Abstract:
The present invention provides a field weldable connection. In one embodiment, the field weldable connection is a downhole connector assembly for sealingly attaching a first and a second segment of a control line. The control line has an outer housing that encapsulates a polymeric secondary housing. A communication line runs therethrough the secondary housing. The connector further comprises a weld coupling welded to the outer housing of the first and second segments of the control line. To protect the communication line from the thermal radiation and heat generated during the welding process, at least one reflective sleeve replaces a portion of the secondary housing at a location intermediate the communication line and the welds of the coupling.

Description:
[0001]     This application is a divisional of pending U.S. patent application Ser. No. 10/449,469 entitled, “FIELD WELDABLE CONNECTIONS,” filed on May 30, 2003, which is a continuation-in-part of U.S. application Ser. No. 09/970,353 filed Oct. 3, 2001. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The subject matter of the present invention relates to communication lines. More specifically, the subject matter of the present invention relates to an apparatus and method of protecting and sealing spliced communication lines.  
       BACKGROUND OF THE INVENTION  
       [0003]     Communication lines are used in a wide range of applications in the oilfield industry. The communication lines transmit monitored data regarding downhole conditions such as temperature and pressure to surface instrumentation. The communication lines can also be used to send information down the well from the surface. Additionally, communication lines may also be used to electrically power downhole equipment. Communication lines may include electrical conduits, optical fibers, and other methods for data or power transmission.  
         [0004]     In environments such as those encountered in downhole wells, the communication lines are exposed to hostile conditions such as elevated temperatures and pressures. To protect the fragile communication lines from the hostile conditions, the communication lines are generally carried within protective tubing that provides an environmental seal. Problems arise when the seal must be broken during assembly, installation and/or repair of the communication line. For example, in downhole applications, in order for the communication line to be fed through production equipment such as packers, the line must be cut and then spliced with the downstream line. Thus, after splicing, the communication line must once again be sealed from the harsh environment.  
         [0005]     There exists, therefore, a need for an apparatus and method of splicing communication lines that provides structural integrity and protects the communication line from the surrounding environment.  
       SUMMARY OF THE INVENTION  
       [0006]     An embodiment of the present invention provides a downhole connector assembly for sealingly attaching a first and a second segment of a control line. The control line has an outer housing that encapsulates a polymeric secondary housing having a communication line therein. The connector assembly comprises at least one weld coupling welded to the outer housing of the first and second segment of the control line. At least one reflective sleeve replaces at least a portion of the secondary housing such that the reflective sleeve is located between the communication line and the welds of the weld coupling. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]      FIG. 1  is a sketch of a communication cable.  
         [0008]      FIG. 2  is a sketch of a section of cable that has been prepared for splicing.  
         [0009]      FIG. 3  is a sketch of the welded splice assembly.  
         [0010]      FIG. 4  is a sketch of another embodiment of the welded splice assembly having a pressure housing.  
         [0011]      FIG. 5  is a sketch of another embodiment of the welded splice assembly having a gel or epoxy material within the pressure housing.  
         [0012]      FIG. 6  is a sketch of another embodiment of the welded splice assembly having a plurality of weld couplings.  
         [0013]      FIG. 7  is a sketch of another embodiment of the welded splice assembly having a plurality of weld couplings and a pressure housing.  
         [0014]      FIG. 8  is a sketch of another embodiment of the welded splice assembly.  
         [0015]      FIG. 9  is a sketch of another embodiment of the welded splice assembly having a plurality of weld couplings.  
         [0016]      FIG. 10  is a sketch of another embodiment of the welded splice assembly attached to a tool.  
         [0017]      FIG. 11  is a sketch of a wellbore completion including a spliced communication line.  
         [0018]      FIG. 12  provides a sketch of the welded splice assembly used for a hydraulic or fluid conduit.  
         [0019]      FIG. 13  provides a sketch of another embodiment of the welded splice assembly of the present invention having a reflective shield.  
         [0020]      FIG. 14  provides a sketch illustrating another embodiment of the welded splice assembly of the present invention.  
         [0021]      FIG. 15  provides a sketch of yet another embodiment of the welded splice assembly of the present invention.  
         [0022]      FIG. 16  provides a sketch of still another embodiment of the welded splice assembly of the present invention.  
         [0023]      FIG. 17  provides a sketch of still another embodiment of the welded splice assembly of the present invention.  
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0024]     In the following detailed description of the subject matter of the present invention, the apparatus and method of splicing communication lines is principally described with reference to downhole well applications. Such description is intended for illustration purposes only and is not intended to limit the scope of the present invention. In addition to downhole well applications, the present invention can be used with any number of applications such as pipeline monitoring, subsea well monitoring, and data transmission, for example. Furthermore, the communication lines may comprise electrical wiring, which may facilitate transfer of information, power, or both. All such types of communication line splicing are intended to fall within the purview of the present invention. However, for purposes of illustration, the present invention will be principally described as being used in downhole well applications. Further as used herein, the term communication line shall refer to those lines comprising electrical lines or fiber optic lines, as well as lines including combinations thereof or combinations with other types of lines.  
         [0025]      FIG. 1  provides a sketch of a typical cable  1  useful in the present invention. The cable  1  comprises an outer housing  5 , a secondary housing  10 , and one or more communication lines  15 . The outer housing  5  provides the structural integrity for the cable  1  and protects the communication lines  15  from the surrounding environment. Further, the outer housing  5  provides structural protection for the communication lines  15  from damage caused by the cable  1  impacting, or being impacted by, nearby tools and equipment. In one embodiment, the outer housing  5  is comprised of a metallic material such as steel, or other metallic alloys, for example. The secondary housing  10  resides within the outer housing  5  and provides protection for the communication lines  15  contained within. In one embodiment, shown in  FIG. 1 , the secondary housing  10  is made from a polymeric material.  
         [0026]      FIG. 2  provides a sketch of a segment of cable that has been prepared for splicing. The cable  1  has been cut so that the communication line  15  extends longitudinally beyond the outer housing  5  and the secondary housing  10 . Afterwards, a portion of the secondary housing  10  is removed in order to create a void  20 , which is defined by the outer housing  5  and the secondary housing  10 .  
         [0027]      FIG. 3  provides a sketch illustrating the communication line splice of the present invention. In  FIG. 3 , the two communication lines being spliced are designated  15   a  and  15   b . Once the cables  1   a ,  1   b  have been prepared for splicing, thermal insulators  25   a ,  25   b  are inserted into the void  20  (shown in  FIG. 2 ) so that the insulators  25   a ,  25   b  lie between the outer housing  5  and the communication lines  15   a ,  25   b . The insulators  25   a ,  25   b  protect the communication lines  15   a ,  15   b  from the heat of the welding. Additionally, the insulators  25   a ,  25   b  prevent the secondary housing from melting and outgassing, which can result in poor weld quality. Prior to splicing, a weld coupling  35  is slid over one of the cables  1   a ,  1   b . The cleaved communication lines  15   a ,  15   b  are then spliced together by conventional techniques, such that the communication lines  15   a ,  15   b  are operatively connected at the splice  30 . The weld coupling  35  is then slid to cover the ends of both cables  1   a ,  1   b , and the weld coupling  35  is secured in place by welds  40 . In one embodiment the welds  40  are formed using an orbital welder. Once welded, the weld coupling  35  protects the splice  30  from corrosion, erosion, and physical damage resulting from environmental and operational conditions. Additional protection is provided against hydrocarbon darkening resulting from contact with conductive fluid.  
         [0028]      FIG. 4  provides a sketch of another embodiment of the weld assembly. In this embodiment, a pressure housing  45  fits over the weld coupling  35 . The pressure housing  45  is slid over the same cable  1   a ,  1   b  as the weld coupling  35 , but is slid prior to the sliding of the weld coupling  35 . After splicing and after the weld coupling  35  is secured in place, the pressure housing  45  is attached to the cables  1   a ,  1   b  such that the weld coupling  35  is isolated from environmental conditions. For example the housing may be attached by welding, ferrules, or elastomeric seals, among other means. A port  50 , located in the pressure housing  45  enables pressure testing of the welded assembly.  
         [0029]      FIG. 5  provides a sketch of another embodiment of the weld assembly. In this embodiment a gel or epoxy material is pumped through the port into a cavity  52  defined by the pressure housing  45 , the cables  1   a ,  1   b , and the weld coupling  35 . This fluid is used for pressure testing. The fluid is pumped into the cavity  52  at a high pressure, and the welded splice assembly is monitored for signs of failure. After pumping, the port  50  is plugged to seal in the viscous fluid. When the spliced section of cable is installed downhole, the viscous fluid cures and hardens due to the high downhole temperatures. The cured material thus provides additional protection for the splice  30  against erosion, corrosion, and other environmental conditions.  
         [0030]      FIG. 6  provides a sketch of another embodiment of the weld assembly having a plurality of weld couplings  35   a ,  35   b . The embodiment shown in  FIG. 6  shows two couplings, but any number can be used and remain within the purview of the invention. The first weld coupling  35   a  is slid over the first cable  1   a  and the second weld coupling  35   b  is slid over the second cable  1   b . An additional thermal insulator  25   c  is inserted to protect the splice  30  at the housing junction  55 . After the cables  1   a ,  1   b  are spliced, the first weld coupling  35   a  is welded to the first cable  1   a  and the second weld coupling  35   b  is welded to the second cable  1   b . The first weld coupling  35   a  is then welded to the second weld coupling  35   b  at the housing junction  55 , thereby enclosing the splice  30 . In this manner, both welds near the secondary housing  10  are formed prior to the weld couplings  35   a ,  35   b  being sealed to the surrounding environment. Thus, any resulting outgassing of the secondary housing  10  is able to escape to the environment and does not affect the weld quality.  
         [0031]      FIG. 7  provides a sketch of another embodiment of the weld assembly. In this embodiment, the pressure housing  45  protects the two weld couplings  35   a ,  35   b  against erosion and other damaging environmental conditions. The pressure housing  45 , through its port  50 , enables testing of the welded connections with a standard fluid for pressure testing, such as hydraulic oil, or by a different viscous fluid, such as a gel or epoxy material.  
         [0032]      FIG. 8  provides a sketch of another embodiment of the pressure housing  45 . In this embodiment, the pressure housing  45  is attached to the cables  1   a ,  1   b  by means of fittings  60   a ,  60   b . The first fitting  60   a  and the pressure housing  45  are slid over the first cable  1   a . The second fitting  60   b  is slid over the second cable  1   b . After splicing, the fittings  60   a ,  60   b  and the pressure housing  45  are positioned such that the weld coupling  35  is contained within the pressure housing  45 . The fittings  60   a ,  60   b  are then tightened, thereby sealing the welded connections inside the pressure housing  45 . The fittings  60   a ,  60   b  in this embodiment seal to the cables  1   a ,  1   b  through a dual ferrule systems  65   a ,  65   b . The fittings  60   a ,  60   b  seal onto the pressure housing  45  by means of an elastomeric seals  70   a ,  70   b . These sealing mechanisms  65   a ,  65   b ,  70   a ,  70   b  are not the only means by which the seals can be made. All mechanisms by which one could sealingly join the pressure housing  45  and the cables  1   a ,  1   b  are intended to fall within the purview of the present invention.  
         [0033]      FIG. 9  provides a sketch of another embodiment of the splice assembly. In this embodiment, the fittings  60   a ,  60   b  are connected to pressure housing  45  by means of a sealing pipe threads  62   b ,  62   c . A removable port  75  is used to pressure test the welded splice assembly.  
         [0034]      FIG. 10  provides a sketch of another embodiment of the splice assembly. In this embodiment, communication line  15  is spliced to a downhole tool  80 . The weld coupling  35  is welded to the outer housing  5  on one side and a section of the tool  80  on the opposite side.  
         [0035]      FIG. 11  provides a sketch of a wellbore completion including a spliced communication line. The cable  1  is installed downhole to communicate with or power a piece of downhole equipment  85 . The equipment  85  may be controlled by a controller located at the surface.  
         [0036]      FIG. 12  provides a sketch of the welded splice assembly used for a hydraulic or fluid conduit. In  FIG. 12 , a weld coupling  35  is secured over the spliced hydraulic or fluid conduits  100   a ,  100   b  by welds  40 . Once welded, the resulting spliced hydraulic or fluid line can be pressure tested prior to placement downhole.  
         [0037]     Another embodiment of the welded splice assembly of the present invention is described with reference to  FIG. 13  that provides a partial sketch of a segment of cable  1  that has been prepared for splicing. In this embodiment, a small reflective sleeve  110  is inserted into the void  20  between the communication line  15  and the outer housing  5 . The reflective sleeve  110  can be comprised of material such as aluminum or steel, or can be coated with a reflective material.  
         [0038]     The reflective sleeve  110  and the communication line  15  are centered inside the outer housing  5  with the use of centralizers  112 . By using the centralizers  112 , a substantially uniform air gap  114  is created that provides insulation around the communication line  15 . The centralizers  112  are preferably made of a non-electrically conductive material that does not out-gas when exposed to high temperatures. An appropriate material for use as the centralizers  112  is PEEK, for example.  
         [0039]     The communication line  15  is spliced and the weld coupling  35  is welded to the outer housing  5  of the cable  1  using a welding electrode  42 , as described with previous embodiments. As discussed above, the weld coupling  35  protects the splice from corrosion, erosion, and physical damage resulting from environmental and operational conditions.  
         [0040]     During the welding process, the reflective sleeve  110  protects the insulation  16  and conductor  17  of the communication line  15  from the heat of the welding. For example, in the case of optical communication lines, the optical fibers are protected. Additionally, at extreme temperatures, the reflective sleeve  110  protects the insulation  16  of the communication line  15  from thermal radiation, which can be the primary means of heat transfer at extreme high temperatures.  
         [0041]     A pressure housing, as detailed in earlier described embodiments (e.g.,  FIGS. 4, 5 ,  7 ,  8 , and  9 ) can be provided for pressure testing the splice assembly and for isolating the weld coupling from environmental conditions.  
         [0042]      FIG. 14  provides an illustrative sketch of an embodiment of the welded splice assembly of the present invention that provides a method adapted to protect the welded splice assembly against problems associated with having air trapped within the weld coupling  35 . As discussed above, after the splice  30  is made, the weld coupling  35  is slid over the connection and welded to the outer housing  5  of the cable  1 . During the welding of the first end of the weld coupling  35 , the opposite end of the weld coupling  35  is open and thus provides a means for equalization of air pressures. However, during the welding of the second end of the weld coupling  35 , problems associated with trapped air can arise. For example, as the electrode  42  moves into the last part of the cross-section of the weld coupling  35  and attempts to trap the air, the expansion of the air caused by the continuous addition of heat can cause a hole to be formed in the weld pool.  
         [0043]     As shown in  FIG. 14 , a grinding or honing wheel  116  is provided to uniformly remove material off of the surface of the outer housing  5  of the cable  1 . The resulting cable  1  has a circular cross-section in which the outer housing  5  has a substantially uniform outside diameter. Thus, a tighter fit with a smaller inner diameter weld coupling  35  can be achieved. By having very close contact between the two welded surfaces, the expansion of air through the last part of the weld pool can be prevented.  
         [0044]      FIG. 15  provides an illustrative sketch of another embodiment of the welded splice assembly of the present invention adapted to protect the welded splice assembly against problems associated with having air trapped within the weld coupling  35 . In this embodiment, after welding the first end of the weld coupling  35  to the outer housing  5  of the first cable  1   a  with a fillet weld  40 , the second end of the weld coupling  35  is welded to the outer housing  5   b  of the second cable  1   b  with a butt weld  44 .  
         [0045]     At the butt weld  44 , the two faces of the weld  44  can have a very tight fit. Provided the weld penetration is not too deep, the molten weld pool can be prevented from contacting the expanding air and causing a defect. The butt weld  44  can be performed using facing tools that are commonly used for butt welding hydraulic tubing but specially adapted to accommodate and protect the communication line  15  during the metal removal operation.  
         [0046]      FIG. 16  provides an illustration of another embodiment of the welded splice assembly of the present invention adapted to protect the welded splice assembly against problems associated with having air trapped within the weld coupling  35 . In this embodiment, compression fittings such as ferrules  118  are used on the end of the weld coupling  35 . The ferrules  118  can be of the type used to create metal-metal seals on small diameter tubing, for example.  
         [0047]     The ferrules  118  are swaged onto the end of the weld coupling  35 , creating a metal-metal seal between the weld coupling  35  and the ferrules  118  and between the ferrules  118  and the outer housing  5  of the cable  1 . The swaging nut  120  is built split to be removable from the cable  1  after swaging. Provided the weld electrode is properly positioned, the entrapped air is isolated from the weld pool  122  by the metal-metal seal, preventing the forming of defects. As before, only the second end of the weld coupling  35  needs to use the ferrules prior to welding.  
         [0048]      FIG. 17  provides an illustrative sketch of yet another embodiment of the welded splice assembly of the present invention adapted to protect the welded splice assembly against problems associated with having air trapped within the weld coupling  35 . In this embodiment, a two-piece weld coupling  35  is used. The two ends of the two-piece weld coupling  35  are first welded to the cables  1   a ,  1   b  with fillet welds  40 . Because the other end of each half of the two-piece weld coupling  35  is open, no air entrapment occurs during application of the fillet welds  40 .  
         [0049]     The two halves of the weld coupling  35  are then welded together using a butt weld  44 . The two faces of the halves of the two-piece weld coupling  35  have the required finish and geometry to prevent air escape during the welding process. The weld penetration is selected to be less than full to prevent the weld pool  122  from coming in contact with the expanding air. The wall of the weld coupling  35  and the resultant penetration are designed so that the resultant assembly has the required collapse strength.  
         [0050]     It should be noted that the above embodiments described with reference to  FIGS. 14 through 17  can be used to advantage with any of the earlier described embodiments of the welded splice assembly. The methods and apparatus used to protect against problems associated with having air trapped within the weld coupling  35  can be used to advantage in embodiments employing thermal insulators or reflective sleeves.  
         [0051]     The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such are intended to be included within the scope of the following non-limiting claims.