BR112021002731A2 - METHOD AND SYSTEM FOR TRANSFERING LIQUID HYDROCARBONS FROM SHIP TO SHIP - Google Patents

Abstract

method and system for transferring liquid hydrocarbons from ship to field ship of the invention. the present invention relates to a system and method for transferring liquid hydrocarbons between ships. a method for transferring liquid hydrocarbons from ship to ship comprises the mooring of a first tanker (2) to a single point mooring buoy (10), the buoy (10) having a first port (16) and a second port (18) and a fluid conduit (14) connecting the first and second ports; connect a first hose column (26) between the first port (16) of the buoy (10) and the first tanker (2); positioning a second tanker (4) close to the buoy (10), the second tanker (4) having a dynamic positioning system; connect a second hose column (30) between the second port (18) of the buoy (10) and the second tanker (4); and pumping a hydrocarbon product between the first and second tankers, through the second hose (30), the fluid conduit (14) of the float (10) and the first hose (26).

Description

1/16

METHOD AND SYSTEM FOR TRANSFER OF LIQUID SHIP HYDROCARBONS FIELD OF THE INVENTION

[001] The present invention relates to a system and method for transferring liquid hydrocarbons between ships. In particular, the present invention relates to a system and method for transferring oil between tankers using a single point mooring buoy.

BACKGROUND OF THE INVENTION

[002] The offshore oil and gas industry usually uses floating production storage and offloading units (FPSO) to produce and store hydrocarbons. The FPSO can, for example, receive hydrocarbons from an underwater platform, process them and store the resulting oil. The FPSO unit will then normally transfer the oil to a tanker that transports the oil to shore or to a transhipment point for export.

[003] The following process describes the use of a dynamic positioning tanker (DP) to discharge the oil. A DP tanker is used to receive oil from the FPSO unit. Typically this will be a long-range tanker or a Suezmax tanker that has a size of 120,000-200,000 DWT (deadweight tons). A DP tanker is equipped with systems that allow the tanker to automatically maintain its position and direction using its own propellers and thrusters. These DP tankers are therefore specialized vessels and are significantly more expensive than conventional tankers to build, charter and operate.

[004] Once the DP tanker is loaded with oil, the DP tanker can then move to a location where the oil can be transferred to a conventional (non-DP) tanker using ship to ship transfer methods. ship. The conventional tanker can be another

2/16 Suezmax tanker or a VLCC (very large crude oil carrier). In these operations, the two tankers are fixed side by side and continue to remain side by side during the transfer. When transferring the oil to a conventional tanker, the most expensive DP tanker is released in order to return to FPSO.

[005] These transfers from ship to ship, however, are not possible in adverse weather conditions, such as when waves of more than 3 m are experienced, for example. As adverse conditions such as these are often encountered in the seas and oceans near oil production facilities and where the transfer of oil from a tanker to a tanker is desired, it is often not possible to use this method, or the delay due to the adverse weather, the export schedule is interrupted.

[006] In some cases, therefore, it is necessary for the DP tanker to transport the oil over significant distances to a suitable port or location where the oil can be discharged or transferred. This means that the DP tanker has been in use for a significant period of time transporting the oil to port and returning to the FPSO unit. The time spent can be around 14 days at a cost of around $ 50,000 a day and about $ 800,000 of fuel in total. In addition, additional DP tankers are required to meet the FPSO during this period. These DP tankers can cost around US $ 120 million each.

[007] A solution that is being considered to reduce the FPSO DP tanker’s clearance time is the provision of adequate ports or terminals at the desired locations closest to the FPSO or another production facility. Their construction cost, however, is in the region of $ 2 billion each.

[008] There is, therefore, a need for a more reliable and more economical system that allows oil, or other liquid hydrocarbons,

3/16 are discharged from an FPSO or other offshore hydrocarbon production facility and which minimizes the period of time during which a DP tanker is away from the production facility.

SUMMARY OF THE INVENTION

[009] The present invention provides, in a first aspect, a method for transferring liquid hydrocarbons from ship to ship comprising: - lashing a first tanker to a single point mooring buoy, the buoy having a first port and a second port and a fluid conduit connecting the first and second ports; - connect a first hose column between the first float door and the first tanker; - positioning a second tanker close to the buoy, the second tanker having a dynamic positioning system; - connect a second hose column between the second float door and the second tanker; and - pumping a liquid hydrocarbon between the first and the second tankers, through the first hose, the fluid conduit of the buoy and the second hose.

[0010] In a second aspect, the present invention provides a system for transferring liquid hydrocarbons from ship to ship comprising: - a single point mooring buoy, the buoy having a first port and a second port and a fluid conduit connecting the first and second doors; - a first tanker tied to the buoy; - a first hose column connected between the first tanker and the first buoy door; - a second tanker maintaining position close to the buoy; and

4/16 - a second hose column connected between the second tanker and the second buoy port, in which the first hose column, the fluid conduit and the second hose column are configured to allow liquid hydrocarbon to be pumped between the first and second tankers.

[0011] The system and method of the invention allows the transfer of liquid hydrocarbons from ship to ship in conditions where a direct connection between two tankers may not be possible. The liquid hydrocarbon will typically be oil, but it may be another hydrocarbon or a product derived from hydrocarbon processing. Liquid hydrocarbon can be a petrochemical product.

[0012] In some embodiments, liquid hydrocarbon is pumped from the first tanker to the second tanker. In these modalities, the liquid hydrocarbon is pumped from the first tanker, through the first hose column, through the fluid conduit, through the second hose column and to the second tanker. In other modalities, the liquid hydrocarbon is pumped from the second tanker to the first tanker. In these modalities, the liquid hydrocarbon is pumped from the second tanker, through the second hose column, through the fluid conduit, through the first hose column and to the first tanker.

[0013] Preferably, the first hose column is a floating hose column and the second hose column is a floating hose column. Ideally, when not in use, the hose columns are preferably tied back to the buoy in a stall. The first and second hose columns can be tied back to the buoy in a bay during tanker maneuver and then untied as soon as the tankers leave. In preferred embodiments, one or

5/16 both of the first hose column and the second hose column include a marine disconnect coupling. The first hose column is preferably connected to an emergency disconnect coupling provided on the first tanker. The second hose column is preferably connected to an emergency disconnect coupling provided on the second tanker.

[0014] The first tanker is preferably tied to the buoy by a mooring. The second tanker is positioned at a safe distance from the first tanker and the buoy, and maintains position using its dynamic positioning system. The second tanker is preferably positioned between 50m and 600m away from the first tanker.

[0015] The first hose column is preferably connected to the midship collector of the first tanker. In some embodiments, the second hose column is connected to the second tanker at the bow of the second tanker. In other modalities, the second hose column is connected to the midship collector of the second tanker.

[0016] After the hydrocarbon product has been pumped between the first and second tankers, the method preferably includes washing the second hose column with sea water. The method may include washing the first hose column with seawater.

[0017] After the transfer of liquid hydrocarbon between the tankers, the method comprises disconnecting the second hose column from the second tanker and tying the second hose column back to the buoy in a bay. The method preferably further comprises disconnecting the first hose column from the first tanker and tying the first hose column back to the buoy in a bay.

[0018] The system for transferring liquid hydrocarbons from

6/16 ship to ship, preferably still comprises a first support vessel equipped to handle the first hose column for connection and disconnection of the first tanker. The system can additionally comprise a second support vessel equipped to handle the second hose column for connecting and disconnecting the second tanker.

[0019] Preferably, the buoy comprises an overvoltage protection system including a compensation tank connected to the fluid conduit. A pressure relief valve between the fluid conduit and the compensation tank allows the hydrocarbon liquid to enter the compensation tank from the fluid conduit when the pressure in the fluid conduit exceeds a predetermined level. A telemetry-based monitoring system determines the level in the compensation tank and includes an alarm function.

[0020] In preferred modalities, the buoy comprises a telemetry system arranged to transmit data and receive data from at least one of the first and second tankers.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The invention will now be described by way of example only and with reference to the accompanying drawings, in which: Figure 1 is a block diagram illustrating a system for transferring hydrocarbon products from ship to ship in accordance with the present invention; Figure 2 illustrates a system for transferring hydrocarbon products from ship to ship by means of a single point mooring buoy in accordance with an embodiment of the present invention; Figure 3 illustrates a system for transferring hydrocarbon products from ship to ship by means of a single point mooring buoy according to another embodiment of the present invention;

7/16 Figure 4 illustrates a system for transferring hydrocarbon products from ship to ship by means of a single point mooring buoy according to another embodiment of the present invention; Figure 5 shows an end view and a side view of a midship connection from a hose to a tanker that is part of a system for transferring hydrocarbon products from ship to ship according to an embodiment of the present invention. ; Figure 6 is another view of the midship connection of Figure 5 showing one end of the hose connected to a tanker midship collector; Figure 7 shows a side view of an arched connection from a hose to a tanker as part of a system for transferring hydrocarbon products from ship to ship according to an embodiment of the present invention; and Figure 8 is another view of the arc connection of Figure 7 showing an arc loading system and an end of the hose connected to the tank through an arc slot.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] The present invention provides a method for transferring liquid hydrocarbons between two tankers using a single point mooring buoy (SPM). The method will normally be used to transfer crude oil, but it can be used to transfer other liquid hydrocarbons, including refined hydrocarbon products, liquefied natural gas and liquefied petroleum gas. Consequently, it will be understood that in the following description, references to oil and crude oil can more generally be considered to be references to any liquid hydrocarbon.

[0023] It is anticipated that this system will be used to transfer oil from a tanker equipped with a dynamic positioning system (

8/16 DP tank) for a conventional tanker, which does not include a dynamic positioning system. This frees the DP tanker to return to an offshore oil production or processing facility, while the conventional tanker can travel longer distances to a local onshore processing facility or ahead to another destination. This is advantageous, as DP tankers are significantly more expensive than conventional tankers, both in terms of construction costs and daily operating costs.

[0024] This system has particular advantages in offshore locations that often experience adverse weather conditions and where there is dependence on tankers equipped with dynamic positioning to transfer oil safely for export or transportation away from the offshore location or oil field.

[0025] The following description describes an embodiment of the invention in which a DP tanker is transferring liquid hydrocarbon to a convention tanker by means of a single point mooring buoy.

[0026] The single point mooring buoy 10 is located in the vicinity of a floating production, storage and offloading unit (FPSO) or other offshore oil production facility, such as an oil well or oil platform. Preferably, buoy 10 is located less than a day from the transit time of the DP vessel from the FPSO unit or other facility. The float may, for example, be located between 8,046 to 1126.5 km (5 miles and 700 miles) away from the FPSO unit or other facility. Most preferably, the buoy is located about 80.46 km (50 miles) away from the FPSO unit or other facility.

[0027] The buoy SPM 10 comprises a main body 12 and a plurality of anchor chains or mooring chains 13 that anchor

9/16 buoy 10 at the bottom of the sea. In the system of the present invention, the SPM 10 buoy is not connected to a pipeline end collector or subsea pipe and therefore does not include a flexible riser. The SPM 10 buoy is configured to allow direct transfer of goods from ship to ship and comprises a fluid conduit 14 terminating at a first end at a first hose connector or first port 16 and at a second end at a second hose connector or second port 18. Fluid conduit 14, therefore, directly connects first port 16 and second port 18.

[0028] In the illustrated embodiment, the SPM 10 buoy additionally comprises an overvoltage protection system including an accumulator vessel or compensation tank 20. A tube 22 extends from the fluid conduit 14 to the compensation tank 20. A control valve pressure relief 24 is arranged in the tube 22 and is configured to allow fluid flow through the tube 22 when the pressure in the fluid conduit 14 exceeds a predefined value. If the pressure in the fluid conduit 14 rises above the preset value due to, for example, a valve in one of the tankers suddenly closing, the pressure relief valve 24 will open and allow oil to flow from the fluid conduit 14 for the compensation tank 20. The SPM buoy 10 may include a pump arranged to pump liquid hydrocarbon from the compensation tank 20. This allows the compensation tank 20 to be emptied and the liquid hydrocarbon to be transferred to a tanker 2, 4.

[0029] The SPM 10 buoy additionally comprises a telemetry system configured to gather information and transmit data to and from tankers 2, 4. The data preferably includes weather conditions, sea conditions, as well as wave currents and location data. Tankers 2, 4 will receive the telemetry data from the buoy 10 and will use the data, in particular, to assist during the mooring.

10/16 The data will be used by the tanker DP 4 to maintain the position in relation to buoy 10 and the other tanker, as described below. The tanker DP 4 will therefore be equipped with the necessary software to receive and process the telemetry data from the buoy 10, as well as from the other tanker. In addition, when transferring liquid hydrocarbons from ship to ship, the data will include pressure, flow rates and other data related to the transfer of the liquid. The telemetry system can be configured to provide an emergency shutdown system. The emergency shutdown system can be configured to trigger emergency disconnect couplings on tankers and to monitor conditions, such as overvoltage protection.

[0030] The SPM float telemetry system may include means to detect if there is an oil spill around the float. Such a system can, for example, be a system developed by modifying the advanced technology of the instrument, such as https://www.nortekgroup.com

[0031] A first hose or hose column 26 is connected at a first end 28 to the first hose connector (first port) 16 of the float 10. A second hose or hose column 30 is connected at a first end 32 to the second connector hose (second door) 18 of the float 10. Each of the first and second hose columns 26, 30 is preferably between 200m and 400m in length and, more preferably, about 300m in length. The second hose column 30 may be longer than the first hose column 26. In the embodiment, each of the hose columns 26, 30 comprises a floating hose. Each of the hose columns 26, 30 also includes a marine separation coupling (MBC) 34. The MBC 34 is configured to automatically shut off flow along the hose column 26, 30 in the event of an adverse tensile load on the column of hose 26, 30.

11/16

[0032] Each of the tankers 2, 4 preferably includes an emergency disconnect coupling, emergency disconnect and disconnect coupling or emergency release coupling (ERC) 36 connected to a collector. When each of the hose columns 26, 30 is connected to the respective tanker 2, 4, the ERC is therefore arranged on a second end 38, 40 of the hose column 26, 30. The ERC will be part of a system emergency disconnect that also includes software or associated control systems. The ERC 36 is designed, in an emergency situation, or when activated by the SPM 10 float telemetry system, to interrupt the flow through coupling 36 and to separate. ERC 36 therefore causes hose column 26, 30 to separate from tanker 2, 4. A shut-off valve mechanism within ERC 36 blocks flow so that when coupling 36 separates both parts of coupling 36 are blocked or disconnected such that there is no minimum loss or loss of oil from the hose column 26, 30.

[0033] When not in use, each of the hose columns 26, 30 is tied back to the buoy 10 in a stall. Hose columns 26, 30 therefore remain floating on the surface of the sea around buoy 10.

[0034] A mooring cable 42 is connected to the SPM 10 buoy at its first end. Cable 42 will normally be about 60 m long. Another pickup line or rope is preferably attached to cable 42. The pickup line is preferably about 200 m long.

[0035] Two support vessels or support boats, such as tugs, (not shown) are available to help connect cable 42 and hose columns 26, 30 to tankers 2, 4, as described below. Support vessels are also configured to

12/16 assist in maintaining the position of one or both tankers 2, 4, if necessary. Each of the support vessels will also be equipped with pollution and safety equipment, such as one or more barriers, oil spill recovery equipment (skimmers), storage tanks for recovered liquid, detergent spray, spray arms and spray equipment. Fire fighting.

[0036] In a first phase of the method for transferring liquid hydrocarbons from ship to ship, a first, conventional tanker 2 approaches the buoy SPM 10. A first of the support vessel extends the mooring cable 42. The first tanker 2 is tied to buoy 10 by cable 42.

[0037] The first hose column 26 is then extended and presented to the tanker 2 by the support vessel. The second end 38 of the first hose column 26 is connected to the first tanker 2 on its midship collector 44. The first support vessel remains close to the first tanker 2, to assist in maneuvering the first tanker 2 , if necessary.

[0038] As the first tanker 2 is connected to the SPM 10 buoy by cable 42, it will be appreciated that the first tanker 2 is free to check the vane around the buoy 10.

[0039] A DP 4 tanker then approaches the SPM 10 buoy and maintains its position in a predefined location in relation to the SPM 10 buoy and the first tanker 2. The DP 4 tanker is preferably positioned between 50m and 600m from both the first tanker 2 and the SPM 10 buoy. In some situations, the tanker DP 4 will maintain its position outside the starboard room of the first tanker 2. Telemetry received by the tanker DP 4 from the SPM buoy 10 and / or the first tanker will help maintain the correct position, even when the first tanker 2 is moving in the wind.

13/16

[0040] The second hose column 30 is then extended and presented to the tanker DP 4 by the second support vessel. The second end 40 of the second hose column 30 is connected to the tanker DP 4 on its midship collector 46 or through its bow slot 48. Typically, the bow slot of a tanker is configured for loading; however, the DP tanker bow slot can be configured or adapted to allow for the discharge of oil from the DP tanker at the required flow rates.

[0041] Figure 2 illustrates an arrangement in which the second hose column 30 is connected to the midship collector 46 of the tanker DP 4. Figures 3 and 4 illustrate arrangements in which the second hose column 30 is connected through the slit in the bow 48 of the DP 4 tanker.

[0042] Once both hose columns 26, 30 are connected, tanker DP 4 pumps oil through the second hose column 30, through the fluid conduit 14 of the float 10, and through the first hose column 26 for the first tanker 2.

[0043] After the oil transfer is complete, the tanker DP 4 preferably unloads the second hose column 30 with seawater before the second hose column 30 is disconnected from the tanker DP 4. More preferably, the tanker DP 4 unloads the second hose column 30, the fluid conduit 14 and the first hose column 26 with sea water. This means that the hose columns 26, 30 are not left full of oil when they are disconnected from tankers 2, 4. This minimizes the risk of oil spillage when disconnecting the hose columns 26, 30 and when the hose columns 26, 30 are tied back to the float 10, for example, if one or both of the hose columns 26, 30 are damaged due to a contact.

[0044] The second hose column 30 is disconnected from the

14/16 DP 4 tank and is tied back to the SPM 10 buoy in a bay. The tanker DP 4 is then free to depart and return to the oil field or FPSO to reload.

[0045] The first hose column 26 is disconnected from the first tanker 2 and is tied back to buoy 10 in a bay. Cable 42 is disconnected from tanker 2 and tanker 2 is free to depart. The first tanker 2 can transport the oil to a local refinery or to another destination.

[0046] In preferred embodiments, the hose columns 26, 30 are tied back to the buoy 10 in a bay during the maneuvers of tankers 2, 4. Once tankers 2, 4 have broken the second ends 38 , 40 of the hose columns 26, 30 can be released from the buoy 10 so that the hose columns 26, 30 extend from the buoy 10. The hose columns 26, 30 can therefore move around the buoy 10.

[0047] In the scenario above, the first tanker 2 and the tanker DP 4 were of similar size or capacity such that a single tanker DP 4 transferred its cargo to the conventional tanker 2, which then departed. In these scenarios, the class of both tankers DP 4 and conventional tanker 2 can be Suezmax, having a size of

120,000 - 200,000 DWT (deadweight tons).

[0048] In other scenarios, the conventional tanker 2 can be significantly larger than the tanker DP 4. In these scenarios, a first tanker DP 4 can transfer its cargo to the conventional tanker 2 that is moored to the buoy SPM 10. After the first tanker DP 4 has departed, conventional tanker 2 can remain tied up and wait for a second tanker DP 4. A second tanker DP 4 can then transfer its cargo to the same conventional tanker 2. In these scenarios, the class of each of the DP tankers 4

15/16 can be Suezmax, having a size of 120,000 - 200,000 DWT (tons deadweight) and the conventional tanker class 2 can be Very Large Crude Oil Conveyors (VLCC) having a size of 200,000 - 320,000 DWT.

[0049] In other embodiments, the first tanker may be a floating storage tanker. In these modalities, the floating storage tanker is tied to the buoy by the mooring line, as described above. The second end of the first hose column is connected to the midship collector of the floating storage tanker.

[0050] In use, the DP tanker pumps oil through the second hose column, through the float fluid conduit and through the first hose column to the floating storage tanker. In some circumstances, the oil (or other hydrocarbon) may then be stored for a period of time in the floating storage tanker for future transfer to an export tanker. In other circumstances, an export tanker may be tied to the floating storage tanker, while the DP tanker is connected to the buoy by the second hose column. In these modalities, a third hose column is connected between the floating storage tanker and the export tanker. In use, the DP tanker preferably pumps oil through the second hose column, through the float fluid conduit, through the first hose column, through the pipes of the floating storage tanker, and directly into the tanker. through the third hose column.

[0051] Although in the modality described above the oil was transferred from the tanker DP 4 to the conventional tanker 2, in other modalities the transfer of liquid hydrocarbon can be of the

16/16 first tanker 2 to second tanker 4. In particular, the transfer of liquid hydrocarbon can be from conventional tanker 2 to tanker DP 4, instead of tanker DP 4 for conventional tanker 2.

[0052] It will be appreciated that the system of the present invention is more flexible than providing doors at fixed locations, and can be used in various locations around the world. In addition, the use of a single point mooring buoy for transferring liquid hydrocarbons can be safer than bringing a tanker to a port.

[0053] The present invention offers benefits and risk reduction, keeping tankers in deep waters away from environmentally sensitive areas and, therefore, provides a safer, more reliable and flexible system and method that allows oil or other liquid hydrocarbon, be transferred between a DP tanker and a conventional tanker and that can be used to minimize the length of time for which a DP tanker is away from an offshore production facility, such as an FPSO.

[0054] Other modifications and variations not explicitly described above can also be contemplated without departing from the scope of the invention, as defined in the attached claims.

Claims (24)

1. Method for transferring liquid hydrocarbons from ship to ship, characterized by the fact that it comprises: - mooring a first tanker (2) to a single point mooring buoy (10), the buoy having a first port ( 16) and a second port (18) and a fluid conduit (14) connecting the first and second ports; - connect a first hose column (26) between the first float door (10) and the first tanker (2); - positioning a second tanker (4) close to the buoy (10), the second tanker (4) having a dynamic positioning system to maintain position close to the buoy; - connect a second hose column (30) between the second port (18) of the buoy and the second tanker (4); and - pumping a liquid hydrocarbon between the first and the second tankers (2, 4), through the first hose (26), the fluid conduit (14) of the float (10) and the second hose (30), in that the single point mooring buoy is located between 8.04 km (5 miles) and 1,126.54 km (700 miles) away from an FPSO unit. Method according to claim 1, characterized in that the first hose column (26) is a floating hose column and the second hose column (30) is a floating hose column. Method according to claim 1 or 2, characterized by the fact that the first tanker (2) is tied to the buoy (10) by a mooring (42). Method according to any one of the preceding claims, characterized in that one or both of the first hose column (26) and the second hose column (30) include a marine separation coupling (34). Method according to any one of the preceding claims, characterized by the fact that the first hose column (26) is connected to an emergency disconnect coupling (36) provided on the first tanker (2). 6. Method according to any of the preceding claims, characterized by the fact that the second hose column (30) is connected to an emergency disconnect coupling (36) provided on the second tanker (4). Method according to any one of the preceding claims, characterized by the fact that the second hose column (30) is connected to the second tanker (4) at the bow of the second tanker. 8. Method according to any one of the preceding claims, characterized by the fact that the second tanker (4) is positioned between 50m and 600m away from the first tanker (2). 9. Method according to any one of the preceding claims, characterized in that it additionally comprises, after liquid hydrocarbon has been pumped between the first and the second tankers (2, 4), washing the second hose column (30) with sea water. 10. Method according to any one of the preceding claims, characterized in that it additionally comprises, after liquid hydrocarbon has been pumped between the first and the second tankers (2, 4), washing the first hose column (26) with sea water. 11. Method according to any one of the preceding claims, characterized in that it additionally comprises disconnecting the second hose column (30) from the second tanker (4) and tie the second hose column (30) back to the buoy (10) in a stall. 12. Method according to any one of the preceding claims, characterized in that it additionally comprises disconnecting the first hose column (26) from the first tanker (2) and tying the first hose column (26) back to the buoy (10) in a stall. 13. System for transferring liquid hydrocarbons from ship to ship, characterized by the fact that it comprises: - a single point mooring buoy (10), the buoy having a first port (16) and a second port (18) and a fluid conduit (14) connecting the first and second ports (16, 18), and the single point mooring buoy being located between 8.04 km (5 miles) and 1,126.54 km (700 miles) away an FPSO unit; - a first tanker (2) tied to the buoy (10); - a first hose column (26) connected between the first tanker (2) and the first port (16) of the buoy (10); - a second tanker (4) having a dynamic positioning system, the second tanker (4) maintaining position close to the buoy (10); and - a second hose column (30) connected between the second tanker (4) and the second port (18) of the buoy (10), in which the first hose column (26), the fluid conduit (14 ) and the second hose column (30) are configured to allow liquid hydrocarbon to be pumped between the first and second tankers (2, 4). System according to claim 13, characterized in that the first hose column (26) is a floating hose column and the second hose column (30) is a floating hose column. System according to claim 13 or 14, characterized by the fact that the first tanker (2) is tied to the buoy (10) by a mooring (42). System according to any one of claims 13 to 15, characterized in that one or both of the first hose column (26) and the second hose column (30) include a marine separation coupling (34). 17. System according to any one of claims 13 to 16, characterized in that the first hose column (26) is connected to an emergency disconnect coupling (36) provided on the first tanker (2). System according to any one of claims 13 to 17, characterized in that the second hose column (30) is connected to an emergency disconnect coupling (36) provided on the second tanker (4). 19. System according to any one of claims 13 to 18, characterized in that the second hose column (30) is connected to the second tanker (4) at the bow of the second tanker. 20. System according to any one of claims 13 to 19, characterized by the fact that the second tanker (4) is positioned between 50m and 600m from the first tanker (2). 21. System according to any one of claims 13 to 20, characterized in that it additionally comprises a first support vessel equipped to handle the first hose column (26) for connection and disconnection of the first tanker (2) . 22. System according to claim 21, characterized by the fact that it additionally comprises a second support vessel equipped to handle the second hose column (30) for connection and disconnection of the second tanker (4). 23. System according to any one of claims 13 to 22, characterized in that the float (10) comprises a compensation tank (20) connected to the fluid conduit (14). 24. System according to any one of claims 13 to 23, characterized in that the buoy (10) comprises a telemetry system arranged to transmit data and receive data from at least one of the first and second tankers (2, 4).