GB2512885A

GB2512885A - Method and apparatus for repositioning and controlling an underwater riser from a structure on the surface

Info

Publication number: GB2512885A
Application number: GB201306473A
Authority: GB
Inventors: Martin Klaus Alios Isolde Horn
Original assignee: Individual
Current assignee: Individual
Priority date: 2013-04-10
Filing date: 2013-04-10
Publication date: 2014-10-15
Anticipated expiration: 2033-04-10
Also published as: GB2512885B; GB201306473D0

Abstract

A system and method for raising and controlling a riser joint 70 from a surface structure; said system comprising: an internal profile 74, preformed in, or to be fitted into, a riser joint 70; and a tool 20 comprising: means 22 for engaging said tool 20 with said internal profile, 74of said riser joint, wherein the means for engaging said tool 20 with said internal profile transfers an axial load to said internal profile such that, in use; the tool 20 can raise the riser joint 70. The means 22 for engaging the profile 74 may be arms located on a tool head 21and the profile may include a series of grooves 71 - 73. The method involves lowering the tool 20 via a hoisting system to the riser joint, engaging the riser joint with the internal profile 74, transferring an axial load to the internal profile and raising the riser with the tool.

Description

METhOD AND APPARATUS FOR REPOSITIONING AND CONTROLLING AN

UNDERWATER RISER FROM A STRUCTURE ON THE SURFACE

FIELD OF INVENTION

The present invention relates to a method and to an apparatus for facilitating the repositioning and control of an underwater riser coming from the seabed to a structure located at the sea surface.

BACKGROUND OF ThE INVENTION

The object of the present invention Is to provide an apparatus arid a method for using the apparatus, which enables marine risers coming from the sea bed to be connected to and controlled directly from the receiving structure located at the sea surface.

The present invention is for use in subsea or marine drilling installations such as oil rigs, particulaily off-shore or floating oil rigs.

OIl rigs are generally located above the sea bed where sources of oil or other resources have been located, to enable drilling to those sources and recovery of the resource.

The sea bed source or well is accessed from the rig above the surface of the water by means of a line or conduit known as a riser coming up from the sea bed to the rig.

The risers extend from the well head on the sea bed up to the rIgs to allow access From the rig to the well for tools, etc., cameras, and also for supplying drillIng fluid which can then be circulated back to the tig.

In the case of a floating rig, a slip joint Is generally provided where the riser line is attached to the rig, to compensate for the relative movement or heave between the floating rig and the riser fixedly connected to the well head. A conventional slip joint is a telescopic joint comprising an outer barrel and an inner barrel, with a pressure seal therebetween.

Usually, a diverter Is connected between the top inner barrel of the slip Joint and the rig to control gas accumulations in the riser or low pressure formation gas and preventing this from venting to the floor of the rig.

The last of the riser joints, closest to the seabed, Is attached to a tower marine riser package (LMRP), the bottom of which connects to the blow-out preventer (BOP), the bottom of which connects to the well head on the seafloor.

in typical subsea drilling arrangements, floating structures are used to install and receive facilities at a desired oil site. As Is known in the field, lines extend from the sea bed to convey materials associated with subsea oil sites, such as drilling work strings, hydraulic lines, electric cable, or a combination of these, for example. These lines are known to specialists in the field as "risers". The risers extend from the sea bed to what Is known as a slip jolnr, which allows for a connection to the oil rig underneath the rig floor at what is known as a dlverter" in

the field.

A problem associated with the floating structures and risers discussed above is that, when the weather becomes too severe, the oil rig motion can cause the slip joint to collide with the diverter, which can cause damage to the arrangement To avoid damage, the floating structure and risers disconnect from a 26 blow-out preventer (BOP) located on the sea bed and are lifted away from the seabed. The risers are then disconnected from the BOP until the weather conditions improve.

Current methods of disconnecting the risers from the SOP require that a riser be kept on the deck of the floating structure surface to facilitate picking up the riser olnts by being connected to the slip joint. The riser kept on the deck is known as the landing joint". The slip joint is then collapsed and locked manually by workers on the oil rig or by hydraulic functions located within the slip joint. The risers below the landing Joint are then controlled by a hoisting system located on the floating structure surface. Once the weather has improved to a sale climate, the operation of the oil rig is resumed by reversing these steps to re-latch the risers to the oil welt.

Similarly, it is sometimes necessary to relocate the risers and the BOP to a different welihead. Conventionally, a similar hoIsting procedure is used.

The above operations have associated risks, such as lifting of the heavy equipment by manual labour, failure of hydraubo systems which then need to be repaired by engineers, the health and safety Implications of workers swinging out on harnesses to manually lock the slip joint, having a bulky "landing joint" on the deck of the oil rig, and the time required to carry out the operation Is considerably high (sometimes between 12-14 hours). It Is therefore an object of the present invention to provide an apparatus and a method of using the apparatus to overcome these shortfalls.

WO 98123845 relates to an apparatus and method for facilitating the connection of underwater flexible risers comIng from the sea bed and arranging for the riser to be raised by a single cable. However, WO 98/23845 describes a locking system that may also prove to be a problem if they are faulty or need repair.

For example, if the mechanical locking mechanisms raft, an engineer would still be required to be harnessed to the oil rig and lowered to the joints to repair the locking feature. Also, the risers require significant alteration for the locking mechanism to fit the riser joint. It is therefore an object of the present Invention to provide a more efficient and reliable way for the riser to be raised from the oil well.

SUMMARY OF THE INVENTION

In one aspect of the present invention, there Is provided a system for raising and controlling a riser joint from a surface structure, said system comprising: an internal profile preformed In, or to be fitted Into, a riser joint; and a tool, said tool comprisIng: means (or engaging said tool with said internal profile of said riser joint, wherein the means for engaging said tool with said internal profile transrers an axial load to said internal profile such that, in use, the tool can raise the riser joint. -4..

In a preferred form, the means for engaging the tool with the internal profile includes arms that protrude radially from the tool These arms can then be engaged with the internal profile by the user. In a preferred aspect, the tool includes an elongate tool body having a tool head attached thereto. In a preferred form, the arms are located on the toot head. Preferably, the tool body can take forms such as a cuboid, hexagonal prism, an oval or elliptical cylinder, or a triangular prism, but is preferably cylindrical, and most preferably circular cylindrical.

In a preferred form, the tool head may take forms such as a cuboid, hexagonal prism, an oval or elliptical cylinder, or a triangular prism, but is preferably cylindrical, and most preferably circular cylindrical.

Preferably, the tool head has a greater diameter than the tool body.

In a preferred embodIment, The arms protrude from the tool head by less than or equal lo 20 cm. In a preferred form, the arms have a dIameter of between 5-20 cm, and most preferably the diameter of the arms is 12.7 cm.

In a preferred aspect, the tool is made of steel.

In a preferred form, the tool head includes radial holes to receive the arms. In this aspect, the arms can be inserted into the radial holes of the tool head.

Preferably, the number of radial holes included on the tool head is one or more. In a preferred form, the radial holes are in a symmetrical arrangement around the tool head. Alternatively, the radial holes are in an arranged asymmetrically around the tool head.

In a preferred embodiment, the internal profile comprises a first groove extending from a first open end to a second end; a second groove extending from a second end to a third closed end; a third groove extending between the first groove and the second groove. This allows for the tool to be engaged and lowered into the first groove, passed down the first groove, rotated through the third groove and then lifted up through the second groove to the third dosed end. The riser Joint can then be lifted by transferring an axial load to the internal proflle and lifting the tool.

In a preferred embodiment, the internal profile is manufactured into the riser joint. In an alternative preferred embodiment, the internal profile Is a preformed profile that can be inserted into the riser Joint.

In a preferred torni, the first open end of the internal profile has a chamfered portion. The chamfered portion acts as a guide to easily lower the tool into the first groove of the internal profile.

In another aspect of the present invention, there is provided a method For raising and controlling a riser joint from a surface structure, said method comprising: lowering a tool via a hoisting system to an Internal profile preformed In, or fitted into, the riser joint; engaging said tool with the internal profile of the riser joint; transferring an axial load to the Internal profile: raising said riser joint with said tool.

In a preferred embodiment, the tool Is engaged with the internal profile by arms located on the tool that protrude radially from the tool.

In a preferred embodiment, the tool Is lowered into the internal profile through a first open end to engage with a first groove; and lowering the tool through the first groove to a second end; rotatIng the tool through a third groove to engage with a second groove; lifting the tool from a second end through the second groove to a closed third end and raising the riser joint by raising the tool via a hoisting system located on the surface structure.

Exemplary embodiments of the present invention will now be described, by way of example only, with reference to the figures.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 shows a typical subsea drilling arrangement when connected to an oil well located at an oil site on the sea bed.

Figure 2 shows an enlarged view of a slip joint used In the typical subsea drilling arrangement of Figure 1.

Figure 3 shows a toot in accordance with an embodiment of the present Invention, Figure 4 shows a view of a head of the tool shown in Figure 3.

Figure 4a shows a plan view of a head of the tool shown in Figure 3 Figure 5 shows an isometric view of a head of the tool shown in Figure 3.

Figure 6 shows an alternative embodiment of a head of the tool shown in Figure 3.

Figure ea shows a plan view of an alternative embodiment of the head of the tool shown in Figure 3.

Figure 7 shows a riser joint including a profile in accordance with the present invention.

Figure 8 shows an expanded profile that can be inserted into a riser Joint in accordance with an embodiment of the present Invention.

Figure 9 shows a riser Joint including a profile In accordance with the present Invention.

DETAILED DESCRIPTiON OF THE INVENTION

Generally, an apparatus and a method for using the apparatus, which enables knes coming from the sea bed to be repositioned and controlled directly from the receiving structure located at the sea surface is disclosed, A typical subsea drifting arrangement is shown in Figure 1. As is known in the field of subsea drilling, the arrangement has a blow-out preventer I which connects to a welihead (not shown) located on the sea floor. The blow-out preventer (GOP) lie used to seal, monitor and control oil and gas wells located at a sea floor. A lower marine riser package (LMRP) 2 connects to the blow-out preventer 1 in order to form a conduit between the LMRP and the BOP. As is Known In the field, risers 6 extend from the LMRP and SOP, which provides a conduit to convey materials associated with subsea oIl sItes, such as drilling work strings, tools, hydraulic lines, electric cable, fluids to be circulated, or a combination of these, for example. The risers 6 extend from the LMRP 2 to a slip joint 10 which connects to a diverter 12 located on the floor of an oil rIg 5. The risers 6 are then in connection with the oil rigS via the diverter 12. This arrangement then allows for well activities to take place through the connection of the BOP 1, the LMRP 2, the risers 8, the slip joint 10 and diverter 12.

Figure 2 shows an enlarged view of the slip joint 10 shown in Figure 1. The sUp joint 10 has a first end 18 and a second end 17. A dlverter 12 Is located at the first end 16 and a slip joint outer barrel 14 is located at the second end 17 with a slip joint inner barrel 13 located between the slip Joint outer barrel 14 and the diverter 12. Riser tension cables 11 are attached to the slip joint outer barrel 14. A flange 15 Is located at the bottom of the slip joint outer barrel 14 to fixedly attach to a first riser 6 (shown in Fig 1).

The slip Joint outer barrel 14, when attached to a riser 6, does not move relative to the sea floor. The slip joint inner barrel 13 telescopes with the tig motion sliding up and down within the slip joint outer barrel 14. Riser tension cables 11 * In use, keep tension on the slip joint outer barrel 14 and risers 6 (when the slip joint outer barrel 14 is fixedly attached to a first riser 6) to prevent buckling of the components. This arrangement allows the oil rig 5 to move relative to any wave motion from the sea, whilst keeping the slip joint outer barrel 14 and risers 6 free from movement. In circumstances when the weather becomes too severe to provide a safe operation of this arrangement, It is necessary to detach the L.MRP 2 and risers 8 from the GOP I as the motion from the oIl rIg 5 may cause collisions between the slip joint outer barrel 14 and the diverter 12, which may cause signifIcant damage.

The current methods used to detach the LMRP 2 and risers 6 from the SOP us flOW described. When it is noted that the weather is becoming too severe such that the motion of the oil rig 5 will cause the slip joint outer barrel 14 to collide with the diverter 12, the following steps are undertaken: extra tension is applied to the riser tension cables 11; a valve located in the SOP I is closed to shut an oil well; the LMRP 2 is disconnected from the SOP I the oil rig 5 is then moved away from the GOP -for example in the directIon indicated by arrow 3.

The following sequence of activities are performed to re-attach the LMRP2to the SOP 1: the diverter 12 Is removed so that the slip joInt inner barrel 13 can be accessed from the floor of the oil rIg 5; -a landing riser joint (riot shown) Is connected to the slip joint Inner barrel 13; the slip joint inner barrel 13 is then coliapsed into the slip joint outer barrel 14-i.e., the slip joint inner barrel 13 is entirely concealed in the slip joint outer barrel 14; the slip joint 10, in a collapsed state, Is then locked by a) workers of the oil rIg 5 swinging out on harnesses to bolt together the sUp joint Inner barrel 13 and the slip joint outer barrel 14, or by b) hydraulics; -a hoisting system (not shown) then raises the risers 6 and the LMRP 2 in the direction Indicated by armw 4; the oil rIg 5 with the suspended Riser/LMRP is then moved back over the wellhead to lower the LMRP onto the BOP and re-latch.

The method described above cart be time consuming due to the necessary step of providing workers from the oil rig 5 to bolt together the slip joint inner barrel 13 to the slip joint inner barrel 14 to lock the slip joInt 10 in a collapsed state. The time necessary for this step alone can be in the region of 2-4 hours.

Further, the use of hydraulics does not always lead to an efficient method of locking .9-the slip joint 10. if the hydraulics fail, it Is necessary for workers from the oil rIg 5 to "harness up" and swing from the oil rig floor to the hydraulic parts In order to perform a repair. This also can be time consuming. It Is therefore an object of the present invention to reduce the amount of time, and necessary workers, needed and to perform a more efficient and safe way of raising the LMRP 2 and the risers 8 from the BOP 1.

The present invention provides a method and an apparatus for facilitating the connection and control of an underwater riser coming from the seabed to a structure located at the sea surface.

As shown in Figure 3, there is provided a tool 20 in accordance with an embodiment of the present invention. The tool body 24 extends from a first end 24 to a second end 25. In a preferred embodiment, the tool body 24 Is cylindrical and can be circular cylindrical as shown in Fig. 3. The tool body 24 can take forms such as, but not exclusive to, a cuboid, a hexagonal prism, an oval or elliptical cylinder, or a triangular prism.

The tool body 24 may have a handling joint 23 located at a first end 24 or the shaft 20 to assist the user to handle the tool, In use. The handling joInt 23 Is. in a preferred embodiment, cylindrical and, as shown In FIg. 3, can be of a circular cylindrical nature. The handling joint 23 can take forms such as, but not exclusive to, a cubold, a hexagonal prism, an oval or elliptical cylinder, or a triangular prism. The handling joint 23, in a preferred embodiment, has a greater diameter than the tool body 24 to provide an increased torque on rotation. The handling joint 23 may, however, have a diameter that Is equal to, or less than, the tool body 24.

The handling joint 23 may also be a standard handling unit that is used throughout the oil industry. The handling joint 23 may receive the tool body 24 so that the user can move and rotate the shaft 20.

At the second end 25 of the tool body 24 is provided a tool head 21.

The tool head 21 is, in a preferred embodiment, cylindrical and, as shown in Fig. 3, can be of a circular cylindrical nature. The tool head 21 can take forms such as, but not exclusive to, a cuboid, a hexagonal prism, an oval or elliptical cylinder, or a triangular prism. The tool head 21, in a preferred embodiment, has a greater diameter than the tool body 24. The tool head 21 may, however, have a diameter that is equal to, or less than, the tool body 24.

The tool head 21 is configured to be inserted into a standard riser and to engage with the Interior of the wiser.

As mentioned above, the tool body 24 may be Inserted into a standard handling JoInt 23 so as to be controlled by the user. The tool body 24 and shaft 20 are not, therefore, limited to includIng a handling joint 23.

As shown in Fig. 3, the tool head 21 may include radial protrusions (or load arms) 22 for the engagement of the riser. The load arms 22 can be fixedly attached to the tool head 21, and preferably Inserted in to the tool head 21, or can be manufactured on to the tool head 21, for example, by moulding etc.. The load arms 22 shown in FIg. 3 are located on the tool head 21. However, the bad arms may be, in alternative arrangements, located on the tool body 24, or the handling joInt 23. Fig. 3 shows that the load arms 22 extend radially out from the tool head 21. In one embodiment, the load arms 22 may protrude from the tool head 21 by a range of between 0.1 -20 cm. The load arms 22 have a diameter of between 5-20 cm, and preferably the diameter of the load arms Is 12.7 cm.

In a preferred embodiment, the material of the tool body 24. handling joint 23, tool head 21 and load arms 22 is steel. Of course, the tool body 24, handling joint 23, tool head 21 and load arms 22 could be made of other grades of steel, such as X56, LCD, P110, 8135 or V150.

Figure 4 shows a view of the tool head 21 without the load arms 22.

The tool head 21 of FIg. 4 has radial holes 40 bored into a side 35 of the tool head 21. The radial holes 40 are sized and shaped to receive the load arms 22. In this arrangement, the load arms 22 are inserted into and secured in the tool head 21 to allow for a load, such as a user joInt as detailed below, to be lifted by the load arms 22, whIch protrude from the tool head 21. -11 -

Figure 4a shows a plan view of the tool head 21 without load arms 22. As shown in Fig 4a. the tool head 21 may include a plurality of radial holes 40 bored into the side 35 of the tool head 21. In the arrangement shown in Fig. 4a, there are preferably four radial holes 40 bored Into the tool head 21 in a symmetrical arrangement. However, the radial holes 40 may be positioned asymmetrically around the tool head 21 and the number of radial holes 40 provided in the tool head 21 may be one or more.

An isometric view of the tool head 21 is shown in Figure 5 before the load arms 22 are inserted Into the radial holes 40.

Figure 6 shows an alternative embodiment of the tool head 21 shown in Figure 3. Tool head 21, as shown in Fig. 6, is an elliptical cylinder that provides for elliptical movement of the tool head 21. The tool body 24 (shown in Fig. 3) extends from a point 211 (shown in Fig. 6) so as to provide the elliptical movement of the tool head 21'. An advantage of having elliptical movement is that a larger contact area is provided on the tool head 21' to engage with an internal riser profile 74 (as shown In Figure 7). In this embodiment, the riser profile 74 discussed below has a curvature that matches the tool head 21.

Figure 6a shows a further alternative embodiment of the tool head 21 shown in Figure 3. In this embodiment, the tool head 21" is a circular cylindrical shape. The tool body 24 (shown in Fig. 3) extends from the point 212, which is offset from the centre of the circular cylinder. This provides for an offset circular motion of the tool head 21". The advantage of having an offset circular motIon Is to prevent the tool head 21" from rotating around its central axis and potentially causing the tool head 21" to jam in an internal riser profile 74(as shown in Figure 7). In this embodiment, the riser profile 74 discussed below has a curvature that matches the tool head 21".

Figure? shows an orthographic view of a riser joint 70 having an internal profile 74. The Internal profile 74 may be provided in the riser Joint 10 as an insert (as described below and as shown in Fig. 8) or may be provided on the riser joint 70 during manufacture of the riser joInt 70. The internal profile 74 includes a first groove 71 extending from a first open end 77 to a second end 75 and a second groove 72 extending from the second end 75 to a third dosed end 76. The first groove 71 and the second groove 72 are connected by a third groove 73 that extends between the first groove 71 and the second groove 72. In a preferred embodiment, the first groove 71 and the second groove 72 are parallel to one another, and the thIrd groove 73 Is perpendicular to the first groove 71 and the second groove 72. The first groove 71, second groove 72 and third groove 73 are, preferably, sized and shaped to receive the load arms 22 (shown in Fig. 3) of the tool 20 (shown in Pig. 3). in a preferred embodIment, the first groove 71, second groove 72 and third groove 73 have the same width, and have a width matching, or greater than, the diameter of the load arms 22 (shown in FIg. 3). At the first open end 77, there is preferably provided a chamfered portion to guide the load arms 22 (shown In Fig. 3) into the first groove 71, In use.

Figure 8 shows a view of an expanded preformed internal profile 84 that may be used as an insert to fit into a rlserjoint 70 (as shown in Fig. 7). The internal profile 84 Includes a first groove 81 extending from a first open end 87 to a second end 85 and a second groove 82 extending from the second end 85 to a third closed end 86. The first groove 81 and the second groove 82 are connected by a third groove 83 that extends between the first groove 81 and the second groove 82. In a preferred embodiment, the first groove 81 and the second groove 82 are parallel to one another. The first groove 81, second groove 82 and third groove 83 are, preferably, sized and shaped to receive the load arms 22 (shown in FIg. 3) of the tool 20 (shown in 19g. 3). In a preferred embodIment, the first groove 81, second groove 82 and third groove 83 have the same width, and have a width matching, or greater than, the diameter of the load arms 22 (shown in Fig. 3). At the first open end 87, there is preferably provided a chamfered portion to guide the load arms 22 (shown in Fig. 3) Into the first groove 81, In use. It is envisaged that the internal profile 84 can be closed to match the Inner circular dimension of the riser Joint 70 (shown in Ag. 7) so as to act as a removable inner profile in the riser JoInt 70.

Of course, other arrangements may be provided on the tool head (21) to engage the tool (20) with an internal profile (74, 84). Such arrangements can include: but are not exclusive to. a lIp, a flange or any other coupling arrangement.

-13*-A method of engaging the tool 20 (shown in Fig. 3) with an internal profile 74, 84 (as shown in Figs 7 and 8) Is now described. The tool 20 can be lowered from an oil rig surface (not shown) to a riser Joint 70 vIa a conventional hoisting system located on the surface of the oil rig (not shown). The tool 20 is lowered such that the tool head 21 and load arms 22 are guided into the first open end 77, 87 (shown in Fig. 9). The tool 20 is then lowered through the first groove 713 81 in a direction of the arrow 92 shown in Fig. 9. The tool 20 is lowered to the second end 75, 85 (shown In FIgs. 7 and 8) and is then rotated so that the load arms 22 move through a third groove 73, 83 (shown in Figs. 7 and 8)80 as to be introduced into the second groove 72, 82 (shown in FIgs. 7 and 8). The tool 20 is then raised via a hoisting system (not shown) such that the load arms 22 move in a direction or the arrow 94 shown in Fig. 9. The load arms 22 engage with the third dosed end 76, 86. The axial load from the hoisting motor (not shown) is then transferred, via the tool 20, into the internal profile 74, 84 ci the riser Joint 70. This allows for the riser joint to then be lifted and controlled through the hoisting system (not shown). To remove the tool 20, the method described herein is then reversed.

The above method allows risers 6 (as shown iii Fig. 1)1 which are, for example, connected to the riser Joint (70), to be raIsed via tool 20 and riser joInt 70 without the need for heavy lifting or manual labour. The method described above can also reduce the time needed for raising the risers 6 by providing a tool 20 to engage with an internal profile 74, 84 of a riser joint 70.

Although the invention has been described in terms of preferred embodiments as set forth above, It should be understood that these embodiments are illustrative only and that the claims are not limited to those embodiments.

Those skilled in the art will be able to make modilications and alternatives in view of the disclosure which are contemplated as falling within the scope of the appended claims.

Claims

CLAIMS1, A system for raising and controlling a riser Joint (70) from a surface structure, said system comprising: an Internal profile (74, 84) preformed in, or to be fitted into, a riser joint (70); and a tool (20), saId tool comprising: means (22) for engaging said tool (20) with said internal profile (74,84) of said riser joint (70), wherein the means for engaging said tool (20) wIth said internal profile (74, 84) transfers an axial load to said internal profile (74, 84) such that In use, the tool (20) can raise the riser joint (70).
2. The system of claim I wherein the means for engaging said tool (20) with said internal profile (74, 84) includes arms (22) that protrude radially from said tool (20).
3. The system or claim 2 wherein the tool (20) includes an elongate tool body (24) having a tool head (21) attached thereto.
4. The system of claIm 3 whereIn the arms (22) are located on the tool head (21).
5. The system of any preceding claim wherein the tool (20) is a circular cylinder; 6. The system of any preceding claim wherein the tool (20) is made of steel 7. The system of claIm 4 wherein the arms protrude from the tool head (21) by less than or equal to 20 cm.8. The system of claim 4 whereIn the tool head (21) has a greater diameter than the tool body (24).9. The system of claim 3 wherein the tool head (21) includes radial holes (44) for receiving the arms (22).10. The system of claim 1 wherein the Internal proThe (74, 84) comprIses: a first groove (71, 81) extending from a first open end (77, 67) to a second end (75, 85); a second groove (72, 82) extending from the second end (75, 85) to a third closed end (76, 86); a third groove (73, 83) extending between the first groove (71, 81) and the second groove (72, 82).11. The system of claim 10 whereIn the internal profile (74, 84) is manufactured Into the riser JoInt (70). or wherein the Internal profile (74, 84) is a preformed profile that can be inserted into the riser Joint (70).12. The system of claim 10 wherein the first open end (77, 87) has a chamfered portion.13. A method for raising and controlling a rlserJolnt (70) from a surface structure, said method comprising: lowering a tool (20) via a hoisting system to an internal profile (74, 84) preformed in, or fitted into, the riser Joint (70); engaging said tool (20) with the Internal profile (74, 64) of the riser Joint (70); transferring an axial load to the internal profile (14, 84); raising said riser Joint (70) with said tool (20).14. The method as claimed In claim 13, whereIn the tool (20) is engaged with the Internal profile (74, 84) by arms (22) located on the tool (20) that protrude radially from the tool (20).15. The method as claimed In claIm 13, whereIn the tool (20) Is lowered Into the internal profile (74. 84) through a first open end (77, 87) to engage with a first groove (71, 81); and lowering said tool (20) through said first groove (71, 81) to a second end (75, 85); rotating said tool (20) through a third groove (73, 83) to engage with a second groove (72, 82); ifting said bo (20) train a second end (75, 86), through said second groove (72, 82), to a dosed third end (76, 86); raising said riser joint (70) by raising the too! (20) via a hoisting system coated on the surface structure.Amended claims have been filed as follows:-CLAIMS1. A system for raising and controlling a riser joint (70) from a surface structure, said system comprising: an internal profile (74, 84) preformed in, or to be fitted into, a riser joint (70), wherein said riser joint (70) is a conduit for fluids; and a tool (20) having an elongate tool body (24) and a tool head (21), and configured to be lowered into the riser joint; and wherein said tool comprises: means (22) for engaging said tool (20) with said internal profile (74,84) of said riser joint (70) into which the tool has been lowered, wherein the means for engaging said tool (20) with said internal profile (74, 84) transfers an axial load to said internal profile (74, 84) such that, in use, the tool (20), engaged inside the riser joint, can raise the riser joint (70), as the tool is raised, and wherein the means for engaging said tool (20) with said internal profile (74, 84) includes arms (22) that protrude radially from said tool (20).2. The system of claim 1 wherein the arms (22) are located on the tool head (21).0 3. The system of any preceding claim wherein the tool (20) is a circular cylinder.CJ 4. The system of any preceding claim wherein the tool (20) is made of steel.5. The system of claim 2 wherein the arms protrude from the tool head (21) by less than or equal to 20 cm.
6. The system of claim 2 wherein the tool head (21) has a greater diameter than the tool body (24).
7. The system of claim 1 wherein the tool head (21) includes radial holes (44) for receiving the arms (22).
8. The system of claim 1 wherein the internal profile (74, 84) comprises: a first groove (71, 81) extending from a first open end (77, 87) to a second end (75, 85); a second groove (72, 82) extending from the second end (75, 85) to a third closed end (76, 86); a third groove (73, 83) extending between the first groove (71, 81) and the second groove (72, 82).
9. The system of claim 8 wherein the internal profile (74, 84) is manufactured into the riser joint (70), or wherein the internal profile (74, 84) is a preformed profile that can be inserted into the riser joint (70).
10. The system of claim 8 wherein the first open end (77, 87) has a chamfered portion.
11. A method for raising and controlling a riser joint (70) from a surface structure, said method comprising: lowering a tool (20) via a hoisting system to an internal profile (74, 84) preformed in, or fitted into, the riser joint (70), wherein said tool has an elongate tool body (24) and a tool head (21), and wherein said riser joint is a conduit for fluids; engaging said tool (20) with the internal profile (74, 84) of the riser joint (70); transferring an axial load to the internal profile (74, 84); raising said riser joint (70) with said tool (20); and wherein the tool (20) is engaged with the internal profile (74, 84) by arms (22) 0 located on the tool (20) that protrude radially from the tool (20).CJ
12. The method as claimed in claim 11, wherein the tool (20) is lowered into the internal profile (74, 84) through a first open end (77, 87) to engage with a first groove (71, 81); and lowering said tool (20) through said first groove (71, 81) to a second end (75, 85); rotating said tool (20) through a third groove (73, 83) to engage with a second groove (72, 82); lifting said tool (20) from a second end (75, 85), through said second groove (72, 82), to a closed third end (76, 86); raising said riser joint (70) by raising the tool (20) via a hoisting system located on the surface structure.