GB2214897A - Template handling device - Google Patents

Abstract

A plurality of jacking tools (5), e.g. piston-and-cylinder devices, are attached to a cylindrical support (1) adapted for insertion into a first structure, e.g. a pile guide (16, 11) (Fig. 2, not shown), attached to one corner of a template structure (not shown), and arranged to jack up this structure relative to a second structure therewithin, e.g. a pile (10), (Fig. 2, not shown). The upper ends of the jacking tools are mounted on the support by cam means, e.g. an angled slot (6), whereby upon extension of the tools, the upper end of each moves outwardly and upwardly to engage a shoulder (19) formed inside the first structure. <IMAGE>

Description

Improvements in and relating to handling systems This invention relates to a method and apparatus for handling structures. In particular, it relates to the manipulation of massive structures, typically stetlwork, under water.

It is common in the offshore oil and/or gas industries to construct a drilling guide and support frame, called a "template", which is sunk into place on the sea bed prior to drilling the production wells through it, to facilitate recovering of oil/gas from a number of carefully selected parts of the oil/gas field.

Accurate drilling requires that the template be properly located and aligned. It is normal to locate it precisely and then to level it accurately before fixing it in place on the sea bed. This is not easy, since templates are both extremely large and heaxry, far in excess of what might be handled by divers. Nor is it practicable to use cranes, from a surface vessel, since the sea is never calm enough to enable the desired accuracy to be achieved. The conventional means for anchoring a template are piles, typically at each corner of the structure. These piles are anchored rigidly in the sea bed; the corners of the templates are provided with pile guides and are jacked up or down relative to the pile, prior to locking the pile in place on the pile guide when the desired attitude has been achieved.

This jacking operation is not easy and the normal approach to it has been to construct massive hydraulic jacks integral with the template itself. Massive jacks are required to overcome friction and dynamic loading, as well as to handle the weights involved.

Because these jacks are integral with the template they are extremely costly and of course they are only used once. After use and when the pile is locked to the pile guide, the jack is completely redundant.

It is an object of the present invention to provide a re-usable jacking system for levelling and/or handling structures such as templates.

According to this invention, jacking apparatus comprises a generally cylindrical supporting frame having at least two jacking tools equally spaced about the circumference thereof and disposed generally parallel to the axis of the cylinder, the jacking tools being attached to the frame at one end only by means of a pivot including cam means whereby operation of each jacking tool causes radially-outward movement of the jacking tool in the vicinity of the pivot to engage a structure which is to be lifted, in response to the other end of the jacking tool reacting, in use, against an abutment relative to which the structure is to be lifted.

Preferably the abutment is the top of a pile, and the one end of the jacking tool which moves radially outwardly does so to engage the inside of a pile guide forming part of a template structure. The generally cylindrical supporting frame is preferably hollow and includes locating means whereby the frame is self-locating on a pile top so as to ensure even engagement of the jacking tools with the latter. The apparatus is preferably provided with radial location means to centre it inside the pile guide. Conveniently the free ends of the jacking tools are attached to a support ring which carries the radial location means.

The pivot with cam means may be constituted by an arcuate or anoled slot in the radial location means and the 9 associated end oi the jacking tool preferably includes a latch member adapted to engage with the inside of a pile guide. The latter may include abutment means for the latch members to abut against, for example, an internal lip or flange.

Because only the radially-outward movement of the jacking tools causes engagement with the structure which is to be lifted, the complete apparatus may be removed after use.

Additionally, it need not be installed until after the pile against which it is t-o react has been driven home through the pile guide.

The number of individual jacking tools used will be selected according to lifting capacity and total weight to be lifted.

To lock a pile against a pile guide after use of the apparatus to effect a desired relative axial displacement of the two, for example to level a template or similar structure, it is convenient to lower hydraulic expansion tooling through the frame, to a point below the pile top, followed b expanding or swaging an annular zone of the pile outwardly to internally grip the pile guide. However other methods of locking the respective members together are feasible.

In order that the invention be better understood, a preferrred embodiment of it will now be described by way of example with reference to the accompanying drawings in which Figure 1 is a perspective view of a jacking apparatus according to the invention, and Figure 2 is a composite cross-sectional side view showing the apparatus of Figure 1 in use.

In the interests of convenience common reference numerals will be used in both Figures, as far as practicable.

Referring now to Figure 1 a generally cylindrical frame 1 has a plurality of axially and radially extending locating fins 2 disposed around its circumference. Between alternate pairs of fins 2 there are jacking tools 5. The upper end of each jacking tool is connected to the fins by means of a pivot emobodying cam means. The latter consists of an angled slot 6 as best seen in Figure 2. The associated head of each jacking tool carries a latch member 7 which is radially-outwardly displaceable relative to the fins 2 when the jacking tool is operated causing its attachment point to slide upwards along the slot 6. At the opposite end of the jacking tools there are feet 17 secured to a supporting ring structure 3. The underside of the ring carries a number of locating feet 4 which will shortly be described further in relation to Figure 2.As seen in Figure 1, the jacking tools are in the un-operated condition and accordingly the ring 3 is fully retracted against the bottom or lower end of the supporting frame 1.

Figure 2 is a composite view through a pile and pile guide. The guide 11 is attached to one corne-r of a template structure (not shown) and the pile 10 is located inside it. The top of the pile guide is provided with a flared funnel 16 the lower part of which is welded inside the top of the pile guide to form an internal collar 18.

The lower edge 19 of the collar constitutes an internal annular lip inside the pile guide. The apparatus of Figure 1 is lowered into the pile guide for example by means of the cable indicated at 20 in Figure 1, and as seen in the right hand half of Figure 2 it is lowered until the members 4 engage the upper end of the pile 10 and cause the apparatus to centre itself with respect to the pile.

Further lowering locates the ring 3 against the pile top.

At this time the jacking tools may be simultaneously operated. Because of the weight of the supporting frame 1 the latter will not be lifted to any significant extent before the individual cam means 6 cause the latch members 7 to move outwardly into engagement with the inside of the pile guide. As the supporting frame is progressively lifted the latch members 7 will engage against lip 19. In this particular instance the jacking tools are hydraulic piston and cylinder devices. Progressive extension of each piston 15 from its associated cylinder 5 will cause the pile guide to rise relative to the pile. When the pile guide and its associated structure has reached the correct height relative to its pile, the lifting operation may be stopped. The pile and guide may now be locked together, for example by lowering hydraulic expansion tooling down through the centre of the cylindrical frame 1 until it is located within the pile 10, but below the ring 3 and the locating members 4. The tobling may then be operated to swage the pile radially outwards to engage the inner surface of the pile guide 11. Once the two have been locked together the jacking tools may be retracted, lifting the ring 3 clear from the pile top. Once the ring is clear of the pile top its weight will pull the latch members 7 downwards away from the lip 19. As the pivots follow the arcuate slots 6 the latch members will be retracted between the respective fins 2. At this point the whole jacking apparatus may be withdrawn from the top of the pile guide for re-use.

Claims (8)

1. Jacking apparatus comprising a generally cylindrical supporting frame having at least two jacking tools equally spaced about the circumference thereof and disposed generally parallel to the axis of the cylinder, the jacking tools being attached to the frame at one end only by means of a pivot including cam means whereby operation of each jacking tool causes radially-outwardly movement of the jacking tool in the vicinity of the pivot to engage a structure which is to be lifted in response to the other end of the jacking tool reacting against an abutment relative to which the structure is to be lifted.

2. Jacking apparatus according to claim 1 wherein the abutment is the top of a pile and the one end of the jacking tool which moves radially outwardly does so to engage the inside of a pile guide forming part of a template structure.

3. Apparatus according to claim 1 or claim 2 wherein the generally cylindrical supporting frame is hollow and includes locating means whereby the frame is self-locating on a pile top so as to ensure even engagement of the jacking tools v.ith the latter.

4. Apparatus according to claim 3 wherein the free ends of the jacking tools are attached to a support ring which carries said locating means.

5. Apparatus according to any preceding claim wherein the frame is provided with radial location means to centre it inside a pile guide.

6. Apparatus according to any preceding claim wherein the pivot with cam means is constituted by an arcuate or angled slot in the radial location means and the associated end of the jacking tool includes a latch member adapted to engage with the inside of a pile guide.

7. Apparatus according to the preceding claim wherein the pile guide includes abutment means against which the latch members may abut when the apparatus is in use.

8. Jacking apparatus substantially as described with reference to and as illustrated by the accompanying drawings.