A selectably elevatable coiled tubing injector is described that is suitable for a mobile self-contained unitized coil tubing rig for the drilling and workover of petroleum wells. The selectably elevatable coiled tubing injector includes a mechanism for positioning a trailer mounted coiled tubing injector either in a first stowed position on the deck of the transport trailer or in a second position resting on an elevated rig floor of a drilling rig. Furthermore, the selectably elevatable coiled tubing injector includes a further mechanism for selectably elevating the injector above its second position on the rig floor while clamping the tubing in order to provide additional tension on the tubing string or to raise the tubing deployed within a well.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a selectably elevatable coiled tubing injector for a mobile self-contained unitized coil tubing rig for the drilling and workover of petroleum wells. In particular, the present invention concerns a mechanism for positioning a trailer mounted coiled tubing injector either in a first stowed position on the deck of the transport trailer or in a second position resting on an elevated rig floor of a drilling rig.

2. Description of the Related Art

Coiled tubing rigs primarily include a tubing storage reel and a coiled tubing injector for forcing a string of coiled tubing into or pulling it out of a well. Coiled tubing rigs are commonly used in the oilfield for reasons of speed and low cost operation. Due to advances in the ability to run downhole drilling motors on the lower end of a coiled tubing drill string, a need has arisen for coiled tubing injectors which can be positioned on a rig floor so that the tubing from the injector is coaxially aligned with the well bore. Previously, this need has been filled by lifting a self-contained conventional injector from a transport trailer to the rig floor using large forklift trucks, cranes, or other means. Upon completion of a job by such an injector, the injector has to be lifted back onto the transport trailer.

When being transported, such a conventional injector must be restrained by tiedown means, so the conventional approach involves considerable setup and rig down time, as well as necessitating lifting equipment. Additionally, the storage reel must be carefully positioned during the lifting to and from the rig floor in order to avoid damaging the tubing, particularly when the tubing is left engaged with the injector. If the tubing is released from the injector for lifting, then it must be rethreaded through the injector after the injector has been lifted.

Accordingly, a need exists for a coiled tubing injector which can be moved more readily between a transport trailer and a rig floor.

Furthermore, whenever a coiled tubing string is used to drill wells with a downhole motor, the tubing often becomes stuck in the hole due to pressure differentials between the hole and adjacent formations. Whenever this happens, it is necessary to exert considerable upward force on the tubing to free it from the well. Likewise, to retrieve packers from a well and for a variety of other downhole operations, large vertical pulls are needed. These vertical uplift forces are often in excess of what can be provided by the drive means of conventional coiled tubing injectors.

Thus, there is a need for a mechanism that can easily provide additional tension to a coiled tubing string beyond that which can be provided by a conventional coiled tubing injector.

SUMMARY OF THE INVENTION

This invention pertains to a selectably elevatable tubing injector for a mobile self-contained unitized coil tubing rig for the drilling and workover of petroleum wells. In particular, the present invention concerns a mechanism for positioning a trailer mounted coiled tubing injector either in a first stowed position on the deck of the transport trailer or in a second position resting on an elevated rig floor of a drilling rig. Further, the present invention provides a mechanism for selectably elevating the injector above its second position on the rig floor, while clamping onto the tubing, in order to provide additional vertical tension on the tubing string or to raise the tubing deployed within a well.

One embodiment of the present invention includes a positioning mechanism for a trailer mounted coiled tubing injector, the positioning mechanism comprising: (a) a coiled tubing injector support system including an injector cradle providing a framework for mounting the coiled tubing injector, wherein the injector cradle has a cradle opening wherein a portion of a drive wheel of the coiled tubing injector is rotatably housed, a frame assembly having a frame opening, wherein the injector cradle is nested within the frame opening, and a lifting mechanism for selectably elevating and lowering the injector cradle and the coiled tubing injector within the frame opening; (b) a selectably engageable coiled tubing clamp assembly mounted on a first end of the frame assembly; and (c) a swing arm assembly including a plurality of hinged support arms, wherein each support arm is attached at one end to the frame assembly and at a second end to a trailer, and a rotation device that reciprocably rotates the coiled tubing injector support system between a stowed position on the trailer and an operating position.

A second embodiment of the present invention includes a positioning mechanism for a trailer mounted coiled tubing injector system, the positioning mechanism comprising: (a) a coiled tubing injector support system mounted on a trailer, the injector support system including a coiled tubing injector having a rotatable drive wheel and a radially acting coiled tubing hold down mechanism, an injector cradle providing a framework for mounting the coiled tubing injector, wherein the injector cradle has a cradle opening on a top side and wherein a portion of the drive wheel of the coiled tubing injector is rotatably housed and the radially acting coiled tubing hold down mechanism sits above the injector cradle, a frame assembly having a frame opening on a top side, wherein the injector cradle is nested within the frame opening such that the drive wheel of the coiled tubing injector remains rotatable within the injector cradle and the radially acting coiled tubing hold down mechanism sits above the frame assembly, and a lifting mechanism for selectably elevating or lowering the injector cradle and the coiled tubing injector within the frame opening, wherein a first end of the lifting mechanism is attached to the injector cradle and a second end of the lifting mechanism is attached to the frame assembly; (b) a coiled tubing clamp assembly mounted on a first end of the frame assembly, wherein the coiled tubing clamp assembly has two grip blocks for selectably gripping a coiled tubing exiting the coiled tubing hold down mechanism; and (c) a swing arm assembly including a plurality of hinged support arms, wherein each support arm is attached at one end to the frame assembly and at a second end to the trailer, and a rotation device that reciprocably rotates the support arms thereby moving the coiled tubing injector support system into a stowed position on the trailer or to an operating position.

The foregoing has outlined rather broadly several aspects of the present invention in order that the detailed description of the invention that follows may be better understood and thus is not intended to narrow or limit in any manner the appended claims which define the invention. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and the specific embodiments disclosed may be readily utilized as a basis for modifying or designing derivative structures for carrying out the same purposes as the invention. It should be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

As a note, the use of the terms “invention”, “present invention” and variations thereof throughout the subject patent application (and headings therein) are intended to refer or relate to one or more embodiments of the present application, not necessarily every embodiment or claim of the application.

Referring now to the drawings, it is noted that like reference characters designate like or similar parts throughout the drawings. The figures, or drawings, are not intended to be to scale. For example, purely for the sake of greater clarity in the drawings, wall thicknesses and spacings are not dimensioned as they actually exist in the assembled embodiments.

The structural components of the selectably elevatable coiled tubing injector are normally constructed of steel. For some purposes involving contact between the tubing and the tensioning wheel, high stiffness rubber or plastics are typically used.

Much of the equipment mounted on the trailer inFIG. 1is commercially available and is included herein only for purposes of illustrating the need for and use of the selectably elevatable coiled tubing injector.

For the figures herein, certain components are not shown in order to avoid overly complicating the drawings. For example, control cables, hydraulic lines, and the fluid system for feeding the reel are not shown. All of these features are well known to those skilled in the art and so they are not described herein.

Referring toFIGS. 1 and 2, an integrated trailer mounted coiled tubing rig10utilizing the coiled tubing injector50of the present invention is shown in an oblique and a side profile view, respectively. This mobile coiled tubing rig10is suitable for use in drilling or servicing wells. The rig10is shown positioned prior to having its injector50set up and working on a drilling rig floor160at a well location. The rig arrangement shown is fairly typical of commercially available coiled tubing rig layouts, with the exception of the supporting arrangements for the injector50and the combination of the control room48and the auxiliary water tank47into an integrated control room assembly46.

The basic elements of a trailer mounted coiled tubing rig10are a tractor (not shown) for pulling the trailer20, a rig power unit31fed by fuel tank30, a tubing storage reel40, a tubing injector system50, tubing70, and a control room48. The power source31, the fuel tank30, the tubing storage reel40, the tubing injector50, the tubing70, and the control room48are all mounted on the trailer20. Trailer20is normally of the “low boy” type, given that the tubing storage reel40is normally rather tall. The length of the low boy trailer is at or close to a maximum practical length for transport over the unimproved roads that frequently are the only access to well locations. The entire rig10is supported on surface18, which can be either a roadway or the surface of the ground.

The low boy trailer20has an elevated rear deck21, a depressed central deck23, and an elevated forward deck22. All of the deck segments21,22, and23are parallel to the ground. The rear deck21has multiple axles with tires26and a suspension system (not shown) supporting it underneath. This sort of arrangement for the trailer20is in common use in the trucking industry. The decks21,22, and23have longitudinal beams underneath which are structurally connected to the decks to provide bending strength and stiffness to the trailer20.

Selectably axially reciprocable stabilizing jacks28are located at the forward outboard corners of the central deck23and the rear outboard corners of the rear deck21of the trailer20. These jacks28are extended to firmly engage the surface18when the trailer20is positioned ready to service a well. The jacks28are used so that the trailer20is stabilized as the amount of tubing70on the tubing storage reel40changes or and/or the injector is moved thereby shifting the load on the trailer. In addition, the loads on the trailer20and its jacks28will change whenever the tension changes on the tubing71adjacent the wellhead.

The fuel tank30is located adjacent the forward end of the central deck23, and the power unit31is located slightly to the rear of the fuel tank. The fuel tank30is mounted on a pair of pedestals and is a standard cylindrical tank with elliptical ends. The fuel tank30provides a sufficient supply of fuel to operate the power unit31for a period long enough to complete most jobs without refueling. The power unit31drives one or more hydraulic pumps and an electrical generator to power the reeling and tensioning of the coiled tubing70and other functions of the trailer mounted rig10.

The tubing storage reel40is a large device which stores a sufficient amount of steel tubing70to permit reaching the bottom of the wells for which the rig10is capable. The tubing storage reel40both pays out and retrieves the tubing70, although most of the tension or compression in the tubing string is provided by the injector50. The location of the tubing storage reel40is on the central deck23to the rear of the power unit31and forward of the rear deck21of the trailer20. Levelwinding of the tubing70is required to achieve compact storage and avoid overstressing the tubing70where wraps of tubing cross each other. The hub of the reel40has a diameter sufficiently large that repetitive bending cycles of the tubing70will not prematurely fatigue the tubing. The tubing70coiled on the reel40is laterally constrained between opposed side flanges.

The reel40has a horizontal shaft which provides a rotational axis which is transverse to the longitudinal vertical midplane of the trailer20. The shaft is supported by a large pillow block bearing on each side, while the pillow blocks are in turn supported on a pedestal41. The pedestal41consists of a pair of trapezoidal vertical spaced apart slabs parallel to the sides of the trailer20and joined by a rectangular base plate. The width of the pedestal41is approximately half of the width of the trailer20. The base plate of the pedestal41extends a short distance forward of the forward edge of the pedestal slabs. The two slabs of the pedestal41each have a transverse forward and rear through hole parallel to and slightly above the base plate. The forward holes are mutually coaxial, as are the rear holes.

A large driven chain sprocket is mounted on the reel shaft on the lefthand side of the reel40so that the reel can be rotated bidirectionally by its drive chain. The drive chain is bidirectionally driven in turn by a small chain sprocket mounted on the output shaft of the hydraulic motor of hydraulic motor assembly. A hydraulic motor is mounted on a mounting base for the hydraulic motor assembly rigidly attached to the upper surface of the forward extension of the pedestal41so that the chain sprockets are in alignment.

A double acting hydraulic levelwind actuation cylinder selectably controlled from the control room assembly46has its cylinder body mounted transversely in a horizontal position to the upper surface of the central deck23of the trailer. The rod end of the levelwind actuation cylinder is attached to the middle of the base plate of the pedestal41on its rear vertical side. The pedestal41of the tubing storage reel40is supported slightly above the central deck23of the trailer20on a pair of tubular horizontal transverse guide rails engaged in the transverse holes at the bottom of the slabs of the pedestal.

Each of the two transverse guide rails is mounted by a pair of end blocks, with the outside transverse face of each end block flush with its respective side of the trailer20. The combination of the length of the transverse guide rails45and the width between flanges of the reel40is selected so that system operator can controlled lateral shifting of the position of the reel by the levelwind actuation cylinder, thereby causing the coiled tubing70to properly nest on the reel.

The control room assembly46is positioned on the forward deck22of the trailer20. The control room assembly46consists of an auxiliary tank47and the control room module48. For travel, the control room module48is nested within the tank47, but the control room can be selectably elevated to its upper position so that a human operator positioned there can more readily observe the general operation of the coiled tubing rig10and, particularly, the level winding of tubing70onto the storage reel40. Alternatively, a more conventional control room arrangement can also be used satisfactorily.

The tubing injector system50is mounted on the longitudinal centerline of the rear deck21of the trailer20. Although a variety of tubing injectors are suitable for use, the particular tubing injector shown here is a reversible wheel type injector and is used to apply the primary tractive loads to the tubing70to urge the tubing into or out of the well. Often a well servicing job requires that the tubing70be forcefully injected through a blowout preventer device150which seals between the wellhead and the portion of the tubing71which is entered within the well bore. Likewise, frequently the weight of the tubing71in the well exceeds the axial pressure load applied to the tubing, requiring tractive force to lift the tubing from the well.

Referring toFIG. 5, the tubing injector system50consists of a drive wheel55mounted on a pair of pillow block bearings52and driven by a hydraulic motor assembly54engaging a drive chain53. A structure supporting a series of coacting radially inwardly urged rollers constitutes a radially inwardly acting holddown mechanism57.

The drive wheel55has two parallel circular side plates connected by a cylindrical annular ring set inwardly a short distance from their outer circumference. An array of multiple closely spaced support blocks66are fitted to the annular ring on their inward side and have an annular groove in the center of their outer side. Through bolts with nuts parallel to the wheel axis penetrate the side plates and the support blocks to provide support to the tubing70in the groove of the support blocks.

The drive wheel55has an axial horizontal shaft coaxially attached to the side plates which provides a rotational axis transverse to the longitudinal vertical midplane of the trailer20. The shaft is supported by a large bearing pillow block52on each side, while the pillow blocks are in turn supported on the upper surface of the injector cradle assembly81of the tubing injector support system80.

A large drive chain sprocket56is mounted on the shaft on the lefthand side of the drive wheel55so that the wheel can be rotated bidirectionally by drive chain53. Drive chain53is bidirectionally driven in turn by a small chain sprocket mounted on the output shaft of the hydraulic motor of hydraulic motor assembly54. The hydraulic motor is mounted on a mounting base for the hydraulic motor assembly54which is in turn rigidly attached to the upper surface of the injector cradle81so that the chain sprockets are in alignment.

The tubing injector system50is provided with a radially inwardly acting holddown mechanism57which serves to force the tubing70engaged around the drive wheel inwardly against the tubing support blocks66of the drive wheel55. This radially inward forcing ensures high frictional forces can be developed between the drive wheel55and the tubing70, regardless what the tension in the tubing is. The radially acting holddown mechanism57is coaxially structurally supported on the shaft of the drive wheel by a holddown support frame59consisting of two nonrotating mirror image reinforced plate arcuate sectors which straddle drive wheel55. The holddown support frame59is prevented from rotating by two mirror image antirotation braces67which connect between the support frame59and the upper surface of the injector cradle81.

The radially inward holddown reaction on the tubing70in the groove of the tubing support blocks66of the drive wheel55is provided by a set of circumferentially spaced apart parallel centrally grooved tubing rollers having axes parallel to the drive wheel and engaging the coiled tubing70over its arc of contact with the drive wheel. The tubing rollers are mounted on radially movable holddown roller assemblies63which are retained and guided within radial slots on the outer peripheral inward faces of the arcuate plate sectors of the holddown support frame59. The radial slots are formed by circumferentially spaced apart guide plates60attached to the periphery of the opposed inward facing arcuate plates of the holddown support frame59.

Each holddown roller assembly63has a pair of static sheaves62located adjacent each of its opposed distal ends. Static sheaves62are located on both outer sides of the arcuate plate sectors of the holddown support frame59inwardly from the periphery, with each static sheave mounted on the radial center plane of each guide plate60so that a static sheave straddles each radial guide slot. Each of the holddown roller assembly end sheaves64has its shaft parallel to the shafts of the static sheaves62. Additionally, on each side of the holddown support frame59, the grooves of the end sheaves64are coplanar with the grooves of the static sheaves.

On each side of the holddown mechanism57, a single pulldown cable is anchored by a cale anchor61adjacent the bottom end of the array of static sheaves62and tensioned on its opposed end by a hydraulic tensioning cylinder58. The hydraulic tensioning cylinders58are mounted on the upper end of the radially acting holddown mechanism57approximately tangentially to the rim of the drive wheel55. The tensioning cables65are engaged alternately in the direction towards their tensioning hydraulic cylinders by the static sheaves62and the holddown roller assembly end sheaves64. The net reaction force on each tubing roller of the holddown roller assemblies63is thus radially inward. This radially inward force enhances the frictional forces between the drive wheel55and the tubing70, thereby permitting the tubing to be engaged only over a relatively small arc of the drive wheel in order to develop any necessary frictional tractive force.

As best seen inFIGS. 5 through 7, the coiled tubing injector system50is mounted in an injector cradle assembly81. The injector cradle81has a space frame82constructed primarily of square or rectangular tubing and provided with lift cylinders84and guide rollers88,89and a clamp assembly90. The space frame82has two mirror image trussed panel sides, a horizontal trussed panel bottom, and a trussed panel forward end. The lower portion of the rear side of the space frame82is spanned by a clamp assembly90which is supported on a mounting plate91, while the upper portion of the rear side of the space frame is open.

The width of the space frame82is the same as the spacing between the pillow block bearings52of the coiled tubing injector50. The length of the space frame82is sufficient to mount the coiled tubing injector50so that its motor assembly54is supported at the front end and the vertical tangent to the drive wheel55is slightly to the rear of the rear end of the space frame. The height of the space frame82is such that when the coiled tubing injector50is mounted on the space frame, a small clearance will exist between the bottom panel of the space frame and the outer rim of the drive wheel55of the coiled tubing injector50.

The upper horizontal chord of each side panel is provided with two outwardly projecting horizontal rectangular prismatic ears83, with one ear near the forward end of the frame82and the other near the rear end of the frame. Each ear83has a central vertical tapped hole which is engaged by the male threaded rod end of the lift cylinder rod86of a hydraulic lift cylinder84, with the bodies85of the lift cylinders below the ears.

A horizontal transverse cross bar joins the upper horizontal chords of the space frame82a short distance to the rear of the front panel of the space frame82. This cross bar, along with the top chord of the front panel, serves as a support for the hydraulic drive motor assembly54used to activate the drive wheel55of the coiled tubing injector50. Each side panel has a pillow block mounting pad projecting upwardly on its upper horizontal chord slightly to the rear of midlength of the space frame82. The pillow block bearings52for the coiled tubing injector50are mounted there. A vertically upwardly extending plate lifting eye100is located flush with the side panel outside face and at approximately midlength of the upper horizontal chord of each side panel.

A short distance to the rear of the rear cylinder mounting ear83on each of the side panels of the space frame, a vertical structural guidance angle87is rigidly mounted with one leg of the angle projecting forward and flush with the outside of its side panel and with the other leg of the angle extending transversely outwardly. An intermediate vertical side frame member92is located between the rearward cylinder attachment ear83and the guidance angle87in each space frame82.

On each side of the space frame82, a horizontal axis bracket mounted lateral restraint roller assembly88is mounted at the bottom end of each intermediate vertical side frame member positioned between the rearward cylinder attachment ear83and the guidance angle87. The axes of the lateral restraint rollers88extend fore and aft and are positioned outboard of the side frames. On each side of the space frame82, a horizontal axis bracket mounted longitudinal restraint roller assembly89is mounted at the bottom end of the transversely outwardly extending leg of the structural guidance angle87on that side so that the axis of the roller is to the rear of the angle.

On the forward end panel of the space frame82, a horizontal axis longitudinal restraint roller assembly89is mounted at the intersection of the bottom chord of the front panel and each side panel so that the axes of the rollers are forward of the lower chord of the front panel. At the lower forward corner of each side panel of the space frame82, a horizontal axis lateral restraint roller assembly88is mounted with its axis outboard of the outer side of the panel. The lateral restraint roller assemblies88are similar to or identical to the longitudinal restraint roller assemblies89.

Referring toFIGS. 5,6, and7, the clamp assembly90consists of mounting plate91, a pair of clamp hydraulic cylinders94, a pivot pin95for each cylinder94, a pair of mirror image clamp support blocks96with each containing a grip block97, a pair of clamp support block pivot pins98, and a pair of clamp cylinder rod end pins99. The mounting plate91of the clamp assembly90is a transversely extending thick rectangular plate lapped onto and spanning between the side panels of the space frame82of the injector cradle81of the tubing injector support system80. The mounting plate91is positioned slightly above the bottom side of the rear face of the space frame82.

The upper corners of the mounting plate91each have a horizontal through drilled and tapped hole extending parallel to the side panels of the space frame82. These drilled and tapped holes serve to mount the pivot pins95for the eye brackets located at the blind ends of the cylinder bodies of the double acting single rod clamp cylinders94. Another pair of mirror image drilled and tapped horizontal through holes are spaced apart by approximately 30 percent of the width of the mounting plate91approximately one third of the height of the mounting plate down from its upper edge. This second pair of holes serves to mount the clamp support block pins98. The pivot pins95for the cylinders94are typically headed bolts having large diameter shanks and distal end threads which are threadedly engaged with the outer upper corner tapped holes of the mounting plate91. The clamp support block pins98are generally hex head bolts having large diameter shanks and distal end threads threadedly engaged with the central tapped holes of the mounting plate91.

The clamp support blocks96, which are best seen inFIG. 5in an oblique view, are mirror image pieces which each have an elongated planar mounting plate onto which is integrally mounted a heavy U-shaped channel member. Each planar mounting plate has a through hole for journaling the shank of a clamp support pin98and has its channel radially spaced outwardly from its through hole. The trough of a channel extends parallel to and offset from the plane of its planar mounting plate. The flanges of each channel have a pair of through holes on their rear flange and a pair of tapped through holes on the forward channel leg. Each rear flange through hole is coaxial with a tapped forward hole.

The back of each channel is perpendicular to its mounting plate and approximately coplanar with the through hole in the planar mounting plate of each clamp support block96. A vertical integral swing arm projects on the vertical plane of symmetry of the channel back on the section of the channel distal from the pivot pin hole. The swing arms are parallel to and offset from the planar mounting plates. Each swing arm extends in a direction opposed to the legs of its channel and has a through hole parallel to the through hole in the mounting plate of the clamp support block96. The through hole in each swing arm is engaged with and journals a screw with a cylindrical shank and distal male threads which serves as a rod end pin99for the clamp cylinder94. The rod end of the clamp cylinder94is provided with a female rod eye knuckle having a tapped hole transverse to and intersecting the longitudinal axis of the cylinder. The rod end pin99of each cylinder94is threadedly engaged with the tapped hole of the female rod eye knuckle.

The grip blocks97of the clamp assembly90are rectangular cross section blocks which are mounted in the channels of the clamp support blocks96. The grip blocks97have circular cross section grooves which are a close fit to the tubing70. The depth of a groove is approximately 40 percent of the diameter of the tubing, and the groove runs in the middle of one side of the grip block. The grip block cross section is a close fit to the inside faces of the channel of a clamp support block, and the length of the grip block is the same as the length of its mounting channel. The grip blocks97extend slightly outwardly from the channels. Transverse through holes parallel to the grooved face of the grip blocks97are coaxial with the holes in the flanges of the channels of the clamp support blocks96so that bolts can be extended through those holes and the corresponding holes in the grip blocks in order to retain the grip blocks.

The clamp support blocks96with their integrally mounted grip blocks97are pivotable about their clamp support block pins98when the cylinders94are actuated. The cylinders94are operated in parallel by a single valve (not shown). The extension of the cylinders94causes the clamp support blocks96to jointly pivot about their clamp support pins98as seen inFIG. 6. Similarly, the retraction of the cylinders94causes the clamp support blocks96to move apart as shown inFIG. 7. The relative positioning of the grooves of the grip blocks97and the vertically extending coiled tubing section71deploying into a well is such that the midplanes of the grooves are coplanar with the axis of the vertical tubing section.

FIG. 8shows an oblique view of the intermediate frame assembly110of the tubing injector support system80. The intermediate frame assembly110supports the injector cradle assembly81which in turn supports the coiled tubing injector50. The intermediate frame110consists of a space frame111constructed primarily of square or rectangular tubing and provided with guide rollers118and119. The space frame111has two mirror image trussed panel sides, a horizontal trussed bottom panel, and a transverse trussed forward end panel at the forward end112of the space frame. The trussed forward end panel has two vertical tubular members set inwardly from the side panels by a short distance and a single diagonal between those verticals. The rear side of the space frame111is open except for a transverse horizontal member of the bottom panel.

The width of the space frame111is sufficiently large that the interior faces of its side frames will have a fit with the lateral restraint rollers88of the injector cradle81such that the rollers can readily guide the vertical movement of the injector cradle relative to the intermediate frame110. The length of the space frame111is slightly less than that of the injector cradle assembly81. The height of the space frame111is such that when the injector cradle81is mounted within the space frame and reciprocated vertically to its highest position by the lift cylinders84, enough of the cradle81is retained within the intermediate frame to ensure stability under operating loads.

The lower horizontal chord of each side panel of the intermediate space frame111is provided with two inwardly projecting horizontal rectangular prismatic ears which serve as lift cylinder mounting pads114, with one ear near the forward end of the frame and the other near the rear end of the frame. The spacing between the lift cylinder mount pads114on each side frame panel is the same as that for the lift cylinder rod attachment ears83of the injector cradle81. Each lift cylinder mounting pad114has a central vertical through hole which journals a machine screw (not shown) which can be threadedly engaged with a tapped mounting hole on the blind end of a lift cylinder84to rigidly attach the cylinder body of a lift cylinder to the upper surface of the lift cylinder mounting pad.

A short distance to the rear of the rear cylinder mounting pad114on each of the side panels of the space frame, two coaxial segments of a first pair of vertical structural guidance angles115are rigidly mounted with one leg of the angles projecting to the rear flush with the inside face of its side panel and with the other leg of the angles extending transversely outwardly. These first angle115segments are cut so that each one has one end attached to a horizontal chord and the other end attached to an adjacent diagonal of its side panel.

A short distance to the rear of the front transverse panel of the space frame111on each of the side panels of the space frame, two coaxial segments of a second pair of vertical structural guidance angles115are rigidly mounted with one leg of the angles projecting to the rear flush with the inside face of its side panel and with the other leg of the angles extending transversely outwardly. These second angle115segments also are cut so that each one has one end attached to a horizontal chord and the other end attached to an adjacent diagonal of its side panel.

A short distance to the rear of the first set of guidance angles115is a third pair of guidance angles. For the third pair, on each of the side panels of the space frame111, a vertical structural guidance angle115is rigidly mounted with one leg of the angle projecting to the rear and flush with the inside of its side panel and with the other leg of the angle extending transversely inwardly. The forward transverse faces of the third pair of guidance angles115are flush with the rear transverse horizontal cross member of the bottom frame panel.

Each side panel of the space frame111has a pair of horizontally outwardly projecting cylindrical pivot arm mounting bosses116on its upper horizontal chord. The first boss116of the pair on a side panel is located at the forward end112of the space frame111, while the second boss is located approximately 65 percent of the length of the space frame to the rear. Each boss116has a tapped centrally located transverse horizontal hole for threaded engagement with an arm end pin129so that either a first126or second127swing arm can be pivotably mounted there as shown inFIG. 12.

On each side of the space frame111of the intermediate frame assembly110, a horizontal axis bracket mounted lateral restraint roller assembly118is mounted at the upper end of each first pair of vertical guidance angles115. The axes of the lateral restraint rollers118extend fore and aft and are positioned inboard of the side frames. The spacing between these opposed lateral restraint rollers118is such that they can bear on and freely roll on the outwardly facing planar vertical face of the intermediate vertical side members92of the injector cradle81.

On each side of the space frame111, a horizontal axis bracket mounted longitudinal restraint roller assembly119is mounted at the upper end of the transversely inwardly extending leg of the third structural guidance angle115on that side so that the axis of the roller is to the front of the angle. The lateral restraint roller assemblies118are similar to or identical to the longitudinal restraint roller assemblies119. The spacing between these longitudinal restraint roller assemblies119is such that the rollers bear on the rear face of the vertical guidance angles87of the injector cradle81.

On the forward end panel of the space frame111, a horizontal axis longitudinal restraint roller assembly119is mounted on the rear face of the top chord of the front panel so that the axes of the rollers are to the rear of the upper chord of the front panel. The spacing of the roller assemblies119is such that the rollers can bear on and freely roll on the front face of the forward vertical members of the side frames of the injector cradle81when that cradle is positioning within the intermediate frame assembly.

A few inches to the rear of the front frame panel of the space frame111, two opposed horizontal axis lateral restraint roller assemblies118are mounted with their axes inboard of the inner sides of their respective side frame panels. When the injector cradle81is positioned in the intermediate frame assembly110, the spacing between these opposed lateral restraint rollers118is such that they can bear on and freely roll on the outwardly facing planar vertical face of the second (forward) pair of vertical guidance angle segments115.

The positioning of the forward longitudinal restraint rollers89of the injector cradle81is such that they bear on and roll on the rear face of the inwardly set vertical members in the front frame panel of the space frame111of the intermediate frame assembly110. The positioning of the third (rear) pair of vertical guidance angles115of the intermediate frame110is such that the rear longitudinal restraint rollers119of the injector cradle81bear on the forward vertical faces of those angles.

The location of the second (forward) pair vertical guidance angle segments115is such that the forward lateral restraint roller assemblies88of the injector cradle bear on and roll on the inner face of those angle segments115. The location of the first (rear) pair of vertical guidance angle segments115is such that the rear lateral restraint roller assemblies88of the injector cradle81bear on and roll on the inner face of those angle segments115.

Accordingly, the location in the horizontal plane of the injector cradle81relative to the intermediate frame110is closely controlled by the restraint roller assemblies88,89,118, and119when the lift cylinders84vertically reciprocate the injector cradle81within the intermediate frame110.FIG. 9illustrates a side view of the intermediate frame assembly110housing the injector cradle81in its lower position.

The swing arm assembly125, best seen inFIG. 12in its lower position andFIG. 13in its upper position, consists of a pair of first arms126, a pair of second arms127, arm end pins129, four arm pedestals130, a pair of cylinder bases133, and a pair of swing cylinders134. The first126and second127swing arms are similar rectangular constant cross section tubular members having parallel horizontal axis through pivot holes at their ends. Both the first126and second127swing arms have the same length and distance between their pivot holes, but the first swing arms126also have a boss with a through hole parallel to their distal pivot holes on their lower sides positioned approximately 40 percent of the arm length from the pivot holes on their lower ends.

The arm end pins129are large bolts with cylindrical shanks which are close fits to the distal pivot holes of swing arms126,127. The upper four of the arm end pins129are journaled in the upper end pivot holes of the swing arms126,127and have distal male threads which are threadedly engaged with the tapped holes in the cylindrical pivot arm mounting bosses on the outer sides of the intermediate frame110.

Two identical arm pedestals130are located on each side of the rear deck21of the trailer20. An arm pedestal130consists of a vertical main plate with a shorter central transverse vertical stiffening plate welded to the outboard side of the main plate. The main plate and the stiffening plate have coplanar horizontal bases, and the upper end of the main plate has a central transverse through hole which has tapped threads comatable with the distal threads of an arm end pin129.

The forward arm pedestals130are mounted to the rear deck21with their tapped holes coaxial and their main plates equally offset from the centerline of the rear deck so that their main plates are parallel to the trailer centerline with their stiffening plates on their outboard sides. The rear arm pedestals130are positioned to the rear of the forward arm pedestals and mounted similarly. The spacing between the tapped holes at the upper ends of the forward and rear arm pedestals and the distance between the outer faces of the main plates of the opposed arm pedestals130is the same as the distance between the pivot arm mounting bosses116of the intermediate frame assembly110.

The pivot holes, at the lower end of each of the first swing arms126and the second swing arms127, journal arm end pins129which are threadedly engaged in the tapped holes of the arm pedestals130. Thus, both first swing arms126and both second swing arms127are all mutually parallel. Because the first and second swing arms126,127have the same length and are always parallel, the intermediate frame assembly110is always parallel to the rear deck21of the trailer20.

The cylinder base133is a long rectangular prismatic box with integral opposed devises for mounting of the swing cylinders134. The cylinder base is symmetrically transversely mounted on the central deck23of the trailer20and is itself symmetrical about the longitudinal midplane of the trailer. The cylinder base133extends across most of the width of the central deck. Each clevis on the upper side of the cylinder base consists of two parallel spaced apart vertical plates having coaxial through holes which are perpendicular to the longitudinal midplane of the trailer20. The gap between an adjacent pair of plates in the devises is a loose slip fit to the mount139of the swing cylinder body135of the swing cylinder134. The spacing between the devises of the cylinder base133is such that the lateral spacing of the axes of the swing cylinders134is the same as the spacing between the opposed first swing arms126.

The two swing cylinders134are substantially identical double acting hydraulic cylinders, each with a rod clevis137having a clevis pin138on the distal end of its cylinder rod136. The mounting of the body135of a swing cylinder134is provided by a swing cylinder mount139having mirror image horizontally transversely extending external upsets located close to the blind end of the cylinder body135. The outer ends of the upsets are vertical and have central tapped horizontal holes with axes intersecting the longitudinal axis of their cylinder134. The width of the swing cylinder mount139is such that it is a close slip fit between a pair of adjacent clevis plates on the cylinder base133.

A pair of opposed bolts serve as an opposed pair of swing cylinder body pivot pins140. For each swing cylinder134, the swing cylinder body pivot pins140have their shanks journaled in the pivot holes of an adjacent pair of clevis plates of the cylinder base133and threadedly engaged with the female threads of the swing cylinder mount139. Thus, the swing cylinder bodies135are pivotably mounted near their blind ends about the clevises of the cylinder base133. Each swing cylinder134has its rod clevis connected by a rod clevis pin138to the transverse hole in the intermediate boss on the lower side of its first swing arm126.

The swing cylinders134are actuated to extend or retract by pressured hydraulic fluid from the hydraulic system (not shown) of the coiled tubing rig10and controlled from the control room48by means of a four-way three position hydraulic valve. Reciprocation of the swing cylinders134causes the swing arm assembly125to move the intermediate frame assembly110with its attached injector cradle81in an arc between a traveling position on the rear deck21of the trailer20, shown inFIG. 12, and an elevated position, shown inFIG. 13.

Referring toFIGS. 3,4,10, and11, the coiled tubing rig10with the tubing injector support system80of the present invention is seen set up on a well location at which a drilling rig is present. For clarity in description, the drilling mast164, drawworks165, and crown block assembly166are not shown for these figures. These rig items and other equipment associated with the drilling rig are familiar to those skilled in the art, so the description herein is limited. The well is provided with a blowout preventer assembly150mounted on its wellhead. The substructure161of the rig straddles the wellhead and preventer150and supports a rig floor160above the preventer. A rotary table162is positioned on the rig floor160coaxially with the well bore. The coiled tubing rig10has its tubing deployed into the well, with the tubing section between the injector50and the well designated by numeral71.

FIGS. 14,15, and16describe a coiled tubing rig10having an alternative lifting means for the movement of the swing arms126and127with the attached tubing injector support system80. Here the movement of the swing arms126and127is effected by using a lifting line169which is controlled by the rig drawworks165and is dependent from the crown block assembly166mast164of the drilling rig.

Whenever the lifting line169is used as the lifting means for the swing arm assembly125, a central pad eye on the upper side of a horizontal spreader bar170is attached to the free end of the lifting line169. Lifting line169is dependent from the crown block assembly166at the upper end of the rig mast164and is wound around the drum of the drawworks165of the drilling rig. Mirror image spreader rods171or cables are attached at their upper ends to the distal ends of the spreader bar170. At their lower ends, the opposed spreader rods171have clevises which are attached by spreader clevis pins172to the lifting eyes100on the upper chords of the side frames of the cradle space frame82of the injector cradle assembly81. Whenever it is desired to move the tubing injector support system80in either direction between its first stowed position on the rear deck21of the trailer or its second position on the rig floor160, the tubing is clamped by the clamp assembly90.

Rather than using the hydraulic system of the coiled tubing rig10to actuate the swing cylinders134and thereby raise or lower the tubing injector support system80, the cylinders134can either serve as hydraulic dampers or be replaced by commercially available hydraulic dampers. Using the conventional swing cylinders134as dampers is done either by installing one or more restrictive orifices in each of the piston heads of the cylinders134or by interconnecting the two extreme ends of each cylinder cavity of the individual cylinder bodies135by means of a connecting line having an in-line restrictive orifice. Either of these approaches provides the functional equivalent of a commercially available hydraulic damper.

OPERATION OF THE INVENTION

The operation of the tubing injector support system80of the coiled tubing rig10proceeds as described below. The trailer20supporting the coiled tubing rig is delivered to the well location in the configuration shown in bothFIGS. 1 and 2. Typically, the tractor rig used for towing the coiled tubing rig10would be attached throughout the job, but the tractor is not shown herein for reasons of clarity.

To begin the job setup, the trailer20is backed up towards the drilling rig so that the midplane of the trailer20intersects the vertical axis of the well. When the trailer20is in its approximate position for swinging the intermediate frame assembly110with its injector cradle81and injector50up onto the rig floor160, the jacks28supporting the trailer20are set to bear against the ground surface18so that the trailer is stabilized. Following this, the control room module48is elevated to its working position and the operator occupies the control room. The lift cylinders134are extended then by the coiled tubing rig operator so that the intermediate frame110is swung upwardly and towards the rig floor160.

While the intermediate frame110is being raised or lowered by the lift cylinders134, the clamp assembly90on the injector cradle81is used to clamp and immobilize the free end72of the tubing string70. The operation of the clamp assembly90is discussed in the material below. During lifting of the tubing injector support system80, the storage reel40is allowed to freewheel so that the tubing70is tensioned only by reel turning friction between the reel and the injector50. During lowering of the tubing injector support system80, the reel40is rotated so that excess tubing length between the reel and the injector50is retrieved onto the reel.

The length of the swing arms126and127is preselected to ensure that the intermediate frame110can reach the rig floor160. After the swing arms126and127pass vertical, the intermediate frame110is lowered so that it rests on the rig floor. Counterbalance valves are used in the hydraulic control circuit for the lift cylinders134to prevent the sudden dropping of the tubing injector support system80when that system is being lowered in either direction.

If the free end72of the coiled tubing string70is not concentric with the well bore, the error is measured, the intermediate frame assembly110is lowered, the jacks28raised, and the trailer is moved to correct the trailer placement error. The jacks28are again lowered and the intermediate frame assembly110is again elevated so that the free end72of the coiled tubing string70can be entered coaxially into the well. The injector50can then be used to insert tubing70into or retract it from the well.

In the event that the tubing string71in the well becomes stuck or it is being used to pull a packer from the well, then it can be necessary to exert more tension on the tubing than can be provided by the rotational drive means of the injector50. In such a case, the following procedure is used.

The initial, lower position of the injector cradle81relative to the intermediate frame110is shown inFIG. 10. First, the tubing is clamped by extending the previously retracted clamp cylinders94of the clamp assembly90of the injector cradle81so that the clamp support blocks96supporting the grip blocks97are rotated about their clamp support block pins98. The extension of the clamp cylinders94is continued until the tubing section71between the drive wheel55of the injector50and the blowout preventer150is firmly gripped between the grip blocks97. The positions of the components of the clamp assembly90when clamping are shown inFIG. 11.

When the tubing section71deployed into the well is gripped at its upper end, then pressurized hydraulic fluid is directed to extend the four lift cylinders84by a selectably operable four-way three-position closed-center control valve. The longitudinal restraint roller assemblies89and119and the lateral restraint roller assemblies88and118centralize the injector cradle81within the intermediate frame110during raising and lowering. This raising of the injector cradle81with its clamped integral clamp assembly90gripping the upper end of the clamped tubing produces additional tension in the tubing section71.FIG. 11shows the injector cradle81in its position when fully raised by the lift cylinders84.

In the event that this additional tension is insufficient to free the tubing or the packer, standard oilfield coiled tubing slips (not shown) can be used to hold the tubing71temporarily at the rotary table162while the clamp assembly90is released from the tubing71by retracting the clamp cylinders94. The injector cradle81then can be lowered by the lift cylinders84preparatory to reclamping the tubing71for another lifting cycle to further tension the tubing71. If the tubing section71is freed, then the injector cradle81can be lowered while the injector50and the tubing reel are rotated to retrieve the slack in the tubing. Further operations of the coiled tubing rig are then free to proceed as necessary.

When the job is complete, all of the tubing section71is pulled from the well and the clamp assembly is used to clamp the free end72of the tubing string70. The tubing injector support system80can then be lowered to the rear deck21of the trailer20by retracting the swing cylinders134while the storage reel40is rotated to retrieve the excess tubing70between reel and the injector50. The jacks28for the trailer of the coiled tubing rig10are then raised and the control room48lowered to its travel position. At this point, the coiled tubing rig is again roadworthy.

Alternatively, the swing cylinders134with restrictive orifices (or the equivalent commercially available hydraulic dampers) only provide motion damping when the tubing injector support system80is raised or lowered by cooperative manipulation of the tubing reel40and a lifting line169dependent from the crown block assembly166of the rig mast164.

To raise the tubing injector support system80using the lifting line169, the following steps replace the use of the hydraulic pressure to extend the lift cylinders134. A lifting line169controlled by the drilling rig drawworks165and dependent from the crown block assembly166of the drilling rig mast is attached to the spreader bar170. The spreader rods171at the ends of the spreader bar170are attached to the lifting eyes100of the injector cradle81of the injector support system80while the lift cylinders84are held in their retracted positions.

With the clamp assembly90gripping the tubing end72, the tubing injector support system80is then raised from the rear deck21of the trailer20by reeling on the lifting line169while the tubing reel is allowed to freewheel. When the swing arms126and127are vertical, then additional tension on the tubing70between the reel40and the injector50is provided by braking the reel. The resulting lateral force in the forward direction on the tubing injector support system80is controlled by the coiled tubing rig operator so that the intermediate frame110of the injector support system will not impact the rig floor160. The restraint on the motion of the tubing injector support system80provided by the damping of the swing cylinders134further aids the controlled lowering of the intermediate frame110to the rig floor160. This allows the coiled tubing injector50to be emplaced on the rig floor160so that coiled tubing operations can begin following disconnection of the spreader bar170with its spreader rods171and spreader bar clevis pins172.

To lower the tubing injector support system to the rear deck21of the trailer20for transport upon job completion, the following steps are used. The lifting line169with its spreader bar170and spreader rods171and spreader bar clevis pins172is reattached to the lifting eyes100of the injector cradle81. With the end72of the tubing string70rigidly held by the clamp assembly90of the injector cradle81, the storage reel40is rotated to initiate additional retrieval of the tubing70. This initially pulls the swing arms126,127towards a vertical position.

As the swing arms126,127approach vertical, the slack in the lifting line169is taken up so that the tubing injector support system80will not fall to the rear deck21of the trailer20after the swing arms pass their vertical position. The hydraulic damping action provided by the swing cylinders134further aids avoidance of the dropping of the injector support system80after the swing arms126,127pass vertical during the lowering operation. The slowing of the lowering operation thus permits the tubing storage reel40to take up excess slack in the tubing70between the reel and the injector50.

ADVANTAGES OF THE INVENTION

The moveable tubing injector support assembly80is a self-contained means and apparatus for operating a coiled tubing rig either with its tubing injector located on the deck at the rear of its trailer in the conventional manner or operating the tubing injector on the rig floor of a drilling rig.

It is operationally much more convenient to have integral, rapidly operable means for both transferring and operating the coiled tubing injector either in its conventional position on the rear deck of the rig trailer or on the rig floor of a drilling rig. This saves operating time when the injector is to be transferred to and from a drilling rig floor and may avoid the need for providing a separate lifting means such as a crane or large forklift truck to effect the transfer. The transfer between the trailer and the drilling rig floor is easily accomplished with the self-contained lifting system shown inFIG. 3.

The second means of transferring the coiled tubing injector between the trailer and the rig floor of a drilling rig uses routinely available drilling rig equipment as a lifting means. Since the drilling rig lifting means is always available, this second lifting means is almost as easy to use as the hydraulic cylinders. Normally, hydraulic dampers do not need to be as large and expensive as the large hydraulic swing cylinders which would be needed to transfer the injector between the trailer and the drilling rig floor.

In addition, the lifting of the tubing injector support system between a first and second position provide can be used to induce additional tension in a coiled tubing string deployed into a well beyond that commonly available using only the coiled tubing injector. This novel feature is useful in the event that either the tubing has become stuck in the well or the tubing string is being used to unseat a packer or shift a downhole valve. These and other advantages of the present invention are readily recognizable by those skilled in the art.

Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. For example, the configuration of various elements and/or the structure of the individual elements of the selectably elevatable coiled tubing injector can be varied without departing from the spirit of the invention.