Patent Publication Number: US-7708078-B2

Title: Apparatus and method for delivering a conductor downhole

Description:
BACKGROUND OF THE INVENTION 
   Modern wells, including hydrocarbon wells, utilize an ever-increasing amount of instrumentation. Such instrumentation is very helpful to the art in that it provides information about the downhole environment including parameters such as temperature, pressure, chemical constituency, strain and flow rate as well as many other parameters. Knowledge of such parameters allows a well operator to optimize efficiency of the well either through surface intervention, by pre-programmed downhole controllers or both. The result, of course, is greater production or higher quality production of target fluids. With all of the instrumentation in the downhole environment, conductors to convey the information to remote locations become very important. Such conductors may be electrical, hydraulic and even optical. While in many cases the conductor is attached to or made a part of a downhole tool before running, it is also not uncommon to deliver conductors to the downhole environment at sometime later than the time of installation of the tool. The “time later” may be a matter of minutes to a matter of years or decades depending upon the particular situation and the needs of the well operator. 
   For more stiff conductors such as electrical cable, running in the hole is accomplished in several known ways but for optic fiber, or other highly flexible and less durable conductors difficulty has been experienced by the art. Therefore, a relatively simple and cost effective means for delivering conductors including optic fibers to the downhole environment will be well received by the art. 
   SUMMARY 
   A conductor delivery arrangement includes a length of feedable tubing; a landing tool in operable communication with the feedable tubing; and a conductor in operable communication with the landing tool. 
   A method for delivery of a conductor to a tool in a wellbore includes installing a length of a conductor in a length of feedable tubing; running the feedable tubing and conductor therein into a wellbore; connecting the conductor to a preinstalled downhole connector; and pulling the feedable tubing while leaving the conductor in place. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Referring now to the drawings wherein like elements are numbered alike in the several Figures: 
       FIG. 1  is a schematic view of a well having a coil tubing unit disposed at surface and a connection site in the downhole environment; 
       FIG. 2  is an enlarged view of the circumscribed area  2 - 2  in  FIG. 1 ; 
       FIG. 3  is an enlarged view of the circumscribed area  3 - 3  in  FIG. 2 ; 
       FIG. 4  is essentially the view of  FIG. 2  but illustrated with the conductor received at the connector site. 
   

   DETAILED DESCRIPTION OF THE DRAWINGS 
   Referring to  FIG. 1 , an overview of the concept hereof is provided, with  FIGS. 2 ,  3  and  4  adding detail thereto. While the embodiment specifically shown and described considers an optic fiber delivery, it is to be appreciated that other conductors such as electrical conductors, etc. may also be placed in accordance with the teaching herein. Accordingly, limitation is not to be inferred by the ensuing discussion of fiber, which is merely one example of a particularly difficult conductor to place by other methods and apparatus. 
   In the  FIG. 1  illustration, a wellbore  10  is shown extending from surface  12  into a subterranean environment. A feedable tubing unit  14  is positioned at the surface  12  and is illustrated in  FIG. 1  having a length of feedable tubing (with a conductor  40  therein), just one example of which is coil tubing  16 , extending into the wellbore  10  and into proximity with a preinstalled downhole tool connector  18 . 
   Referring to  FIG. 2 , the circumscribed portion of  FIG. 1  designated  2 - 2  is illustrated in enlarged form. In the  FIG. 2  view, a landing tool  20  is visible. It is landing tool  20  that is either directly receivable in downhole tool connector  18 , or otherwise operably attachable to downhole tool connector  18 . 
   In one embodiment, two things occur at the downhole receiving tool  18 , one is a mechanical connection of the landing tool  20  with the receiving tool  18  and the other is a signal connection. Mechanical connection may be effected in a number of ways such through a collet latch, engageable profile, etc. with the point being to positively locate and retain the landing tool  20  at the receiving tool  18 . Many arrangements exist in the art for effecting this mechanical connection. Landing tool  20  is disposed at the end of the feedable tubing and may be configured to be retained in the receiving tool  18  and partable from coil tubing  16  at a parting line  22  or may be removed with the feedable tubing as it is withdrawn from the wellbore. IN the event that parting line  22  is included, indicating that the landing tool  20  is to be retained in the downhole environment, the parting line may represent an interference press fit connection or other defeatable connection between the landing tool  20  and the feedable tubing  16  upon a pull from uphole or a pressure buildup inside the feedable tubing, for example. The signal connection may also be effected by a number of commercially available arrangements and methods (identified below) for receiving the signal connection  42  disposed at landing tool  20 , these being merely schematically illustrated at downhole tool connector  18  through the representation of an optical receiver  30  (or electrical connector, etc.). For signal connection, whether for transmission or monitoring, a means for effecting the connection while maintaining the connector in a clean condition to avoid loss of signal at the connection site is employed. Several such means are available from various sources. In addition, a debris barrier  28  such as that incorporated in a Hydraulic Wet Connect, which is commercially available from Baker Oil Tools, Houston Tex. may be included in some embodiments. Debris barrier  24  is illustrated schematically in  FIG. 3 . The downhole tool connector  18  includes an optical receiver  30  (or electrical connector, etc.). 
   In accordance with the teaching, hereof, the feedable tubing  16  is only temporarily installed in the wellbore for the purpose of conveying the conductor to the downhole tool. The length of feedable tubing  16  is then removed from the wellbore once the conductor  40  is secured to the downhole tool connector  18 . 
   In operation, a length of conductor  40  which has previously been pumped or otherwise installed in a length of coil tubing  16  is run into the hole with the coil tubing  16 . Before running, the conductor  40  is connected to landing tool  20  at parting line  22 . In one embodiment the conductor (optical embodiment) includes an optical connection  42  (see  FIG. 3 ), which may be a part of any of the exemplary connection means. It is to be understood that the connection components are illustrated simply to provide environment and enhance understanding since extensive disclosure here is not needed in view of the commercial availability of these connections. Landing tool  20  further may include the temporary debris barrier  24  as noted above to prevent wellbore fluids and/or solids from soiling the connection  42 . The landing tool  20  is connected to the coil tubing  16  such that it is of a stable nature but configured to release from the coil tubing  16  through such as hydraulic pressure or overpull. Landing tool  20  then stays in contact with the downhole tool connector  18 . 
   In order to facilitate removal of the coil tubing  16  from the wellbore  10  while ensuring that the conductor  40  stays in place and does not experience significant tensile stress, a fluid is pumped through the coil tubing, from a source pressurized fluid  15  in fluidic communication with the feedable tubing  16 , contemporaneously with the withdrawal of the coil tubing  16  from the wellbore. As one of skill in the art will recognize, conductors, and particularly light conductors such as optic fibers, can be pumped through lengths of tubing by being carried along with the pumped fluid based upon frictional forces. This same principal is employed in the present invention but is used in reverse to leave the fiber in place while moving the tubing  16 . The difference is that instead of causing the conductor to advance through a stationary tubing, the tubing is moved and the conductor remains stationary. The fluid pumped through the tubing allows for withdrawal of the tubing without the tensile stress on the conductor. Pumping and contemporaneous coil tubing removal is continued until the tubing  16  is completely removed from the wellbore. The conductor is then connected to surface equipment or any other desired connectivity. 
   While preferred embodiments have been shown and described, modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustrations and not limitation.