GB2098171A

GB2098171A - Tanker loading station

Info

Publication number: GB2098171A
Application number: GB8209711A
Authority: GB
Original assignee: Coflexip SA
Current assignee: Technip Energies France SAS
Priority date: 1981-04-02
Filing date: 1982-04-01
Publication date: 1982-11-17
Also published as: MX164510B; IT1150514B; NO821098L; OA07056A; JPS58485A; BR8201864A; FR2503123B1; ES8302600A1; NL8201381A; IT8220545A0; ES511628A0; FR2503123A1

Abstract

An open-sea loading station for tankships, comprising a flexible pipe 6 connecting a first structure 2 situated at the bottom of the sea, to a second structure 3 on the surface or submerged close to the surface, the said second structure including a lead 5 for the flexible pipe to pass through. A terminal 7 is mounted on the end of the flexible pipe in order to prevent it from passing through the lead, the flexible pipe having an excess of length which enables its end equipped with the terminal to be brought over to a loading junction on the tankship by making it slide in the lead. <IMAGE>

Description

SPECIFICATION Tanker loading station The object of the present invention is an open-sea loading station for tankships such as oiltankers and more particularly a loading station of that kind which comprises a flexible pipe connecting a first structure such as a baseplate situated at the bottom of the sea, to a second structure on the surface or submerged close to the surface, for example, a floating buoy which is submersible or semi-submersible, or else the upper portion of a device such as a mooring post.

Loading stations of this kind are already known. In a typical case petroleum is brought from a wellhead to a baseplate through a pipe and the second structure is arranged substantially above the base plate and is connected to it through a flexible pipe.

The loading of the tankship is effected by connecting it through another flexible pipe to the second structure.

The present invention is aimed at providing a loading station which is simpler in use and which in particular avoids the majority of the manipulations which have to be carried out beforehand by the tankship and which enables the length of life of the flexible pipe employed to be increased.

For this purpose the object of the present invention is an open-sea loading station fortankships, comprising a flexible pipe connecting a first structure situated at the bottom of the sea, to a second structure on the surface or submerged closed to the surface, the said second structure including a lead for the flexible pipe to pass through, characterised by the fact that a terminal is mounted on the end of the flexible pipe in order to prevent it from passing through the lead, the flexible pipe having an excess of length which enables its end equipped with the terminal to be brought over to a loading junction on the tankship by making it slide in the lead.

It is thus sufficient for the ship to come to anchor near to the structure and then, for example, by means of a loading mastto raise the terminal on board whilst making the flexible pipe slide inside the lead on the structure, which is possible because of the excess length of this pipe.

In one embodiment the excess length is laid on the bottom but it may as a variant be held above the bottom by a float.

In either case the lower portion of the flexible pipe is preferably coated in a metal ribbon for outer protection.

When the flexible pipe is laid on the bottom, this coating enables its wear to be minimized. Further, whether the flexible pipe is laid on the bottom or whether it is held above the bottom by a float, this coating ballasts the lower portion of the flexible pipe, which ensures that when the terminal is released by the ship the excess length of flexible pipe drops well inside the lead until being stopped by the terminal. In the opposite case it might be feared that the excess length of flexible pipe and the terminal might remain outside the buoy.

In one preferred embodiment of the invention, especially in the case where the structure is a flat buoy, the lead exhibits a substantially toroidal inner shape, that is to say, it exhibits circular crosssections and widens out towards its two ends in order to enable easy sliding of the flexible pipe.

In orderto prevent the end of the flexible pipe from passing through the lead, the terminal may, for example, have a shape complimentary with that of the lead (for example, toroidal) or else include a bearing surface capable of being laid on the upper surface of the structure at the periphery of the lead.

The terminal advantageously includes on the upper portion of it an elbow connector for connection of it to the loading junction on the tank ship.

The ship may thus be equipped, for example, with a fork for receiving the terminal in a position similar to that which it adopts on the structure so that the junction from the terminal lies substantially horizontal and may, for example, be connected to the loading junction on the ship by way of a flexible connector.

Finally, there is preferably provided on the terminal means enabling itto be raised up to the loading junction on the ship.

Embodiments of the invention will now be described by way of non-restrictive examples by reference to the diagrammatic drawing attached in which: Figure 1 is a vertical section illustrating the loading station in accordance with the invention; Figure2 is a section representing a variant embodiment; Figure 3 is a partial section on a larger scale, of the buoy of the loading station in accordance with the invention; and, Figure 4 is a variant upon the device represented in Figure 3.

Figure 1 represents an open-sea loading station in which a pipe 1 brings to a base plate 2 arranged at the bottom of the sea, a hydrocarbon proceeding from a system of production which is not shown.

Substantially above the base plate 2 there has been provided a structure such as a buoy 3 which is floating and is anchored in known manner by means of lines 4.

The buoy 3 is a flat buoy, that is to say, its height is relatively small with respect to its horizontal dimensions. In the buoy 3 a lead 5 is provided, the inner walls of which exhibit a substantially toroidal shape and thus form a hawse pipe for a flexible pipe 6 connected at one end of it to the base plate 2 and equipped at its free end with a terminal 7 which will be described in greater detail below.

The terminal 7 includes known junction means enabling itto be received on a loading junction on tankships.

The terminal 7 likewise includes a lifting ring 8 the function of which will be described below.

The depth of the water at the location of this loading station may be, for example, greater than 30 metres but the flexible pipe 6 has an excess length without any intermediate connection, which may, for example, lie between 50 and 100 metres.

In the embodiment shown in Figure 1 this excess length is laid on the bottom when the terminal 7 is lying on the buoy 3.

It is therefore preferably provided that the lower portion of the flexible pipe 6 is coated with a metal ribbon, for example, of stainless steel in order to limit its wear by friction.

The loading of a tankship 9 is carried out in the following manner: The ship is anchored by any known means nearto the buoy 3, for example, at a distance of the order of 20 to 30 metres or even less. The lifting ring 8 is then seized by means of a loading mast 10 on the ship and the terminal 7 is brought on board, the excess length of the flexible pipe 6 then passing through the lead 5 in the buoy 3.

The terminal 7 is then connected by any known means to the loading junction on the ship 9, after which loading may be carried out.

When the loading is finished it is sufficient to bring the terminal 7 back on to the buoy 3, the excess length of the flexible pipe 6 running back through the lead 5 in the buoy 3. This operation is carried out easily because of the ballasting of the lower portion of the flexible pipe 6 effected by its metal coating. It is thus ensured that the excess length of the flexible pipe 6 and the terminal 7 do not remain at the side of the buoy.

Figure 2 represents a variant embodiment in which the pipe 1 and the base plate 2 are however identical with those in Figure 1.

In this variant the excess length of the flexible pipe 6 is no longer laid on the bottom but it passes over a support 11 held above the bottom by a float 12. The float 12 is further held substantially fixed with respect to the base plate 2 by means of an anchor 13.

In difficult seas this embodiment avoids wear of the lower portion of the flexible pipe.

Figure 3 represents on a larger scale an embodiment of the terminal 7.

It may be seen first of all that the lead 5 has substantially the toroidal shape described above with reference to Figure 1 in order to enable easy sliding of the excess length of the flexible pipe 6.

The terminal 7 includes in this embodiment a member 14 the surface 15 of which exhibits a shape complementary with the toroidal surface of the lead 5. This surface 15 is consequently of substantially circular cross-section and widens out towards its upper end.

The stopping of the terminal 7 against the buoy 3 is therefore effected by the contact of the surface 15 of the member 14 with the inner surface of the lead 5.

Figure 4 represents another embodiment in which the terminal 7 includes a member 16 which exhibits a bearing surface 17 which is, for example, circular with a diameter greater than the diameter of the orifice of the lead 5. Thus the bearing surface 17 may come into contact with the upper surface of the buoy 3 at the periphery of the orifice of the lead 5. Wear resistant members 18 may, for example, be provided at the periphery of the lead 5 for receiving the member 17.

In the embodiment as Figure 4 there is likewise shown at the upper part of the terminal 7 an elbow connector 19 the outlet 20 from which is consequently effected substantially horizontally.

One may thus provide on the tankship a receiver fork for the terminal 7 and then connect the outlet 20 of the connector 19 to the loading junction on the ship by means of a short complementary flexible pipe.

The invention consequently enables the loading of a tankship in the open sea to be ensured by providing for a minimum of manoeuvres on the part of the latter, whilst avoiding risks of damage to the flexible loading pipe.

The invention is obviously not restricted to the embodiments described above, to which sundry variants and modifications may be applied without thereby departing from the scope of the invention.

Claims

1. An open-sea loading station fortankships, comprising a flexible pipe connecting a first structure situated at the bottom of the sea, to a second structure on the surface or submerged close to the surface, the said second structure including a lead for the flexible pipe to pass through, in which a terminal is mounted on the end of the flexible pipe in order to prevent it from passing through the lead, the flexible pipe having an excess of length which enables its end equipped with the terminal to be brought over to a loading junction on the tankship by making it slide in the lead.

2. A loading station as claimed in claim 1, in which the said excess length is laid on the bottom.

3. A loading station as claimed in claim 1, in which the said excess length is held above the bottom by a float.

4. A loading station as claimed in any one of claims 1 to 3, in which the lower portion of the flexible pipe is coated in a metal ribbon.

5. A loading station as claimed in any one of claims 1 to 4, in which the lead exhibits a substantiallytoroidal shape.

6. A loading station as claimed in any one of claims 1 to 5, in which the terminal exhibits a shape complementary with that of the lead.

7. A loading station as claimed in any one of claims 1 to 5, in which the terminal includes a bearing surface capable of being laid on the upper surface of the structure at the periphery of the lead.

8. A loading station as claimed in any one of claims 1 to 7, in which the terminal includes on the upper portion of it an elbow connector for connec- tion of itto the loading junction on the tankship.

9. A loading station as claimed in any one of claims 1 to 8, in which the terminal includes means enabling itto be raised up to the loading junction on the tankship.