NO20190034A1 - Coiled tube injector with integrated HIV compensation and procedure for HIV compensation of coiled tubing - Google Patents

Description

COIL PIPE INJECTOR WITH INTEGRATED HIV COMPENSATION AND PROCEDURE FOR COIL PIPE HIV COMPENSATION

The invention relates to a coiled pipe injector which comprises an injector head provided with propellants arranged to displace a coiled pipe in the axial direction of the coiled pipe, and a control unit which is connected to the propellants and which, by means of a first set of control signals, is arranged to be able to control the propellant's axial displacement of the coiled pipe. The invention also relates to a procedure for simultaneous axial displacement of a coiled pipe relative to an underwater well and heave compensation relative to the heave movement of a floating installation.

When coiled pipe operations are carried out on subsea wells from a floating installation, the so-called coiled pipe injector with associated components (blowout protection, gaskets, etc.) must be heave compensated by the coiled pipe injector being placed in a frame that is suspended in a heave compensation system, for example by said frame being suspended in a heave-compensated top-driven drilling machine or a heave-compensated hoist block, possibly that said frame is equipped with an integrated heave compensation system that compensates for the floating installation's vertical movements.

A disadvantage of heave compensation of coiled pipe injectors according to prior art is that relatively tall structures are required to provide vertical guideways, for example in a tower, and this implies that relatively large structures are in vertical movement in relation to the floating installation, and it is required relatively much energy to the constantly changing direction of movement and the speed change that the coiled pipe injector must apply so that the vertical movement of the floating installation is not transferred to the part of the coiled pipe located in or at the wellhead or in the subsea well.

The purpose of the invention is to remedy or to reduce at least one of the disadvantages of known technology, or at least to provide a useful alternative to known technology.

The purpose is achieved by the features indicated in the description below and in the subsequent patent claims.

The invention provides a surface unit for coiled pipe operations in connection with a subsea well where an injector head of a coiled pipe injector in a manner known per se comprises several propellants comprising one or more drive motors which are coupled to drive devices which are arranged to abut against a coiled pipe in order to displacing the coil tube in its axial direction through the coil tube injector. The drive devices can be wheels, rollers, chains with gripping blocks, etc. according to per se known technology. The coiled pipe injector also includes, in a manner known per se, additional equipment that is required to carry out a coiled pipe operation in a regulated and safe manner, typically in that the coiled pipe injector is provided with a gooseneck that guides the coiled pipe from a coil that is connected to the coiled pipe injector, and into the injector head, strippers that close tightly around the coil tubing and form active pressure barriers between the injector head and the well, and one or more blowout preventers. A drive unit is connected to the coiled pipe injector for the supply of electrical energy, pressure fluid, etc. for the operation of motors and actuators. Finally, a control unit is connected to the coiled pipe injector for monitoring and controlling the coiled pipe operation.

The coiled pipe injector is supported on a suitable structure on the floating installation from which the coiled pipe operation is carried out. Said structure is typically a deck, for example a well deck or a drilling deck, the coiled pipe injector being positioned so that the central axis of the coiled pipe injector is arranged over a production pipe, a marine riser or an opening in said deck.

In order to provide an active heave compensation, means are connected to the control unit which register the vertical movements of the floating installation (heave movement) and generate control signals for heave compensation means connected to the coil pipe injector.

The active heave compensation can be combined with passive heave compensation of a suitable type to relieve a tool that is to be landed in or at the well, for example by connecting one or more hydraulic accumulators to the heave compensation means. Active and passive hiv compensation can preferably be operated independently of each other.

In one embodiment, the heave compensation means are arranged to vertically displace the entire coiled pipe injector in counterphase with the floating installation's heave movement, typically in the form of a platform carrying the coiled pipe injector, the platform hanging from or resting on one or more heave compensating cylinders.

Alternatively, the lift compensating means can be made up of the drive motors in the coil pipe injector, as the drive motors can thus displace the coil pipe in counterphase with the vertical movement of the floating installation. In this embodiment, these control signals for compensating the lifting movement can be superimposed on the control signals for the ordinary vertical displacement of the coiled pipe when driving the coiled pipe into or out of the well. Thus, the injector head can displace the coiled pipe in relation to the well and at the same time ensure that the coiled pipe is heave compensated by the floating installation's vertical movement in relation to the well being equalised.

Alternatively, the active heave compensation can be provided as a constant tension control (constant tension control), i.e. the coil tube injector's heave compensating means are set to maintain a constant tension of a prescribed order of magnitude in the coil tube.

The invention is defined by the independent patent claims. The independent claims define advantageous embodiments of the invention.

In a first aspect, the invention relates more specifically to a coiled pipe injector comprising an injector head provided with propellants arranged to displace a coiled pipe in the axial direction of the coiled pipe, and

a control unit which is connected to the propellants and by means of a first set of control signals is arranged to be able to control the propellants' axial displacement of the coil tube, characterized in that

the injector head is supported by a heave compensator which forms a connection between a substrate formed on a floating installation, and the injector head, and the heave compensator is provided with one or more heave compensating cylinders which are arranged to generate a heave-compensated vertical movement of the injector head.

The lift compensation cylinders can be connected to a drive unit,

a heave detection unit which is arranged to be able to register a vertical movement of a floating installation supporting the coiled pipe injector, may be associated with the control unit and may be arranged to be able to generate a second control signal set, and the control unit may be associated with the drive unit and is by means of the second control signal set arranged to be able to control the heave compensation cylinders' displacement of the heave compensator in order to thereby be able to generate an active heave compensated vertical movement of the injector head independently of the first set of control signals.

The HIV registration unit can be a motion reference unit (Motion Reference Unit) arranged on the floating installation.

The heave registration unit can alternatively be a unit designed to measure an axial stretch in the coil tube.

A coiled pipe which can be arranged on the injector head can be provided with heave compensating means.

The coil piping can be provided with passive heave compensating means. Alternatively, the coil piping may be provided with active heave compensating means arranged to be regulated by means of the second control signal set.

The heave compensator's heave compensating cylinders may be connected to a platform adapted to support the injector head.

In a second aspect, the invention relates more specifically to a method for heave compensation of a coiled pipe during a coiled pipe operation in a subsea well carried out from a floating installation, where the method comprises the following steps:

- to provide a coiled pipe injector according to the first aspect of the invention,

- to provide a first control signal set to generate an axial displacement of the coil pipe relative to the well by means of the propellants arranged in the injector head,

by means of a heave detection unit to provide a second control signal set, characterized in that the method comprises the further step:

- controlling the displacement of the lift compensating cylinders by the lift compensator by means of the second signal control set to generate a lift compensated vertical movement of the injector head independently of the first control signal set.

The motion registration unit can be a motion reference unit (Motion Reference Unit) associated with the floating installation's control systems. Alternatively, the heave detection unit can measure an axial stretch in the coil tube.

The method may include the further step

- displacing a coiled conduit arranged on the injector head, by means of heave compensating means in step with the heave compensating vertical displacement of the injector head generated by means of the heave compensator.

The displacement of the coil piping can be provided as a passive heave compensation of the coil piping. Alternatively, the displacement of the coiled pipe routing can be provided as an active heave compensation of the coiled pipe routing, the displacement being regulated by means of the second set of control signals.

In a third aspect, the invention relates more specifically to a coiled pipe injector comprising an injector head provided with propellants comprising at least one drive motor arranged to displace a coiled pipe in the axial direction of the coiled pipe, and

a control unit which is connected to the at least one drive motor and by means of a first control signal set is arranged to be able to control the at least one drive motor's axial displacement of the coil tube,

characterized by that

a heave detection unit which is arranged to be able to register a vertical movement of a floating installation supporting the coiled pipe injector, is connected to the control unit and is arranged to be able to generate a second set of control signals for the at least one drive motor to thereby be able to generate a heave compensated axial displacement of the coiled pipe independently of the first control signal set.

The HIV registration unit can be a motion reference unit (Motion Reference Unit) arranged on a floating installation that supports the coiled pipe injector.

The heave registration unit can be a unit designed for measuring an axial stretch in the coil tube.

A coiled pipe which is arranged on the injector head can be provided with a heave compensator. The hiv compensator may be passive, or it may be active, arranged to be regulated by means of the second set of control signals.

In a fourth aspect, the invention relates more specifically to a method for heave compensation of a coiled pipe during a coiled pipe operation in a subsea well carried out from a floating installation, where the method comprises the following steps:

- to provide a coiled pipe injector according to the first aspect of the invention,

- to provide a first control signal set to generate an axial displacement of the coiled pipe relative to the subsea well by means of the propellants arranged in the injector head,

by means of a heave detection unit to provide a second control signal set to generate an axial displacement of the coil tube relative to the floating installation to thereby compensate for the heave movement of the floating installation, characterized in that the method comprises the following step:

- to control the propellants in the injector head by means of a combination of the first control signal set and the second signal control set, the first control signal set for axial displacement of the coil pipe relative to the subsea well being superimposed on the second signal control set for compensating the floating installation's heave movement.

The motion registration unit can be a motion reference unit (Motion Reference Unit) associated with the floating installation's control systems.

The heave registration unit can alternatively measure an axial stretch in the coil tube.

The method may comprise the further step of displacing a coil pipe guide which is arranged on the injector head, by means of a heave compensator in step with a heave compensating axial displacement of the coil pipe generated by means of the driving means arranged in the injector head.

The displacement of the coil piping can be provided as a passive heave compensation of the coil piping, i.e. by the coil piping being, for example, resiliently supported in the injector head. Alternatively, the displacement of the coil piping can be provided as an active heave compensation of the coil piping, the displacement being regulated by means of one or more actuators which are regulated by means of the second set of control signals.

In the following, examples of preferred embodiments are described which are illustrated in the accompanying drawings, where:

Fig. 1 shows in a partially cut side view a first embodiment of a coiled pipe injector according to the invention in a configuration with a marine riser;

Fig. 2 shows in a partially cut-away side view the first embodiment of the coil pipe injector according to the invention in a riser-less configuration;

Fig. 3 shows an example of speed curves for a coiled pipe, with curve I showing the speed at which the coiled pipe is displaced during entry into and withdrawal from a well, curve II showing the speed at which the coiled pipe must be displaced to cancel a heaving movement for the floating installation, and curve I+II shows a resulting speed for simultaneous coil tube driving and heave compensation with the coil tube injector according to the first embodiment in that curve II is superimposed on curve I; and

Fig. 4 shows a partially cross-sectional side view of a second embodiment of a coil pipe injector according to the invention in a configuration with a marine riser pipe.

Reference is first made to figure 1, where the reference number 1 denotes a coiled pipe injector comprising an injector head 13 of known design in and of itself, where drive means comprising at least one drive motor 131 connected to drive devices 132 are arranged to rest against a coiled pipe 4 which, by means of the coiled pipe injector 1 is to be driven into or pulled out of an underwater well 6. The drive devices 132 are only shown here in principle. On top of the injector head 13, a gooseneck-shaped coiled pipe guide 12 is arranged. Below

the injector head

13, there are arranged active pressure barriers in the form of strippers 14 which close tightly around the periphery of the coil tube 4. The coiled pipe injector 1 is further provided with a blowout protection 15, and is connected to a surface well head (flow head) 16 where well fluid can flow out of or into a well pipe 31, for example a production pipe which in a fluid communicating manner connects the well 6 and a floating installation 3, here shown schematically and in section as a support structure or a deck. The well pipe 31 is arranged in a marine riser 32 which extends through a body of water 7 between the well 6 and the floating installation 3.

The coil pipe 4 is stored on a coil pipe spool 5 which is arranged on the floating installation 3 near the coil pipe injector 1.

The coiled pipe injector 1 is connected to a drive unit 2 which is designed to supply the coiled pipe injector 1 and possibly the coiled pipe coil 4 with electric current, pressure fluids, etc. for operation of motors, actuators, activation of seals, etc.

The coiled pipe injector 1 is provided with a control unit 133 arranged to generate a first set I of control signals for maneuvering the coiled pipe injector 1 so that the coiled pipe 4 is displaced axially at a prescribed speed and direction relative to the well 6. To the control unit 133 is connected a heave registration unit 1331 arranged to generation of a second set II of control signals for, by means of the injector head 13 drive means 131, 132, to give the coil pipe 4 an axial displacement in counterphase with a vertical movement of the coil pipe injector 1 caused by the heaving movements of the floating installation 3 caused by waves, currents in the water masses, changes in the floating installation's load, etc., thereby, by active heave compensation, to eliminate the impact of the heave movement on the axial movement of the coil pipe 4 in relation to the well 6.

To take up slack in the coil tube 4 caused by the heave compensation, the coil tube guide 12 may be provided with separate heave compensating means 121 formed as a vertically telescoping attachment connecting the coil tube guide 12 and the underlying injector head 13. The heave compensating means 121 may be passive, formed as a spring suspension, or active in that it includes means which, based on said second set II of control signals, displaces the coil pipe guide 12 in relation to the injector head 13 in order thereby to maintain support for the coil pipe 4 in all phases of the coil pipe run.

The HIV registration unit 1331 which is connected to the control unit 133 can be a separate unit or it can be a so-called motion reference unit (Motion Reference Unit (MRU)) which is connected to the floating installation's 3 control systems.

Figure 2 shows a riserless configuration where the coil pipe 4 extends through the water mass 7 between the floating installation 3 and a loose mass 8 below the water mass 7 in an initial drilling operation, for example drilling a pilot hole in the loose mass 8 using drilling equipment (not shown) associated with the coil pipe 4. In this configuration, the coiled pipe injector 1 is shown without blowout protection and surface wellhead, but is otherwise provided with or associated with the same elements as described above in connection with the description of the configuration shown in figure 1.

Figure 3 shows an example of axial displacement rate v as a function of time t for prescribed speed of a coiled pipe when driving into and out of a well (short dashed curve I), a required axial displacement rate (dashed/dotted curve II) for to cancel the vertical heave movement, and a resulting speed curve (solid curve I+II) for the prescribed coil tube travel speed to be achieved while the coil tube is heave compensated.

Reference is then made to Figure 4, which shows a second exemplary embodiment of the invention. The injector head 13 is supported by a heave compensator 134 which is supported by the support structure 3, the injector head 13 being supported by an arrangement which here comprises several heave compensation cylinders 1342 that extend between the injector head 13 and a base 33, here shown as a frame that rests on the support structure 3. The injector head 13 is shown here arranged on a platform 1341 which forms a transition between the injector head 13 and the heave compensation cylinders 1342. This can be advantageous as no technical adaptation of the injector head 13 is then required in order for it to be able to cooperate with the heave compensator 134. The heave compensator 134 is provided with stabilizer means, here schematically shown as a telescoping guide 1343 which extends between the injector head 13 and the substrate 33.

Alternatively, the injector head 13 can hang in the heave compensation cylinders 1342 which extend downwards from a frame 33 which in this embodiment, not shown, rises sufficiently far up from the support structure 3, typically to a level above the top of the injector head 13.

In the embodiment according to Figure 4, the control unit 133 is arranged to regulate the heave compensation cylinders 1342 so that the injector head 13 is compensated for heave by means of the heave compensator 134, the second set II of control signals generated by the heave registration unit 1331 which is connected to the control unit 133 is used in the control unit 133 to regulate the heave compensator's 134 heave compensation cylinders 1342 by means of the drive unit 2 so that the injector head 13 is given an axial displacement in counterphase with the heave movements of the floating installation 3 caused by waves, currents in the water masses, changes in the floating installation's load, etc., thereby, with active heave compensation, to eliminate the impact of the heaving movement on the axial movement of the coil tube 4 in relation to the well 6.

The design example according to figure 4 can also be used in a riser-less configuration similar to that shown in figure 2, where the coiled pipe 4 extends through the body of water 7 between the floating installation 3 and the loose mass 8 below the body of water 7 in an initial drilling operation, for example drilling a pilot hole in the loose mass 8 using drilling equipment (not shown) connected to the coil pipe 4.

The principle shown in Figure 4 and described above for heave compensation of a coiled pipe injector 1 can also be used in a so-called wireline operation in a well 6 carried out from a floating installation 3, where a wireline (cable) which is connected to a tool to be guided down into the well 6, can be led from a drum which is supported on the floating installation, and over a cable guide (for example a pulley) which is arranged on a heave compensator 134 of the type shown in Figure 4.

It should be noted that all of the above embodiments illustrate the invention, but do not limit it, and those skilled in the art will be able to devise many alternative embodiments without departing from the scope of the appended claims. In the requirements, reference numbers in parentheses should not be seen as limiting.

The use of the verb "to comprise" and its various forms does not exclude the presence of elements or steps not mentioned in the claims. The indefinite articles "an", "ei" or "et" before an element do not exclude the presence of several such elements.

The fact that certain features are listed in different mutually dependent claims does not indicate that a combination of these features cannot be advantageously used.

Claims (14)

Patent claims 1. Coil tube injector (1) comprising an injector head (13) provided with drive means (131, 132) arranged to displace a coil tube (13) in the axial direction of the coil tube (13), and a control unit (133) which is connected to the propellants (131, 132) and by means of a first control signal set (I) is arranged to be able to control the axial displacement of the propellants (131, 132) of the coil tube (4), c a r a c t e r i s e r t w e d that the injector head (13) is supported by a heave compensator (134) which forms a connection between a substrate (33) formed on a floating installation (3) and the injector head (13), and the heave compensator (134) is provided with one or more heave compensation cylinders (1342) which are arranged to generate a heave-compensated vertical movement of the injector head (13). 2. Coiled pipe injector (1) according to claim 1, where the heave compensation cylinders (1342) are associated with a drive unit (2), a heave registration unit (1331) which is arranged to be able to register a vertical movement of a floating installation (3) which supports the coiled pipe injector (1), is associated with the control unit (133) and is arranged to be able to generate a second control signal set (II), and the control unit (133) is connected to the drive unit (2) and with the help of the second control signal set (II) is arranged to be able to control the displacement of the heave compensation cylinders (1342) of the heave compensator (134) in order to thereby be able to generate an active heave compensated vertical movement of the injector head (13 ) independently of the first control signal set (I). 3. Coiled pipe injector (1) according to claim 2, where the lift registration unit (1331) is a motion reference unit (Motion Reference Unit) arranged on the floating installation (3). 4. Coiled pipe injector (1) according to claim 2, where the heave registration unit (1331) is a unit designed for measuring an axial stretch in the coiled pipe (13). 5. Coiled pipe injector (1) according to claim 2, where a coiled pipe guide (12) which is arranged on the injector head (13) is provided with lift compensating means (121). 6. Coiled pipe injector (1) according to claim 5, where the coiled pipe guide (12) is provided with passive heave compensating means (121). 7. Coil pipe injector (1) according to claim 5, where the coil pipe guide (12) is provided with active heave compensating means (121) designed to be regulated by means of the second control signal set (II). 8. Coiled pipe injector (1) according to claim 1, where the heave compensator's (134) heave compensation cylinders (1342) are connected to a platform (1341) arranged to support the injector head (13). 9. Procedure for heave compensation of a coiled pipe (4) during a coiled pipe operation in a subsea well (6) carried out from a floating installation (3), where the procedure includes the following steps: - to provide a coiled pipe injector (1) according to claim 1, - to provide a first control signal set (I) to generate an axial displacement of the coil tube (4) relative to the well (6) by means of the driving means (131, 132) arranged in the injector head (13), by means of a heave detection unit (1331) to provide a second control signal set (II), characterized in that the procedure includes the further step: - to control the displacement of the heave compensating cylinders (1342) of the heave compensator (134) by means of the second signal control set (II) to generate a heave compensated vertical movement of the injector head (13) independently of the first control signal set (I). 10. Method according to claim 9, where the heave registration unit (1331) is a motion reference unit (Motion Reference Unit) associated with the floating installation's (3) control systems. 11. Method according to claim 9, where the heave registration unit (1331) measures an axial stretch in the coil tube (13). 12. Method according to claim 9, wherein the method comprises the further step - displacing a coil pipe guide (12) which is arranged on the injector head (13), by means of heave compensating means (121) in time with the heave compensating vertical displacement of the injector head (13) generated by means of the heave compensator (134). 13. Method according to claim 9, where the displacement of the coil pipe guide (12) is provided as a passive heave compensation of the coil pipe guide (12). 14. Method according to claim 9, where the displacement of the coil pipe guide (12) is provided as an active heave compensation of the coil pipe guide (12), the displacement being regulated by means of the second control signal set (II).