JPH01145292A - Device for joining upper part of tendon of tension leg platform - Google Patents

Abstract

PURPOSE:To facilitate joining and disengagement operation of a tendon by making a cylindrical load bearing at the upper end of the tendon possible to engage with a cylindrical bearing carrier having larger longitudinal slit than the dia. of the tendon on the outside of the lower part of a column through a two-divided ringlike load ring. CONSTITUTION:On the lower outside of column of a platform capable of floating, a cyrindrical bearing carrier 7 having a larger longitudinal slit 11 than the dia. of a tendon 5 is fixed. On the upper end of the tendon 5, a cylindrical load bearing 9 mounted at a back flange 8 formed through a flexible element 10 is made to be able to engage through a two-divided ringlike load ring 12, and the engaging part is covered with a cap 13. The thickness of the load ring 12 can be adjusted while the tendon is easily and surely mounted even in a shallow water area, and also the disengagement operation can be made with a simple operation.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a system for mooring a semi-submersible platform, etc. for offshore oil production, offshore construction, and other offshore development to a submarine foundation using tendons when installing it in a sea area. The present invention relates to an upper coupling device of a tendon of a tension leg platform.

[Prior art]

As mentioned above, when mooring a buoyant semi-submersible platform to a seabed foundation with a tendon made of steel pipes,
As shown in FIG. 5, when mooring is performed by connecting the upper end of a tendon 5 whose lower end is connected to the template 4 side of the seabed foundation in the mooring device room 3 provided inside the column 2 of the platform 1, the mooring device It is necessary to provide a device for coupling the tendons 5 and many other devices in the chamber 3.

Therefore, as shown in Fig. 6, a structure in which the tendon 5 is connected to the outer lower end of the column 2 at the bottom of the platform 1 is already in use, and the upper connecting device of the tendon 5 is simplified and its inspection is also easier. This has the advantage that it is easy, and furthermore, the tendons 5 can be easily connected and removed.

Such a tension leg platform is a powerful piece of equipment, especially as a platform for use in deep sea areas, and as shown in Figure 6, when multiple tendons 5 are attached, tension is applied to the legs to cause elastic elongation. A method of mooring the column 2 by latching it to the tendon support structure 6 at the outer lower end of the column 2 is being considered.

In this case, if the water depth is, for example, about 500 m, elastic elongation of about 10 to 20 ω will occur in the steel tube type tendon 5 by applying tension, and therefore latching to the tendon support structure 6 will be easily performed. become.

However, in shallow water, the amount of elastic expansion is small even when tension is applied, so latching is difficult and the operation of connecting the upper end of the tendon 5 to the tendon support structure 6 cannot be performed smoothly.

Therefore, it is conceivable to screw the joint part into two, but there is a problem that the threaded part is easily rusted by seawater, making it difficult to separate when removed.

[Purpose of the invention]

The present invention has been made in order to solve the above-mentioned conventional problems, and it is possible to easily and reliably attach a plurality of tendons to a tendon support structure even in shallow water depths.
Furthermore, the object is to provide a tendon upper coupling device that can be easily separated during removal.

[Structure of the invention]

To achieve the above object, the tension leg platform tendon upper coupling device of the present invention is such that a component of the tendon support structure provided outside the column of the buoyant platform is pre-attached to the upper end of the tendon. between a cylindrical bearing carrier having an outer diameter capable of locking a cylindrical load bearing and having a slit in the vertical direction on its peripheral surface that is slightly larger than the diameter of the tendon, and the load bearing and the bearing carrier; It is characterized by consisting of two split ring-shaped load rings that can be inserted into the load ring, and a cap that can be fitted to securely maintain the moored state in which the load bearing and bearing carrier are set with the load rings inserted. That is.

With the tendon upper coupling device having the above configuration, when the lower end is fixed to the seabed foundation by latching etc. and the upper end of the tendon is loaded with tension using a tensioner etc., even if there is little elastic elongation of the tendon at shallow water depth, By inserting a split ring-shaped load ring with an appropriate thickness into the gap between the load bearing and the bearing carrier, the load ring can be smoothly and easily inserted into the gap between the load bearing and the bearing carrier while applying tension to the tendon built into the bearing carrier from the slit. The tendon support structure and the upper end of the tendon can be attached, and the moored state of the tendon can be reliably maintained by fitting the cap in the attached set state.

〔Example〕

The present invention will be described in detail below with reference to the drawings. FIG. 1 is a side sectional view of an upper coupling device of a tendon according to an embodiment of the present invention, and FIG. 3 is a plan sectional view taken along the line CC in FIG. 1, and FIG. 4 is an overall view of a tension leg platform to which the upper coupling device of FIG. 1 is applied.

First, in this embodiment shown in FIG. 4, similar to the conventional example shown in FIG. Four tendons 5 with their lower ends attached to
The upper ends of the four tendons 5 are respectively connected to tendon support structures 6, so that the platform 1 is moored with the four tendons 5.

Next, as shown in FIGS. 1, 2, and 3, a cylindrical bearing carrier 7 is fixed to this tendon support structure 6, and this bearing carrier 7 is attached to the tendon 5.
An opening having an outer diameter capable of locking a cylindrical mouth bearing 9 pre-attached to a back flange 8 formed through a flexible element 10 at the upper end, and slightly larger than the diameter d of the tendon 5. It has a vertical slit 11 on its circumferential surface.

Also, a load ring 12 in the form of a split ring that can be inserted between the load bearing 9 and the bearing carrier 7 is provided.
Prepare in advance various thicknesses.

Further, as shown in FIG. 1, a camp 13 is provided into which the load bearing 9 with the load ring 12 inserted and the bearing carrier 7 are fitted in such a manner that the set mooring state can be reliably maintained.

Next, to explain the outline of the procedure for installing the tendon 5 using the above-mentioned tendon 5 upper coupling device of the present invention, the tendon 5 is created on land using a steel pipe, etc., and then floated horizontally and guided to the installation position. It will stop at the side of platform 1 where it is temporarily moored.

Then, attach the suspension line 1 to one end of the tendon 5.
4 are connected and suspended by a davit 15, and this suspension line 14 passes through the inside of the tension rod 15.

Next, the tendon 5, which has been appropriately suspended by the suspension line 14, is inserted from the side of the tendon support structure 6. At this time, the tension rod 15 is inserted into the tensioner 1.
6, it is lifted by the required amount.

Further, the lower anchor connector is guided by the guideline directly above the anchor housing of the template 4 of the submarine foundation, the suspension line 14 is unwound, and the anchor connector is lowered until it almost contacts the guide frame.

On the other hand, the upper end of the tendon 5 is connected to the tension rod 15 which is suspended by the tensioner 16, and the tendon 5 is lowered along the guide frame by the tensioner 16.

Next, after latching the lower end of the tendon to the template, the tendon 5 is pulled up by the tensioner 16, and a tension that is preset in consideration of elongation due to elastic strain is applied to the tendon 5.

Therefore, the gap between the load bearing 9 and the bearing carrier 7 of this upper coupling device was measured using a dieper, and a two-part load ring 1 having the optimum thickness was placed in the gap.
2 is lowered along the guide of the tension rod 15 and inserted with the support of the dial.

Then, the tension of the tensioner 16 is released and the tension rod 15 is removed from the upper end of the tendon 5.

Furthermore, the camp 13 is suspended along the tension rod 15, and the cap 13 is fitted and rotated using the support of the diameter holder to complete the installation, but when removing the cap 13, the above order is reversed.

〔Effect of the invention〕

As explained above, with the tension leg platform that employs the tendon upper coupling device of the present invention, it is possible to easily and reliably attach multiple tendons to the tendon support structure even in shallow waters. This has the effect that it can be easily detached during removal.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of an upper coupling device for tendons according to the present invention, FIG. 2 is a plan sectional view taken along the line B-B in FIG. 1, and FIG. 3 is a plan sectional view taken along the line C-C in FIG. 1. 4 is an overall view of a tension leg platform to which the upper coupling device of FIG. 1 is applied, and FIGS. 5 and 6 are overall views of a conventional tension leg platform. ...Column, 5...
・Tendon, 6...Tendon support structure, 7...Bearing carrier, 9...Load bearing, 11...
・Slit, 12...Load ring, 13...Cap. Agent Patent Attorney Nobuo Ogawa −

Claims (1)

[Claims] An upper coupling device for a tendon support structure provided outside the lower part of a column of a platform, which has an outer diameter that can lock a cylindrical load bearing attached to the upper end of the tendon, and has an outer diameter slightly smaller than the diameter of the tendon. A cylindrical bearing carrier having a large slit on its circumferential surface, a split ring-shaped load ring that can be inserted between the load bearing and the bearing carrier, and a load bearing and the bearing with the load ring inserted. An upper coupling device for a tendon of a tension leg platform consisting of a cap that can be fitted to maintain the set state of the carrier.