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This non-provisional patent application claims priority to provisional application Ser. No. 60/743,818 filed Mar. 27, 2006. 
    
    
     BACKGROUND 
     Coiled tubing rigs are used for a variety of well related operations. Generally, coiled tubing rigs are used to deliver a variety of well tools downhole and/or to perform a variety of well related procedures via coiled tubing or jointed tubing. Coiled tubing is unspooled and injected into a wellbore to move a well tool, e.g. a bottom hole assembly, to a desired position downhole. Similarly, the coiled tubing and attached well tool can be retrieved from the well by spooling the coiled tubing onto a coiled tubing reel. A variety of factors, including environmental factors and the interchangeability of well tools, can limit the efficiency of the coiled tubing rig and otherwise detrimentally affect operation of the coiled tubing rig. 
     SUMMARY 
     In general, the present invention provides a system and method for improving the functionality and efficient operation of a coiled tubing rig. The rig comprises one or more features that facilitate its operation in many types of environments, including harsh environments. Alternatively, or in addition, the coiled tubing rig may comprise one or more features that facilitate the interchangeability of well tools, e.g. the interchangeability of bottom hole assemblies. The ease of interchangeability lowers operational cost and increases the efficiency of performing a variety of well related operations. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Certain embodiments of the invention will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements, and: 
         FIG. 1  is a side view of a coiled tubing rig located at a well site, according to an embodiment of the present invention; 
         FIG. 2  is a top view of a mouse hole utilized with the coiled tubing rig illustrated in  FIG. 1 , according to an embodiment of the present invention; and 
         FIG. 3  is a plan view of a well site including the coiled tubing rig illustrated in  FIG. 1  and additional support equipment, according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description, numerous details are set forth to provide an understanding of the present invention. However, it will be understood by those of ordinary skill in the art that the present invention may be practiced without these details and that numerous variations or modifications from the described embodiments may be possible. 
     The present invention relates to a system and methodology for utilizing a coiled tubing rig. The coiled tubing rig comprises one or more transportable components that are moved to one or more selected well sites to perform well related procedures. The transportable components often are placed on movable platforms, such as road legal trailer beds, that can be transported over public highways. In this manner, the coiled tubing rig components can be easily moved from to one well site to another to perform, for example, well servicing operations. 
     Generally, the coiled tubing rig may be equipped to handle both tubing joints and coiled tubing as well as a variety of downhole components, e.g. bottom hole assemblies. The coiled tubing rig comprises a mast that can be transitioned to a vertical orientation to facilitate the lifting of tubing, well tools and other well related components. The mast also can be used in corporation with, for example, a lubricator and a coiled tubing injector. Transportable coiled tubing reels enable coiled tubing to be rapidly deployed or retrieved via the coiled tubing injector. Additionally, many other or alternate components can be used with or incorporated into the coiled tubing rig to facilitate a variety of well servicing operations. 
     One embodiment of a coiled tubing rig  10  is illustrated in  FIG. 1  as positioned at a well site  12 . In this example, coiled tubing rig  10  comprises a base or platform  14 , a mast  16  mounted to base  14 , and a coiled tubing reel  18 . Additionally, coiled tubing rig  10  comprises a coiled tubing injector  20 , a lubricator  22 , a lubricator handling system  24  having upper and lower lubricator handling arms  26 ,  28 , and jointed pipe  30  that may be manipulated by a pipe elevator  32 . Coiled tubing reel  18  is positioned in a coiled tubing reel housing  34 , and lubricator handling system  24  may be used to select and move well tools, e.g. bottom hole assemblies, into cooperation with lubricator  22 , as discussed in greater detail below. 
     In the embodiment illustrated, base  14  comprises a trailer  36  having a plurality of wheels  38  supporting a trailer platform  40  to enable movement of coiled tubing rig  10  from one well site to another. Trailer  36  may be designed as a road legal trailer to allow legal transport over a public highway system. Base  14  also may comprise a plurality of stabilizer arms  42  that can be lowered and pressed against a ground surface  44  to stabilize the overall system when mast  16  is raised for a coiled tubing rig operation. 
     Mast  16  is pivotably mounted to base  14  so the mast may be raised to facilitate coiled tubing rig operations at a well  46 . Upon completion of the well related operation, mast  16  can be pivoted to a generally horizontal position for transport, as illustrated by the mast outline  47  in  FIG. 1 . Mast  16  is used in cooperation with a variety of components, such as lubricator  22 . Additionally, lubricator handling system  24  may be mounted to mast  16  in a manner that facilitates the handling of bottom hole assemblies and lubricators without extending the mast height. In this embodiment, lubricator  22  is held upright in the mast by handling arms  26 ,  28  or similar devices. Mast  16  also can be used in cooperation with other components, such as a lubricator winch  48  and a fingerboard  50 . 
     When raised, mast  16  is positioned above a well installation  52  mounted over well  46 . Well installation  52  may comprise a variety of conventional components, such as blowout preventers  54 , illustrated as engaged by a blowout preventer handling system  56 . Blowout preventer handling system  56  may be coupled to a rig floor section  58  of base  14  that is positioned below mast  16 . 
     The coiled tubing injector  20  is mounted for rotation through multiple positions, e.g. a position over well center and a position out of alignment with well center. The coiled tubing injector  20  may be mounted on rig floor section  58  for the rotating movement without requiring removal of coiled tubing  60  from the coiled tubing injector. When the coiled tubing injector  20  is rotated out of alignment with the well center, the lubricator  22  and bottom hole assemblies or other downhole equipment can be maneuvered over the well center above well  46 . 
     For example, lubricator handling system  24  can be used to manipulate lubricator  22  over well  46 . In the illustrated embodiment, lubricator handling system  24  can be used to move lubricator  22  vertically along mast  16 . Additionally, lubricator handling system  24  can be used to retrieve downhole equipment, e.g. bottom hole assemblies, from a mouse hole  62  for deployment into well  46 . The lubricator handling system  24 , via handling arms  26 ,  28 , can be pivoted between a plurality of positions, e.g. an over the well position, an over the mouse hole position, and an at-rest position. Accordingly, the lubricator handling system can be pivoted to mouse hole  62  for retrieval of selected bottom hole assemblies or other downhole equipment. The selected equipment is lifted from mouse hole  62  and moved into position over well  46  for deployment into the well. 
     As further illustrated in  FIG. 2 , mouse hole  62  comprises a plurality of cartridges/receptacles  64  that are each designed to receive a bottom hole assembly or other appropriate downhole equipment  66 , as illustrated in dashed lines. By way of example, mouse hole  62  is illustrated as having three receptacles  64  with three corresponding bottom hole assemblies  66 . However, the number of receptacles  64  can vary depending on the applications for which the coiled tubing rig is designed. Mouse hole  62  is an indexing mouse hole that indexes receptacles  64  and the corresponding bottom hole assemblies  66  into a proper retrieval position, e.g. retrieval position  67 , for selection and retrieval by lubricator handling system  24 . 
     The receptacles  64  can be moved to retrieval position  67  by a variety of mechanisms. For example, the receptacles  64  can be rotated to a desired angular position, and then the corresponding bottom hole assembly  66  can be lifted slightly for grasping by lubricator handling system  24 . In other embodiments, the receptacles and bottom hole assemblies can be moved and/or lifted by different mechanisms and along different paths to enable retrieval by the lubricator handling system. In the example illustrated, a selected bottom hole assembly  66  is lifted slightly from its corresponding receptacle  64  by a wedge member  68  rotated by a motor  70 , such as a hydraulic motor or stepper motor. As wedge member  68  is rotated beneath the bottom hole assembly  66 , the wedge sufficiently lifts the desired bottom hole assembly to a position for grasping by the lubricator handling system. Additionally, motor  70  or other motors can be used to rotate receptacles  64  within mouse hole  62  to present the selected bottom hole assembly  66  at a desired angular position for easy retrieval. 
     During coiled tubing operations, coiled tubing  60  is delivered to coiled tubing injector  20  from a coiled tubing module  72 , as illustrated in  FIGS. 1 and 3 . Coiled tubing module  72  comprises coiled tubing reel  18  rotatably mounted on a mounting structure  74  within coiled tubing reel housing  34 . Coiled tubing module  72  also is climate controlled to protect coiled tubing reel  18  and coiled tubing  60  from environmental factors, e.g. freezing temperatures. For example, housing  34  may be climate controlled by appropriate climate control equipment  76  positioned within coiled tubing module  72  or externally of coiled tubing module  72 . Climate control equipment  76  may comprise a heater for heating coiled tubing reel housing  34  as well as other climate control equipment as desired for coiled tubing rig operations in specific environments. 
     In the embodiment illustrated, coiled tubing module  72  is mounted on a transportable platform  78 . By way of example, transportable platform  78  may comprise a road legal trailer  80  having a trailer platform  82  supported on a plurality of wheels  84 . The road legal trailer  80  also may comprise a plurality of stabilizer arms  86  to stabilize transportable platform  78  when positioned for operation at well site  12 . In this embodiment, transportable platform  78  is positioned adjacent base  14  during the rig operations, as best illustrated in  FIG. 1 . 
     The coiled tubing  60  also may be protected from environmental elements by a protective structure  88 . Protective structure  88  is a partial or full enclosure that protects the coiled tubing from environmental elements as it travels from coiled tubing module  72  to coiled tubing injector  20 . Protective structure  88  also can be expanded to enclose coiled tubing  60  over its entire travel path from coiled tubing module  72  into well  46 . Additionally, climate control equipment  76  or additional climate control equipment can be used to heat or otherwise control conditions within protective structure  88 . 
     Depending on the type of well related operations for which coiled tubing rig  10  is utilized, a variety of other equipment and components can be mounted over base  14 . For example, a slick line unit  90  can be mounted over rig floor section  58 . An operations cabin  92  can be mounted above the base  14  and coupled to a stairway  94  that provides access to the operations cabin. The operations cabin can be used to control the assembly and deployment of coiled tubing rig  10  as well as operation of the coiled tubing rig once it is properly positioned over well  46 . A mast rest  96  is located to support mast  16  when the well related operations are completed and the coiled tubing rig is converted to its transport configuration. 
     In addition to the equipment mounted on transportable base  14  and transportable platforms  78 , a variety of other vehicles, components and equipment can be utilized in a coiled tubing rig well operation. As illustrated in  FIG. 3 , for example, a back up reel or reel module  98  can be mounted on a separate transportable platform  100  which may be transported by a suitable truck  102  over a public highway system. The backup reel  98  is interchangeable with coiled tubing reel  18  when needed. In the embodiment illustrated, coiled tubing reel housing  34  comprises a door  104  that may be opened to interchange coiled tubing reel  18  with the backup reel  98 . Door  104  may be a role-up type door or other style of door that provides ready access to coiled tubing reel housing  34  for interchanging coiled tubing reels. 
     A generator  106  may be provided to provide power for climate control equipment  76  and to provide power for operating the various other systems of coiled tubing rig  10  and the systems supporting coiled tubing rig  10 . By way of example, generator  106  may comprise a standard generator unit or suitable equipment for utilizing highline power from the electric grid. The use of standard generator units can reduce maintenance cost and improve service quality. The generator  106  also may be trailer mounted to facilitate its easy transport from one well site to another. 
     Furthermore, a fluid module  108  may be positioned adjacent base  14 . By way of example, fluid module  108  comprises one or more mud pumps  110  fluidly coupled with coiled tubing  60  via a manifold  112 . Fluid module  108  also may be trailer mounted to facilitate its movement between well sites. 
     Other equipment often utilized in well operations includes a flatbed trailer  114  transported by a suitable truck  116 . Flatbed trailer  114  can be used to carry additional jointed pipe  118 . The jointed pipe  118  is used to replace jointed pipe  30  as it is deployed downhole by coiled tubing rig  10 . A forklift  120  or other suitable mechanism can be used to transfer jointed pipe  118  to base  14 . Modular offices  122  also can be set up at well site  12 , as necessary. The modular offices  122  are sized and designed for transport over the public highway system on suitable trailers. 
     A variety of other components and features also can be mounted on or over base  14  and its rig floor section  58 . For example, one or more jib cranes  124  can be mounted at desired locations to facilitate movement of equipment needed in coiled tubing rig operations. Furthermore, additional stairways, e.g. stairway  126 , can be positioned to provide rig operators with access to desired rig locations. 
     In  FIG. 3 , lubricator handling system  24  is illustrated as positioned in its parked or at-rest position. However the lubricator handling system  24  can be pivoted about its pivot axis  128  for selective movement to its position at mouse hole  62  and its position over well  46 . Accordingly, lubricator handling system  24  can be used to rapidly move desired bottom hole assemblies or other downhole equipment from mouse hole  62  into position over well  46  or vice versa. Similarly, the coiled tubing injector  20  can be selectively pivoted, via an injector arm  130 , between a position over the well (shown in dashed lines) and a position away from the well (shown in solid lines). As illustrated, the coiled tubing injector  20  is mounted independently of drilling mast  16 . Injector arm  130  also can be designed to enable the raising and lowering of coiled tubing injector  20 . 
     Depending on the specific coiled tubing rig operation, a variety of additional features can be incorporated into coiled tubing rig  10  and/or utilized at well site  12 . The specific positioning of mouse hole  62  can be adjusted according to the arrangement of other cooperating components. Additionally, the design of the coiled tubing reel housing  34  as well as climate control equipment  76  can vary according to the specific applications anticipated. In extremely cold climates, for example, climate control equipment  76  can be designed to provide additional heating to ensure that the coiled tubing does not freeze and become blocked when flow through the coiled tubing is stopped. 
     Accordingly, although only a few embodiments of the present invention have been described in detail above, those of ordinary skill in the art will readily appreciate that many modifications are possible without materially departing from the teachings of this invention. Accordingly, such modifications are intended to be included within the scope of this invention as defined in the claims.

Summary:
A technique for utilizing a coiled tubing rig improves its operation and functionality. The coiled tubing rig is adapted to enable improved operation in a variety of harsh environments. The coiled tubing rig also may comprise features that facilitate the interchangeability of well tools, e.g. the interchangeability of bottom hole assemblies, to lower operational cost and to increase the efficiency with which a variety of well related operations can be performed.