JPH10252373A - Riser pipe hang-off device for seabed excavation ship - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hang-off device whose maintenance is easy to be executed and structure is simple. SOLUTION: There is provided a hang-off joint 1 which separates the lower end of a riser pipe 3 from a seabed pit mouth and suspends the riser pipe 3 from a ship body in a hang-off state. The joint 1 comprises a head flange 1a and a lower end flange 1d with a ball joint 1e. Since the hang-off joint 1 is used in exchange for a telescopic joint, the head flange 1a is engaged with the upper edge of an opening of a rotary table 11 on the ship and the rise pipe 3 to rock relatively with the ball joint 1e attached to the lower end flange 1d when the ship body is being rocked.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a submarine drilling vessel used for oil extraction from a submarine oil field, and more particularly to a submarine drilling vessel in which the lower end of a riser pipe is cut off from a hull. Suspended state (hang off)
To a device for

[0002]

2. Description of the Related Art Generally, as shown in FIG. 6, an outer barrel 7a (see FIG. 9) of a telescopic joint 7 is hung by a wire 8a of a riser tensioner 8 provided in a hull structure 4, as shown in FIG. The riser pipe 3 is connected to the lower end of the outer barrel 7a via a ball joint 2 '.

The upper end of the inner barrel 7b of the telescopic joint 7 is connected to the lower part of the rotary table 11 via the ball joint 2, as shown in FIG. That is, the ball joints 2 and 2 'are provided at the upper end and the lower end of the telescopic joint 7, respectively.

When the lower end of the riser pipe 3 is connected to the sea bottom pit, the lower end of the riser pipe 3 is removed from the sea bottom pit in response to the intensification of waves, and the riser pipe 3 is suspended (hang-off). In doing so, work is performed in the following procedure.

First, the telescopic joint 7 is moved from the state of FIG. 6 to the rotary table 11 through the traveling tube 10a and the traveling block 10 as shown in FIG.
, And then, as shown in FIG.
Moon pool 6 at the lower end of telescopic joint 7
The ball joint 2 ′ is gripped by the hydraulic hang-off clamp mechanism 5 (see FIG. 10) at the upper part of the telescopic joint 7 thus restrained.
And the riser pipe 3 is suspended. Reference numeral 9 in FIG. 6 indicates a hydraulic line for a hydraulic hang-off clamp mechanism.

[0006]

By the way, in the conventional riser pipe hang-off device for a submarine drilling vessel as described above,
The use of the hydraulic hang-off clamp mechanism 5 complicates the arrangement of hydraulic equipment and hydraulic piping, and requires a ball joint 2 'at the lower end of the telescopic joint 7 to absorb the sway of the hull. Also becomes complicated, and the construction cost and the maintenance cost become expensive. Therefore, an object of the present invention is to provide a riser pipe hang-off device for a submarine drilling vessel which has a simple configuration and is easy to maintain.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a riser pipe hang-off device for a submarine drilling vessel according to the present invention includes a rotary table installed on a ship and an ascent / descent through a diverter immediately below the rotary table. A hang-off joint for suspending a riser pipe to be operated is provided. The hang-off joint can be engaged with a vertical rod-shaped body and an upper edge of an opening of the rotary table provided on a head of the rod-shaped body. A head flange and a lower end flange with a ball joint provided at a lower end of the rod-shaped main body and connected to an upper end of the riser pipe, and protrude from an outer peripheral wall of an intermediate portion of the rod-shaped main body to an inner peripheral wall of the diverter. It is characterized in that it has a swing-preventing overhang that can be engaged.

In the above-described riser pipe hang-off device for a submarine drilling vessel according to the present invention, the telescopic joint connected to the upper end of the riser pipe while the riser pipe is in use is provided.
The hang-off state can be easily achieved by replacing the hang-off joint. That is, after separating the lower end of the riser pipe from the sea bottom wellhead, lift the telescopic joint together with the riser pipe, replace the telescopic joint with the above hang-off joint above the rotary table, and replace the lower end flange with the ball joint of the hang-off joint with the riser pipe. When the hang-off joint is lowered after being connected to the upper end of the hang-off joint, the head flange of the hang-off joint engages with the upper end of the opening of the rotary table, and the overhang of the hang-off joint has a diverter just below the rotary table. And the swing of the hang-off joint is suppressed. Then, the relative swing of the riser pipe at the time of sway of the hull is allowed through a ball joint attached to the lower end flange of the hang-off joint.

As described above, the present device eliminates the need for the conventional hydraulic clamping mechanism, does not require complicated hydraulic equipment and arrangement of hydraulic piping, and eliminates the need to provide a ball joint at the lower end of the telescopic joint. Therefore, the structure is simplified as a whole, and the maintenance is also significantly simplified, resulting in a significant cost reduction.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view showing a main part of a riser pipe hang-off device for a submarine drilling ship according to an embodiment of the present invention. FIG. FIG. 3 is an explanatory view showing a preparation state for use, FIG. 3 is an explanatory view showing a lifting state in which a riser pipe or the like is lifted from the preparation state of FIG. 2, and FIG. FIG. 5 is an explanatory view showing a replaced state, and FIG. 5 is an explanatory view showing a state in which the hang-off joint is lowered together with the riser pipe from the replaced state in FIG. 4 and installed on a rotary table.

As shown in FIG. 1, in this apparatus, a riser pipe 3 which is lifted and lowered through an opening of a rotary table 10 provided on a hull and an inside of a diverter 11a immediately below the rotary table 10 is suspended. The hang-off joint 1 has a vertical bar-shaped main body 1b, a head flange 1a provided at the head of the rod-shaped main body 1b, and a lower end of the rod-shaped main body 1b. It has a lower end flange 1d with a ball joint 1e provided.

Further, the hang-off joint 1 protrudes from the outer peripheral wall of the intermediate portion of the rod-shaped main body 1b and is connected to the diverter.
An anti-oscillation overhang 1c which can be engaged with the inner peripheral wall of 11a.
Is configured.

In the hang-off state of the riser pipe 3 using this apparatus, the head flange 1a of the hang-off joint 1 is engaged with the upper edge of the opening of the rotary table 11, and the lower flange 1d with the ball joint 1e is connected to the riser pipe 3. It is designed to be connected to the upper end.

The diverter 11a has a mechanism for shutting off gas inside the riser pipe 3 and allowing the gas to escape in the lateral direction, and is attached to the lower part of the rotary table 11.

In the above-described riser pipe hang-off device for a submarine drilling vessel of the present embodiment, the telescopic joint (see reference numeral 7 in FIG. 6) connected to the upper end of the riser pipe during use of the riser pipe 3 is replaced with the hang-off joint 1. The hang-off state can be easily achieved by exchanging with. That is, after the lower end of the riser pipe 3 is cut off from the seabed wellhead to be in the preparation state shown in FIG. 2, the telescopic joint 7 is lifted together with the riser pipe 3 as shown in FIG. Then, the telescopic joint 7 is replaced with the hang-off joint 1 above the rotary table 11 as shown in FIG. 4 so that the flange 1d with the ball joint 1e of the hang-off joint 1 is connected to the upper end of the riser pipe 3. Next, when the hang-off joint 1 is lowered, the head flange 1a of the hang-off joint 1 engages with the upper edge of the opening of the rotary table 11 as shown in FIG. 5, and as shown in FIG. 1 is a diverter 11a just below the rotary table 11
And the swing of the hang-off joint 1 is suppressed. Then, the relative swing of the riser pipe 3 during the sway of the hull is allowed through the lower end flange 1d with the ball joint 1e of the hang-off joint 1.

As described above, the present apparatus eliminates the need for the conventional hydraulic clamping mechanism (see reference numeral 5 in FIGS. 8 and 10), does not require complicated hydraulic equipment and hydraulic piping arrangements, and has a telescopic joint. Since there is no need to provide a ball joint (see reference numeral 2 'in FIG. 8) at the lower end of 7, the structure is simplified as a whole, the maintenance is also significantly simplified, and the cost is greatly reduced.

[0017]

As described in detail above, according to the riser pipe hang-off device for a submarine drilling vessel of the present invention, the following effects can be obtained. (1) By replacing the telescopic joint connected to the upper end of the riser pipe with the hang-off joint during use of the riser pipe, the hang-off state can be easily achieved. (2) After separating the lower end of the riser pipe from the submarine wellhead,
Lift the telescopic joint together with the riser pipe, replace the telescopic joint with the above hang-off joint above the rotary table, connect the flange with the ball joint of the hang-off joint to the upper end of the riser pipe, and then lower the hang-off joint When this is done, the head flange of the hang-off joint engages with the upper end of the opening of the rotary table, and the overhang of the hang-off joint engages with the inner peripheral wall of the diverter immediately below the rotary table, causing the hang-off joint to swing. Is suppressed. And, through the ball joint attached to the lower end flange of the hang-off joint,
The relative swing of the riser pipe when the hull sways is allowed. (3) In the device of the present invention, the conventional hydraulic clamping mechanism is not required, and no complicated hydraulic equipment or hydraulic piping arrangement is required, and it is not necessary to provide a ball joint at the lower end of the telescopic joint. As a whole, the structure is simplified, the maintenance is also significantly simplified, and the cost is greatly reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a main part of a riser pipe hang-off device for a submarine drilling ship as one embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a preparation state for using the apparatus of FIG. 1;

FIG. 3 is an explanatory diagram showing a lifting pipe state in which a riser pipe and the like are lifted from the preparation state of FIG. 2;

FIG. 4 is an explanatory view showing a state in which the telescopic joint in the raised pipe state of FIG. 3 is replaced with a hang-off joint.

FIG. 5 is an explanatory view showing a state in which the hang-off joint is lowered together with the riser pipe from the replacement state in FIG. 4 and is mounted on a rotary table.

FIG. 6 is an explanatory view showing a preparation state in a conventional riser pipe hang-off device for a submarine drilling vessel.

FIG. 7 is an explanatory view showing a lifting pipe state in which a riser pipe and the like are lifted from the preparation state of FIG. 6;

8 is an explanatory view showing a state in which the lower end of the telescopic joint is restrained in the raised pipe state in FIG. 7;

FIG. 9 is an enlarged vertical sectional view of the telescopic joint in FIG. 6;

FIG. 10 is an enlarged view taken on line AA of FIG. 8;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hang-off joint 1a Head flange 1b Bar-shaped main body 1c Overhanging part 1d Lower end flange 1e Ball joint 2, 2 'Ball joint 3 Riser pipe 5 Hydraulic hang-off clamp mechanism 6 Moon pool 7 Telescopic joint 7a Outer barrel 7b Inner barrel 8 Riser Tensioner 8a Wire 9 Hydraulic line 10 Traveling block 10a Traveling pipe 11 Rotary table 11a Divertor

Claims (1)

[Claims] 1. A hang-off joint for suspending a riser pipe which is lifted and lowered through an opening of a rotary table installed on a ship and an inside of a diverter directly below the rotary table, wherein the hang-off joint is provided in a vertical direction. A rod-shaped body, a head flange provided on the head of the rod-shaped body and capable of engaging with an upper edge of the opening of the rotary table, and a ball joint provided on a lower end of the rod-shaped body and connected to an upper end of the riser tube A bottom end flange, and a projection for preventing rocking that protrudes from an outer peripheral wall of an intermediate portion of the rod-shaped body and can be engaged with an inner peripheral wall of the diverter. Riser tube hang-off device for drilling boats.