Abstract:
A support system for a lubricator to prevent the lubricator from deflecting during coil tubing operations, particularly on slant wells. A support member is connected to the lubricator through truss members for supporting the lubricator in tension or in compression, depending upon whether the support member is placed above or below the lubricator. A coil tubing injector is provided which is capable of manipulating the supported lubricator axially along a path coaxial to the wellhead to permit fine adjustment with the wellhead.

Description:
FIELD OF THE INVENTION  
       [0001]     The apparatus relates to the field of lubricators used in coil tubing operations in the petroleum industry and more particularly to apparatus for supporting lubricator segments connected between a coil tubing injector and a wellhead.  
       BACKGROUND OF THE INVENTION  
       [0002]     Conventionally, coil tubing operations, such as wellbore stimulation and workover operations, have been performed on vertical wellbores using vertical derricks and coil tubing injectors which are moveable vertically within the derrick. Further, it is known to provide injectors carried in cradles which are movable in two planes, vertically and horizontally to better align the injector with the wellbore.  
         [0003]     With the introduction of directional wellbores and particularly with slant wellbores, it is known to provide vertically-actuable coil tubing injectors on a derrick which can be slanted in at least one vertical plane to orient the injector with the wellbore and permit movement of the injector along the wellhead axis. In some cases the chassis stabilizer&#39;s of the rig are also manipulated somewhat to provide tilt in a second vertical plane.  
         [0004]     Applicant is also aware of injectors which rotate and tilt relative to a trolley and to a derrick along which the trolley slides. The injector is moveable up and down the derrick using a winch mechanism and is capable of being adjusted, using hydraulic cylinders, in an out of the derrick and to rotate and tilt relative to the derrick to roughly align the injector with the wellbore.  
         [0005]     Injectors are typically connected to the wellhead through a lubricator which is comprised of a plurality of lubricator sections which are connected by unions. Each of the lubricator risers may weigh as much as 300-400 lbs and may be rated to handle pressures in the order of about 5000 psi for stimulation or workover operations and the like. Conventional lubricators are designed to be used for vertical wellbores and thus are not designed to handle additional loads placed on them during alignment, connection and operations in a slant wellbore. Additionally, movement of a tiltable injector in any direction causes increased stress loads to be placed on the lubricator which may already be placed under tension as a result of the injection operations. Further, the lubricator may sag, deflect or to bind during injection operations and may not be capable of withstanding the high pressure loads for which they are designed.  
         [0006]     Clearly what is required is means for supporting the lubricator during injection, either to a vertical wellbore or to a slant wellbore, particularly when injected using an injector capable of being rotated and tilted for alignment with the wellbore. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]      FIG. 1  is a side view of a coil tubing rig coupled to a slant well and having an injector arrangement and lubricator support apparatus according to embodiments of the invention;  
         [0008]      FIG. 2  is a partial perspective view according to  FIG. 1 , viewed from below;  
         [0009]      FIG. 3  is a perspective view of a supported lubricator section according to an embodiment of the invention;  
         [0010]      FIG. 4  is a perspective view of an integrated, supported lubricator section according to an embodiment of the invention;  
         [0011]      FIG. 5  is a partial perspective view of a supported lubricator wherein a support member is positioned substantially vertically above lubricator sections and having auxiliary fasteners connecting therebetween;  
         [0012]      FIG. 6  is a rear perspective view of a coil tubing injector support according to an embodiment of the invention (the injector removed for clarity of the support);  
         [0013]      FIG. 7  is front perspective view according to  FIG. 6  and illustrating an embodiment of a supported lubricator connected thereto;  
         [0014]      FIG. 8  is a rear perspective view according to  FIG. 6 , the injector support mounted in a derrick having spaced apart masts;  
         [0015]      FIG. 9  is a front view of an injector according to an embodiment of the invention, the injector mounted in a derrick having spaced apart masts and having a supported lubricator according to  FIG. 5  connected thereto;  
         [0016]      FIG. 10  is a perspective rear view according to  FIG. 9 ;  
         [0017]      FIG. 11  is a perspective front side view according to  FIG. 9 ;  
         [0018]      FIG. 12  is a side schematic illustrating the injector sub-frame and injector frame telescopically mounted in a saddle (the injector, and derrick removed and a tilt bracket shown in dotted line for clarity);  
         [0019]      FIG. 13  is a side schematic according to  FIG. 12  illustrating tiling of the saddle using an hydraulic actuator;  
         [0020]      FIG. 14  is a side schematic according to  FIG. 13 , the injector having been tilted;  
         [0021]      FIG. 15  is a side schematic according to  FIG. 14 , the injector having been moved axially relative to the saddle;  
         [0022]      FIG. 16  is a partial schematic of an embodiment in which the support apparatus is spaced substantially vertically above the lubricator; and  
         [0023]      FIG. 17  is a partial schematic of an embodiment in which the support apparatus is spaced substantially vertically below the lubricator. 
     
    
     SUMMARY OF THE INVENTION  
       [0024]     A support apparatus prevents deflection of a lubricator along a path coaxial with a wellhead. In the case of a slant well, the path is angled, an injector being tilted to align the lubricator with the wellhead for connection thereto with the result that the lubricator is placed into tension or compression. The support apparatus, which provides a linearly extending support member which is connected to the lubricator sections such as through truss members, prevents deflection along the path preventing sagging or binding and ensuring the lubricator is operative at the pressures for which it is designed.  
         [0025]     In a broad aspect a support apparatus, for a lubricator having one or more tubular lubricator sections and connecting between a coil tubing injector and a wellhead, comprises: one or more support members adapted to extend along the lubricator and at least one of which is spaced above or below the lubricator for substantially linearly supporting the lubricator thereon, the support member being supported at a first end at the injector; and one or more connecting members adapted to be connected between at least a portion of the one or more support members and at least a portion of the lubricator for reducing deflection along the lubricator.  
         [0026]     If the support member is positioned above the lubricator, the support member is placed into tension, being cantilevered from the injector and the support member is connected to the injector to further support the lubricator. Preferably, auxiliary fastening means, such as turn buckles, chain boomers and the like, are connected between support member sections to brackets extending from the support member for supporting sections of the support member and lubricator while in tension.  
         [0027]     Alternatively, the support member may be positioned below the lubricator, placing the lubricator into compression. The support member need only be supported at the injector and auxiliary fastening means may or may not be used. Further, a plurality of support members may be spaced circumferentially above and below the lubricator for forming a support cage, each of the support members being connected to the lubricator. Preferably, one of the one or more support members is substantially vertically above or below the lubricator.  
         [0028]     In a further broad aspect a method for supporting a lubricator between a coil tubing injector and a wellhead, comprises: providing a plurality of supported lubricator sections, each supported lubricator section having a lubricator section; one or more support members extending substantially parallel to the lubricator section one of which is spaced substantially vertically therefrom for supporting the lubricator section thereon; and one or more connecting members connected between the one or more substantially linearly extending members and the lubricator section; engaging a first end of the lubricator section of a first supported lubricator section with the coil tubing injector; fastening a first end of one or more subsequent supported lubricator sections of the plurality of supported lubricator sections to a second end of a previous supported lubricator section, in series, for assembling a supported lubricator having a length sufficient to extend from the injector to the wellhead; and aligning the assembled coil tubing injector so as to position the supported lubricator along a path coaxial with an axis of the wellhead so as to permit connection between the supported lubricator and the wellhead, the supported lubricator being supported from deflection along the path to the wellhead.  
         [0029]     In a system for injection of coil tubing into vertical or slant wellbores having a wellhead attached thereto, the combination comprises: a coil tubing injector supported within a carriage in a derrick, the injector and carriage being moveable along the derrick, the injector being tiltable and capable of axial movement in the carriage so as to direct coil tubing at a variety of angled paths therefrom; a lubricator engaged with and cantilevered from the coil tubing injector and extending along an angled path coaxial to an axis of the wellhead for passage of the coil tubing therethrough; and a support apparatus for supporting the lubricator from deflection along the angled path to the wellhead, wherein once aligned along the angled path to the wellhead through tilting of the injector, the injector and supported lubricator are manipulated axially along the path for fine adjustment to permit connection of the lubricator with the wellhead.  
         [0030]     A coil tubing injector arrangement supportable in a derrick for injecting coil tubing into a wellbore comprises: a carriage for mounting the injector in the derrick, the carriage being moveable along the derrick; a saddle pivotally connected to the carriage; a coil tubing injector adjustably supported in the saddle; means for pivoting the saddle and injector supported therein for tilting the saddle and injector relative to the carriage and derrick adapted for alignment of the injector with an axis of a wellhead; and means for axially adjusting the injector within the saddle adapted for permitting fine adjustment of the injector with the wellhead.  
         [0031]     A coil tubing rig adapted for injecting coil tubing in a slant wellbore comprises: a mobile carrier; a derrick pivotally mounted to the mobile carrier; a carriage mounted the injector in the derrick, the carriage being moveable along the derrick; a saddle pivotally connected to the carriage and being moveable relative thereto; a coil tubing injector adjustably supported in the saddle; means for pivoting the saddle and injector supported therein for tilting the saddle and injector relative to the carriage and derrick adapted for alignment of the injector along a path with a wellhead connected to the slant wellbore; and means for axially adjusting the injector within the saddle adapted for permitting fine adjustment of the injector with the wellhead.  
         [0032]     A method of operating a mobile service rig as described for servicing a slant wellbore comprises: positioning the mobile service rig adjacent a slant wellbore; connecting a first supported lubricator section to the injector; connecting one or more additional supported lubricator sections to the first supported lubricator section for forming a substantially linearly extending supported lubricator supported from deflection resulting from manipulation of the injector; raising the carriage in the derrick for raising the saddle and injector to an operational height; actuating the means for pivoting the saddle and injector supported therein for tilting the saddle and injector relative to the carriage and derrick adapted for aligning of the injector with a wellhead connected to the slant wellbore; and actuating the means for axially adjusting the injector within the saddle adapted for permitting fine adjustment of the injector with the wellhead for connection of the supported lubricator thereto; actuating the injector for injecting coil tubing through the lubricator to the wellhead and into the wellbore; and performing a service operation through the coil tubing.  
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0033]     Embodiments of the invention may be used for operations relating to both vertical and slant wellbores, however for the purposes of the description found herein, embodiments of the invention are described in the context of a slant wellbore. Those of skill in the art will understand that this in no way limits the use of embodiments of the invention to slant welbores.  
         [0034]     As shown in  FIG. 1 , a coil tubing injector  10  is supported in a derrick  11  and is connected to a wellhead  12  by a lubricator  14  for injection of coil tubing  15  therethrough. The lubricator  14  typically comprises one or more lubricator sections  16 . Multiple sections  16  are connected to one another by unions  18  for forming the lubricator  14 . The lubricator  14  extends axially from the injector  10  to the wellhead  12  along one of a variety of angled and substantially linearly extending paths determined by the angle of the wellhead  12  relative to the ground. Typically wellheads  12  can vary from about 90 degrees relative to the ground in a vertical wellbore to about 30 degrees relative to the ground in a slant wellbore. In the case of wellheads  12  which are angled less than 90 degrees, the lubricator  14  becomes cantilevered from the injector  10  as it extends along a path coaxial with the wellhead  12 .  
         [0035]     Injection of coil tubing  15 , such as for the purposes of servicing a wellbore and other such operations, is accomplished using a mobile coil tubing rig  30  having an injector arrangement  50  comprising an injector  10  supported in a support assembly or carriage  31 , moveable substantially vertically along the derrick  11 . The lubricator  14  is connected to the injector  10 . Preferably, the injector  10  is further adjustably supported for permitting the injector  10  to be tilted and moved side to side relative to the derrick  11  and moved axially relative to the support  20  for adjusting the alignment of the lubricator  14  for connection to the wellhead  12 . The movement of the injector  10  positions the lubricator  14  along the path to the wellhead  12  which, particularly in the case of slant wellheads, may be angled. The lubricator  14 , if unsupported may deflect from a linear path during use. Deflection of the lubricator  14  may cause binding during injection operations and may compromise the lubricator&#39;s ability to withstand the high pressure loads for which lubricators are typically designed. Thus, the support apparatus  20  disclosed herein prevents deflection of the lubricator  14  and the problems associated therewith.  
         [0036]     In an embodiment of the invention, as shown in  FIGS. 1 , and  6 - 15 , an injector arrangement  50  is capable of being manipulated so as to align the injector  10  and lubricator  14 , supported according to embodiments of the invention described below, to the wellhead  12 . More particularly the injector arrangement  50  is capable of being tilted, moved laterally relative to the derrick  11  and, more particularly, moved axially within the injector arrangement  50  to permit the fine control necessary for connection to the wellhead  12  without the need to tilt the derrick  11  and to minimize connection time and maximize efficiency of a coil tubing operation.  
         [0000]     Lubricator Support Apparatus  
         [0037]     In an embodiment of the invention and having reference to  FIGS. 2-5  and  16 - 17 , a lubricator support apparatus  20  is engaged at a first end  22  to the injector  10 . The lubricator support apparatus  20  comprises one or more support members  21  and one or more connecting members  24 , such as a web or truss members, extending between the one or more support members  21  and the lubricator  14  for supporting the lubricator  14  from deflection along a substantially linearly extending path from the injector  10  to the wellhead  12 . Preferably the connecting members  24  are truss members. The path is along the axis of the wellhead  12 . The one or more truss members  24  are connected between at least a portion of the lubricator sections  16  and the one or more support members  21  for supporting the lubricator sections  16  thereon and for reducing stress loading on the lubricator  14 .  
         [0038]     In one preferred embodiment, a single linearly extending support member  21  is used. The support member  21  is spaced substantially parallel to and above or below the lubricator  14  by the truss members  24 , which are fastened to both the lubricator  14  and the support member  21 .  
         [0039]     The support member  21  can be formed from a plurality of substantially linearly extending support segments  26  which are fastened together using fasteners, such as pins  28  and cooperating sockets  29 , for forming the substantially linearly extending support member  21 .  
         [0040]     Preferably, one or more connecting members  24  are connected between each of the lubricator sections  16  and a corresponding support segment  26  for forming a supported lubricator section  40 . Further, use of corresponding support segments  26  and truss members  24  connected therebetween permits the lubricator support apparatus  20  to be readily constructed of a length required to support the lubricator  14 , regardless the length of the lubricator  14 .  
         [0041]     In one embodiment as shown in  FIG. 3 , one or more truss members  24  are unitary with the support segments  26  and are connected to the lubricator sections  16  through fasteners, such as clamps  25 . In an alternate embodiment, as shown in  FIG. 4 , the one or more truss members  24  are unitary with both the support segments  26  and with the lubricator sections  16 .  
         [0042]     Preferably, as shown in  FIGS. 3 and 4 , the truss members  24  comprise one or more transverse truss members  24   t  which extend transversely between the support segments  26  and the lubricator sections  16  and one or more angled truss members  24   a  which extend at an angle therebetween. Most preferably, there are two transverse truss members  24   t  and two angled truss members  24   a . One transverse truss member  24   t  extends between a first end of the support segment and a first end of a lubricator section  16 . The second transverse truss member  24   t  extends between a second end of the support segment and a second end of a lubricator section  16 . The two angled truss members  24   a  extend, one from the first end of the lubricator section  16  and the second from the second end of the lubricator section  16 , each angling to be connected to the support segment  26  at about a center C of the support segment  26 .  
         [0043]     Having reference to  FIGS. 2, 5  and  16  and in particular to  FIG. 5 , in an embodiment wherein the support member  21  is spaced substantially vertically above the lubricator  14 , the support member  21  is placed into tension when the injector  10  is tilted and is therefore restrained in tension, through connection at the first end  22  to the injector arrangement  50 , for further supporting the support apparatus  20 . Additionally, a plurality of brackets  41  extend outwardly from each of the support segments  26  forming the support member  21  to which auxiliary fastening means  42 , such as turn buckles, chain boomers or the like, are engaged between support segments  26  for further supporting the support apparatus  20  and maintaining tensile connection between the support segments  26 .  
         [0044]     As shown in  FIG. 17 , in an embodiment wherein the support member  21  is spaced substantially vertically below the lubricator  14 , the support member  21  and lubricator  14  are placed into compression and therefore the support member  21  need only be supported at the first end at the injector arrangement  50  and auxiliary fastening means  42  need not be used. The brackets  41  and auxiliary fastening means  42  can however be used, in any event, for additional stability, such as during rig up.  
         [0045]     In another embodiment of the invention, as shown in  FIG. 7 , a plurality of support members  21  may be used, spaced substantially parallel to, and circumferentially above and below the lubricator  14  for forming a cage about the lubricator, each of the support members  21  being connected to the lubricator  14  by truss members  24 , both angled  24   a  and transverse  24   t.    
         [0000]     Injector Arrangement  
         [0046]     Having reference to  FIGS. 6-15 , and in a preferred embodiment of the invention, the injector arrangement  50  provides the ability to manipulate the injector  10  and supported lubricator  14  for connection to the wellhead  12  which may be oriented at a variety of angles relative to the ground.  
         [0047]     As previously stated, the injector  10  is carried in the carriage  31 , the carriage  31  being moveable vertically along the derrick  11 . The derrick  11  preferably comprises two longitudinally extending, spaced apart masts  51 , 51  which are elevated to a substantially vertical position relative to the rig  30  using conventional means, well known in the art. Movement of the injector arrangement  50  along the derrick  11  is typically through a winch  52  connected thereto.  
         [0048]     In a preferred embodiment of the invention, the injector  10  is supported by an injector subframe  43  in an L-shaped injector frame  44  which is telescopically connected to a saddle  32  for axial movement of the injector  10  and lubricator  14  relative to the saddle  32 . More particularly, the saddle  32  comprises a pair of spaced apart opposing substantially vertical sleeves  33  in which the injector  10  housed in the subframe  43  and the injector frame  44  is supported for movement axially therein.  
         [0049]     In an embodiment of the invention, the injector  10  is supported directly on a modified L-shaped injector frame  44  eliminating the additional weight of the injector subframe  43 .  
         [0050]     The saddle  32  is pivotally mounted to the carriage  31  through upper and lower transverse members  34 , 35  which extend between carriage brackets  36  located on opposing sides of the injector  10  and saddle  32  and connected to each of the masts  51 , 51  via C-shaped channel members  37  which slideably engage the masts  51 , 51  for movement therealong.  
         [0051]     Preferably the saddle  32  is pivotally connected to the upper transverse member  34 , such as by brackets  38  and a transverse sleeve  39  through which the upper transverse member  34  extends. Further, the saddle  32  is slideably connected on the upper transverse member  34  and the lower transverse member  35  to permit lateral movement therealong between the masts  51 , 51  of the derrick  11 .  
         [0052]     In order to manipulate the injector arrangement  50  relative to the derrick  11  and along a path parallel, and more particularly coaxial with the axis of the wellhead  12 , actuators  45 ,  46 ,  47  are connected between the injector arrangement  50  and the saddle  12 .  
         [0053]     Best seen in  FIGS. 6, 8  and  15 , an axial actuator  45 , such as a hydraulic cylinder, is connected between the injector frame  44  and the saddle  32  so as to permit axial movement of the injector  10  and injector frame  44  guided within the opposing substantially vertical sleeves  33 , relative to the saddle  32 . After adjusting one or both of the angular and lateral alignment of the injector  10  and lubricator  14 , axial movement of the injector  10  and lubricator  14  permits fine adjustment of the lubricator  14  with the wellhead  12  and permits ease of connection thereto.  
         [0054]     Best seen in  FIGS. 12-15 , actuation means  46 , such as one or more hydraulic actuators for tilting the injector arrangement  50 , are connected between the saddle  32  and the lower transverse member  35  for pivoting the injector  10  and lubricator  14  to align with the path toward the wellhead  12 . Preferably tilt brackets  48  are connected to the outside of each substantially vertical sleeve  33  at a downwardly extending angle, adjacent a bottom end  51 , to permit attachment of the hydraulic actuators  46  between the saddle  32  and the lower transverse member  35  on each side of the saddle  32 . The hydraulic actuators  46  are fastened at a first end  53  to the tilt brackets  48  and are pivotally connected at a second end  54  to the lower transverse member  35 . As the hydraulic tilt actuators  46  extend for tilting a bottom end  55  of the injector arrangement  50  away from the derrick  11 , the second end  54  of the tilt actuator  46  pivots about the lower transverse member  35  to permit the bottom end  55  of the injector arrangement  50  to move outwardly therefrom as the saddle  32  pivots about the upper transverse member  34 .  
         [0055]     As shown in  FIGS. 6 and 8 , one or more lateral actuators  47  are connected between one of the opposing carriage brackets  36  and the saddle  32  so as to move the saddle  32  and injector  10  laterally therealong relative to the derrick  111  for lateral adjustment of the injector  10  and lubricator  14  to align with the wellhead  12 .  
         [0000]     In use  
         [0056]     In operation, the mobile rig  30  is positioned adjacent the wellhead  12  and the derrick  111  is raised to a substantially vertical position. A first supported lubricator section  40  is connected to the injector  10 . Preferably, the first supported lubricator section  40  remains permanently connected to the injector  10 . The carriage  31  is raised in the derrick  11 . As the carriage  31  is raised, subsequent trussed lubricator sections  40  are connected to a previous supported lubricator section  40 , in series, to assemble the support member  21  and for forming the supported lubricator  14  of sufficient length to span between the injector  10  and the wellhead  12 .  
         [0057]     More particularly, supported lubricator sections  40  are positioned beneath the injector  10  typically using a mobile crane. The supported lubricator sections  40  are supported on a stand (not shown) on the ground after which the carriage  31  and the injector  10  are manipulated, typically laterally and axially, first to attach a first supported section  40  and thereafter to permit connection of the unions  18  on the adjacent supported lubricator sections  40  and to align the pin  28  on one support segment  26  with the co-operating socket  29  of the next support segment  26 .  
         [0058]     Best seen in  FIGS. 2 and 5  and in the embodiment wherein the support member  21  is spaced vertically above the lubricator sections  16 , auxiliary fastening means  42  are further connected between the brackets  41  of adjacent supported lubricator sections  40  for further supporting the lubricator  14  which is in tension.  
         [0059]     Once the supported lubricator  14  is assembled, the carriage  31  is raised and lowered within the derrick  111  to a desired operational height and the injector  10  is manipulated angularly, laterally and axially, as required, to align the now substantially linearly extending and supported lubricator  14  with the wellhead  12 . After connection of the supported lubricator  14  to the wellhead  12 , coil tubing (not shown) can be injected therethrough by the injector and service operations and the like can be performed on the wellbore.