Abstract:
A control or other line with a hole downhole can be repaired by pumping a device that is driven by pressure delivered behind a leading seal. The device advances until the leading seal passes the opening in the line where its forward movement is stopped. Upstream of the opening a fluid activated seal is energized so that seals now straddle the opening in the wall. A passage that extends between the seals is opened by blowing a rupture disc with internal pressure to once again give access to the downhole tool through the passage that has external seals to straddle the hole in the tubing wall. Normal operation of the downhole tool can then resume.

Description:
FIELD OF THE INVENTION 
     The field of the invention is repair devices and methods for damaged tubulars downhole and more specifically control lines that conduct pressurized fluid to a variety of downhole tools. 
     BACKGROUND OF THE INVENTION 
     Bottom hole assemblies can use a variety of tools downhole that are surface controlled through hydraulic control lines that run along a tubing string from the surface at one end to the downhole tool at the other end. Safety valves and isolation valve are just some examples. Frequently these lines are run in bundles with different termination points and into wellbores that are not necessarily vertical. These lines have to get past packers in some applications. Generally the lines are secured to the exterior of the tubing string as the joints are added at the surface. Since these lines go through close clearances such as a tubing string moving through a cased and cemented wellbore, there are opportunities for such lines to become damages in various ways. One of the worst ways that such damage can occur is that a hole develops in a control line. Depending on the size of the hole and the resulting ability of the control line to convey the required pressure to the downhole tool, the presence of a hole in a control line can result in the downhole tool being inoperative from the surface. When this happens the string has to be pulled so that the location of the damage can be determined and repaired. This causes significant downtime that can be very costly to the well operator. 
     In the past efforts were directed to protect control lines run into wellbores by encapsulating them or using other protective devices. A few representative examples are U.S. Pat. Nos. 4,262,703; 3,844,345; 3,806,168 and 3,780,802. 
     The present invention provides a method and associated equipment to locate the line break and straddle it while providing sealing on opposed ends of the break whereupon normal pressurized flow can be resumed by opening a passage through the device that straddled the break. The equipment may have limits to certain situations and may not be optimally suitable for other situations. One limiting condition may be a complete control line break or situations where the line is crimped or bent so badly as to impede movement of the repair device through it. However, options are available for unique situations. For example, the crimps in the line can be taken out with a tool that is pumped down the control line to the point of the hole in the wall and then retrieved so as to take the kinks out of the line to a sufficient extend that the repair device will travel to the hole location. Alternatively the repair device can be configured with a leading swage  50  shown in  FIG. 6  to return the internal dimension of the control line to the original dimension as the repair device is advanced to the hole location. 
     In one aspect of the device, the wall hole is straddled with seals before and after and the seal that is uphole of hole energized to close leaving a straddle tube sealed on opposed ends that only needs communication through it to be opened up so that normal control line operations can resume. 
     In another option, a light source and camera can be first run into the control line to determine the hole location or locations as a preliminary indication of whether a repair is even feasible. 
     These and other details of the method and associated apparatus for repair of control or other types of lines in a downhole environment will be more readily understood by those skilled in the art from a review of the description of the preferred embodiment and the associated drawings while understanding that the full scope of the invention is to be found in the appended claims. 
     SUMMARY OF THE INVENTION 
     A control or other line with a hole downhole can be repaired by pumping a device that is driven by pressure delivered behind a leading seal. The device advances until the leading seal passes the opening in the line where its forward movement is stopped. Upstream of the opening a fluid activated seal is energized so that seals now straddle the opening in the wall. A passage that extends between the seals is opened by blowing a rupture disc with internal pressure to once again give access to the downhole tool through the passage that has external seals to straddle the hole in the tubing wall. Normal operation of the downhole tool can then resume. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows the repair tool advancing to the break in the control line; 
         FIG. 2  is the view of  FIG. 1  with the leading seal of the repair tool advanced beyond the control line wall opening; 
         FIG. 3  is the view of  FIG. 2  with activating fluid being pumped to energize the seal on the uphole end of the break in the control line; 
         FIG. 4  is the view of  FIG. 3  with seals now in place on either side of the wall opening while the through passage is still obstructed; 
         FIG. 5  is the view of  FIG. 4  with the through passage opened for flow so that the control line can be put back in service to actuate a downhole tool; 
         FIG. 6  is a close up of a leading end of the tool showing one placement of the swage; 
         FIG. 7  shows the use of multiple tools to straddle spaced apart openings in a control line; and 
         FIG. 8  shows a version of the tool with an initial corrugated body using a shape memory alloy that goes to round when warmed above its transition temperature. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       FIG. 1  shows a hydraulically operated downhole tool  10  that is surface operated with a control line  12  that has been damaged as indicated by a hole  14 . Typically the control line  12  is secured to a tubular  16  that runs from the well surface to the downhole tool  10  using one or more connected strings. Arrows  18  represent flow out the hole  14  as the repair tool  20  is advanced in the control line  12 . 
     The repair tool  20  has a downhole or leading end  22  and a trailing end  24 . The structure is basically a tubular body  23  that is preferably closed at leading end  22  with a breakable member such as a rupture disc  26  that is illustrated schematically. As an option there can be a small conical swage either ahead of the schematically illustrated rupture disc  26  or the swage  50  can also be on the exterior wall of the tubular body  23  as shown in  FIG. 6 . Opposed seals  28  and  30  are mounted on the exterior of the tubular body  23  with seals  28  retaining pressure going uphole toward end  24  and seal  30  retaining pressure in the downhole direction toward end  22 . 
     Located externally to the tubular housing  23  and spaced uphole from seal  30  is a reactive seal  32  that is run in at a smaller dimension and gets larger when exposed to fluid like water to enlarge and seal the annular space outside the housing  23  and within the control line  12 . For example the seal  32  can be water reactive clay like bentonite or montmorillonite. Alternatively the seal  32  can react with oil or other hydraulic fluids. It should be noted that to avoid early actuation of the seal  32  the control line  12  can be flushed into opening  14  with fluid that is not reactive with seal  32  and then, once the seal  32  is in position, the fluid can be changed to induce the seal to enlarge and close off the annular space around the housing  23 , as is shown in  FIG. 4 . 
     Referring to  FIG. 1  the tool  20  is advanced into the control line  12  until the seals  28  and  30  have moved past the hole  14 . Since the leading end  22  is closed, the tool  20  can be delivered with surface pressure applied into the control line  12  at the surface end indicated schematically as  34 . If the seal  32  is water reactive than it is preferred to use hydraulic oil behind the tool  20  to drive it toward the hole  14 . As mentioned before, it is possible to drive a swage with the tool  20  to try to get any smaller kinks or dents in the control line  12  to go back to round so as to assist the tool  20  in its advancement to the  FIG. 2  position. 
     As shown in  FIG. 2  the seals  28  and  30  have gone past the hole  14 . Since there is no outlet from zone  36  in the control line  12 , once the seals  28  and  30  get past the hole  14  forward progress of the tool  20  comes to a halt. Since there is oil in the control line  12  the seal  32  that is still uphole of the hole  14  has not been energized and there is an annular flow passage represented by arrows  38  that allows the oil pumped from the surface  34  to go around the housing  23  and into the hole  14 . Surface personnel will sense that the housing  23  is no longer advancing despite the flow of oil into the control line  12 . They will also notice a distinct change in the flow rate once the seals  28  and  30  go past the hole  14 . Since seal friction at seals  28  and  30  will be reduced because those seals no longer move the flow now going into the hole  14  is likely to increase and the surface pressure may drop depending on previous flow conditions used to advance the tool  20  into the control line  12 . 
     At that point the fluid is changed to admit fluid that will energize the seal  32  now in position above the hole  14 . This is shown in  FIG. 3  as the seal  32  if it is clay is energized by pumped water from the surface  34  as indicated by arrows  40 . The seal  32  can instead be a water reactive polymer as yet another option for the seal energized downhole. Eventually, the seal  32  swells and gets hard to close off the annular space around the housing  23  as shown in  FIG. 4  by the disappearance of the arrows  40 . The hole  14  is now straddled by seals  28  and  30  on the downhole side of hole  14  and activated seal  32  on the uphole side of hole  14 . The through passage  42  is still sealed as the rupture disc  26  is still intact. 
     Arrow  44  in  FIG. 5  indicates that the passage  42  has been opened up either with pressure or some other way to make the rupture disc or end plug go away such as for example by dissolving it. Passage  42  now spans the hole  14  and is open to zone  36  that goes to the downhole tool  10 . The hole  14  is sealed by virtue of seals  28  and  30  on the downhole side and seal  32  on the uphole side. Pressure applied at surface  34  will now reach the tool  10  without leaks as indicated by arrow  44 . 
     If the tool  20  gets stuck before reaching the hole  14  then the passage  42  can just be opened by blowing the rupture disc  26 . If there are several holes  14  in a single line  12  then the tool  20  can be propelled to the furthest hole  14  away from the surface  34  and in series each hole  14  can be straddled in succession.  FIG. 7  shows a first assembly that is already straddling an unseen opening further downstream and a second tool  20 ′ delivered behind it to straddle another opening  14 ′. If a leading swage is used then it needs a passage through it that can be opened when the tool  20  is in position straddling a hole  14 . While seal  32  is shown offset from the hole  14  it can also optionally overlay the hole  14  before it is activated. The tubular housing  23  can be made of a variety of flexible materials such as plastic or malleable metals. 
     As an alternative, the tool  20  can be made of a shape memory material such as an alloy and delivered into the control line in a round or a corrugated cross section  52 , as shown in  FIG. 8 . The corrugations can be along an axis perpendicular to the axis of tool  20 , as shown, or extending axially along the tool  20 . External seals such as  28 ,  30  or/and  32 , as shown in  FIG. 8 , may be used or omitted. Once it is known that the tool  20  is straddling the hole  14  heat can be applied with a heater that is retrievable to the surface or the heat from the well fluids can cause a state change in the shape memory material so that it goes to a larger shape and seals the hole  14  with or without external seals. Once such a design is over a hole  14  and heat is applied by circulating fluid through the control line  12 , surface personnel will note that flow has dropped off as the dimension of the tool has increased to the point where flow around the outside of the tool is no longer possible due to the material having gone past its transition temperature. 
     The above description is illustrative of the preferred embodiment and many modifications may be made by those skilled in the art without departing from the invention whose scope is to be determined from the literal and equivalent scope of the claims below: