EP4677252A1

EP4677252A1 - Retaining device for retaining a cable on a pipeline

Info

Publication number: EP4677252A1
Application number: EP24709877.5A
Authority: EP
Inventors: Francesco Lucchese; Diego Lazzarin
Original assignee: Saipem SpA
Current assignee: Saipem SpA
Priority date: 2023-03-09
Filing date: 2024-03-07
Publication date: 2026-01-14
Also published as: WO2024184847A1

Abstract

A retaining device for retaining a cable on a pipeline is made of an elastic material and has a housing seat (4; 18; 21) configured to accommodate the cable (2); a pair of arms (5) extending about a central axis (A), each arm (5) being shaped so as to fit around the pipeline (3) and comprising a first end (6) coupled to the housing seat (4; 18; 21) and a second end (7) opposite to the first end (6); and a pair of clamping portions (8), each of which is coupled to the second end (7) of the respective arm (5), each arm (5) being shaped so as to ensure a uniform stress state along the retaining device (1) during installation of the retaining device (1) on the pipeline (3) and when the retaining device (1) is installed on the pipeline (3).

Description

"RETAINING DEVICE FOR RETAINING A CABLE ON A PIPELINE"

Cross-Reference To Related Applications

This Patent Application claims priority from Italian Patent Application No . 102023000004413 filed on March 9 , 2023 , the entire disclosure of which is incorporated herein by reference .

Technical Sector

The present invention concerns a retaining device for retaining a cable on a pipeline .

In particular, the present invention concerns a retaining device used on an underwater pipeline laid on a bed of a body of water .

Background of the Invention

Generally, the underwater transport of hydrocarbons comprises several successive steps , the first of which involves transporting hydrocarbons over short distances , from extraction wells to a plant for separation and treatment of said hydrocarbons . This separation and treatment plant is typically located above ground and is configured to make the treated hydrocarbons transportable over long distances , generally to plants located on the mainland . In particular, the separation and treatment plant is generally located tens of kilometres away from the extraction wells .

In general , the extraction wells exploit hydrocarbon reservoirs , which are disposed in a bed of a body of water and contain a multi-phase fluid comprising hydrocarbons .

By way of example , an oil reservoir contains a mixture comprising a first predominant phase , i . e . crude oil , a second phase , i . e . a gas in a saturated condition associated with the oil , and a third phase , i . e . saturated water in the gas .

By way of further example , a natural gas reservoir contains paraf fins , aromatic hydrocarbons , naphthenes and also a wide range of compounds such as water and/or hydrogen sul fide and/or carbon dioxide .

As is known, the separation and treatment plant trans forms the multi-phase fluid into products that are transportable over long distances using transport pipelines and exploiting the natural pressure and temperature of the hydrocarbon reservoir from which the multi-phase fluid is extracted .

Typically, during transport , the multi-phase fluid is subj ect to thermal dispersions to the external environment and pressure losses . Said thermal dispersions and said pressure losses cause a drop in temperature and pressure that modi fies the thermodynamic equilibrium of the multiphase fluid and which can cause the formation of undesired products , such as for example hydrates , waxes or corrosive compounds , which hinder the transport of the multi-phase fluid . Such unwanted products can also form during periods of low production rates and/or during maintenance shutdowns .

To ensure a continuous flow of multi-phase fluid within the transport pipeline , it is necessary to maintain the multi-phase fluid within a predetermined temperature interval by employing pipeline pas sive insulation techniques or pipeline active heating techniques .

A particular type of pipeline active heating is the Direct Electrical Heating ( DEH) , in which an electric current is forced to flow through the pipeline , heating the metal of the pipelines by Joule ef fect .

As is known, a direct electric heating system comprises a cable commonly called "Direct Electrical Heating Piggy Back Cable ( DEH-PBC ) " , which represents a portion of the electrical circuit of the heating system and is fixed astride the pipeline itsel f , in the so-called "piggyback" configuration, through retaining devices called "clamps" .

Typically, said cable is positioned at a short distance from the transport pipeline with the aim of limiting the inductive ef fects linked to the electromagnetic interferences between cable and pipeline that generate an inductive power that is of no use for the purposes of heating the pipeline .

Furthermore , said cable is devoid of a metal protective armour . In fact , the electromagnetic fields would generate eddy currents on the metal armour, and, consequently, would produce additional power that is o f no use for the purposes of heating the pipeline . Therefore , the cable is provided with protections made of polymeric material , such as for example plastic segments , which increase the mechanical strength thereof .

A conventional methodology for installing the cable in the piggyback configuration provides that this cable is installed simultaneously with the laying of the pipeline on the bed of the body of water . This installation methodology also provides for the piggyback configuration to be carried out by the same installation pipe-laying ship . In particular, during laying on the bed of the body of water, the pipeline is subj ected to considerable forces and bendings that result in designing a retaining system between cable and pipeline that is particularly rigid and typically consisting of bolted c 1 amp s .

Said retaining systems have numerous drawbacks .

A first drawback is linked to the possibility of a cable failure . In fact , in this case , it is necessary to carry out particularly complex and expensive replacement operations , as it is impossible to replace the cable through ordinary maintenance operations .

A second drawback is linked to the reduction in the productivity of the pipe-laying ship due to the fact that the cable assembly time is added to the pipeline fabrication time on the pipe-laying ship .

A third drawback lies in the fact that because of the lack of spaces , said installation methodology is often infeasible on some types of pipe-laying ships .

To partially overcome these drawbacks , retaining devices have been developed, commonly called "retrofit clamps" , which can be installed in the underwater environment through unmanned underwater vehicles . Said retaining devices are normally used to install or replace anodes during maintenance operations of cathodic protection systems .

However, the known retaining devices are heavy and cumbersome and are provided with complex locking mechanisms that generally require implementation . Consequently, the known retaining devices are unsuitable for being used to apply a cable to the pipeline in a robotic underwater production line .

Object of the Patent

An aim of the present invention is to reali ze a retaining device for retaining a cable on a pipeline that mitigates the drawbacks of the prior art .

In accordance with the present invention a retaining device for retaining a cable on a pipeline is reali zed, the retaining device being made of an elastic material and comprising :

- a housing seat configured to accommodate the cable ;

- a pair of arms extending about a central axis , each arm being shaped so as to fit around the pipeline and comprising a first end coupled to the housing seat and a second end opposite to the first end; and

- a pair of clamping portions , each of which is coupled to the second end of the respective arm, each arm being shaped so as to ensure a uni form stress state along the retaining device during installation of the retaining device on the pipeline and when the retaining device is installed on the pipeline .

Thanks to the present invention, it is possible to easily and quickly install the retaining device on the pipeline laid on the bed of the body of water . In particular, it is possible to install the retaining device through an unmanned underwater vehicle .

In addition, the housing seat al lows the cable to be accommodated in a given position without causing a compression of the cable against the pipeline .

In particular, each arm extends from the first end to the second end along an arc of circumference .

In this way, it is possible to fit the arms around the pipeline .

In particular, each arm comprises a respective f irst wall , which has a thickness measured in a direction substantially parallel to the central axis decreasing from the first end to the second end .

Thanks to the decreasing thickness of the first wall , during the bending of the arms , it is possible to determine a uni form stress state on the sections of the retaining device . In this way, it is possible to reali ze a retaining device that is light and little cumbersome and, at the same time , able to withstand the stresses due to the bending of the arms .

In particular, each clamping portion comprises a respective second wall having a thickness measured in a direction substantially parallel to the central axis greater than the thicknes s of the respective first wall at the second end of each arm, so as to provide a wide contact surface with the pipeline .

In particular, the arms are flexible between a closed position, in which the second ends of the arms are disposed at a first distance , and an open position, in which the second ends of the arms are disposed at a second distance greater than the first distance .

In practice , it is possible to elastically bend the arms so as to apply the retaining device around the pipeline . Once on the pipeline , the elastic flexibility of the arms determines an elastic return that secures the retaining device to the pipeline .

In particular, the housing seat comprises a plurality of positioning elements configured to retain the cable in the housing seat in a given position .

In this way, the distance between the cable and the pipeline can be adj usted .

In practice , it is possible to suspend the cable on the pipeline , which can assume a variety of di f ferent profiles in the space between two consecutive retaining devices in order to compensate for di f ferent thermal and pressure expansions between the pipeline and the cable . By way of example , the housing seat allows the cable to be accommodated so that the cable assumes catenary configurations along the pipeline .

In accordance with a first embodiment , the housing seat comprises a third wall having a "C" shaped profile .

In this way, the retaining device can be applied after the cable has been laid on the pipeline .

In particular, the third wall comprises two third ends , each of which is coupled to the first end of the respective arm, and an insertion opening, which is disposed between the third ends to allow insertion of the cable into the housing seat .

In particular, the third wall comprises a central portion opposite to the insertion opening and has a thickness measured in a direction substantially parallel to the central axis decreasing from the central portion to the third ends .

In this way, the third wall contributes to determining a uni form stress state on the sections of the retaining device .

In accordance with a second embodiment , the housing seat comprises a connecting wall , which is connected to the first ends of the arms so as to define together with the arms an arcuate body extending about the central axis .

In particular, the housing seat comprises a pair of lateral blocking bodies , which are coupled to opposing bands of the connecting wall and extend from the connecting wall outwardly of the arcuate body so as to delimit the housing of the cable together with the connecting wall .

In this way, it is possible to apply the retaining device on the pipeline and subsequently accommodate the cable in the housing seat .

In particular, the housing seat comprises a locking mechanism coupled to one of the lateral blocking bodies , so as to selectively lock/release the cable .

Brief Description of the Drawings

Further characteristics and advantages of the present invention will become clear from the following description of a non-limiting embodiment example thereof , with reference to the Figures of the attached drawings , wherein :

- Figure 1 is a perspective view, with parts removed for clarity ' s sake , of a retaining device made in accordance with a first embodiment of the present invention and disposed around a pipeline and a cable ;

- Figures 2 and 3 are front views , with parts removed for clarity ' s sake , of the retaining device of Figure 1 in respective operating configurations ;

- Figure 4 is a front view, with parts removed for clarity ' s sake , of a variant of the retaining device of Figure 1 ;

- Figure 5 is a perspective view, with parts removed for clarity ' s sake , of a retaining device made in accordance with a second embodiment of the present invention and disposed around a pipeline and a cable ; and

- Figures 6 and 7 are front views , with parts removed for clarity ' s sake , of the retaining device of Figure 5 in respective operating configurations .

Detailed Description of the Figures

With reference to Figure 1 , number 1 denotes as a whole a retaining device for retaining a cable 2 on a pipeline 3 made in accordance with a first embodiment of the present invention .

In particular, the retaining device 1 is configured to be installed on a pipeline 3 laid on a bed of a body of water and configured to transport hydrocarbons . In particular, the pipeline 3 is made of a metallic material .

It is understood that the pipeline 3 can be used to transport additional fluids without thereby departing from the scope of the present invention .

In greater detail , the cable 2 is electrically conductive and is used in a direct electric heating system of the pipeline 3 , without thereby limiting the wide range of possible applications of the present invention . Alternatively, the cable 2 may be configured to transmit electrical power and/or signals .

In particular, the retaining device 1 is configured to be installed on the pipeline 3 by an unmanned underwater vehicle , not shown in the attached Figures .

The retaining device 1 is made of an elastic material , preferably a metallic material , and comprises a housing seat 4 configured to accommodate the cable 2 ; a pair of arms 5 extending about a central axis A, wherein each arm 5 is shaped so as to fit around the pipeline 3 and comprises an end 6 coupled to the housing seat 4 and an end 7 opposite to the end 6 ; and a pair of clamping portions 8 , each of which is coupled to the end 7 of the respective arm 5.

Each arm 5 comprises a respective wall 9 shaped so as to ensure a uni form stress state along the arms 5 when the retaining device 1 is installed on the pipeline 3 .

In particular, each wall 9 has a thickness measured in a direction substantially parallel to the central axis A decreasing from the end 6 to the end 7 .

In practice , each wall 9 has a maximum thickness measured in a direction substantially parallel to the central axis A at the end 6 and a minimum thickness measured in a direction substantially parallel to the central axis A at the end 7 .

In greater detail , each clamping portion 8 comprises a wall 10 having a thickness measured in a direction substantially parallel to the central axis A greater than the thickness of the wall 9 at the end 7 of the respective arm 5 .

In practice , each wall 10 defines an end of the retaining device 1 with enlarged thickness .

Furthermore , the retaining device 1 comprises a pair of coupling elements 29 ( only one of which is visible in Figure 1 ) configured to allow coupling of the retaining device 1 with a gripping member of an unmanned underwater vehicle , not shown in the attached Figures .

In particular, each coupling element 29 is fixed externally to the wall 10 of the respective clamping portion 8 .

In the non-limiting case described and shown herein of the present invention, each coupling element 29 has a respective through opening 30 configured to receive a coupling pin, not shown in the attached Figures , of the gripping member .

With reference to Figures 2 and 3 , each arm 5 extends from end 6 to end 7 along an arc of circumference . In practice , each arm 5 is arcuate .

In other words , each wall 9 follows the profile of an arc of circumference .

In particular, the arms 5 are flexible between a closed position ( Figure 2 ) , in which the ends 7 of the arms 5 are disposed at a distance DI , and an open position ( Figure 3 ) , in which the ends 7 of the arms 5 are disposed at a distance D2 greater than the distance DI .

In practice , in the configuration of Figure 3 , the bending of the arms 5 determines an elastic return that secures the retaining device 1 to the pipeline 3 . Furthermore , each clamping portion 8 comprises a respective locking element 11 configured to lock the retaining device 1 onto the pipeline 3 . In particular, each locking element 11 is made of a polymeric material and is configured to be interposed between the respective wall 10 and the outer surface of the pipeline 3 when the retaining device 1 is installed on the pipeline 3 ( Figure 3 ) .

In accordance with the first embodiment , the housing seat 4 comprises a wall 12 having a "C" shaped profile .

In particular, the wall 12 comprises two ends 13 , each of which is coupled to the end 6 of the respective arm 5 , and an insertion opening 14 , which is disposed between the ends 13 to allow insertion of the cable 2 into the housing seat 4 .

In practice , the wall 9 , the wall 10 and the wall 12 are made integral in one piece so as to form a single elastic body .

From the constructive point of view, the wall 9 , the wall 10 and the wall 12 are made starting from a single metal sheet subj ected to a bending process .

In greater detail , the wall 12 comprises a central portion 15 opposite to the insertion opening 14 and has a thickness ( Figure 1 ) measured in a direction substantially parallel to the central axis A decreasing from the central portion 15 to the ends 13 .

In the case described and shown herein, the thickness of the walls 9 and of the wall 12 measured in a direction substantially parallel to the central axis A is decreasing from the central portion 15 to the ends 7 ( Figure 1 ) .

Furthermore , the housing seat 4 comprises a plurality of positioning elements 16 , 17 configured to retain the cable 2 in the housing seat 4 in a given position .

In the case described and shown in Figures 2 and 3 , the housing seat 4 comprises two lateral positioning elements 16 , each of which is coupled to a respective inner portion of the wall 12 between the third end 13 and the central portion 15 , and an upper positioning element 17 , which is coupled to the central portion 15 .

In particular, the positioning elements 16 and 17 are interposed between the cable 2 and the wall 12 so as to retain the cable 2 in a given position with respect to the pipeline 3 , when the cable 2 is accommodated inside the housing seat 4 . In greater detail , the positioning elements 16 and 17 are configured to retain the cable 2 in contact with the pipeline 3 .

With reference to Figure 4 , the retaining device 1 made in accordance with a variant of the first embodiment is shown .

In accordance with said variant , the retaining device 1 comprises a housing seat 18 provided with two lateral positioning elements 19 , each of which is coupled to a respective inner portion of the wall 12 between the third end 13 and the central portion 15 .

In particular, the housing seat 18 is devoid of the positioning element 17 ( Figures 2 and 3 ) .

In greater detail , the positioning elements 19 are interposed between the cable 2 and the wall 12 so as to retain the cable 2 suspended at a distance from the pipeline 3 , when the cable 2 is accommodated inside the hous ing seat 18 .

In accordance with a non-limiting embodiment of the present invention, each positioning element 16 , 17 , 19 is made of a polymeric material .

In use and with reference to Figure 1 , a gripping member of an underwater vehicle , not shown in the attached Figures , engages respective pins in the through openings 30 of each coupling element 29 to take the retaining device 1 and positions the retaining device 1 in an installation position at the pipeline 3 laid on the bed of a body of water . In particular, the cable 2 is laid on the pipeline 3 in a "piggyback" configuration .

At this point , the gripping member of the underwater vehicle is operated so as to bend the arms 5 from the closed position ( Figure 2 ) to the open position ( Figure 3 ) . Once the arms 5 are in the open position, the gripping member places the retaining device 1 around the pipeline 3 so that the cable 2 is accommodated in the housing seat 4 .

Subsequently, the gripping member retracts the pins from the through openings 30 so as to disengage itsel f from the retaining device 1 , determining an elastic return of the arms 5 and of the wall 12 that secures the retaining device 1 to the pipeline 3 .

With reference to Figures 5-7 , the retaining device 20 made in accordance with a second embodiment of the present invention is shown .

In accordance with the second embodiment , the retaining device 20 comprises a housing seat 21 provided with a connecting wall 22 , which is connected to the ends 6 of the arms 5 so as to define together with the arms 5 an arcuate body extending about the central axis A.

In other words , the walls 9 of the arms 5 and the connecting wall 22 are made integral in one piece so as to form a single elastic body .

In particular, the connecting wall 22 comprises a central portion 23 and two end portions 24 , which are disposed at opposing bands with respect to the central portion 23 and are directly coupled to the ends 6 of the arms 5 .

In accordance with one embodiment , the thickness of the walls 9 and of the connecting wall 22 measured in a direction substantially parallel to the central axis A is decreasing from the central portion 23 to the ends 7 of the arms 5 .

Furthermore , the housing seat 21 is provided with a pair of lateral blocking bodies 25 , which are coupled to opposing bands of the connecting wall 22 and extend from the connecting wall 22 outwardly of the arcuate body de fined by the arms 5 and by the connecting wall 22 so as to delimit the housing of the cable 2 together with the connecting wall 22 .

In greater detail , each lateral blocking body 25 comprises a respective lead-in 28 configured to facilitate entry of the cable 2 into the housing seat 21 .

Furthermore , the housing seat 21 comprises a locking mechanism 26 coupled to one of the lateral blocking bodies 25 .

In particular, the locking mechanism 26 comprises a locking element 27 movable between an open position, in which the locking mechanism 26 allows entry of the cable 2 into the housing seat 21 , and a closed position, in which the locking mechanism 26 locks the cable 2 into the housing seat 21 .

In the non-limiting case described and shown herein of the present invention, the retaining device 20 comprises a rest element 31 , which is coupled internally to the central portion 23 of the connecting wall 22 and is configured to be interposed between the connecting wall 22 and the outer surface of the pipeline 3 when the retaining device 20 is installed on the pipeline 3 . In particular, the rest element 31 is made of an elastic material .

In practice , when the retaining device 20 is installed on the pipeline 3 , the locking elements 11 and the rest element 31 define three static rest points on the pipeline 3 and exert respective forces converging towards the centre of the pipeline 3 .

In use and with reference to Figure 5 , the gripping member of the underwater vehicle , not shown in the attached Figures , installs the retaining device 20 on the pipeline 3 and subsequently the cable 2 is accommodated in the housing seat 21 .

At this point , the locking mechanism 26 moves the locking element 27 from the open position to the closed position to lock the cable 2 in the housing seat 21 .

Finally, it is evident that variations can be made to the present invention with respect to the embodiment described without thereby departing from the scope of the following claims .

Claims

1. A retaining device for retaining a cable on a pipeline, the retaining device (1; 20) being made of an elastic material and comprising:

- a housing seat (4; 18; 21) configured to accommodate the cable ( 2 ) ;

- a pair of arms (5) extending about a central axis (A) , each arm (5) being shaped so as to fit around the pipeline (3) and comprising a first end (6) coupled to the housing seat (4; 18; 21) and a second end (7) opposite to the first end ( 6 ) ; and

- a pair of clamping portions (8) , each of which is coupled to the second end (7) of the respective arm (5) , each arm (5) being shaped so as to ensure a uniform stress state along the retaining device (1) during installation of the retaining device (1) on the pipeline (3) and when the retaining device (1) is installed on the pipeline ( 3 ) .

2. The retaining device as claimed in Claim 1, wherein each arm (5) extends from the first end (6) to the second end (7) along an arc of circumference.

3. The retaining device as claimed in Claim 1 or 2, wherein each arm (5) comprises a respective first wall (9) , which has a thickness measured in a direction substantially parallel to the central axis (A) decreasing from the first end (6) to the second end (7) .

4. The retaining device as claimed in Claim 3, wherein each clamping portion (8) comprises a respective second wall (10) having a thickness measured in a direction substantially parallel to the central axis (A) greater than the thickness of the respective first wall (9) at the second end (7) of each arm (5) .

5. The retaining device as claimed in any one of the foregoing Claims, wherein each clamping portion (8) comprises a respective locking element (11) configured to lock the retaining device (1; 20) onto the pipeline (3) .

6. The retaining device as claimed in any one of the foregoing Claims, wherein the arms (5) are flexible between a closed position, in which the second ends (7) of the arms (5) are disposed at a first distance (DI) , and an open position, in which the second ends (7) of the arms (5) are disposed at a second distance (D2) greater than the first distance (DI ) .

7. The retaining device as claimed in any one of the foregoing Claims, wherein the housing seat (4; 18; 21) comprises a plurality of positioning elements (16; 17; 19) configured to retain the cable (2) in the housing seat (4; 18; 21) in a given position.

8. The retaining device as claimed in any one of the foregoing Claims, wherein the housing seat (4; 18) comprises a third wall (12) having a "C" shaped profile.

9. The retaining device as claimed in Claim 8, wherein the third wall (12) comprises two third ends (13) , each of which is coupled to the first end (6) of the respective arm

(5) , and an insertion opening (14) , which is disposed between the third ends (13) to allow insertion of the cable (2) into the housing seat (4; 18) .

10. The retaining device as claimed in Claim 9, wherein the third wall (12) comprises a central portion (15) opposite to the insertion opening (14) and has a thickness measured in a direction substantially parallel to the central axis (A) decreasing from the central portion (15) to the third ends ( 13 ) .

11. The retaining device as claimed in any one of Claims 1 to 7, wherein the housing seat (21) comprises a connecting wall (22) , which is connected to the first ends

(6) of the arms (5) so as to define together with the arms (5) an arcuate body extending about the central axis (A) .

12. The retaining device as claimed in Claim 11, wherein the housing seat (21) comprises a pair of lateral blocking bodies (25) , which are coupled to opposing bands of the connecting wall (22) and extend from the connecting wall (22) outwardly of the arcuate body so as to delimit the housing of the cable (2) together with the connecting wall (22) .

13. The retaining device as claimed in Claim 11 or 12, wherein the housing seat (21) comprises a locking mechanism (26) coupled to one of the lateral blocking bodies (25) .

14. The retaining device as claimed in Claim 13, wherein the locking mechanism (26) comprises a locking element (27) movable between an open position, in which the locking mechanism (26) allows entry of the cable (2) into the housing seat (21) , and a closed position, in which the locking mechanism (26) locks the cable (2) into the housing seat (21) .

15. The retaining device as claimed in any one of the foregoing Claims, and comprising a pair of coupling elements (29) configured to allow coupling of the retaining device (1) with a gripping member of an unmanned underwater vehicle; each coupling element (29) being fixed externally to the respective clamping portion (8) and comprising a respective through opening (30) configured to receive a coupling pin of said gripping member.