JPS62141216A - One-point mooring device for oil storage tanker for oil-producing structure in sea - Google Patents

Abstract

PURPOSE:To eliminate the needs to increase the falling resistance of an oil- producing structure by reducing falling moment acting on the oil-producing structure by receiving the mooring force of an oil storage tanker, etc., by the lower part of the oil-producing structure. CONSTITUTION:A structure 2 for oil production is set on the seabed ground 1 to support oil-producing equipments, a turnable guide ring 3 is fixed to the lower part of the structure 2, and a turnable supporter 4 is attached to the ring 3 in a freely turnable manner. One end of a mooring arm 5 is attached to the supporter 4 in a vertically rocking manner, and a flexible mooring cable 7 is attached to the other end of the arm 5 in such a way as to enable it to be connected with oil storage tanker, etc. Since the mooring force of the tanker 6, etc., is received by the lower part of the structure 2, the falling moment acting on the structure 2 can be more reduced than the case where the mooring force is received by the top, and the structure 2 can also be produced at low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for mooring an oil storage tanker at one point to an oil extraction structure erected on the seabed.

[Prior art]

In recent years, in order to reduce investment in the development of offshore oil fields, there has been an increasing number of cases in which crude oil is shipped directly from the offshore oil field by tanker, omitting the submarine pipeline from the offshore oil field to land. Oil storage tankers, which are modified tankers, are often permanently moored at one point in an oil field for oil storage or offshore processing and oil storage.

Conventionally, as an example of single-point mooring equipment for oil storage tankers, as shown in FIG. is installed on the seabed ground, and the front or rear part of the oil storage tanker 6 is moored to the single point mooring device 8. In this case, a submarine pipe line is connected from the oil extraction structure 2 to the single point mooring device 8. 9, the construction cost is extremely high.

As another example of a single point mooring device for oil storage tankers, as shown in FIG.
A weight 61 attached to one end of the mooring arm 11 is connected to both ends of the swing support arm 10 via a chain 12, and the front end of the oil storage tanker 6 is attached to the front end of the oil storage tanker 6. A one-point mooring device is known in which the intermediate portion of the support member 16 fixed to the tanker and the intermediate portion of the other end of the mooring arm 11 are rotatably connected by a horizontal shaft extending in the longitudinal direction of the tanker. Further, as shown in FIG. 7, a swing support member 14 is swingably attached to the top of the tower-shaped oil extraction structure 2, and a mooring arm 11 is attached to the swing support member 14.
One end of the mooring arm 11 is pivotally connected by a horizontal axis, and the mooring arm 11
A support member 15 has a pallast tank 15 attached to the other end, and one end of a connecting arm 16 is pivoted by a horizontal axis, and is fixed to the other end of the connecting arm 16 and the front end of the oil storage tankers 6. A one-point mooring device is also known in which the two are rotatably connected by a universal joint.

However, in the case of the single-point mooring device shown in FIGS. 6 and 7, the mooring force is received at the top of the oil extraction structure 2, so the overturning moment acting on the oil extraction structure 2 due to the mooring force becomes large. Since the oil extraction structure 2 needs to be made particularly sturdy, the equipment cost increases significantly, and as the water depth increases, the overturning moment acting on the oil extraction structure 2 increases, so the range of application is limited to small water depths. The problem is that it is limited to ocean areas.

[Purpose and structure of the invention]

The purpose of this invention is to provide a single point mooring device for oil storage tankers for underwater oil extraction structures that can advantageously solve the above-mentioned problems. A swing guide ring 6 surrounding the lower part of the oil extraction structure 2 is fixed to the oil extraction structure 2 installed in the oil extraction structure 2 supporting the oil extraction equipment, and is attached to the rotation guide ring B so as to be freely swingable. One end of a mooring arm 5 is attached to the swing support member 4 so as to be able to swing up and down, and the other end of the mooring arm 5 and the oil storage tankers 6 are connected via a flexible mooring strip 7. A one-point mooring device for oil storage tankers to an underwater oil extraction structure is characterized by:

〔Example〕

Next, the present invention will be explained in detail using illustrated examples.

1 to 6 show a first embodiment of the present invention, in which a jacketed steel oil extraction structure 2 supporting production equipment such as wellhead equipment is installed on seabed ground 1, and the oil extraction A circular rotating guide ring 6 made of G4 that surrounds the lower part of the oil extraction structure 2 is fixed to the oil extraction structure 2 via a bracket 17, and a large number of idle rollers are fitted into protrusions on the outer periphery of the rotating guide ring 6. Each guide roller 18 adjacent to 18
An annular swing support member 4 consisting of a link 19 connecting the
For example, both widthwise side portions (left and right side portions) of one end of the steel mooring arm 5 having a three-dimensional truss structure, which is fitted in the swinging guide ring 6 so as to be freely swingable, are connected to each other on both sides of the swinging guide ring 6 in the diametrical direction. The mooring arm 5 is attached to the swing support member 4 so as to be able to swing up and down by a horizontal shaft 20, and the other end of the mooring arm 5 is attached with a fixed position holding force generating member 21 made of a pallast tank. One end portion of a flexible mooring strip 7 made of a chain is connected to both width direction portions (left and right side portions) of the end portion via a universal joint 22, respectively.

A support member 26 extending in the left-right direction is fixed to the front end of the oil storage tankers 6 via a bracket 24, and the intermediate portion of the rotary connecting member 25 extending in the left-right direction and the support member are connected at the front of the support member 26. 26 is rotatably connected to the middle part of the tanker by a horizontal shaft 26 extending in the longitudinal direction of the tanker, and each flexible mooring strip 7 is connected to both ends of the rotary connecting member 25.
The other end is connected via a universal joint 27.

Since the support member 25 and the rotational connection member 25 can rotate relative to each other around the horizontal axis 26, even if rolling behavior occurs in the oil storage tankers B, each flexible mooring strip 7 and The rolling motion transmitted to the mooring arm 5 is kept to a minimum.

In addition, the vertical movement 9 of the oil storage tanker A is controlled by the uni-9-surge joints 22.27 at both ends of the flexible mooring strip 7 and the horizontal shaft 20 connecting the mooring arm 5 and the swing support member 4.
The back and forth movement is absorbed, and therefore, the impact caused by the oscillation of the oil storage tankers B is not directly transmitted to the oil extraction structure 2.

A riser pipe 28 connected to an undersea oil field and extending from the seabed to the top of the oil extraction structure 2 is supported by the oil extraction structure 2, and a swivel 29 is attached to the top of the oil extraction structure 2.
The fixed part of the swivel 29 is fixed, and the riser pipe 28 is connected to the fixed part of the swivel 29 through the pulp, and the rotating part of the swivel 29 has a flexible
The riser pipe 28, swivel 29, and flexible pipe 60 constitute a supply channel for supplying produced crude oil from the offshore oil field to the oil storage tankers B, and the rotating part of the swivel 29 connects to the oil storage tanker B. The driving force for rotating along with the turning movement of the tankers 6 is provided by a drive device that automatically controls the connection part between the swivel 29 and the rising pipe 28 to always face the oil storage tankers B. Alternatively, it is applied via an operating member such as a wire rope by a swivel control device installed on an oil storage tanker. Therefore, even if the oil storage tankers 6 make a turning movement,
Excessive tension is not applied to the flexible sleeve 60 or the swivel 29.

FIG. 4 shows a second embodiment of the present invention, in which a base plate 62 and a support body 36 disposed above it are connected via a plurality of stays 34 disposed around a riser pipe 28. The oil extraction structure 2 is constructed by connecting and fixing the base plate 32 with a pile 35 driven into the seabed ground 1, and the swing guide ring 6 is fixed to the pile 35, but the other configurations are as follows. This is the same as in the first embodiment.

When carrying out the present invention, the oil storage tankers may be oil storage tankers equipped with crude oil production and processing facilities or vessels such as purge vessels used for the same purpose. Further, as the oil extraction structure, a jacket structure supporting a wellhead apparatus or a large jacket structure equipped with large-scale production equipment may be used. Furthermore, a wire rope may be used as the flexible mooring strip 7.

〔Effect of the invention〕

According to this invention, the swing guide ring 6 surrounding the lower part of the oil drilling structure 2 is fixed to the oil drilling structure 2 installed on the seabed ground 1 and supporting oil drilling equipment, and the swing guide ring One end of the mooring arm 5 is attached to the swing supporting member 4 so as to be swingable up and down. One end of the mooring arm 5 can be rotatably supported by the lower part of the oil extraction structure 2 without interfering with the equipment, and the mooring force of the oil storage tankers B can be transferred to the flexible mooring strip 7°. Mooring arm 5. Since the mooring force is received at the lower part of the oil extraction structure 2 via the rotation support member 4 and the rotation guide ring 6, the mooring force is applied to the oil extraction structure 2.
The overturning moment acting on the oil extraction structure 2 can be significantly reduced compared to the case where the oil extraction structure 2 receives it at the top, and therefore there is no need to increase the overturning strength of the oil extraction structure 2. 2 can be manufactured at a low cost, and the overturning moment caused by the mooring force can be suppressed to a small level even at large water depths, so the range of application to various water depths can be expanded. ξ Since it is not necessary to lay a line, the construction cost can be reduced and other effects can be obtained.

[Brief explanation of drawings]

1 to 6 show a first embodiment of the present invention, and FIG. 1 is a side view of a single point mooring device of the present invention;
FIG. 2 is a cross-sectional plan view thereof, and FIG. 6 is a vertical cross-sectional side view showing a swing guide ring, a swing support member, and a part of an oil extraction structure. FIG. 4 is a side view showing a single point mooring device according to a second embodiment of the present invention. Fig. 5 is a perspective view showing an example of an offshore oil production facility using a conventional single-point mooring device, Fig. 6 is a perspective view showing a single-point mooring device using a conventional jacket type oil extraction structure, and Fig. 7 is a perspective view showing an example of an offshore oil production facility using a conventional single-point mooring device. FIG. 2 is a side view of a single-point mooring device using a conventional tower-set oil extraction structure. In the figure, 1 is submarine ground, 2 is an oil extraction structure, 6 is a swing guide ring, 4 is a swing support member, 5 is a mooring arm,
6 is an oil storage tanker, 7 is a flexible mooring strip, 18 is a guide roller, 19 is a link, 20 is a horizontal shaft, 21 is a fixed position holding force generating member, 22 is a universal joint, 23 is a support member, 25 26 is a horizontal shaft, 27 is a universal joint, 28 is a riser pipe, 29 is a swivel, 60 is a flexible knob, 62 is a base plate, 63
is a support, 64 is a stay, and 65 is a stake.

Claims (1)

[Claims] A swing guide ring 3 that surrounds the lower part of the oil extraction structure 2 is fixed to an oil extraction structure 2 that is installed on the seabed ground 1 and supports oil extraction equipment, and is attached to the rotation guide ring 3 so as to be freely swingable. One end of a mooring arm 5 is attached to the swing support member 4 that is vertically swingable, and the other end of the mooring arm 5 is connected to the oil storage tankers 6 via a flexible mooring strip 7. A single point mooring device for an oil storage tanker or the like to an underwater oil extraction structure, characterized in that the device is connected to an oil extraction structure in the sea.