JPS6339198Y2 - - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to semi-submersible offshore structures.

For example, in a conventional semi-submersible offshore oil drilling rig, the layout of drilling-related equipment and equipment is basically the same as in an onshore drilling rig, with the ground simply being replaced by the main deck. As shown in the front view of FIG. 1, the upper surface of a substructure 2 provided approximately at the center of a deck member 1 is generally used as a drill floor 3.

Here, the substructure 2 is installed at a predetermined height relative to the deck member 1 in order to carry in and out a blowout prevention device (hereinafter referred to as BOP) 5, and a derrick 4 is installed on the drill floor 3. As part of the process of excavation work, when changing bits, installing casing pipes, logging, etc., the excavation pipe 6, heavy objects,
It is necessary to place a shield or the like against the setback area on the drill floor 3.

However, in this case, in the structure shown in FIG. 1, the center of gravity of the entire semi-submersible offshore oil drilling rig moves upward, and the overturning moment due to the wind increases, which deteriorates safety performance.

Therefore, in the past, the floating body scale was designed and variable loads were set in order to obtain sufficient stability performance even in this state, and as a result, this type of device has disadvantages in terms of economy.

For example, as shown in Japanese Patent Application Laid-Open No. 58-22785, a structure in which the tunnel 6 is housed in a plurality of support columns or braces thereof that support the outer periphery of a deck member is also known.

However, in such a structure, although it is possible to lower the center of gravity as a whole, since multiple braces and support columns are arranged eccentrically, special consideration must be given to weight distribution among the multiple braces and support columns. If this is not done, there is a risk that the entire structure will tilt and collapse.

The present invention was proposed in view of these circumstances, and it provides sufficient stability by lowering the center of gravity without paying special consideration to weight distribution when storing materials such as tunnel pipes and anti-blowout devices. The objective is to provide a safe semi-submersible offshore structure that does not raise the center of gravity or increase the overturning moment due to wind even during excavation work.

To this end, the present invention includes a horizontal flat rectangular buoyancy member that is immersed in water and has a well opening in the center;
Three or more support columns are established around the buoyancy member and the upper ends thereof extend above the water surface, and the deck member is supported around the periphery by the support columns and has a well opening in the center, and has a concentric multi-tubular structure with upper and lower ends. are coaxially connected to the well openings of the deck member and buoyancy member, respectively, and have a vertical well opening in the center, and a plurality of blowout preventers partitioned between the multiple cylinders of the buoyancy and structural member. The apparatus is characterized by comprising a device and a material compartment for storing excavated steel pipes.

An embodiment in which the present invention is applied to an offshore oil drilling rig will be described with reference to the drawings. FIG. 2 is a front view thereof, and FIG. 3 is a horizontal sectional view taken along - in FIG. 2.

In the above figure, the same symbols as in Fig. 1 indicate the same members as in the same figure, 3a is the drill floor sectioned on the deck member 1 by the pillars of the derrick 4, 6a is the tunnel, and 7 is the drill floor. A buoyant and structural member with a double cylinder structure consisting of an outer tube 7a and an inner tube 7b having the same axis;
8 is a well opening, and 9a and 9b are outer cylinders 7, respectively.
A plurality of compartments partitioned between a and the inner cylinder 7b, 1
0 is a buoyancy member that is immersed in the sea and has a well opening in the center, and 11 is four buoyancy members that are established on the four corners of the buoyancy member 10 and whose upper ends are respectively fixed to the four corners of the deck member 1 to support the deck member 1 above the sea surface. It is a support pillar.

In such a structure, a part of the deck member 1 serves as a drill floor 3a on which various drilling equipment devices are arranged.

The heavy objects, such as the tunnel 6a and BOP 5, are stored in the compartments 9a and 9b formed between the inner and outer cylinders of the buoyant and structural member 7 below the deck member 1, so the center of gravity is lowered and the stability of the floating body is reduced. Moreover, since the dug pipe 6a is not placed against the inside of the derrick 4, the overturning moment will not increase due to wind or the like.

In the above embodiment, the substructure shown in FIG.
In addition, it can also be used to store various materials such as muddy water and powder.

In short, according to the present invention, there are provided a horizontal flat rectangular buoyant member immersed in water and having a well opening in the center, three or more support columns each erected around the buoyant member and whose upper ends extend above the water surface, and A deck member whose periphery is supported by support columns and has a well opening in the center, and a concentric multi-tubular structure, the upper and lower ends of which are coaxially connected to the well openings of the deck member and buoyancy member, respectively, and a vertical well opening at the center. a buoyancy/structural member having a buoyancy/structural member, and a plurality of blowout prevention devices partitioned between multiple cylinders of the buoyancy/structural member;
By being equipped with a material compartment for storing excavated steel pipes,
This is because sufficient stability can be obtained by lowering the center of gravity without paying special consideration to weight distribution when storing materials such as tunnels and blowout prevention devices, resulting in a safe and economical semi-submersible offshore structure. , the present invention is extremely useful industrially.

[Brief explanation of drawings]

FIG. 1 is a front view showing a known submarine oil drilling rig, FIG. 2 is a front view showing an embodiment of the present invention, and FIG. 3 is a horizontal sectional view taken along the line - in FIG. 1...Deck member, 2...Substructure,
3a... Drill floor, 4... Derrick, 5...
Blowout prevention device (BOP), 6a...Drill pipe, 7...Buoyant and structural member, 7a...Outer cylinder, 7b...Inner cylinder, 8
...well opening, 9a, 9b...compartment, 10...
... Buoyancy member, 11... Support column.

Claims (1)

[Scope of utility model registration request] A horizontal flat rectangular buoyancy member immersed in water and having a well opening in the center, three or more support columns established around the buoyancy member and having upper ends extending above the water surface, and a surrounding area supported by the support columns. The deck member has a well opening in the center, and the deck member has a concentric multi-tube structure and has upper and lower ends, respectively.
A buoyancy/structural member that is coaxially connected to each well opening of the buoyancy member and has a vertical well opening in the center, a plurality of blowout prevention devices partitioned between multiple cylinders of the buoyancy/structural member, and a drilling steel pipe storage device. A semi-submersible marine structure characterized by comprising a material compartment.