Abstract:
An apparatus or system comprising, or a method utilizing, a pressure-tight head assembly coupling a multi-conductor wireline cable operable for downhole operations within a borehole extending into a subterranean formation. The head assembly comprises: an upper head attachment; a lower head attachment; an upper compression seal assembly; a gripper cone; and a rope socket. The upper compression seal assembly is threaded into and/or otherwise coupled to the upper head attachment in a manner causing the gripper cone to tighten onto the cable jacket.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Patent Application 61/817789, filed Apr. 30, 2013 and entitled “Sealing Wireline Cable Termination”, which is incorporated herein in its entirety. 
     
    
     BACKGROUND 
       [0002]    Existing wireline cables are often terminated in a rope socket inside the tool head of the downhole tool assembly. The layers of strength members in the rope socket may be wedged into place via a series of concentric cones. The cable core passes through the center of the rope socket, and the conductor wires are separated out and connected to conductor wires inside the downhole tool. Insufficient sealing may allow pressurized well fluids and gases to come into contact with the ends of the armor wires and the wiring connections. Such pressurized fluids may travel up the cable along conductors and strength members, perhaps causing damage as described above. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0003]      FIG. 1  depicts an example head assembly. 
           [0004]      FIG. 2  depicts an example lower head attachment. 
           [0005]      FIG. 3  depicts an example feed-through tube assembly. 
           [0006]      FIG. 4  depicts an example of an upper head attachment. 
           [0007]      FIG. 5A  depicts an example upper compression seal assembly. 
           [0008]      FIG. 5B  depicts the example upper compression seal assembly in a pre-assembled configuration. 
           [0009]      FIG. 6  depicts an example gripper cone. 
           [0010]      FIG. 7  depicts an example upper head attachment. 
           [0011]      FIG. 8  depicts an example head assembly. 
           [0012]      FIG. 9  depicts an exploded view of the head assembly of  FIG. 8 . 
           [0013]      FIG. 10  depicts a pressure seal. 
           [0014]      FIG. 11  depicts an example head assembly. 
           [0015]      FIG. 12  depicts an exploded view of the head assembly of  FIG. 11 . 
           [0016]      FIG. 13  depicts an example implementation utilizing a cable with a sealing termination during tractoring. 
           [0017]      FIG. 14  depicts an example implementation utilizing a cable with a sealing termination. 
           [0018]      FIG. 15  depicts an implementation for subsea intervention. 
           [0019]      FIG. 16  depicts an example implementation utilizing a cable with a sealing termination. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0020]    Certain examples are shown in the above-identified figures and described in detail below. In describing these examples, like or identical reference numbers are used to identify common or similar elements. The figures are not necessarily to scale and certain features and certain views of the figures may be shown exaggerated in scale or in schematic for clarity and/or conciseness. 
         [0021]      FIG. 1  depicts an example head assembly. The head assembly  100  includes and upper head attachment  140 . A lower head attachment  160  is located within the upper head attachment  140 . A rope socket  130  is located in the lower head attachment  130 . A gripper cone is connected with the upper head attachment  140 , and a upper compression seal assembly  110  is connected with the gripper cone  120 . 
         [0022]      FIG. 2  depicts an example lower head attachment.  FIG. 3  depicts an example feed-through tube assembly. Referring to  FIGS. 2 and 3 , the lower head attachment  160  has seals  240  located thereabout. The lower head attachment  140  also has feed-through tubes  230  located therein. The feed-through tubes  230  can be operatively aligned with a breakout chamber  220 . A slot  210  for operatively receiving a retaining feature, such as a clip, is formed in the lower head attachment  160 , and a rope socket is adjacent the slot  210 . 
         [0023]      FIG. 4  depicts an example of an upper head attachment. The upper head attachment  140  is configured to receive at least a portion of the lower head attachment. The upper head attachment can be threaded, fastened, or otherwise connected with the lower head attachment. 
         [0024]      FIG. 5A  depicts an example upper compression seal assembly.  FIG. 5B  depicts the example upper compression seal assembly in a pre-assembled configuration. The upper compression seal assembly  110  includes a first member  510 . The first member  510  can be connected with the upper head attachment. The first member  510  can thread or otherwise be fastened to the upper head attachment. The first member  510  can have an internal shape configured to receive compression members  520 . The second member  530  can also have an internal shape to receive the compression members  520 . 
         [0025]    The compression nut  540  can be connected with the first member  510 . The compression nut  540  can compress the compression members  520  as it is tightened onto the first member  510 . 
         [0026]      FIG. 6  depicts an example gripper cone. The gripper cone  610  can have a base and a tapered end  620 . The tapered end  620  can have slit to allow the gripper cone to close onto a cable as the gripper cone is tightened into place. The gripper cone has small angled teeth to hold a cable in place. 
         [0027]      FIG. 7  depicts an example upper head attachment. The upper head attachment  140  can have an area  720  to attach with the gripper cone and area  710  to attach with the upper compression seal assembly. 
         [0028]      FIG. 8  depicts an example head assembly.  FIG. 9  depicts an exploded view of the head assembly of  FIG. 8 . Referring to  FIGS. 8 and 9 , the head assembly  800  includes a fishing neck  810 , an upper packoff bushing  840 , a compression tool  810 , a lower packoff bushing  810 , the rope socket  130 , the breakout chamber  220 , a piston  820 , and a fill port  830 . The breakout chamber  220  can be filled with filler material. The filler material can be oil, liquid, grease, or fluid. The filler material can be supplied to the breakout chamber using the fill port  830 . 
         [0029]    The filler material may expand when in the presence of elevated downhole temperatures. The resulting pressure of the expanding filler material trapped inside the breakout chamber  220  may damage the conductors and/or other components of a cable. The piston  820  can be used to compensate for the expanding pressure. 
         [0030]    For example, the cable may be terminated to the rope socket  130  and wiring may be completed in the breakout chamber. The compression tool  820  located between upper and lower packoff bushings  840  and  810  at the uphole end of the rope socket  130  may provide a high-pressure seal at the uphole end of the breakout chamber  220 . After the head assembly is assembled, the breakout chamber  220  is filled with the filler material (e.g., oil, grease, and/or any other materials) via the fill port  830 . The fill port may then be sealed with a plug and/or other means. 
         [0031]    As the head assembly  800  is exposed to elevated downhole pressures, the expanding filler material in the breakout chamber  220  may push, force, and/or otherwise urge the piston  820  away from the breakout chamber  220 . Such movement of the piston  820  may thus relieve the pressure building within the breakout chamber. As the temperature subsequently decreases, the borehole pressure may similarly urge the piston back toward the breakout chamber. The piston may, thus, also aid in preventing cross-contamination of borehole fluids into the breakout chamber, which may otherwise damage the conductors and/or other components therein. The lower head attachment may also comprise stops operable to limit travel of the piston. 
         [0032]      FIG. 10  depicts a pressure seal. The pressure seal  910  can be a one way seal that allows flow in one way but prevents flow in a second direction. The pressure seal  910  can be located in a housing  930 . Seals in the housing  930  or around the seal  910  can prevent movement of the seal  910 . The housing  930  can have channels  940  in an uphole face. 
         [0033]      FIG. 11  depicts an example head assembly.  FIG. 12  depicts an exploded view of the head assembly of  FIG. 11 . The head assembly includes the fishing neck  810 , the upper packoff bushing  840 , the housing  930  with the pressure seal  930 , a lower packoff bushing  810 , the rope socket  130 , the breakout chamber  220 , a fill port  830 , and the lower head attachment  160 . 
         [0034]    The channels in the housing  930  can provide a flow path for fluid exiting the breakout chamber and the seal can allow fluid to flow out of the breakout chamber. The seal can prevent other fluid from entering the breakout chamber. 
         [0035]    Referring now to  FIG. 13 , a cable having a sealing termination according to one or more aspects of the present disclosure is indicated generally at  1400 .  FIG. 13  depicts an example implementation utilizing a cable with a sealing termination during tractoring, in which a tractor  1402  is attached to the end of the cable  1400  when deployed in a wellbore or borehole  1404 , which may have one or more vertical, horizontal, deviated, dog-legged, and/or multi-lateral wellbore sections. 
         [0036]    Referring now to  FIG. 14 , a cable having a sealing termination according to one or more aspects of the present disclosure is indicated generally at  1500 . Many offshore platforms utilize a means of supporting the wellhead equipment  1502  when performing a wireline operation without the use of the drilling derrick (not shown). A crane  1504  may be one manner of doing this. A mast unit or other temporary derrick (not shown) may also or alternatively be utilized. A standard wireline rig up offshore may utilize a crane  1504  or mobile mast unit (not shown) to support both the upper sheave wheel and the pressure equipment itself. A pack off assembly  1506  may utilize an upper sheave  1508  mounted to the well head equipment  1510  itself at the top of the lubricator  1512 . 
         [0037]    Referring now to  FIG. 15 , a cable having a sealing termination according to one or more aspects of the present disclosure is indicated generally at  1700 .  FIG. 19  depicts an implementation for subsea intervention. A lubricator system may be lowered onto the subsea well head  1702 , using grease injection into flow tubes to establish a dynamic pressure seal (stuffing box  1710 ), with the cable returning through open water back to surface on the intervention vessel (not shown) or the rig/platform  1704 . For shallow water applications, the grease injection system, including the grease tank, can be installed on the vessel or rig/platform  1704 , and pressurized grease can be conveyed to the grease head at the seabed  1706  through a control umbilical (not shown) or through a dedicated hose (not shown). For well intervention operations with a subsea lubricator in deep water, the injection system  1708  may be placed subsea. 
         [0038]    Referring now to  FIG. 16 , a cable having a sealing termination according to one or more aspects of the present disclosure is indicated generally at  1800 . The cable  1800  may be utilized in combination with a spoolable compliant guide system  1802 . A pack-off type dynamic seal may be retrievable through the compliant guide  1802 . 
         [0039]    Other implementations within the scope of the present disclosure may logging with a cable having a sealed termination as described above while a fluid is injected in the well.