opening  45  in the connector member  44  to be used for entrance from the surface of casing strings or other equipment.  
         [0042]     Once the connector member is set in place, as shown in  FIG. 5 , the annular space between the new casing  46  lowered along with the connector member  40  into the well is cemented, as shown by reference numeral  90 , and then a new production casing  98  is lowered through the openings  45  and  43 . The production tubing  24  is connected with a new production tubing string  96  lowered from the surface, and the control valve  22  is activated into an open position. The mineral production can be resumed through the same well. The production tubing as well as the control lines is tied back in a conventional manner well known in the mineral exploration industry.  
         [0043]     The connector apparatus of the present invention can be used for repair damage to the most subterranean or subsurface locations where replacement of pipes is required. The body of the mandrel  42 , grapple  80  and activator ring  56  are formed from a non-corrosive material suitable for subsurface operations. The pack-off element  54  can be made from strong resilient flexible material, such as rubber and the like. Of course, other materials can be used, provided they have similar physical characteristics.  
         [0044]     Many changes and modifications can be made in the design of the present invention without departing from the spirit thereof. I therefore pray that my rights to the present invention be limited only by the scope of the appended claims.