WO2011089397A2

WO2011089397A2 - System and method for deploying a riser anchor monitoring system on a floating vessel

Info

Publication number: WO2011089397A2
Application number: PCT/GB2011/000080
Authority: WO
Inventors: Graeme Mcnay
Original assignee: Graeme Mcnay
Priority date: 2010-01-21
Filing date: 2011-01-21
Publication date: 2011-07-28
Also published as: GB2489869A; WO2011089397A3; GB201213010D0; GB201000975D0

Abstract

A device deployment apparatus comprising: a body normally formed from a plurality of elongate members fastened together end-to-end, the body having a first end with a device often a sonar transducer, and a second end provided with a supporting assembly for supporting the apparatus. The supporting assembly includes movable limbs with feet (126) for locating and supporting the apparatus within a tubular. The invention particularly relates to the deployment of a sonar device in an I -tube (140) of an FPSO to monitor risers connected to the FPSO. The supporting assembly has limbs which are adapted to be set in a stowed position for transit of the apparatus within a tubular, and to radially extend in use to engage with the Mu be. The limbs are normally connected to an axially moveable member which may be a sleeve over the body or an insert with the bore of a body. Particularly preferred embodiments use a solid mechanical activation to move from the stowed to the extended position and so obviate the need for hydraulic components and their associated maintenance.

Description

SYSTEM FOR DEPLOYING AND RETRIEVING A DEVICE

This invention relates to a system for deploying and retrieving a device, and includes a low profile tool assembly enabling use within an operational tubular environment. The device may comprise a transducer, for example for the purposes of implementing a riser and anchor chain monitoring system (RAMS). RAMS is used for floating production storage and offloading (FPSO) vessels. FPSO vessels are essentially short-term storage facilities with production capability, and are equipped for oil/gas processing and offloading periodically to transport tankers. Therefore, they are required to maintain station for extended periods whilst production is underway. Generally anchor chains and mooring lines to a turret are the principal methods of maintaining station. Varying environmental conditions are accommodated to an extent by design parameters for risers, and mooring devices, but exceptional sea states coincident with drift to tolerable limits may lead to an over-load event. Any such event can lead to a mooring line or anchor chain failure, which if undetected could have serious consequences, particularly if the riser is pressurised for production and suffers excessive loadings. Therefore, use of a monitoring system in proximity to the riser hang-off or attachment points is considered to be essential for operational safety.

An object of the present invention is to provide a system for deploying devices for use in a sub-sea environment, particularly where deployment requires access via or within a tubular component. The invention to be more fully described herein provides a deployment tool having a first configuration which may be referred to as the stowed or collapsed mode for transit in which the tool has capability to be passed through tubulars including FPSO l-tubes, and a second configuration which may be referred to as the operational or expanded mode for use in a static position within an l-tube for deployment of the RAMS, This offers a low profile that is advantageous in that deployment will not interfere with normal FPSO operations, and the tool is not affected by FPSO shutdowns. The tool of this invention includes a boom assembly with limbs adapted to provide tool positioning support within an l-tube, and device positioning support, the latter suitably being designed to mount within the l-tube proximate to, but not within the "trumpet bell" cone of the l-tube or similar tubular exit. This offers an advantage in that tool recovery is easy since there is no risk of the tool being trapped within the bell cone in the case of any adverse environmental event causing beyond tolerance bending of mooring or riser. The tool to be more particularly described herein enables a device to be deployed reliably and with less risk of damage to the device. Furthermore, if the tool has to be deployed in a FPSO having a differing l-tube bottom outlet or l-tube extension structure such as an offset, the tool is readily transferable without modification.

Thus, according to a first aspect of this invention, there is provided a device deployment apparatus comprising:

- a body normally formed from a plurality of elongate members releasably fastened together end-to-end to form a

predetermined body length,

- the body having a first end provided with a deployment

assembly for deploying a device, and a second end provided with a supporting assembly for supporting the apparatus, - the supporting assembly including movable limbs with feet for locating and supporting the apparatus within a tubular,

- wherein the limbs are adapted to be set in a stowed position close to the body for transit of the apparatus within a tubular, and to be extended with respect to the body sufficiently to bring the feet into engagement with an inner surface of the tubular.

Said first end may be provided with the deployment assembly and may additionally comprise a device protection sleeve mechanism. Preferably the device protection sleeve mechanism comprises a resilient mounting, and an axially displaceable sleeve with respect to the longitudinal axis of the body of the apparatus.

Other features of the invention to be described herein include means for improving transit of the apparatus through a tubular system which may include gaps.

The limbs are typically extended radially outwards. Preferably roller guide means are provided upon the body at a sufficient spacing along the length of the body to allow the apparatus to traverse any gaps in the tubular.

A still further advantageous feature of this invention lies in providing means for reliably supporting an apparatus, and independent means for selectively securing, within a tubular body, the deployment assembly.

The supporting assembly is hereinafter referred to as the first supporting assembly. The first end provided with the deployment assembly may also be provided with a separate second supporting assembly for supporting the apparatus, the second supporting assembly normally including movable limbs with feet for locating and supporting the deployment assembly within a tubular, said first supporting assembly and said second supporting assembly are preferably independently operable.

Therefore, according to a second aspect of the invention there is provided a device deployment apparatus comprising:

- a body normally formed from a plurality of elongate members releasably fastened together end to end to form a

predetermined body length,

- the body having a first end provided with a deployment

assembly for deployment of a device, and a second end provided with a first supporting assembly for supporting the apparatus,

- the first supporting assembly including movable limbs with feet for locating and supporting the apparatus within a tubular, and

- wherein said first end provided with the deployment assembly is also provided with a second supporting assembly including movable limbs with feet for locating and supporting the deployment assembly within a tubular, said first supporting assembly and said second supporting assembly being independently operable.

The first supporting assembly and/or said second supporting assembly may comprise double acting deployment limbs that are adapted to be set in a stowed position close to the body (inboard) for transit of the apparatus within a tubular, and to be extended with respect to the body (outboard) sufficiently to bring the feet into engagement with an inner surface of the tubular.

This feature is achievable in one form by provision of an axially moveable member mounted upon a body portion and moveable with respect to the body member along the main axis of the body member.

The axially moveable members may be slidable along the length of at least part of a body portion of the apparatus with respect to a fixed limit stop, for example under control of hydraulic or electric actuators.

Alternatively they may be provided inside the bore of the body member.

A plurality of limbs may be hingedly connected by one end thereof to the axially moveable member. The other end of each of said limbs is provided with feet, for example a contact bearing pad, which may be mounted on a pivot, swivel or universal joint mounting.

The axially moveable member assembly may be such that in the inboard stowed position respective pairs of axially moveable members of the double acting mechanism are spaced apart, and upon actuation the axially moveable members are brought together axially, causing radially directed movement of the limbs and feet to a deployed outboard position. Such an arrangement allows contact loads within a tubular to be spread over a relatively large portion of a tubular surface contacted by the feet.

Alternatively, the axially moveable member assembly may be such that in the inboard stowed position respective pairs of axially moveable members of the double acting mechanism are positioned together, and upon actuation the axially moveable members are moved apart axially, causing radially directed movement of the limbs and feet to a deployed outboard position.

In one embodiment the apparatus comprises one of each of the axially moveable member configurations described above.

In preferred embodiments, the first supporting assembly and/or said second supporting assembly may move from a stowed position to an extended position by mechanical activation. Indeed in particularly preferred embodiments hydraulic activation is not used thus obviating the requirement for maintenance of hydraulic components.

Thus moveable limbs comprising said feet may be moved by an actuator at their opposite end. The moveable limbs may be regarded as outer arms.

The moveable limbs may be attached to an outer body of the tool, preferably via lugs. The moveable limbs may extend through a slot provided in the outer body of the tool, typically between the lugs/inner arms.

The moveable limbs may be connected to an axially moveable member in the form of an insert member. The insert member is normally shaped to abut with the actuator in use and/or be connectable with a spacer member/extension which abuts with the actuator in use. Thus in one embodiment, abutment of the actuator with the insert member causes the insert member to move and thus causes the moveable limbs to move the feet from the stowed position to the extended position. The moveable member may have a slot and be connected to the inner arms via said slot by a connection means, such that during movement of from the stowed position to the extended position, the connection means moves through said slot.

Typically the connection between the moveable limbs and the insert member is a pivotable connection, that is in use they can pivot with respect to each other. Similarly typically the connection between the moveable limbs and the feet is a pivotable connection.

Normally there is more than one moveable limb spaced equidistantly around the tool. In a preferred embodiment there are four moveable limbs.

Preferably the feet have an external diameter the same as the internal diameter of the tube to which they abut, typically an l-tube. In the aforesaid, first and second aspects of the invention, the first supporting assembly may comprise feet in the form of contoured pressure or gripper pads to improve grip within the tubular and enhance support capability. The contours may comprise a ridged pattern on the pads to resist slippage in use. Alternatively, the contoured pressure pads may comprise a plurality of tooth projections in a random or regular pattern to the same purpose.

Preferably, the first supporting assembly comprises a double acting set of limbs and feet, extendible from the body to provide contact with a tubular at two regions that are spaced apart along the length thereof The limbs may be mounted upon axially moveable member which may be sleeves (or an insert member) movable over the length of the body, under control of actuators, and provided with bracing elements to provide radial support. This radial arm "spider-like" design offers a low cross-sectional area that will reduce heaving effect on the apparatus.

The second supporting assembly, may similarly comprise positioning means having movable limbs with feet for locating and supporting a device deployment assembly within a tubular, wherein the limbs are adapted to be set in a stowed position close to the body for transit within a tubular, and to be extended with respect to the body sufficiently to bring the feet into engagement with an inner surface of a tubular.

The roller guide means may comprise roller guide wheels attached to one or more of the movable limbs.

The means for supporting the device deployment assembly may comprise feet in the form of contoured pressure pads to improve grip within the tubular and enhance support capability.

The contours may comprise a ridged pattern on the pads to resist slippage in use. Alternatively, the contoured pressure pads may comprise a plurality of tooth projections in a random or regular pattern to the same purpose.

Preferably, the second supporting assembly comprises a double acting set of limbs and feet, extendible from the body to provide contact within a tubular at a predetermined position. In this case, the feet may be closely spaced in the deployed (outboard) position. The limbs may be mounted upon axially moveable members or sleeves movable over the length of the body, under control of actuators, and provided with bracing elements to provide radial support. The device to be deployed may be housed within a movable protective sleeve. The movable protection sleeve may be mounted to be controlled by actuators. The actuators may comprise a hydraulic (or mechanical) actuator, which may include a hydraulic ram mounted to the body or be mechanically connected to an insert member. The actuators may comprise an electrical actuator. In use during transit, the actuators are operative to slide the protection sleeve to cover the device to protect the device. The movable protection sleeve may be mounted to the body on a shock resistant mounting. The device may comprise a scientific instrument or scientific or technical measurement apparatus. The device may be a sonar apparatus such as a sonar transducer, especially a RAMS transducer.

The assembly may comprise a strain gauge or a stress monitoring system for monitoring high load points in components of the body of the apparatus.

Preferably the apparatus may comprise centralising means for positioning the apparatus centrally within the tubular during transit. Thus, the tool can be properly aligned, which assists introduction into successive sections of an l-tube assembly where the sections may be separated by gaps. The centralising means may be mounted to the body and comprises a surface contacting member, which in use may be biased into contact with an inner surface of a tubular to centralise the assembly with respect to the tubular. The centralising means may comprise a plurality of surface contacting members spaced around the body of the assembly. The centralising means may be mounted to the body via a shock resistant mounting, for example, a rubber mounting positioned between the surface contacting member and the body.

According to a still further aspect of the invention, there is provided a method of deploying a retrievable device, the method comprising the steps of:

(a) providing a device deployment apparatus of the first or second aspects discussed above;

(b) normally selecting an appropriate number of sections for forming the body of the tool,

(c) orienting and assembling the sections in proximity to the point of intended usage within a tubular comprising an l-tube section,

(d) running in the apparatus to a position required;

(e) actuating the first supporting assembly within the tubular to grip the tubular to provide support;

(f) actuating the positioning means and the deployment assembly to locate same within a tubular part of the l-tube section, and

(g) deploying the device.

The method may be performed on an FPSO. Alternatively it may be performed on other vessels. Preferred and optional features of the first and second aspect of the invention are also to be regarded as preferred and optional features of the method aspect of the invention.

Whilst both options are possible and within the scope of the present invention, preferably the actuation, especially of the first supporting assembly, is performed by mechanical actuation, normally a solid physical connection as opposed to a non-solid physical connection. For example this may be in the form of an actuating member pushing against moveable limbs of the first supporting assembly to cause them to move rather than non-solid hydraulic fluid driving said limbs. The deployment assembly is a means for deployment of a device. The first supporting assembly is a means for supporting the apparatus. The device deployment apparatus is a device deployment tool assembly. The second supporting assembly is a device positioning support means. Embodiments of the invention will now be further described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 a is a side view of a tool assembly with a

sonar transducer device ready to be deployed according to an embodiment of the invention;

Figure 1 b is a side view of the portion AA of Figure 1 a showing a support assembly of the tool assembly;

Figure 1c is a side view of the portion BB of Figure 1 a showing a sleeve mechanism;

Figure 2a is a side view of the portion CC of Figure 1 a showing a guide means;

Figure 2b is a side view of the portion DD of Figure 1a showing second supporting assembly;

Figure 3 is a side view of the Figure 1 a tool assembly showing additional components of the supporting assembly;

Figure 4 is a side view of the tool assembly of Figure 3 illustrated in transit through a tubular assembly including an l-tube section;

Figure 5 is a side view of the tool assembly of Figure 3 supported within a tubular assembly with the sonar transducer device deployed from the device deployment assembly locked in position within the tubular component of an l-tube section; Figure 6 is a partial cutaway perspective view of an l-tube section with both tool support assembly and device deployment positioning means locked in position within the tubular component of the l-tube, according to a further embodiment of the invention;

Figures 7a to 7c are side views of the deployment tool assembly of Figure 6 during construction of the assembly onsite for running into an l-tube section;

Figure 8 is perspective view of a contoured pressure pad of the deployment tool assembly of Figure 3 and/or Figure 6;

Figure 9 is an end view from below of the l-tube section of Figure 6;

Figure 10 is a perspective view of an elongate tube section of the deployment tool assembly of Figure 3 and/or Figure 6;

Fig. 11 is a front view of a second embodiment of a support assembly for a tool assembly in accordance with the present invention, showing an insert of the support assembly before insertion into a tube of the support assembly;

Fig. 12a is a plan view of the Fig. 11 embodiment, showing the insert of the support assembly provided within the tube of the support assembly;

Fig. 12b is a front perspective view of the Fig. 11 support assembly, during assembly;

Fig. 13 is a front view of the Fig. 11 tool assembly during assembly in an l-tube;

Fig. 14 is a front view of the Fig. 13 tool assembly at a later stage of assembly;

Fig. 15 is a front perspective view of the Fig. 13 tool assembly showing a further body section being added;

Fig. 16 is a front cross-sectional perspective view of the complete Fig. 13 tool assembly in a collapsed mode, and an actuator; Fig. 17 is a front cross-sectional perspective view of the compete Fig. 13 tool assembly and attached actuator, in radially extended operational mode;

Fig. 18 is a cut-away perspective view of a further embodiment in accordance with the present invention;

Fig. 19 is a perspective view of a support assembly in accordance with the present invention.

Referring firstly to Figure 1 , there is shown a deployment tool assembly 10 including a number of discrete tube sections 12 (constituting elongate members), which are threadably connected together to form a main body 1 of the tool assembly 10. The tool assembly 10 is modular in the sense that different components can be interchanged, for example, to form a deployment tool with a main body of a desired length. Further, the tool assembly 10 takes a slim-line, low-profile design such that it can be readily deployed through l-tube sections provided in an FPSO vessel.

More specifically, the assembly 0 is designed to be positioned and mounted in an l-tube to support a RAMS sonar transducer 16 (constituting a device) for location sub-sea below the FPSO vessel. In the example of Figure 1 , the transducer 16 is connected to an end section 18 at a first, lower or "transducer" end of the tool assembly 10.

Along the main body 14, there is provided a first, lower support assembly 20 and a second, upper support assembly 22 upward of the transducer end. Each support assembly has a number of movable limbs 24 spaced around the main body and are provided with feet in the form of gripper pads 26. The first support assembly 22 is shown in more detail in Figure 1 b. The movable limbs 24 are pivotally mounted to the main body at pivots 28 such that the limbs can move from a first position where the movable limbs are located closely alongside the main body 14 in a collapsed mode as shown in Figure 1a, 1b, to a second position where the gripper pads 26 are moved radially outwards from the main body 14 to engage and grip an inner surface of an l-tube in an operational mode.

Actuation of the tool into the operational configuration is hydraulically controlled, although for other embodiments can also be mechanically controlled. In this regard, the support assemblies 20, 22 include hydraulic rams 30 connected to an axially moveable member in the form of collars or sleeves 32 that are slidably mounted around the main body 4. In more detail and with particular reference to the configuration of the upper support assembly 22, each movable limb 24 defines an outer arm 38 and includes an inner arm 34 (constituting a bracing support) having one end which is pivotally coupled to the outer arm 38. Thus, each movable limb 24 has, moving from the gripper pad end, two extensions in the form of the inner arm 34 and outer arm 38. The inner and outer arms provide radial support for the tool assembly within the l-tube, the inner arm providing additional stiffness to the assembly.

The opposing end of the inner arm 34 is coupled to an inner pivot 36 fixedly attached to the main body 14, while the outer arm 38 is pivotally coupled to pivot 28 provided on the slidable sleeve 32. The arms are connected to the pivots 28,36 using quick connect pins for ease of assembly and deployment. The sleeve 32 is mounted on TEFLON® runners to protect the tool coating. The hydraulic rams 30 are actuated to force the sleeve 32 to slide along the body 14, and cause rotation of the inner and outer arms about the pivots 28,36. As the arms move, the gripper pads 26 are moved outwards in turn until they are brought into engagement with the l-tube in an expanded, operational mode. In this configuration, the upper assembly, via the double acting sets of limbs 24a, 24b, function to support the weight of the tool. The support assembly 22 provides contact load support from feet positioned at opposite ends of the support assembly, to provide stiffness to lower parts of the tool assembly.

The hydraulic rams 30 are supplied with hydraulic fluid and controlled from a topsides location.

The lower support assembly 20, shown in more detail in Fig. 2b is configured for operation in a similar fashion to that of the upper support assembly 22, although it is provided with double acting sets of limbs 24 and gripper pads 26 arranged with the feet and gripper pad ends of the respective sets centrally within the assembly facing each other, such that the pivot mounting points of the limbs 24 are positioned at the opposing end of the assembly, i.e. the double acting sets of the lower support assembly are reversed, compared with the upper support assembly 22.

As shown more clearly in Figures 1 b, 2b, to assist during transit, the support assemblies 20,22 are provided with roller guide wheels 42a, b connected to the limbs 24 which are in contact with an inner surface 45 of the l-tube. The wheels function to keep the tool main body and the support assemblies (in their collapsed configuration) off or away from the inner wall 44 so that deployment can progress safely without components of the assembly being dragged against the wall. Thus, the roller guide wheels act to protect the tool and l-tube from damage due to swaying and heaving of the FPSO vessel turret.

In Figures 1a, 2b some of the moveable limbs and associated gripper pads are removed for clarity from the lower support assembly 20. These are shown is Figure 3, which is otherwise a similar view to that shown in Figure 1a.

The Figure 1a, 3 configuration of the deployment tool assembly shows the support assemblies in a stowed position for transit through the l-tube. As can be seen with further reference now to Figure 4, the deployment tool assembly 0 is shown during transit through an l-tube section 40 of an FPSO vessel. The roller guide wheels 42a, b are spaced out along the main body so that the tool can successfully traverse gaps between l-tube sections. In the Figure 4 example, a lower l-tube section or bottom stiffener support 48 is shown in alignment with the l-tube 40. As the tool is deployed, the lower support assembly 22 will exit cone 50 of the l-tube 40, whilst the upper assembly and upper guide wheels 42a will remain within the l-tube section 40 providing the necessary guiding of the tool through the upper l-tube section and into the stiffener support 48, ensuring proper alignment.

Further, the main body 14 is provided with a centralising assembly 44 shown in more detail in Fig. 2a, with centraliser limbs spaced around the main body. The centraliser limbs comprise upper and lower arms 51 , 49, which are pivotally connected to each other at centraliser pivot 47. The centraliser pivot 47 comprises a wheel 55. In a similar manner to the support assemblies 20,22, the other end of the lower arm 49 is mounted to a sleeve 59 provided around the main body 14, and the other end of the upper arm 51 is mounted to a pivot that is fixedly attached to the main body. It is also similar in that it is formed from interchangeable

components. The sleeve 59 is moved to a position such that the centraliser arms are brought into low-friction contact with the inner surface of the l-tube at the pivots 47, to centralise the device within the tube.

The sleeve 59 has a neoprene buffer 53, which resiliently acts to resist shock loading. This improves integrity of and protects the tool assembly 10 in the event of any shocks imparted to it through centraliser/l-tube contact points. Further, this assists to align the sonar transducer 16 for guiding it through the bottom stiffener support 48 associated with the I- tube, as vibrations which could otherwise be felt by the sonar transducer 16 at the lowermost end of the tool assembly, are damped out by the centraliser sleeve arrangement. The centralising assembly acts to reduce bending moments imparted to the tool assembly when traversing a gap between l-tube sections, and generally provides additional stiffness, particularly to central portions, of the tool assembly 10.

The tool assembly 10 includes further measures to protect components during transit for deployment or retrieval. In particular, the assembly includes a retractable protection sleeve 46 for the transducer, which is in Figure 4 is shown slid over the sonar transducer 16 and shown in more detail in Fig. c retracted to expose the sonar transducer 6. The sleeve 46 is hydraulically (or mechanically) actuated to be slid into this position. This provides protection against knocks or other impacts to the end of the tool assembly during deployment and recovery. The protection sleeve 46 has a shock resistant neoprene guide studs 57 extending along an outer surface of the protection sleeve. These studs damp vibrations and shocks that may be imparted to the sleeve, and in turn shields the transducer from damage due to such shock or vibration events. In addition, the tool assembly 10 has a "spyball" camera 61 fitted to the main body 14. The camera may rotate about the main body and can be set at different angles. Camera control is provided topsides. The camera is used to provide pictures to help operators with deployment of the assembly and to monitor conditions more generally. In addition, it is provided to check for marine growth in the l-tube section, and to check for any high-frequency vibrations. In Figure 5, the tool is shown in its deployed, expanded configuration with the support limbs 24 radially extended and the gripper pads 26 of the upper support assembly 22 in engagement with the inner surfaces of the I- tube section 40 and the lower support assembly 20 in engagement with the inner surface of the larger diameter bottom stiffener support 48.

This demonstrates that the assembly 10 may be applied effectively in tubular sections of different diameter to position the transducer and provide support from a location as required. As the support limbs 24 are unfolded into the extended configuration as shown in Figure 5, the roller guide wheels which are attached to the limbs are folded out of the way allowing for engagement of the feet with the I- tube section. The "opposed" sets of gripper pad and limbs of the lower support assembly facilitates mounting of the deployment tool over a limited length of tubing, in this case the lower stiffener support 48. The limbs 24 of the lower set extend from the pads downward beyond the extremity of the stiffener support cone 54 providing stability of the tool at a lowermost mounting point 70 along the boom assembly 52 near the transducer. The weight of the assembly 10 is borne and transferred to through the limbs 24d to the mounting point 70 to produce a "compression" mounting at this point of the boom assembly 52. This gives significant stability to the boom, providing a stable platform for operation of the RAMS transducer, minimising boom assembly deflection, and avoiding unwanted vibration of the boom assembly during transit for deployment. To assist to provide stiffness at this weight-bearing, high load mounting point 70, the tool section 71 of the boom assembly is constructed from thicker materials.

The boom assembly 52 is immersed in the water below the bottom stiffener support, and is exposed to the subsea environment which can impart significant forces to the boom assembly 52. In this example, the boom portion extends approximately 4 metres below the stiffener support cone 54. A stress monitoring system (not shown) is used to monitor this point to check for anomalous behaviour and strain to the boom assembly.

To maximise support for the boom assembly 52, the lower set of gripper pads engage adjacent to the lower l-tube cone 54.

With reference to further embodiment, Figure 6 shows a deployment tool 100 in its deployed configuration in an l-tube section 140 with gripper pads 126 in engagement with an inner surface of the l-tube 140. In this embodiment, similar components of the assembly to that described with reference to Figures 1 to 5, are denoted with the same reference numerals incremented by one hundred.

In this embodiment, the main body 1 14 is constructed from removable 1 metre lengths of tube sections 112 in a similar manner to the example described above. However, the configuration of the support assemblies differ in that the lower support assembly 122 comprises a single set of gripper pads supported by upper and lower arms 82,180 from above and below. The upper support assembly 120 takes a similar form to that of Figure 1 , although it is positioned closer to the lower support assembly 122. In general, the support assembly configuration can be provided according to requirements, for example, according to the length and type of tube of any given FPSO vessel.

The components of the present assembly 100 are interchangeable and are assembled on-site as it is lowered into the l-tube 140. This principle is demonstrated by Figures 7a to 7c, showing progressively the construction of the tool 100 on site. In the first stage of Figure 7a, a number of the tube sections 112 forming the main body 14 are connected along with the RAMS sonar transducer 1 16 and sections with static pivots attached. Sleeves 132 including pivots 128 are mounted in place, and connected to hydraulic rams 130. In Figure 7b, additional components including the gripper pads 126 and movable limbs 124 are mounted, Further, in Figure 7c, the tool 100 is shown fully assembled in its transit configuration for moving the tool 100 into position for fixing within the l-tube 140.

Specific components of the tool assembly 100 are described in further detail below with reference to Figures 8 to 10.

In Figure 8, an example of the gripper pads 126 is shown in close-up. These are designed to engage and grip an inner surface of the l-tube. In this case, the gripper pads are provided with a contoured and grooved outer surface 156 that acts to resist slippage across its surface. The gripper pad surface 156 is also curved to enhance the area of contact with an inner tubular surface. It will be appreciated that in other embodiments, the gripper pads may have a different surface configuration to assist for example with gripping l-tubes of different materials or to take account of other properties. The gripper pads also have a corrosion resistant friction coating applied (not shown). The individual support tube sections 12 are substantially hollow and they are provided with orthogonal support plates 158 extending internally along the support tube section, as can be seen in Figure 10. The support plates add stiffness and strength to the support tube section 1 12, such that when constructed, deformation and movement due to forces imparted to the deployment tool assembly is resisted. The hollow construction allows cabling to be provided from topsides through the tool, which may be needed, for example, to control electronic or hydraulic devices. Adjacent such sections 1 12, are connected together via a thread 1 13, and are provided with XYLON® coatings for corrosion protection.

In this regard, the configuration of the upper and lower support assemblies is also significant. As can be seen more specifically in Figure 9 in an end on view of the assembly from below the cone 154 of the l-tube section, movable limbs 124 of the assembly 100 are spaced around the main body 114 and present a small cross-sectional area of the l-tube. Thus, the effects of forces on the assembly 100 due to the heave and throw of the sea from below and within the l-tube are limited.

In other embodiments of the invention (not shown), a deployment tool assembly as described above, is additionally provided with sensors that continuously monitor stresses and fatigue of the boom section, which may result from loads imparted due to the sub-sea environment.

An alternative embodiment of an upper support assembly is shown in Figs. 11 to 19. The tool 200 comprises four pairs of rigid lugs 233, each pair spaced equidistantly around the circumference of a main body 214 and extending radially outwards. Between each pair of inner arms 233 a slot 235 is provided. An axially moveable member or insert 260, sized to fit within the bore of the main body 214, also comprises four pairs of lugs 262, each pair equidistantly spaced around, and extending radially from, a tubular section 264 of the insert 260. The insert 260 is moved from the position shown in Fig. 11 to that shown in plan view in Fig. 12a, inside the main body 214, and respective arms 262, 233 are aligned. As shown in Fig. 12b, a "moveable limb" or arm 238 is positioned between each pair of arms 235 of the main body 214, extending through the slot 235 and - though not shown in Fig. 12b - between each pair of arms 262 of the insert 260.

The arms 238 are secured at their inner end, to the arms 262 of the insert 260, and at their outer end, to gripper pads 226. Suitable bores are provided on the arms 238 for this purpose; bolt and nut connections are sufficient. In use and as described below, the arms 238 can pivot around both these connections.

The arms 238 also define a slot 278 therein (shown only in Figs. 16 and 17) and a bolt and nut connection attaches the arms 238 to the lugs 233 via said slot 278. In use, and as described below, the bolt of this connection moves through the slot 278 as the support assembly moves from one configuration to another.

The tool 200 is assembled in an l-tube 240 of an FPSO as described hereinafter. As shown in Fig. 13 a first modular body section 214a of the tool 200 is placed in the l-tube 240 of a Floating Production Storage and Offloading (FPSO) vessel. The section 214a comprises a sonar transducer 216 at its lower end. A spreader beam 270 is moved in the direction of the arrow 271 and slotted through slots 275 provided around the section 214a.

The spreader beam holds the body section 2 4a in position whilst a further body section 214b is moved downwards as shown by arrow 273 and is threadebly connected with the body section 214a.

The spreader 270 is removed and the body sections 214a, 214b are moved together downwards. They can be seen in a lowered position in Fig. 4, with the spreader 270 engaged in a higher pair of slots to hold the body sections 214a, 214b in this lower position. The upper end of the section 214b comprises the upper support assembly described above with reference to Figs 11 , 12a, 12b.

An extension 266 is threadably engaged with the insert 260 and a third body section 214c is moved (Fig. 15) downwards to threadably engage with the body section 214b. A further support assembly can then be provided in the same manner at the upper, opposite end of the body section 2 3c.

Fig. 6 shows the further support assembly which has the same configuration as that described above and reference numbers preceded by a '3'.

The body section 214c is secured to the l-tube flange 272 by a

complementary flange 215 provided at the top of the body section 214c. An actuator 274 is threadably engaged in the section 214c and it abuts with the insert 360. An operator continues to move the actuator 274 and so cause the insert 360 to move in a downwards direction. The arm 338 pivots at both ends: at its inner end where it is connected to the lugs 362 of the insert 360, and at its outer end where it is attached to the grippers 326. Moreover the bolt connection 337 holding the lugs and arms together moves through the slot 378. This movement causes the gripper pads 326 to move radially outwards until the position shown in Fig. 17 is achieved. There, the gripper pads 326 engage with the l-tube 240 and so adopt an expanded operational mode.

The extension 266 is also moved down by such activation and so activates the lower support assembly on the body section 214b in the same manner. Indeed a series of other body sections and extensions may be provided to provide the required number of support and/or deployment assemblies.

Fig. 18 shows such an arrangement with a number of vertically spaced apart support assemblies in an l-tube and the lowermost body

extending below the l-tube 240. It should also be noted that, for this embodiments at least, four sets of gripper pads and associated lugs/arms/slots etc operate at one vertical position, spaced equidistantly around the circumference of the support assembly. Fig. 19 shows this more clearly. An advantage of such an embodiments is that the upper support assembly, and preferably the entire tool 200, does not require hydraulic activation. Thus the maintenance associated with hydraulic components can be avoided. Moreover power (hydraulic or electric) is not required to maintain the gripper pads in the radially extended position after the actuator has been moved into position. As can be seen from the drawings, a series of four slots are provided equidistantly around various sections 214 at various vertical locations. These are normally used by the spreader beam 270 to hold the section in place during assembly. However a further important function is to mitigate drag caused by water currents when they extend under the l-tube 240 into the sea; the slots allow currents to flow through the tube 214 rather than dragging on it. The slots also reduce the overall weight of the body 214.

Thus the apparatus of the present embodiments may be secured to the i- tube in such a manner and a sonar transducer 216 on the end of the apparatus extending beyond the l-tube in to the sea. From there it can monitor the risers or any other lines, such as mooring lines, in order to alert an operator should the lines stray from their intended position. In preferred embodiments, the accuracy of the measurements from the sonar transducer is also improved by the stability afforded by the support assemblies described herein.

The present tool provides a number of advantages. In particular, it is constructed from readily interchangeable components, allowing

customisation according to deployment requirements, and facilitating quick installation of the tool on site. Further, this provides advantages in the event that repairs may need to be carried out. Indeed, many FPSOs have a limited height requirement and so the modular nature of their preferred embodiments of the present invention allow a sufficiently long tool to be provided in the l-tube by assembling it from modular form.

The design of the sections and support assemblies provide stiffness and rigidity of the tool, providing stability for the RAMS sonar transducer such that good quality measurements can be carried out. In particular, the extending arm configuration of the support assembly assist with providing support and stability near the transducer end of the tool assembly.

Further, the support assemblies are relatively unaffected by heave and throw of the sea water through the l-tube from below, due to the slim design of the movable limbs providing low resistance to fluid flow by presenting a low cross-sectional area and/or the inclusion of slots. Yet further, the tool is versatile as it can be used with l-tube separated by gaps and in tubes having different diameters. The tool is constructed to engage with different diameter piping, and roller wheels are spaced along the body to enable deployment through such gaps. In addition, the tool can be set in a collapsed or stowed position whereby the movable limbs are pulled alongside the body and the transducer is covered by a protection sleeve such that tool components are protected from damaged during transit of the tool through the l-tube for deployment or retrieval.

Thus deployment of a sonar transducer in this position can obviate the need for Remotely Operated Vehicle (ROV) fly past to check on the I- tubes, thus saving on associated ROV costs. The sonar transducer can be connected to controls or automatic alarms which trip when the transducer senses that the risers coming into the FPSO are not in the correct position. A camera may also be provided close to the sonar transducer and can be operated at a user's discretion and is particularly useful when such alarms are activated.

Various modifications and improvements may be made within the scope of the invention herein described. For example embodiments of the present invention may be used on drill ships or other types of vessels.

Claims

1. A device deployment apparatus comprising:

a body having a first end provided with a deployment assembly for deploying a device, and a second end provided with a supporting assembly for supporting the apparatus,

the supporting assembly including movable limbs with feet for locating and supporting the apparatus within a tubular,

wherein the limbs are adapted to be set in a stowed position close to the body for transit of the apparatus within a tubular, and to a radially extended position.

2. Apparatus as claimed in claim 1 , wherein a body formed from a plurality of elongate members releasably fastened together end-to-end to form a predetermined body length.

3. Apparatus as claimed in claim 1 or claim 2, wherein the supporting

assembly is moveable from a stowed position to an extended position by solid mechanical activation.

4. Apparatus as claimed in any preceding claim, wherein the apparatus comprises an axially moveable member, axially moveable with respect to the body and attached to the moveable limbs.

5. Apparatus as claimed in any preceding claim, wherein the moveable limbs define a slot and are connected to the body by a connection means, such that during movement between the stowed position and the extended position, said connection means moves through said slot.

6. Apparatus as claimed in any preceding claim, wherein the moveable limbs extend through slots provided in the body of the tool.

7. Apparatus as claimed in claim 6, comprising an axially moveable member in the form of an insert member provided within a bore of the body, the insert member shaped to abut with an actuator wherein the moveable limbs extend through said slots in the body and connect to the insert member.

8. Apparatus as claimed in claim 7, wherein the connection between the moveable limbs and the insert member is a pivotable connection, that is in use they can pivot with respect to each other.

9. Apparatus as claimed in any one of claims 1 to 6, comprising an axially moveable member in the form of a slidable collar assembly mounted upon the body, each such collar being slidable along the length of at least part of the body of the apparatus and each collar being hingedly connected to the moveable limbs.

10. Apparatus as claimed in any preceding claim, wherein the connection between the moveable limbs and the feet is a pivotable connection, that is in use they can pivot with respect to each other.

11. Apparatus as claimed in any preceding claim, comprising the device to be deployed, the device adapted to obtain data from its environment

12. Apparatus as claimed in claim 11 , wherein the device to be deployed is housed within a movable protective sleeve.

13. Apparatus as claimed in claim 11 or claim 12, wherein the device

comprises a sonar apparatus.

14. Apparatus as claimed in any preceding claim, wherein roller guide means are provided upon the body.

15. Apparatus as claimed in any preceding claim, wherein a centralising means is mounted to the body and comprises a surface contacting member, which in use is biased into contact with an inner surface of a tubular to centralise the apparatus with respect to the tubular.

16. Apparatus as claimed in any preceding claim, wherein the supporting assembly comprises a double acting set of limbs and feet, extendible from the body to provide contact with a tubular at two regions that are spaced apart along the length thereof.

17. Apparatus as claimed in any preceding claim, wherein the deployment assembly comprises positioning means having movable limbs with feet for locating and supporting a device deployment assembly within a tubular, wherein the limbs are adapted to be set in a stowed position close to the body for transit within a tubular, and to be extended with respect to the body sufficiently to bring the feet into engagement with an inner surface of a tubular.

18. A method of deploying a retrievable device, the method comprising the steps of:

providing a device deployment apparatus as claimed in any preceding claim comprising the device;

running in the apparatus to a position required in an l-tube section thus deploying the device below the l-tube section;

and actuating the supporting assembly within the l-tube section to grip the l-tube section to provide support to the apparatus. .

19. A method as claimed in claim 18, which is performed on a Floating Production Storage and Offloading (FPSO) vessel.

20. A method as claimed in claim 18 or 19, wherein the actuation of the supporting assembly is performed by a solid physical connection.