FLANNERY, Mike (Appletree Bam, Wittington GreenMedmenham,Marlow, SL7 2ES Bucks, GB)
| C l a i m s 1. System for feeding a coiled tubing (26) in or out of a subsea well (34), comprising a injector head apparatus (10) placed on a well head (24) of the well (34), said injector head apparatus (10) comprises: a plurality of annular-shaped electromagnetic means (12) stacked to form a through channel (16); and a power supply means (20) for supplying electrical power to the electromagnetic means, wherein the plurality of electromagnetic means (12) are adapted to exert a magnetic force along the longitudinal axis of the coiled tubing (26) when the coiled tubing is at least partly inserted into the through channel (16) of the structure so as to drive the coiled tubing (26) through the through channel (16) and in or out of the well (34) as electrical power is supplied to the electromagnetic means (12) by the power supply means (20), and wherein the power supply means (20) further is adapted to supply a variable amount of electrical power to the electromagnetic means (12). 2. System according to claim 1, wherein the power supply means (20) further is adapted to reverse the current flow of the electrical power supplied to the electromagnetic means (12). 3. System according to any preceding claim, wherein the power supply means (20) further is adapted to supply electrical power of different property or properties to different electromagnetic means (12). 4. System according to any preceding claim, wherein the electromagnetic means (12) are non-serially connected with the power supply means (20). 5. System according to any preceding claim, wherein each of the electromagnetic means (12) is torus-shaped. 6. System according to any preceding claim, wherein the electromagnetic means (12) are separated by electrically isolating elements (18). 7. System according to claim any preceding claim, further comprising a first slip means (42) arranged at one end of said through channel (16) and a second slip means (44) arranged at the other end of said through channel (16). 8. System according to any preceding claim, further comprising coupling means for securing the apparatus to a wellhead of the well. 9. System according to any preceding claim, further comprising coupling means for serially connecting the apparatus to another such injector head apparatus. 10. System according to claim any preceding claim, further comprising a straightening device (46) arranged at one end of said through channel and adapted to at least partly linearize the coiled tubing before or when the coiled tubing is entered into said through channel of the structure. 11. System according to any preceding claim, further comprising cooling means for allowing water to pass through the apparatus when the apparatus is submerged in water. 12. System according to any preceding claim, further comprising a coiled tubing cleaning unit (100) arranged at one end of said through channel (16), the cleaning unit including two rubber sleeves (104a, 104b) adapted to strip off any pollution on the coiled tubing as the coiled tubing is passed through the rubber sleeves, and between the two rubber sleeves a washing chamber (106) with an inlet (108a) and an outlet (108b) for allowing water to pass through the washing chamber when the apparatus is submerged in water. 13. System according to claim 12, wherein the outlet (108b) for the coiled tubing water cleaning fluid is connected to a soft umbilical return line 14. A method of feeding a coiled tubing (26) in or out of a subsea well (34), the method comprising: positioning onto a wellhead (24) of the well an injector head apparatus (10) comprising a plurality of annular-shaped electromagnetic means (12) stacked to form a through channel (16), placing a portion (40) of the coiled tubing in the through channel (16) of the injector head apparatus; and initiating a power supply means (20) of the injector head apparatus to individually energize the electromagnetic means (12) in order to drive the coiled tubing in or out of the well by electromagnetic forces, wherein the feeding speed of the coiled tubing (26) in or out of the well (34) is controlled by the power supply means (20) supplying a variable amount of electrical power to the electromagnetic means (12). 15. A method according to claim 14, wherein a blowout preventer (BOP) is placed between the wellhead (24) and the injector head apparatus (10). |
Field of the invention
The present invention relates to a system with an injector head apparatus and method for feeding a coiled tubing in or out of a well.
Background of the invention
Future ultra deep water well intervention projects dictate the use of injector heads for feeding a coiled tubing in or out of the well. These injector heads are mounted on the seabed at depths of up to about 3000 meters. At this depth conditions it is difficult, if not impossible, to properly maintain the injector heads.
However, existing injector heads generally include mechanical grips or other moving parts, which mechanical grips or other moving parts generally do require maintenance.
WO 2006126886 Al discloses a device for selective movement of well tools in or out through a portion of a pipe string, using electromagnetic means.
GB 2005865 A relates to a method and apparatus for logging earth boreholes. GB 1428297 A relates to an apparatus for maintaining high speed movement of bodies in a tube using magnetic field pulses, while US 4071086 A disclose a pulling tool for helping equipment descend down a borehole.
Summary of the invention
It is an object of the present invention to at least partly overcome the above problem, and to provide improved means for feeding a coiled tubing in or out of a well.
This object, and other objects that will be apparent from the following description, is achieved by an apparatus and a method according to the appended claims.
According to one aspect of the present invention, there is provided a system for feeding a coiled tubing in or out of a subsea well, comprising a injector head apparatus placed on a well head of the well, said injector head apparatus comprises: a plurality of annular-shaped electromagnetic means stacked to form a through channel; and a power supply means for supplying electrical power to the electromagnetic means, wherein the plurality of electromagnetic means are adapted to exert a magnetic force along the longitudinal axis of the coiled tubing when the coiled tubing is at least partly inserted into the through channel of the structure so as to drive the coiled tubing through the through channel and in or out of the well as electrical power is supplied to the electromagnetic means by the power supply means, and wherein the power supply means further is adapted to supply a variable amount of electrical power to the electromagnetic means.
The invention is based on the understanding that by using magnetic forces to feed the coiled tubing in or out of the well, no mechanical grips or other moving parts are necessary for feeding the coiled tubing, and maintenance of the injector head apparatus may be kept at a minimum. Though mainly beneficial for (deep) subsea oil or gas wells where maintenance may be very difficult to provide, the present injector head apparatus may also be used on land.
In one embodiment, the power supply means further is adapted to supply a variable amount of electrical power to the electromagnetic means, thereby beneficially changing the driving or feeding speed of the coiled tubing.
In one embodiment, the power supply means further is adapted to reverse the current flow of the electrical power supplied to the electromagnetic means, thereby advantageously reversing the driving or feeding direction of the coiled tubing. Hence, the injector head apparatus does not have to be physically turned around to change the feeding direction.
In one embodiment, the power supply means further is adapted to supply electrical power of different property or properties (e.g. different quantity, pulsing, and/or direction of current) to different electromagnetic means, as required, in order to control (e.g. maximize) the thrust of the injector head apparatus.
In one embodiment, the electromagnetic means are non-serially connected with the power supply means. The electromagnetic means may for instance be connected in parallel with the power supply means, or each electromagnetic means may be individually connected to the power supply means, such that if for instance one of the electromagnetic means fails, the remaining electromagnetic means may still function. This advantageously results in that the overall functionality of the injector head apparatus is maintained, albeit with reduced thrust.
In one embodiment, each of the electromagnetic means is torus-shaped. Each electromagnetic means may for instance be a circular ring-shaped magnetic core around which a wire is coiled.
In one embodiment, the electromagnetic means are separated by electrically isolating elements, to ensure that the operation of an electromagnetic means is not (too) affected by the operation of a neighbouring electromagnetic means.
In one embodiment, the apparatus further comprises a first slip means arranged at one end of said through channel and a second slip means arranged at the other end of said through channel, for accommodating tubing movement while sealing the apparatus. In one embodiment, the apparatus further comprises coupling means for securing the apparatus to a wellhead of the well.
In one embodiment, the apparatus further comprises coupling means for serially connecting the apparatus, preferably both mechanically and electrically, to another such injector head apparatus, in order to produce greater forces.
In one embodiment, the apparatus further comprises a straightening device arranged at one end of said through channel and adapted to at least partly linearize the coiled tubing before or when the coiled tubing is entered into said through channel of the structure. Linearization of the coiled tubing, which coiled tubing previously may have been stored on a drum on a vessel, may increase the exerted magnetic force. The straightening device may for instance be a funnel structure. Also, the straightening device may comprise two wheel sets oriented at about 90 degrees to each other.
In one embodiment, the apparatus further comprises cooling means for allowing water to pass through the apparatus when the apparatus is submerged in water. Cooling the apparatus helps ensuring consistent and long term performance. Preferably, the cooling means is adapted to allow free passage of cooling water around each
electromagnetic means, which electromagnetic means may generate excessive heat during operation. The cooling means may for instance be at least one channel leading outside water through the apparatus.
In one embodiment, the apparatus further comprises a coiled tubing cleaning unit arranged at one end of said through channel, the cleaning unit including two rubber sleeves adapted to strip off any pollution on the coiled tubing as the coiled tubing is passed through the rubber sleeves, and between the two rubber sleeves a washing chamber with an inlet and an outlet for allowing water to pass through the washing chamber and remove any pollution stripped off the coiled tubing when the apparatus is submerged in water. It is contemplated that the coiled tubing cleaning unit also may be embodied alone, i.e. without the rest of the present apparatus. The outlet for the coiled tubing water cleaning fluid can be connected to a soft umbilical return line
According to another aspect of the present invention, there is provided a method of feeding a coiled tubing in or out of a well, the method comprising: placing an injector head apparatus onto a wellhead of the well; placing a portion of the coiled tubing in the through channel of the injector head apparatus; and initiating a power supply means of the injector head apparatus to individually energize the electromagnetic means in order to drive the coiled tubing in or out of the well by electromagnetic forces. Advantages and features of this aspect of the invention are analogous to those of the previously described aspect of the invention, and vice versa. In one embodiment, the well is a subsea well. Further, a blowout preventer (BOP) may be placed between the wellhead and the injector head apparatus.
Brief description of the drawings
These and other aspects of the present invention will now be described in more detail, with reference to the appended drawings showing currently preferred
embodiments of the invention.
Fig. 1 is a schematic, cross-sectional side view of an injector head apparatus according to an embodiment of the present invention.
Fig. 2 is a schematic perspective view of the apparatus of fig. 1.
Fig. 3 illustrates a method of feeding a coiled tubing in or out of a subsea well according to the present invention.
Figs. 4-5 are schematic, cross-sectional side views of injector head apparatuses according to other embodiments of the present invention.
Fig. 6 is a schematic, cross-sectional side view of a coiled tubing cleaning unit that may be used in conjunction with an injector head apparatus of the present invention.
Detailed description
Figs. 1 and 2 illustrate an injector head apparatus 10 for feeding a coiled tubing in or out of a well according to an embodiment of the present invention.
The injector head apparatus comprises a plurality of annular or ring-shaped electromagnetic means 12 of uniform size. The exemplary apparatus 10 in fig. 1 comprises four electromagnetic means 12. Each electromagnetic means 12 may for instance be a toroid or toroidal electromagnet with a circular ring-shaped magnetic core around which a wire is coiled. The electromagnetic means 12 are co-axially stacked on top of each other to form a cylinder-like or tubular structure 14 with a central through channel 16, as illustrated in figs. 1 and 2. Between each electromagnetic means 12, there is provided an electrically isolating element 18, as illustrated. The electrically isolating elements 18 may for instance be ring-shaped.
The injector head 10 apparatus further comprises a power supply means 20. In the embodiment shown in fig. 1, each electromagnetic means 12 is connected to its own dedicated output of the power supply means 20. This enables current of different quantity and/or direction to be supplied to different electromagnetic means 12. Also, the injector head apparatus 10 may still function even if one of the electromagnetic means 12 fails. However, in a simpler embodiment the electromagnetic means 12 can be connected to the same power output, and comprise a controller for individual supply of power to each electromagnetic means 12.
The injector head apparatus 10 is further adapted to communicate with a control unit 22 via a wired or wireless connection. The control unit 22 is adapted to
communicate commands to the power supply means 20 from an operator in order to control the injector head apparatus 10.
In use, the injector head apparatus 10 is typically placed on a wellhead 24 of a well, for instance an oil or natural gas well. To this end, the injector head apparatus 10 may further comprise coupling means (not shown) for securing the apparatus 10 to the wellhead 24.
A portion of an elongated coiled tubing 26 is further placed in the channel 16, with the longitudinal axis of the coiled tubing 26 essentially aligned with the central axis of the channel 16. The coiled tubing 24 is a windable metal piping, typically about 2,5 to 5 centimetres in diameter, and with a length of up to several thousand meters.
Then, the operator instructs the power supply means 20 via the control unit 22 to supply electrical power to the electromagnetic means 12 such that a magnetic force is exerted along the longitudinal axis of the coiled tubing 26 so as to drive the coiled tubing 26 axially through the cylinder-like structure 14 and in or out of the well in the direction indicated by arrow 28. Specifically, the electromagnetic means 12 are fluttered on and off to produce the forward or reverse movement of the coiled tubing 26, like in a linear induction motor.
Hence, no mechanical grips or other moving parts are necessary for feeding the coiled tubing 26 in or out of the well.
A method of feeding a coiled tubing in or out of a well according to an embodiment of the present invention will now be described with reference to fig. 3. The method will be described in the context of a subsea gas or oil well intervention, which is a preferred application of the present invention.
First, an injector head apparatus of the present invention (e.g. the injector head apparatus 10 of fig. 1) is lowered into the sea 30 from a marine vessel 32. The injector head apparatus 10 is positioned on the wellhead 24 of a new or existing subsea well 34 using a dynamic positioning system. The dynamic positioning system may for instance be a remotely operated underwater vehicle (ROV) 36 with a GPS-unit (Global
Positioning System). After being positioned on the wellhead 24, fluid umbilicals and power and control cables (not shown) are connected to the injector head apparatus.
Then, the coiled tubing 26, which typically comes spooled on a large reel 38 onboard the vessel 32, is lowered into the sea 30. In particular, the free end portion 40 of the coiled tubing 26 is placed in the injector head apparatus 10, also for instance using an ROV 34 and GPS technology.
Then, the electromagnetic means 12 of the injector head apparatus 10 are energized as explained per se above, whereby the coiled tubing 26 is driven or fed into the well 34. When the coiled tubing 26 is to be extracted or pulled out from the well 34, the current flow and pulsing to the electromagnetic means 12 of the injector head apparatus 10 may simply be reversed, as explained above. Also, by varying the amount of electrical power supplied to the electromagnetic means 12, the driving or feeding speed of the coiled tubing 26 in or out of the well 34 may be controlled.
It should be noted that a blowout preventer (BOP) may be placed between the wellhead 24 and the injector head apparatus 10. The blowout preventer may be separate or included in the injector head apparatus 10.
Also, the injector head apparatus 10 may further comprise coupling means (not shown) for serially connecting the apparatus to another such injector head apparatus, in order to increase the thrust.
In one embodiment, the apparatus may further comprise tilting means for angling a portion of the apparatus in relation to the remaining apparatus. This beneficially allows operation on a slanting well, without having to prepare other components of a system in which the present injector head apparatus may be included for inclined operation.
Also, the injector head apparatus 10 may further comprise cooling means for cooling the apparatus 10 when the apparatus 10 is submerged in water. An exemplary cooling means (not shown) comprises a plurality of channels arranged in the apparatus 10 such that outside cooling water may be led around each electromagnetic means 12.
Figs. 4-5 are schematic, cross-sectional side views of injector head apparatuses according to other embodiments of the present invention.
The injector head apparatus 10 in fig. 4 may be similar to that of fig. 1, but further comprises a first slip joint 42 arranged at one end of the cylinder-like structure 14 and a second slip joint 44 arranged at the other end of the structure 14. The slip joints 42, 44 may be mechanical, but they are preferably hydraulically operated.
The injector head apparatus 10 in fig. 5 may be similar to that of fig. 1, but further comprises a straightening device 46. The straightening device 46 is arranged at the end of the apparatus 10 opposite the wellhead 24. Generally, the straightening device 46 is adapted to at least partly linearize the coiled tubing 26 before or when it is entered into the central channel 16 of the apparatus 10. An exemplary straightening device as shown in fig. 5 comprises a funnel structure 46. Fig. 6 is a schematic, cross-sectional side view of a coiled tubing cleaning unit 100 that may be used in conjunction with an injector head apparatus of the present invention.
The coiled tubing cleaning unit 100 comprises a housing 102. In the housing 102, there is provided two rubber sleeves 104a, 104b through which the coiled tubing 26 may pass. The two rubber sleeves 104a, 104b are co-axially arranged separate from each other, as illustrated in fig. 7. The inner diameter of each rubber sleeve 104a, 104b is preferably somewhat smaller than the diameter of the coiled tubing 26. Between the two rubber sleeves 104a, 104b, the housing 102 is shaped so as to form a washing chamber 106 with one opening or inlet 108a and another opening or outlet 108b.
In use, the coiled tubing 26 is passed though the cleaning unit 100, or the cleaning unit 100 is moved along the coiled tubing 26, whereby any pollution such as oil or algae on the outside of the coiled tubing 26 is stripped off by the rubber sleeves 104a, 104b. At the same time, when the cleaning unit 100 is submerged in the sea, seawater passes the cleaning chamber 106, as indicated by the dashed arrows in fig. 6. The passing seawater further cleans the coiled tubing 26 exposed between the rubber sleeves 104a, 104b. Also, the passing seawater may remove any debris from the cleaning chamber 106. The coiled tubing water cleaning fluid may be fed into the soft umbilical return line.
The person skilled in the art realized that the present invention by no means is limited to the preferred embodiment(s) described above. On the contrary, many modifications and variations are possible within the scope of the appended claims. For instance, present invention may also be used for interventions in land or surface wells.
Also, the different features described above may be combined in various ways.
Also, the end portion 40 of the coiled tubing may be placed in the injector head apparatus before the injector head apparatus is positioned on the wellhead. In this case, the coiled tubing "follows" the injector head apparatus as the latter is transported down to the wellhead.