The invention relates to the field of fastening devices, also known as "clamps". The latter are used for all types of uses and preferably, but non-limitingly, for underwater lines used with drilling systems, in the offshore field.

Today, oil, natural mineral oil and hydrocarbon mixtures are abundantly exploited, thus being found at the heart of everyone's life and consequently, at the heart of the worldwide economy. Traditionally, oil is extracted using oil wells within oil fields or deposits, areas where large quantities of oil are buried, since the latter is a natural energy source. Such fields or deposits are situated in oil-producing regions or oil basins, locations on or below the soil, or below the ocean floor in which multiple oil resources or natural reservoirs are present. Some oilfields may extend over areas of several hundred square kilometers, requiring the presence of multiple wells to allow the exploitation of an entire zone. The presence of oilfields and the extraction of oil using wells make it possible to form oil reserves. Thus, the exploitation of any oil deposit to obtain oil reserves is in principle made up of two major steps: first, an exploration or prospecting step, then an oil production step.

Advantageously, but non-limitingly, the production step requires the use of oil wells. In the case of underwater deposits, such oil wells are used in combination with oil platforms, advantageously stationary or mobile. One non-limiting example of such a system is described in connection with figure 1.

During operations, by way of non-limiting examples installation or maintenance operations, on underwater oil wells, a drilling vessel or platform 1 is generally used. Such a platform 1 is, advantageously but non-limitingly, connected to a well, positioned on the seabed SB, by a large hollow tube 2 (also called "marine riser"), said marine riser 2 in particular making it possible to lower various pieces of equipment to the seabed, sometimes several thousands of meters below the surface. The connection between said hollow tube 2 and the vessel or the platform 1 is provided by an elastic coupling 3 (also known as "Flex-Joint"). Indeed, the marine riser 2 is fixed to the seabed and subjected to different temperature and pressure conditions. The vessel or platform 1 is subjected to the weather conditions, as non limiting examples, the movements of the swell. Inside said marine riser 2, a hollow tube 4 with a small diameter (also called "Drilling Riser Pipe" or abbreviated "DRP") and a so-called umbilical cable 5 are lowered, said cable advantageously being attached to the drilling riser pipe 4. Alternatively, said drilling riser pipe 4 and umbilical cable 5 can be lowered directly into the sea, without requiring the use of a marine riser 2 as previously described.

"Umbilical cable" refers to any cable making it possible to supply consumables to an apparatus. In the case of underwater deposits, such an umbilical cable 5, deployed as close as possible to the seabed SB, allows a connection between the host establishment, i.e., the platform 1, through which the necessary control commands, the energy, whether electrical, hydraulic or pneumatic, is transmitted, or even various chemical products are delivered to an underwater oil well. Such an umbilical cable 5 can also be used in connection with underwater manifolds, blowout preventers or any underwater system requiring remote control. An umbilical cable generally consists of a long flexible assembly of tubes, cables, etc. contained within a protective sheath: in principle, also contained within the umbilical cable are power cables to transmit control commands and energy signals and low-or high-pressure pipes to convey hydraulic fluids to the control valves and chemical products to be injected within the oil well. Such an umbilical cable is called "electrohydraulic cable". Furthermore, the umbilical cable 5 can also comprise other additional elements, as non-limiting examples, fiber-optic cables, for monitoring purposes. The design of an umbilical cable is modular, adaptable to each installation: it thus depends on several factors, including the water depth, function, environmental conditions and temperature.

Said drilling riser pipe 4 generally comprises one or several tubular segments or sections 4s, advantageously, but non-limitingly, measuring twelve meters, the sections being fixed to one another by any means, as non-limiting examples screwed, bolted to one another. Advantageously but non-limitingly, the drilling riser pipe 4 may serve to house different mechanical tools, as non-limiting examples drills or drill bits, or to allow the injection of different chemical products, as non-limiting examples glycol or concrete.

During drilling or maintenance operations, the underwater drilling line, comprising a riser and/or drilling riser pipe 4 and at least one umbilical cable 5, must remain substantially stationary relative to the wellhead 6.

The umbilical cable 5 is advantageously wound and/or unwound using a winch 7, optionally motorized, said winch being positioned on the deck of the vessel or platform 1. As a non-limiting example, the drilling riser pipe 4 is advantageously connected to the vessel or to the platform 1, optionally using a mooring turret. In order to limit the forces of the umbilical cable 5 on the winch 7 and avoid any friction and/or contact between the umbilical cable 5 and the drilling riser pipe 4 and/or the marine riser 2, the umbilical cable 5 and the drilling riser pipe 4 must cooperate with, or even be connected to, one another, optionally at regular intervals.

The umbilical cable 5 and the drilling riser pipe 4 advantageously being inserted within the large tube 2, the cooperation or connection between the umbilical cable 5 and the drilling riser pipe 4 must be put into place just before deploying said cable 5 and pipe 4 in the marine riser 2, advantageously on the deck of the vessel or platform 1. Such a cooperation or connection must thus be established as quickly as possible, in a minimum time, and preferably by a minimum time, since the umbilical cable 5 and the drilling riser pipe 4 are lowered almost instantaneously and continuously.

Today, techniques already exist to provide such cooperation or connection. The most widespread solution consists of fastening equipment or devices, also known as "clamps". Such fastening devices are used for different applications, such as, by way of non-limiting examples: the fastening and maintenance of the umbilical cable on the drilling riser pipe; a limitation of the tensions at a carousel system, allowing the winding and/or unwinding of the umbilical cable; the fastening of other pieces of equipment or elements on the umbilical cable and/or the drilling riser pipe.

Such fastening equipment or devices can be arranged on each seal of the pipe sections. Said fastening equipment or devices are positioned during the lowering of the umbilical cable and drilling riser pipe and over the course of the assembly of the drilling riser pipe modules.

A first example of an embodiment of a known fastening device is described in connection with figure 2A. A fastening device 10 includes a one-piece body 11, optionally made from a semi-rigid polymer, and non-adjustable closing and/or locking means 12. Furthermore, said fastening device 10 advantageously has a hole L. Throughout the document, "hole" refers to any central orifice, recess or cavity arranged in the fastening device in order to allow the passage therein of one or several underwater lines, namely in the case of a drilling system for one or several umbilical cables and one or several drilling riser pipes. To that end, the fastening device 10, more particularly the one-piece body 11, comprises one or several housings or recesses, advantageously two Hr' and llr”, arranged to accommodate said underwater lines, i.e., respectively a drilling riser pipe 4 and an umbilical cable 5.

At this time, the fastening devices used in particular have, among a large number of drawbacks, the following drawbacks: assembly difficulties related to the stiffness of the parts, in particularthe one-piece body, and consequently substantial installation times and costs; a transmission of tightening forces in the polymer material making up the fastening devices, said transmission generating creep, i.e., a deferred irreversible deformation, of said polymer material making up said fastening devices and therefore a loss of these forces and ultimately a loss of effectiveness; a limited friction or drag coefficient due to the rigidity of the parts.

A second example of an embodiment of a known fastening device is described in connection with figure 2B. A fastening device 10 includes a one-piece body 11, optionally made from semi-rigid polymer, and closing and/or locking means 12, optionally and also fixing means, which may assume the form of a screw and bolt assembly. Furthermore, said fastening device 10 advantageously has a hole L. In this second embodiment, the hole L consists of a central orifice or cavity, advantageously cylindrical, arranged in the fastening device in order to allow the passage therein of a single underwater line. Such a fastening device 10 is particularly suitable for example for fixing buoys on submerged lines but does not allow the fixing and maintenance of an umbilical cable 5 on the drilling riser pipe 4.

To address such drawbacks, WO2015/162384A2 discloses new structures and arrangements, designated hereinafter third example of an embodiment of a fastening device for underwater lines as described in connection with Figures 3A and 3B.

A fastening device 10 for underwater lines 4 and 5 has a hole L. To ensure the maintenance and fixing of at least two underwater lines, said hole L has a section greater than or equal to the sum of the respective sections of the two underwater lines 4 and 5. "Section of an underwater line" refers to the section of the underwater line including the outer wall of said line. The fastening device 10 comprises a one-piece body 11, arranged to encircle and jointly maintain the underwater lines 4 and 5: the hole L is thus defined when the fastening device 10 is in the closed position, i.e., the one-piece body forms a single and same closed entity. The one-piece body 11 of a fastening device 10 may primarily be made up of a flexible polymer or one of its derivatives, for example polyurethane, in particular in foam form.

To avoid a transmission of tightening forces in the polymer material making up the one-piece body 11 and creation of creep phenomena, the fastening device 10 further comprises a flexible element 13 cooperating with the one-piece body 11 along a sliding or embedding connection. Preferably, the flexible element 13 of the fastening device 10 consists of one or more straps. Such flexible element 13 is made up of a polymer and/or fibrous material or one of its derivatives, for example a polyaramid (also known as aramid), more particularly but non-limitingly poly-paraphenylene terephthalamide also known as kevlar™. Preferably, as described in connection with Figures 3A and 3B, the one-piece body 11 is advantageously hollow and the flexible element 13 is inserted within said one-piece body 11: the flexible element 13 can thus be "embedded" within the one-piece body 11. Furthermore, the one-piece body 11 also includes one or several orifices or "windows" llv formed on the inner wall of the one-piece body 11. Such orifices in particular make it possible to lighten the one-piece body 11, but also to participate in the maintenance of the fastening device 10 on the underwater lines 4 and 5.

As described in connection with figure 3B, for facilitating the positioning of the fastening device 10, the one-piece body includes an opening 18 arranged parallel to the axis (A) of the hole, said opening 18 defining two lips 19 opposite one another. The fastening device 10 further comprises locking and/or closing means cooperating with said lips, arranged for maintaining the position of the fastening device 10 along respective segments of the underwater lines 4 and 5 and encircle said segments of said underwater lines 4 and 5. Such locking and/or closing means can advantageously include any single bolts, fastening screws or captive screws allowing a quick installation and tightening or locking of the one-piece body 11 around the underwater lines 4 and 5 and their fastenings. Additionally, according to figure 3B, one or several orifices or recesses 14o, depending on the number of captive screws included in the fastening device, are arranged in the one-piece body 11, in order to accommodate the captive screws 14. Furthermore, the flexible element 13 consisting of a strap buckled at each of its ends, the locking and/or closing means include two inserts 15, advantageously in the form of cylindrical bars or in a "T" shape, said inserts 15 cooperating with the buckled ends of the strap : the captive screw(s) 14 cooperate then with said inserts 15 to perform the tightening function. According to figure 3A, the captive screw(s) 14, at its or their proximal parts, emerge from one of the two inserts, while at its or their distal parts, i.e., the screw heads, traversing the other insert.

Although such a third embodiment of a fastening device can address many drawbacks of other known solutions, said fastening device also has some drawbacks, regarding more particularly and non-limitingly: the positioning and the alignment of the fastening device on the underwater lines; the centralization of the underwater lines into the marine riser.

The invention makes it possible to address the large majority of the drawbacks raised by the known solutions and provides an improvement of the third embodiment in which the locking and/or closing of the fastening device is facilitated.

The invention provides a fastening device for fixing at least one cable to a drilling riser pipe consisting in a one-piece body of a flexible polymer comprising a central hole for encircling the drilling riser pipe and the at least one cable, an opening for allowing the installation of the one-piece body around the drilling riser pipe and the at least one cable, and locking means for tightening the fastening device around the drilling riser pipe and the at least one cable. The opening comprises two lips having complementary shapes for forming a guide for closing the fastening device and the locking means comprises at least one screw crossing the lips for tightening the fastening device.

In a preferred embodiment, the lips may define an alignment grove, one of the lips corresponding to a female member and the other lip corresponding to a male member, the alignment groove allowing a correct positioning of the locking means and a sliding of the lips during the closing of the fastening device.

Preferentially, the lips are molded parts of the one-piece body.

In a variant, one of the lips may comprise a bore hole containing a cylinder that is threaded for receiving the screw, the bore hole including an aperture for allowing the rotation of the cylinder when the screw is engaged inside said cylinder. The other lip may comprise an aperture having a thickness higher than the diameter of the shank of the screw and smaller than the head of the screw.

For enabling a centralization inside a marine riser, the fastening device may comprise protrusions positioned on an outside surface of the one-piece body, the outside surface being opposite to the central hole. The extremities of the protrusions can be sensibly aligned on a circle for centralizing the fastening device inside a marine riser.

The invention also provides a drilling system consisting in a platform or a vessel and comprising a drilling riser pipe and at least one umbilical cable, in which the drilling riser pipe and at least one umbilical cable are affixed together by one or more fastening device as previously defined.

Other objectives, characteristics, and advantages of the present invention will become more apparent from the following detailed description when view together with the accompanying drawings to the present specification, in which:

FIG.l shows an oil platform which needs fastening devices,

FIG.2A shows a first embodiment of a fastening device according to prior art,

FIG.2B shows a second embodiment of a fastening device according to prior art

FIG.3A and FIG.3B show a third embodiment of a fastening device according to prior art,

FIG.4A to FIG.4E show a preferred embodiment of a fastening device according to the invention,

FIG.5 shows an improved embodiment of the fastening device of FIG.3.

One preferred but non-limiting example of a fastening device according to the invention is described in connection with figures 4A to 4E. Such preferred embodiment is an improvement of the third embodiment of prior art previously detailed in relation with figures 3A and 3B. Consequently, same references are used on figures 4A to 4E for designating same features or analog features that are disclosed in figures 3A and 3B.

A fastening device 10 for underwater lines 4 and 5, according to the invention, has a hole L. To ensure the maintenance and fixing of at least two underwater lines, said hole L has a section greater than or equal to the sum of the respective sections of the two underwater lines 4 and 5. "Section of an underwater line" refers to the section of the underwater line including the outer wall of said line. Said respective sections of the underwater lines may advantageously be square, circular, oblong, or have any other sections that may be adapted for an underwater line, or even in some cases several underwater lines. The invention has been described during its use in connection with the maintenance and fastening of an umbilical cable and a drilling riser pipe, i.e., advantageously two underwater lines, associated with wells in oil deposits or fields. They can also be implemented for all types of underwater lines that require stabilization and protection functions. It would also be possible to consider the fastening device maintaining and fixing more than two underwater lines. The invention cannot be limited to the number or type of underwater lines maintained by the fastening device according to the invention.

The fastening device 10 according to the invention also comprises a one-piece body 11, arranged to encircle and jointly maintain the underwater lines 4 and 5: the hole L is thus defined when the fastening device 10 is in the closed position, i.e., the one-piece body forms a single and same closed entity, situation in particular described in connection with figures 4A to 4E. The one-piece body 11 of a fastening device 10 according to the invention may primarily be made up of a flexible polymer or one of its derivatives, for example a lighten polyurethane form. Polyurethane also has particularly interesting plastic deformation properties, since polyurethane is considered a ductile material. Indeed, ductility may be defined as the ability of a material, and in particular polymers, to deform plastically, without reaching a breaking point and consequently an irreversible deformation. In addition, the fastening device 10 made up of a flexible polymer or one of its derivatives, more particularly polyurethane, may be designed to provide the capability of buoyancy in fluid density equal to that of water or higher. In addition, the polyurethane polymer has the ability to resist certain concentration levels of drilling mud & completion fluids, resist mechanical impacts and abrasion. Indeed, during the installation of the fastening device on the underwater lines by an operator, the fastening device 10 might be not properly fixed to the underwater lines 4, 5 in the marine riser 2, leading to the fall of said fastening device 10 and the loss of the latter into the marine riser 2 potentially filled with water. Using a buoyant fastening device prevents such loss of the fastening device into the marine riser 2, the buoyant fastening device brought back to the edge of the marine riser on the surface of the water, thanks to the composition of the fastening device.

In principle, in the offshore field, more particularly of oil systems, underwater lines 4 and 5, such as, by way of non-limiting examples, as previously described, the umbilical cables and the drilling riser pipes of an oil system according to figure 1 advantageously have substantially circular sections. According to the first and second embodiments as described in connection with figures 4A and 4B, the hole L, which has a fastening device 10 according to the invention, may have a section adapted to fit the section of each underwater lines: the hole L might define two sectors. Such an ovoid section is particularly suitable for encircling and maintaining two underwater lines 4 and 5. In this case, the hole L defines two circular sectors whereof the respective radii r' and r" are substantially equal to the respective radii of the outer walls of the underwater lines 4 and 5. Depending on the type of underwater lines that a fastening device 10 according to the invention seeks to maintain, the radii r' and r” can be equal or different. The one-piece body 11 can thus advantageously be adapted based on the underwater lines. To that end, according to figure 4C, the one-piece body 11 of a device 10 according to the invention may comprise a first "primary" through hole Hr' comprising a first radius r' and a second through hole llr” comprising a second radius r”. The first hole Hr' may advantageously serve as a housing for the drilling riser pipe 4, while the second hole llr” may serve to house the umbilical cable 5.

To avoid a transmission of tightening forces in the polymer material making up the one-piece body 11 and creation of creep phenomena, the fastening device 10 further comprises a flexible element 13 (not illustrated in the figures 4A to 4E but illustrated in figure 3A), cooperating with the one-piece body 11 along a sliding or embedding connection. Preferably, the flexible element 13 of the fastening device 10 consists of a reinforcement strap. However, the invention cannot be limited to the presence of a single strap: alternatively, or additionally, a plurality of straps or any equivalent means may be provided, arranged to perform the same function. "Strap" refers to any band, advantageously but non-limitingly wide and flat, made from a material suitable to perform a flexible function, arranged to keep the underwater lines together. Such element or strap is made up of a polymer and/or fibrous material or one of its derivatives, for example a polyaramid (also known as aramid), more particularly but non-limitingly poly-paraphenylene terephthalamide also known as kevlar™. Due to its properties, such an element allows a great decrease, or even an elimination of the creep phenomena, thereby guaranteeing preservation of the tightening forces. Preferably, as described in connection with Figures 4A to 4E, the one-piece body 11 is advantageously hollow and the flexible element 13 is inserted within said one-piece body 11: the flexible element 13 can thus be "embedded" within the one-piece body 11. Furthermore, the one-piece body 11 also includes one or several orifices or "windows" llv formed on the inner wall of the one- piece body 11. Such orifices in particular make it possible to lighten the one-piece body 11. As described in connection with figure 4B, for facilitating the positioning of the fastening device 10, the one-piece body includes an opening 18, said opening 18 defining two lips 19 opposite one another. According to this advantageous alternative, the one-piece body 11 is described as "open one-piece body". Such an alternative is particularly suitable for facilitating the positioning of a fastening device 10 according to the invention on the underwater lines.

To perform its fastening and tightening function optimally, the fastening device 10 must be able to be adjusted so as to encircle the respective segments of the underwater lines 4 and 5. To that end, the fastening device 10 according to the invention further comprises locking and/or closing means cooperating with said lips, arranged for maintaining the position of the fastening device 10 along respective segments of the underwater lines 4 and 5 and encircle said segments of said underwater lines 4 and 5. Such locking and/or closing means make it possible to maintain the position of a fastening device 10 according to the invention along respective segments of the underwater lines 4 and 5 and encircle said segments of said underwater lines 4 and 5. Said locking and/or closing means also guarantee the cohesion of the fastening device 10 around the underwater lines 4 and 5, in the so-called closed position.

However, as described with the third know embodiment of the fastening device illustrated in connection with the Figures 3A and 3B, the arrangement of such opening 18 and the lips 19 parallel to the axis (A) of the hole might raise some drawbacks as the operator installing the fastening device on site might have difficulties to properly position the lips and the locking and/or closing means.

To simplify the installation of a fastening device according to the invention as described in Figures 4A and 4B, the opening 18 may define or incorporate an alignment groove defined by two lips 19', 19”. The dimensions and the shape of the two lips 19', 19” are determined and arranged to be complementary and adjusted during the fitment and interlocking of the two lips 19', 19” in the so-called closed position. The existence of such alignment groove enables correct positioning for the locking and/or closing means to be torqued during closure and tightening of the fastening device. According to the embodiment described in connection with Figures 4D and 4E, a first lip 19' defines a female member and a second lip 19” defines a male member, such first and second lips 19', 19” being arranged to be adjusted by sliding when fitted. Such locking and/or closing means can advantageously include any single bolts, fastening screws or captive screws 14 allowing the tightening or locking of the one-piece body 11 around the underwater lines 4 and 5 and their fastenings. Advantageously but non- limitingly, to guarantee the longevity of a fastening device 10 according to the invention, the locking and/or closing means may be made up of galvanized steel, standard structural steel, Nikaflex ^® steel, bronze and/or stainless steel. The locking and/or closing means 14 made up of metallic parts of the fastening device 10, more particularly may be designed to resist hydrogen embrittlement. Amongst all the examples of locking and/or closing previously cited, the captive screws 14 have many advantages, since they make it possible to obtain a captive screw function, so as to limit the number of parts to be handled during operations. Indeed, during assembly operations, a screw 14 may easily escape the hands of an operator, which can have serious consequences, in particular involving the safety of said operator and/or slowing the assembly and/or positioning process of said fastening device 10. Such captive screws 14 can advantageously be integrated within the one-piece body 11. Additionally, according to figure 4B, one or several orifices or recesses 14o, depending on the number of captive screws included in the fastening device, are arranged in the one-piece body 11, in order to accommodate the captive screws 14. The captive screw may also be designed to be replaceable should it deteriorate over time, and as such giving the one-piece body 11 a prolonged lifetime use.

While the underwater lines and the fastening device are being installed or uninstalled in the marine riser 2 during offshore drilling and retrieval operations, they might hit and snag the marine riser or any other elements that might be an obstacle. Such snagging or hitting might create abrasion of the underwater lines and cause some mechanical or functional damages, even the failures of such underwater lines. Therefore, it is necessary to protect and centralize the underwater lines inside the marine riser 2. Advantageously but non-limitingly, in order to perform a centralization and/or protection function within the marine riser, a fastening device according to the invention may include one or more external winglets or protrusions 20 positioned on the outside surface of the fastening device 10 and made up of a flexible polymer or its derivatives. Preferably, to facilitate the manufacture the external winglets or protrusions 20 may be made up of the same polymer as the one-piece body, preferably but non-limitingly, of polyurethane. Such winglets or protrusions 20, more particularly their shapes and dimensions, are arranged to enable the fastening device and consequently the underwater lines to be centralized and protected, preventing any snagging or abrasion during offshore drilling and retrieval operations. In accordance with Figures 4A to 4E, the fastening device may include five external winglets 20 positioned all around the external surface of said fastening device. The shape of the five external winglets 20 might be of any shape and preferably of pyramid shape to reduce the quantity of material needed to manufacture the fastening device. However, the extremities of the winglets 20 are sensibly aligned on a circle for centralizing the fastening device 10 inside a marine riser 2. The invention cannot be limited to the number or shape of the external winglets included in the fastening device according to the invention.

An alternative embodiment of the invention is disclosed on figure 5. The alternative embodiment mainly differs from the preferred embodiment by a variant of locking and/or closing means. In this alternative embodiment, the lip 19' comprises a bore hole perpendicular an opening direction for receiving a cylinder 21. The cylinder 21 is threaded for receiving the screw 14. The lips 19' and 19" comprise respective aperture 14' and 14" having a thickness higher than the diameter of the screw 14 for allowing the screw 14 to pass through said apertures 14' and 14". In an open position of the locking and/or closing means, the screw 14 is engaged in the cylinder 21 which is turned for having the screw 14 perpendicular to the one- piece body 11. For closing the fastening device 10, the two lips 19' and 19" are engaged together, then the screw 14 can be moved by rotation of the cylinder 21 inside the aperture 14". For ensuring the locking, the aperture 14" must be smaller than the head of the screw 14 for enabling the screwing of the screw 14 causes the closing of the lips 19' and 19' and consequently the tightening of the fastening device 10. Such a locking and/or closing means allows an easier manipulation by operators. Preferably, the cylinder 21 may cooperate with the flexible reinforcement element 13 as the insert 15 of figure 3A.

Alternatively or additionally, a fastening device 10 according to the invention may comprise gripping means. Such gripping means allow easier handling of a fastening device 10 according to the invention. As a non-limiting example, the gripping means of a fastening device 10 according to the invention comprise a notch 16. Said notches primarily may also act as flexible notches for the opening and closing on the one-piece body 11 during installation and removal operations. They may advantageously be formed on the outer wall of the one- piece body 11 of a fastening device 10 according to the invention. The invention cannot be limited to the presence of a single notch: it could be considered to have a plurality of notches 16 formed on the outer wall of the one-piece body 11. Preferably but non-limitingly, the gripping means consist of two notches 16, advantageously but non-limitingly positioned symmetrically on the one-piece body 11 relative to one another: in combination with the fibrous materials or polymers, the presence of two notches 16 allows the creation of elastic hinges, simplifying the positioning of a fastening device 10 according to the invention.

Furthermore, alternatively or additionally, a fastening device 10 according to the invention comprise two chamfers 17, also known as beveled edges, formed on the upper and lower faces of the one-piece body 11. "Chamfer" refers to any small surface formed by a pitched edge, advantageously formed on the upper or lower face of the one-piece body 11 of a fastening device 10 according to the invention. Such chamfers make it possible to prevent a fastening device 10 according to the invention from catching on other external structures that may be present in the environment of said device, as well as minimizing the hydrodynamic profile of said device to avoid the appearance of drag forces and to divert and help centralizing the underwater lines.

Furthermore, the invention provides a hollow marine riser 2, including two underwater lines 4 and 5 within it. Preferably, said underwater lines can advantageously, but non- limitingly, be an umbilical cable 5 and a drilling riser pipe 4, as previously described. To decrease the costs and time of installing said lines within the marine riser 2, said marine riser comprises at least one fastening device 10 according to the invention, said device 10 encircling the underwater lines 4 and 5.

The invention also provides a drilling system comprising a platform 1, underwater lines 4 and 5 cooperating with said platform 1 and an oil well 6 cooperating with said underwater lines 4 and 5. To decrease the installation costs and time of said system, said system comprises at least one fastening device according to the invention encircling respective segments of said underwater lines. Preferably, said underwater lines can advantageously, but non-limitingly, be an umbilical cable 5 and a drilling riser pipe 4, as previously described. Said oil platform may advantageously be stationary or mobile, or even constitute a floating unit, i.e. a drilling vessel. The invention cannot be limited to the type of platform comprised by said system. The embodiment of the invention shows a fastening device for fixing one umbilical cable 5 to a drilling riser pipe 4. The person skilled in the art can easily understand that the shape of the central hole L can be changed and adapted for allowing the tightening of more than one umbilical cable 5 to the drilling riser pipe 4. The person skilled in the art may also understand that the umbilical cable 5 can be of different types like, for example, an electric cable, a hydraulic or electro-hydraulic hose, or any other kind of tube that could joint to the drilling riser pipe 4.