FIELD OF THE INVENTION
The present invention relates, in general, to a handling system for injecting continuous tubes such as coiled tubing, through an injector head and then through lubricator strings, for inserting tools into a wellhead. Likewise, the invention also relates to pulling of coiled tubing through injectors, which operation is in the opposite direction, for retrieving tools from wellhead.
The wellhead is primarily meant for oil and natural gas exploration and production operations.
Particularly, the present invention relates to a technology for rapid and safe assembling and disassembling of lubricator string sections on and from top of wellheads and for inserting and retrieval of drill tools being supported by coiled tubing running through the lubricator string sections.
More particularly, the present invention relates to a handling system for injecting and pulling coiled tubing into and from a borehole according to the preamble of claim 1 .
TECHNICAL BACKGROUND OF THE INVENTION Use of continuous tubes such as coiled tubing, sourced from a hydraulically operated reel is known in oil and natural gas exploration and production operations. These tubings, generally refer to metal pipes, with diameter ranging between 1 inch and 4 inches. It is also known, that coiled tubing can perform many different oil well operations, and these include use in interventions in oil and gas wells, and also use as production tubing in gas wells.
Application of such coiled tubing in oil and gas operations involves deploying the tubing as support for drill tools for inserting those tools into boreholes or for retrieving those tools from boreholes. Such tools can be packers, valves, sleeves, sensors, plugs, gauges and so on, which have to be run into and retrieved from the boreholes. These tools may find use for servicing the well.
The operations as stated in the preceding paragraph are done through lubricator string sections and those sections serve as a sluice for undertaking such operations.
In the above context, telescopic injector masts are also known which extend from a base up to a substantial height and supports an injector head at its top end and a lubricator string suspended from the injector head. Coiled tubing is injected/stabbed through the injector head and then through the lubricator string, which is located just above the borehole. The purpose is to insert tools into the borehole as stated before. The pulling operation of coiled tubing takes place in just the opposite direction of retrieving the tools from the borehole.
As stated before, injector masts for ensuring lifting of injector heads to undertake the operation as stated in the preceding paragraph are already known. For example, granted US patent numbered US 7077209, teaches a telescopic mast having two arms, which can telescopically rise for supporting an injector at a height and positioning it above the wellhead. The mast is pivotally mounted to a vehicle.
The above document and likewise prior art known in the field does not have any teaching for rapid, accurate and safe assembling of lubricator strings below the injector head and aligning these above the well head, thereby ensuring smooth passage of the coiled tubing. Additionally, no teaching exist in such prior art for safely disassembling the lubricator strings from atop the wellhead.
Furthermore, no teaching exist in prior art on how to precisely receive the coiled tubing from any direction and to pass it through the injector head, and simultaneously ensuring that the injector head is appropriately positioned above the well head.
The present invention meets the need of providing the aforesaid teachings, which are lacking in prior art, and other associated needs, by providing a handling system equipped with a telescopic mast, mounting an injector head at its top end, which mast can swivel about a vertical axis for correct injection or pulling out of the continuous tube from any direction, through the injector head and through lubricator strings. The mast also has a handling device for efficiently and rapidly assembling and disassembling lubricator strings on and from the top of the wellhead and for proper positioning and alignment of the strings beneath the injector head.
OBJECTS OF THE INVENTION
It is the principal object of the present invention to provide a handling system for injecting or pulling a continuous tube into or from a borehole, which ensures rapid, accurate and safe assembling of lubricator strings, so that these are aligned below the injector head and above the wellhead for passage of the continuous tubing therethrough.
In addition to the above object, it is another object of the present invention to ensure safe and rapid disassembling of the lubricator strings from above the wellhead, as may be required.
It is another object of the present invention to provide a handling system for injecting or pulling a continuous tube into or from a borehole which ensures that the continuous tubing is receive properly from any direction and to pass it through the injector head accurately and simultaneously ensuring that the injector head is appropriately
positioned above the well head.
All throughout the specification including the claims, the words "handling system", "handling device", "continuous tubing", "coiled tubing", "borehole ", "wellhead", "lubricator strings", "bearing", "BOP", "injector head", "injector mast", "tool strings/sections" are to be interpreted in the broadest sense of the respective terms and includes all similar items in the field, known by other terms, as may be clear to persons skilled in the art.
Restriction/limitation, if any, referred to in the specification, is solely by way of example and understanding the present invention. More specifically, hereinafter, the term "coiled tubing" has been referred to for the sake of understanding. It should be understood that "coiled tubing" also includes other similar continuous tubing as may be known to persons skilled in the field of the present invention, such as wire-line operations.
SUMMARY OF THE INVENTION
In its most basic embodiment, the invention relates to a handling system for injecting or pulling a continuous tube or wire into or pulling the same from a bore hole through an injector head and through a lubricator string, comprising a telescopic mast extending upwards from its base and carrying the injector head at its top end. The invention is contributing to the field of technology by providing a mast that has a handling device for assembling and disassembling lubricator sections by moving the lubricator sections successively into alignment with the injector head or a previous section and connecting the section to the injector head or the previous section. Thereby assembling and disassembling of the lubricator string can be done with minimal human interference, and hence increased safety and efficiency.
In a preferred embodiment the telescopic mast is capable of swiveling about a vertical
axis. Thereby the feeding of the coiled tube or the wireline can be done from different directions.
In a further preferred embodiment the side of the injector mast, which is facing upward when the mast is in the horizontal position, is provided with the handling device for the lubricator sections.
In a detailed embodiment, the handling device comprises one or more gripper units that are capable of holding the lubricator string sections substantially parallel to the axis of the mast.
In an even further embodiment, the handling device comprises at least one trolley that carries the at least one gripper unit, the at least one trolley being arranged to move lubricator string sections along at least a part of the length of the mast by interaction with rails located on the mast.
In an even further detailed embodiment, the gripper units are pivotal about an axis parallel to the mast in order to swing lubricator sections into alignment with the longitudinal axis of the injector head.
In a further detailed embodiment, each gripper units comprises at least two gripper arms, each gripper arm being are able to grip and hold one lubricator sections. In a still further detailed embodiment, one of the gripper arms is longer than the other gripper arm, so that the longer gripper arm is capable of extending over two lubricator sections.
In a preferred embodiment, the injection or pulling of the coiled tubing through the injector head is facilitated by an arch guide located at the top of a frame supporting the injector head, and that the supporting frame can be tilted to ensure alignment of the injector head with the well center.
Moreover, the arch guide is capable of rotation substantially through 180° to receive coiled tubing from any direction around the mast.
Further, the arch guide can be folded and unfolded for transportation and operation.
In one embodiment, the mast is positioned on a truck having a carrier at its rear end for parking one or more BOP units for transportation or for use during subsequent operation.
In a further embodiment, the mast is positioned on a slew base equipped with a pivot joint for the mast that is capable of slewing the mast over a sector of about +/- 15 degrees.
BRIEF DESCRIPTION OF THE DRAWINGS Having described the main features of the invention above, a more detailed and non- limiting description of an exemplary embodiment is given below, with reference to the drawings.
Figure 1 is a detailed view of the handling system according to a preferred embodiment of the present invention together with other associated aspects of the present invention.
Figure 2 is an enlarged view of the basal portion of the injector mast of the present invention.
Figure 3 is a perspective view of the injector mast resting on the injector mast truck according to the present invention.
Figure 4 is a view of the handling system similar to figure 1 , but with the position of the injector mast truck and the reel truck reversed.
Figure 5 is a side view of the injector mast truck having the injector mast on its base.
Figure 6 is an enlarged view of the guide arch mounted on the injector head. Figure 7 is a bottom view of the guide arch and the injector head.
Figure 8 is a perspective view of the reel truck and the injector mast truck in transport mode with other features onboard. Figure 9 is a front view of only the injector mast truck in transport mode with other features onboard.
Figure 10 is an enlarged view of the handling device of the injector mast. Figure 1 1 is a rear perspective view of the injector mast truck showing the building up of lubricator strings.
Figure 12 is an enlarged view of the tools resting on the horizontal tray at the rear portion of the injector mast truck.
Figure 13 is a rear perspective view of the injector mast truck showing how the tool strings are loaded into the lubricator strings.
Figure 14 is a perspective view of the injector mast truck during transport.
DETAILED DESCRIPTION OF THE INVENTION
The following describes a preferred embodiment of the present invention which is exemplary for the sake of understanding the invention and non-limiting.
In all the figures, like reference numerals represent like features. Further, when in the following it is referred to "top", "bottom", "upward", "downward", "above" or "below" , "right" or "left" and similar terms , this is strictly referring to an orientation with reference to the base of the handling system, where the base is horizontal and at the bottom. The front of the injector mast is referred to with reference to the front side of the truck on which it is installed.
It should also be understood that the orientation of some the various components may be otherwise than shown in the drawings, without deviating from the principle of the invention and this is within the scope of the present invention.
Furthermore, the present invention is explained and described below with reference to an injector mast truck and reel truck for the sake of convenience. The injector mast and the drop-in reel can also rest on other platforms, such as fixed structures, as known to persons skilled in the field of the present invention.
Figure 1 is a view of the basic layout according to the present invention. The handling system comprises an injector mast 1 , which is telescopic. The injector mast 1 and the guide arch 10 are mounted to a supporting frame or cage 9a (also shown in figure 6) on top of the mast 1 . This support frame 9a can be hydraulically moved, e.g. rotated, to ensure alignment of the injector head 9 above the wellhead 7 and also for ensuring smooth feeding of the coiled tubing through the lubricator string.
Apart from being telescopic, the mast is also swivelling, as explained with reference to figure 2 below. The mast rests on an injector mast truck 3. The injector mast truck 3, at its rear end has a carrier 6 for parking a BOP unit 8, when this is not in use. The rear portion of the injector mast truck 3 also has a rigging winch 5 and a sheave (not shown) for stabbing/pulling coiled tubing 12 through the injector head 9. The guide arch 10 facilitates this stabbing/pulling operation of coil tubing 12 through the injector head 9.
It should be also clear from figure 1 that the rear face of the injector mast 1 is the one, adjacent to the injector head 9. This rear face is equipped with a handling device 2 for the lubricator strings 4. The handling device 2 allows accurate, rapid and safe assembly and disassembly of the lubricator string sections 4 on and from the top of the wellhead 7. Figure 1 also shows the hydraulic power unit 1 1 located along the chassis of the injector mast truck 3. The operations are mostly hydraulically powered and this unit supplies hydraulic fluid under pressure to the various hydraulic motors used in the system. The BOP unit 8 and the lubricator string 4 on top of the wellhead 7 can also be seen. Figure 1 also shows the reel truck 15 and the reel trailer 16 and other features. These are not consequential to the present invention and are all known to persons skilled in the art. The coiled tubing 12 is sourced from the drop in reel 17. The drop in reel 17 rests on the reel trailer 16 and it has a tubing tensioner 13 for facilitating release. The tensioner 13 is hydraulically powered by a hydraulic unit 18 at the rear portion of the reel trailer 16. The central portion of the reel truck 15 has a control room 14.
Figure 2 is an enlarged view of the basal portion of the injector mast 1 . A structural box 18 runs along and above the center of the truck chassis 3. The box 18 is structurally tied to truck outrigger legs 22 and the mast slew base bearings 19b. All platforms and storage and machinery boxes etc. are attached to the box spine. The intention is to maximize layout flexibility.
The mast 1 is supported by a base structure 25 that is able to swivel about a vertical axis. The slew base 25 is arranged with an upper bearing 19c and a lower bearing 19a. This solution resembles a door or gate hinge system in that the lifting moment on the mast 1 is resisted by a momentum pair between the upper 19c and lower bearings 19a. This arrangement and the swiveling arms 20a 20b, 21 a, 21 b ensure swiveling of the mast around +/- 15 ° on either side of the truck base centerline. The swiveling arm 20a, 20b has a bearing 19a on either side of the truck 3 centerline, as it would be clear from figure 2.
The slew base structure 25 is slewed about the vertical axis by the use of actuator cylinder(s) 24 on either side of the centre line of the truck. In figure 2, the cylinders are shown attached to the swiveling arms 20a, 20b. Other possibilities exist such as electric, hydraulic or pneumatic actuators with or without screw, roller screw jacks etc.
It can be seen that from figure 2 that the slew base structure is equipped with a main horizontal pivot joint 19a for the mast 1 . The actuators 24 for moving the mast 1 through an angle in the vertical plane are grounded to the slew base structure 25 so that they slew together with the slew base structure 25. Further, it should be clear from figure 2 that bearings 19a and 19c are present on either side of the mast 1 .
A typical truck installation would be stabilized by extendable legs 22 fitted with adjustable footpads 23, on either side of the truck chassis as shown in figure 2.
The above aspects would be further clear from the rear perspective view of the injector mast truck installation in figure 3. This figure also shows the guardrails 26 for pathways for giving people to access the top of the truck and a ladder 27 for boarding the truck 3. It also shows lubricator string sections 4 stored along the mast. These are to be assemble onto a lubricator string and connected on top of the well head 7 (best shown in figure 1 ) and below the injector 9 (best shown in figure 1 ). The BOP 8 rests on a horizontal tray 29 extending from the BOP stowage platform 6 (best shown in figure 1 ).
Figure 4 is a view of the entire layout involved in the operation. It shows both the arrangements on the reel truck 15 and on the injector mast truck 3. The features shown are all essentially the same as in figure 1 and so is the functioning.
It is worth pointing out that the positions of the two trucks have changed in figure 3 as compared to figure 1 . The injector mast truck 3 is now at the left, while the reel truck 15 is now at the right.
The guide arch 10 is rotatable for accepting tubing from any orientation of the reel 17, from which the coiled tubing is sourced. Not all orientations have been shown, but these can be construed from figures 1 and 4.
Figure 5 only shows the injector mast 1 according to the present invention on a truck 3. It has the lubricator strings 4 parked substantially parallel to the mast at the lower portion of its rear end, with the help of a handling device 2, 26. The handling device comprises rails 2 along which trolleys 26 can move up and down. The trolleys have gripping units 27 (best shown in figure 10). This arrangement not only facilitates parking, but also assembling and disassembling of lubricator strings 4 on and from the top of the well head 7. How this is done is to be explained with reference to figure 10 later. The injector head 9 is located on top of the lubricator string 4 when in use, which in turn is placed above and is connected to the BOP unit 8. The latter is located above the wellhead 7.
From figure 5 it would be clear that the injector head 9, the lubricator string 4 in use beneath it, the BOP are aligned correctly on top the well head 7 in order to insert tools into the well head 7 and down the borehole.
Figure 6 is an enlarged view of the injector head 9 and the guide arch 10. The injector head is supported by a frame 9a. The guide arch 10 is mounted on top of the frame 9a. The frame 9a having the injector head 9 within it and the guide arch 10 mounted on top rests on the top of the injector mast 1 . The frame 9a can tilt such that the injector 9 remains vertical despite the mast 1 being angled, in order to align the lubricator string 4 with the well center 7. This is achieved
using hydraulic cylinders (not shown) and is done to ensure accurate alignment relative to the flange plane of well center 7 or BOP 8.
Figure 7 is an enlarged bottom view, showing the guide arch 10 mounted on top of the frame 9a of the injector 9. It also shows lubricator string sections 4, which are being assembled beneath the injector 9 and above the BOP and well head (these are not shown in this figure).
Figure 7 also illustrates the assembling of the lubricator string 4. The upper section 4a of the lubricator string is attached to the injector head 9 during transport and will lie substantially parallel to the mast 1 during transport (as shown in figure 8). Four additional lubricator sections 4b, c, d and e are held by grippers 27 arranged on two trolleys 26. In figure 7, the first section 4b of the four additional sections has been attached to the lower end of the upper section 4a. The grippers 27 can swing laterally to place each of the sections 4b, c, d, e into the centerline of the upper section 4a. When the first of the four additional sections 4b has been attached to the lower end of the upper section 4b, the mast 1 is extended further a distance equal to a section length. Then the next additional section is swung into the centerline of the already assembled lubricator section. These steps are repeated until all sections have been attached into a complete lubricator string 4. The trolley 26 is also capable of movement along the mast so that the sections can be placed properly for mating with the string 4.
Figure 7 also shows a working platform 31 . This platform is normally separate (standard, commercially available) and portable man-lift unit. This unit is used for various tasks including access to the BOP at the well head.
Figure 8 is a view of the reel truck 15 and the injector mast truck 3 in preparation mode with the components onboard. Here, the mast 1 has swung down so that it is substantially parallel to the chassis of the injector mast truck 1 . This is also the position where the outer end of the coiled tubing 12 or wireline is fed, i.e. stabbed, into the injector 9 or taken completely out of the injector 9. When the coiled tubing 12 or wireline has been pulled completely out of the injector 9, this is also the transport mode of the mast and lubricator.
Figure 8 further illustrates that the lubricator sections 4a-e can be transported with the upper section 4a attached to the injector 9 and the others 4b-e being parked along the mast 1 . The handling device 26, 27, described above, can also facilitate securing the lubricator sections 4b-e during the transport.
Figure 9 is a front view of the injector mast 3 in same mode, as shown in figure 8. Figure 9 specifically shows how stabbing of coiled tubing 12 through the injector 9 can be carried out in the lowered position, with the reel 17 in front of the mast truck 3.
Figure 10 is an enlarged view of the lubricator section handling device. The rear face of the mast 1 is equipped with the handling device 26, 27. This device allows rapid and safe assembly and disassembly of the lubricator string sections 4b-e with a substantially reduced amount of human intervention.
The device comprises a travelling trolley 26 on one or both sides of the mast 1 centerline on its rear face. The trolley 26 can move up and down along rails 2 provided along the rear face of the mast 1 .
The trolleys 26 are equipped with one or more gripping units 27. These gripping units 27 hold the lubricator sections 4b-e parallel to the mast axis 1 and are able to carry the weight of the lubricator sections when the mast 1 both in vertical and horizontal position of the mast 1 . Each trolley 26 is able to carry two sections 4b, c or 4d, e of the lubricator string sections 4b-e. It is however also possible to configure the gripping units so that they can carry more than two sections each. To facilitate the gripping of two sections, the outer end of each gripping unit 27 has a first gripping arm 27a, which is able to swing about a hinge 27c and a second gripping arm 27b, which is able to swing about a hinge 27d. The second gripping arm 27b extends beyond the first gripping arm 27a. Both arms 27a and 27b are shaped complementary to the outer circumference of the lubricator sections.
When lubricator sections are loaded into the gripping units 27, both gripping arms 27a and 27b are swung outwards. Then the first or inner gripping arm 27a grips a first lubricator section. Next, the second or outer gripping arm 27b grips a second lubricator section.
In the embodiment shown, the gripping units 27 are couple to the trolley 26 at a fixed distance. However, the distance between the gripping units 27 could also be made adjustable by use of a suitable trolley design.
The gripping units 27 are pivotal about a hinge 30 having an axis parallel to the mast 1 , and it can be swung by hydraulic or other type of actuators (not shown) between a stowed position and a position where a lubricator section is aligned with the injector axis.
The gripper units are spaced to accommodate a wide range of lubricator section lengths. The jaws themselves can be adjusted for a range of lubricator diameters.
The gripper units are spring applied and actively released by hydraulic, pneumatic, or electric actuators.
The grip units 27 can be mechanically or otherwise interlinked so that they will move in synchronicity.
The lubricator sections can be moved to the required vertical position by traversing the trolleys 26 up or down the vertical mast along the rails 2. It is also possible to lock the trolleys 26 relative to the rails 2 during transport.
This combined with the telescoping ability of the mast 1 allows the lubricator sections 4a-e to be assembled rapidly and in a safe and controlled manner.
Figure 1 1 is a view of the rear end of the mast truck 3. It shows the vertical building up of lubricator strings 4.
Figure 12 is an enlarged view showing the BOP 8 resting on the horizontal tray 29 at the rear portion of the injector mast truck 3, as well as the lubricator sections in a transport position.
It would be clear from figure 13 that the BOP 8 can be placed in a vertical position directly beneath and coincident the axis of the lubricator sections 4. The BOP 8 can be connected to the lower end of the lowermost lubricator section 4e and lifted onto the wellhead by the lubricator string 4 and the mast 1 . The horizontal tray 29 can be retracted into the truck when the BOP 8 has been lifted off in order to get the tray out of the injector and lubricator axis.
Figure 14 is a view of the injector mast in transportation mode. The coiled tubing 12 has been disconnected. It also shows the folded guide arch 10.
Now having described the basic structure of the handling system according to the present invention, its basic functioning is now explained and for that purpose, the figures are again referred to. The structural details are however, not reiterated as those have been adequately described hereinbefore.
The figures 2 and 3 show the truck 3 in stabilized position which should be first step. Typically, the truck 3 with legs 22 extended would be longer than it is wide. Therefore, the slew angle of the extended mast 1 is kept within a relatively small sector in order to better exploit the stabilizing moment of the truck 3. A sector of +/- 15° on either side of the truck base centerline, nevertheless gives a significant advantage in terms of mast truck 3 and coiled tubing reel truck 15 positioning flexibility at the well site.
The slewing system described here resists overturning moments from the mast 1 by a moment pair acting on the vertically spaced bearings, rather than by a couple across a conventional slew ring. By spacing the bearings along a vertical axis, a smaller "footprint" on the truck base is allowed, thereby freeing up space for other equipment such as the stowed BOP 8. There is also a cost saving compared to a conventional slew ring bearing system.
The slew base may alternatively take the form of a conventional 360-degree rotation slew ring mounting as often seen on mobile cranes.
Referring to figures 1 and 3 the mast 1 is of telescoping type or a combination of folding plus telescoping type.
The mast has one telescope section for simplicity, however additional sections are possible if required. The mast cross section is of self-centering type.
Expected maximum height from ground to injector support frame 9a is approximately 20 meters. The mast 1 extends from the base 25 and lifts the injector head 9 supported by the frame 9a. The injector 9 and guide arch 10 are mounted to the supporting frame 9a, on top of the mast 1 . The guide arch 10 actually rests on the top portion of the frame 9a.
The frame 9a can be tilted hydraulically so that the injector 9 can be set vertically as the mast 1 is angled to align with the well center 7.
Now the handling device 2 at the rear portion of the mast 1 becomes active. In this connection the figure 10 and the elaborate structural and functional description provided should be referred again. The lubricator sections 4b-e are moved to the required vertical position by traversing the trolleys 26 up and down the vertical mast 1 . This combined with the telescoping ability of the mast allows the lubricator sections 4b- e to be assembled rapidly and in a safe and controlled manner beneath the injector head 9.
As the mast 1 is telescoped and the lower end of the upper section 4a has reached the height of the upper end of the first section 4b to be connected, the first lubricator section 4b is brought into engagement with the lower end of the upper section 4a, connected and then released by the gripper units 27. The next lubricator string 4c is likewise installed beneath the previous lubricator section 4b and this process is
repeated in respect of subsequent lubricator sections one after another until the lubricator string has been completely built.
The normal operational set-up is that as much length as possible of the lubricator string is pre-assembled (the upper section 4a) and attached to the injector frame 9a. The additional lubricator sections 4b-e are added from below as it would be clear from figures 7 and 1 1 and the description above.
Referring to figures 6 and 7 the guide arch 10 is now rotated suitably relative to the frame 9a, to accept coiled tubing 12 from the reel 17 (best shown in figure 1 ). The guide arch 10 can rotate 360 degrees to accept coiled tubing 12 from all directions around the mast 1 , depending upon the position of the reel 17 (best shown in figure 1 ).
Referring again to figure 1 the mast slew base 25 is equipped with a rigging winch 5 and sheaves that enable stabbing (and pulling as well) of the tubing 12 through the injector 9.The stabbing is carried out with the mast 1 vertically if the reel 17 is behind the mast truck 3. If the reel 17 is positioned in front of the mast truck 3 then the stabbing can be done with the mast in the lowered position.
The guide arch 10 can be folded for transport. It can be unfolded and rotated downward with the mast in the stowed position. This allows stabbing to be carried out in the lowered position with the reel 17 in front of the mast truck 3. These aspects would be clear from figures 8 and 9.
Now referring to figure 13, once the lubricator string 4 is of sufficient length, tool string 28 is added from below the lubricator strings 4. Tool string sections can be assembled
and inserted into the lubricator string 4 using a simple manual or semi-automatic system on the BOP stowage platform 6 at the rear of the truck 3.
To connect to the tool string, the coiled tubing 12, which has been inserted through the injector 9, is now injected further down through the lubricator string 4 until it emerges from the bottom of the lubricator sting. The coiled tubing 12 is connected with the first tool string section 28 and the latter is pulled into the lubricator string 4 through by the coiled tubing. While the first tool section is still extending somewhat below the lubricator string 4, the next tool section is connected to the first. These steps are repeated until the whole tool string has been assembled and is situated within the lubricator string 4.
Tool string handling as explained above is undertaken after the BOP has been moved into position on top of the wellhead 7. When the tool string has been completely assembled and pulled into the lubricator string 4, the lubricator is lifted on top of the BOP 8, which is located on top of the wellhead 7 and then attached to the BOP 8.
Alternatively, the bottom end of the lubricator with the tool string inside is attached to the BOP with the BOP in its stowed position. Stabilizing wires are then attached to the BOP and it is moved and landed at the wellhead 7.
Once, the entire method as narrated hereinbefore is has been performed, the set up would look somewhat as in figure 5. From figure 5 it would be clear that the injector head 9, the lubricator string 4 in use beneath it and the BOP 8 are aligned properly on top of the well head 7. The lubricator string 4 in use has a tool string 28 (best shown in figure 13) inside it along its lower portion, which is just above the BOP 8. Hence, this cannot be seen in figure 5. Now the operation of inserting the tool 28 into the well can begin.
The BOP handling will now be explained elaborately. As explained with reference to figure 1 the truck has a position 6 for transport and stowage of one or more BOP units 8. This is ideally at the rear of the truck 3 on or close to the centerline. The mast 1 can be used as a crane to lift the BOP 8 off its stowage position and move it to the wellhead 7.
BOP handling methods would include the two following alternatives:
1 . Fixed length lifting wire(s) hung from beneath the Injector support frame 9a.
The mast 1 is lifted to approximately vertical position and is telescopically extended to less than maximum stroke.
The lower end of the wire(s) is attached to lifting points on the BOP. Stabilizing ropes/wires extend from a ring at the lower end of the wire(s) out to pad-eyes at the end of each of the extended rear stabilizing legs of the truck. The BOP is then lifted from its stowed position by further extending the telescoping mast 1 . The mast 1 is then angled rearwards from the vertical and slewed as necessary in order position the BOP 8 above and ideally slightly beyond (relative to the truck) the wellhead 7. Ideally, the BOP 8 would be a short distance (approx 100 -150mm) above the flange that it is to be bolted to. The stabilizing ropes/wires are then tightened to both stabilize and align the BOP precisely above the flange. The BOP is then lowered into place by using the limited vertical travel capability of the injector support frame 9a. This system allows precise alignment and gentle movement of the BOP without use of the telescoping or mast lifting cylinders.
2. BOP attached to lower end of the lubricator string.
The lubricator string is assembled using the lubricator handling system. The bottom end of the lubricator with the tool string 29 inside is then attached to the BOP with the BOP in its stowed position. The stabilizing wires are attached as in (1 .) The BOP is then moved and landed on the wellhead 7 in the same fashion as (1 .) The only difference between alternatives (1 .) and (2.) is that (2.) does not utilize the lifting wire.
The process of retrieving tools from the wellhead 7 will involve a movement opposite to stabbing of the coiled tubing 12. The tubing 12 would be pulled up the injector 9 for retrieving the tools and the entire operation is not described herein as it would be clear to persons skilled in the art.
The short range of vertical movement of the injector frame 9a having the injector 9 may be used to separate the injector frame 9a and the upper lubricator section 4a. This may or may not be the beginning of disassembling operation of the lubricator string depending upon requirement. Alternatively, the disassembling may be carried out keeping the upper lubricator section 4a attached to the injector support frame 9a.
Once the disassembling operation is over, the equipment is brought into transportation mode, as shown in figures 8, 9 and 14. The additional lubricator sections 4b-e are supported in the grippers 27 on the rear side (upper side when the mast is horizontal) of the mast 3 during transport. The upper lubricator section 4a can be transported either connected or disconnected from the injector frame 9a. These figures also reveal that the movement capability of the support frame 9a along the mast 1 also ensures proper positioning of the same and of the upper lubricator section during transport.
The movement of the support frame 9a is achieved using hydraulic cylinders and is in order to ensure accurate alignment relative to the flange plane of well center/BOP. It
also allows fine and delicate landing of the connections and flanges between lubricators and BOP.
Hence, from the description hereinbefore it would be clear that all the objects of the invention are achieved.
The present invention has been described with reference to a preferred embodiment and some drawings for the sake of understanding only and it should be clear to persons skilled in the art that the present invention includes all legitimate modifications within the ambit of what has been described hereinbefore and claimed in the appended claims.