CN104805814A - Self-elevating platform pile leg mounting method - Google Patents

Abstract

The invention provides a method for installing legs of a self-elevating platform, which includes the steps of: positioning and floating the main hull with base leg sections in a dry dock; keeping the base leg sections in a vertical direction relative to the main hull In the static state on the ship, use the sea crane to hoist the pile legs to be installed in sections to the closing opening one by one, and perform positioning welding on the pile leg sections until the pile leg sections on the main hull reach the predetermined height; among them, the sea crane positioning at a designated location in the sea outside the dry dock. The present invention does not need to lift legs, does not need to stand piles, and shortens the construction period. Since the main hull and the sea crane are all in a floating state, it is beneficial to adjust the relative positions of the two, thereby facilitating the closing of the pile legs.

Description

Installation method of jack-up platform legs

technical field

The invention relates to the construction field of self-elevating platforms, in particular to a method for installing legs of self-elevating platforms.

Background technique

According to the current development trend of jack-up platforms worldwide, the construction height of jack-up platform legs will be higher and higher. In the next few years, jack-up platforms with operating water depths of 400 feet and 500 feet will become jack-up platforms. mainstream products. Jack-up platforms generally include a main hull and three truss-type legs that can be raised and lowered relative to the main hull. When the platform is operating, the legs extend down to the seabed and stand on the seabed to support the main hull, so that the main hull and the sea surface have a certain distance. distance.

When the jack-up platform is built, the legs need to be installed on the main hull. As the working water depth of the jack-up platform increases, the height of the legs also increases. When the jack-up platform is built, the legs will be divided into multiple segments, and then each leg segment will be closed in turn in the height direction. As the height of the legs increases, the swing at the top of the legs will increase. The installation of pile leg segmentation has brought very big difficult problem.

At present, there are mainly four installation methods for the legs of large-scale truss-type leg platforms:

1. Shore crane closing method: For example, the Chinese invention patent with the application number 201010115089.8 discloses a method for closing the truss-type pile legs of a self-elevating drilling platform. Pre-close on land; fix the launched hull on the wharf, and use a shore crane with strong lifting capacity on the wharf to close the pre-closed pile legs in sections. The advantage of this method is that the closing work at the wharf is less affected by the sea conditions, and the steps of closing the legs can be performed in parallel. The disadvantage is that this method of leg installation needs to be completed by shore cranes with strong lifting capacity, which is too limited by resources, and as the height of the legs increases, the requirements for the lifting capacity of the crane are also increasing. For example, the leg height of a 400-foot platform is currently 167 meters, and a shore crane of about 170 meters is required to complete the hoisting. However, the cost of building a crane is huge, and this method is not easy to use universally.

2. Water towing installation method: For example, the Chinese invention patent with the application number of 200710157586.2 discloses a large truss type pile leg water towing installation method. The overview of the installation method is as follows: predetermined sea area insertion; installation of towing mechanism; crane Lift the pile legs segmentally to the dragging mechanism, use the lifting device to raise the platform to the specified height; use the dragging mechanism to close up; lower the platform to close up in the next cycle. The advantage of this water towing installation method is that the segmental installation of pile legs can be completed without large sea cranes. The disadvantage is that the main hull (that is, the platform) needs to be lifted. During the lifting process of the hull, construction cannot be carried out on the platform, and it is inconvenient for personnel to go up and down. .

3. Pile closing method: The general steps of this method are: after the main hull is launched, the lifting system of the pile legs is debugged first; the seabed to be closed is selected; the platform stands on the seabed; Install the legs at the closing opening of the legs.

4. Deep-sea closing method: The general steps of this method are: establish base pile leg segments, drive the platform into the deep sea area, use barges to transport the pile leg segments to the closing area, and use guide rails or sea cranes to close the pile leg segments Go to the sub-sections of the pile legs at the base level, and after the closing is completed, lower the pile legs to carry out the next cycle of closing. Although this method means that the platform is always in a floating state when it is closed, it is basically not adopted by shipyards due to the limitation of wind and surge conditions because it must be closed in a deep sea area.

The second and third methods are the pile leg installation methods commonly used in the ocean engineering industry at present, but both require the main hull to stand. However, two conditions must be met to carry out the main hull station piling: 1. The geological conditions of the seabed are very strict for the pressure piling. Pile puncture” will destroy the leg structure. Therefore, it is necessary to find a suitable seabed for standing piles; 2. Since the pile legs need to be lowered when standing piles, the pile leg lifting system must be fully debugged. According to the construction process, the commissioning of the leg lifting system and the closing of the legs are carried out in series, which delays the entire construction period of the platform by about 2 months.

Under the general trend that all shipyards are trying their best to shorten the construction period, a method is needed to avoid the restrictions on the installation of pile legs due to factors such as the failure to complete the commissioning of the lifting system on time, and the seabed is not suitable for standing piles, so as to reduce the platform production cycle.

Contents of the invention

Based on the shortcomings of the above-mentioned background technology, the present invention provides a method for installing the legs of a jack-up platform to solve the problems of long closing time, low work efficiency, and serious influence by sea conditions of the existing platform legs.

In order to solve the above-mentioned technical problems, the present invention adopts the following technical solutions: a method for installing legs of a self-elevating platform, comprising steps:

Position and float the main hull with base leg sections in dry dock;

Keep the static state of the base pile leg section relative to the main hull in the vertical direction, use the sea crane to hoist the pile leg sections to be installed to the closing mouth one by one, and carry out positioning welding on the pile leg sections until the The leg section reaches a predetermined height; wherein, the sea crane is positioned at a designated position in the sea area outside the dry dock.

Preferably, the step of positioning and floating the main hull with base pile leg sections in the dry dock is as follows:

launching the main hull with base leg sections established;

Move the main hull to a predetermined position in the dry dock, close the dock door of the dry dock, adjust the water level in the dry dock to a specified height, and moor the main ship.

Preferably, the specified height is lower than the sea level of the sea area outside the dry dock.

Preferably, the draft of the main hull in the dry dock is a set value.

Preferably, before hoisting the leg segments to the closing opening by using the sea crane, the method further includes the step of: adjusting the relative position between the sea crane and the leg segments to be installed on the main hull.

Preferably, the step of adjusting the relative position between the sea crane and the section of the legs to be installed on the main hull is specifically: rotating the main hull in the dry dock to adjust the distance between the sections of the legs to be installed and the sea crane. distance and angle.

Preferably, after one leg segment is closed and before the next leg leg segment is closed, a step is further included: adjusting the floating state of the main hull so that the installation position of the next leg segment is in a horizontal state.

Preferably, the adjustment of the floating state of the main hull is realized by adjusting the ballast water in the main hull.

Preferably, the segmental section of the pile legs is an equilateral triangle, and the sea crane hoistes the leg segments from the apex of the equilateral triangle to the side of the extension line in the direction of the center of gravity.

Preferably, the leg segments to be installed are positioned on the base leg segments of the main hull by means of closing tooling and fixed to the base leg segments by tack welding.

Preferably, before positioning and floating the main hull with base leg sections in the dry dock, using a gantry crane or a shore crane to install the legs on the main hull in sections to form the base leg sections.

As can be seen from the foregoing technical solutions, the advantages and positive effects of the present invention are:

1. The method of the present invention does not need to lift the legs up and down when installing the legs, which ensures that the legs do not need to be raised and lowered repeatedly when they are closed, and protects the lifting system.

2. The method of the present invention does not need to be carried out under the condition that the commissioning of the leg lifting system is completed, and the pre-commissioning of the lifting system can be carried out simultaneously during the leg installation process, and the parameters of the lifting system, especially the gearbox, are checked, and The lifting system, especially the inching lifting and debugging of the gearbox, can be interspersed in parallel in the installation gap of the whole cycle of pile leg installation, shortening the production cycle and improving production efficiency.

3. In the method of the present invention, the main hull floats in the dry dock, and the sea crane is located outside the dry dock. Both of them are in a floating state, and the position of the main hull can be easily adjusted by using tools such as winches and cables. The position and angle of the pile legs relative to the sea crane can further adjust the height difference between the main hull and the sea crane through the control of the water level in the dry dock.

Four, in the method of the present invention, do not need to stand pile, have avoided being subjected to the influence of seabed geological regulation, have avoided pile leg being destroyed by seabed geological influence.

Description of drawings

Fig. 1 is a flow chart of an embodiment of a method for installing legs of a self-elevating platform according to the present invention.

Fig. 2 is a schematic diagram of the layout of the sea crane and the jack-up platform when the method for installing the legs of the jack-up platform according to the present invention is implemented.

Fig. 3 is a schematic diagram of the relative positions of the sea crane and the jack-up platform legs during implementation of the method for installing the legs of the jack-up platform according to the present invention.

Fig. 4 is a top view schematic diagram of the sub-sections of the hoisting legs of the jack-up platform in the method for installing the legs of the jack-up platform according to the present invention.

Fig. 5 is a schematic diagram of a sea crane hoisting a leg segment from one side of the extension line from the center of gravity of the leg segment equilateral triangle to the apex direction.

Fig. 6 is a schematic diagram of a sea crane hoisting a leg segment from one side of the extension line from the apex of the equilateral triangle of the leg segment to the direction of the center of gravity.

Explanation of symbols: 1. self-elevating platform; 11. main hull; 12. legs; 120. spud boots; 121. base leg section; 122. leg segment; 2. sea crane; Boom; 3, dry dock; 31, dock door.

Detailed ways

Typical embodiments that embody the features and advantages of the present invention will be described in detail in the following description. It should be understood that the present invention is capable of various changes in different embodiments without departing from the scope of the present invention, and that the description and illustrations therein are illustrative in nature and not limiting. this invention.

The present invention provides a method for installing the legs of a self-elevating platform, wherein, as shown in Figure 2, the self-elevating platform 1 includes a main hull 11 and a leg 12 that can be raised and lowered relative to the main hull 11, which is different from the current common The self-elevating platform has the same structure, the self-elevating platform 1 has three legs 12, and the legs 12 are arranged in an equilateral triangle on the main hull 11. Method of the present invention promptly solves the installation problem of pile leg 12, referring to Fig. 1, this method mainly comprises steps:

S10: positioning and floating the main hull with base pile leg sections in the dry dock;

S20: Keep the static state of the pile leg section of the base layer relative to the main hull in the vertical direction, hoist the pile leg sections to be installed to the closing opening one by one with a sea crane, and carry out positioning welding on the pile leg sections until the main hull The leg section on the top reaches a predetermined height; wherein, the sea crane is positioned at a designated position in the sea area outside the dry dock. "Closed mouth" refers to the position where the leg segments need to be installed, which is a dynamic position. Taking the construction process of a pile leg as an example, the construction process of the pile leg is to close the pile leg segments along the height direction successively on the basis of the base pile leg section, and the specific process is to close the first section of pile leg on the base pile leg section in sequence segment, then close the second leg segment on the first leg segment, then close the third leg segment on the second leg segment, ..., and finally close the top leg Segmentation; in this process, the "closed mouth" refers to the upper end surface of the base leg section, the upper end surface of the first leg section, the upper end surface of the second leg section... During the construction of the pile legs, there is no relative displacement in the vertical direction between the pile legs and the main hull, that is, the pile legs do not go up and down, and are not affected by the pile leg lifting system.

Among them, before step S10, the shipyard can install as many leg segments as possible on the main hull through all available resources such as gantry cranes and shore cranes according to the lifting capacity of the shipyard, thereby forming base leg segments on the main hull . The lifting height of the existing large-scale gantry crane is generally 80 meters to 90 meters, and the leg segments higher than this height can be installed by using the sea crane in the above step S20. The sea crane is a kind of crane ship with lifting capacity floating on the sea. A crane is installed on it to carry out lifting operations. The sea crane is divided into self-propelled type and non-self-propelled type. The ship as a whole needs to be towed by a tugboat. At present, there are only a few large-scale sea cranes, and the shipyard needs to lease them when they need to use them. Due to the high rental cost of sea cranes, first use gantry cranes or shore cranes to complete the installation of the base pile legs with a certain height, and then only need to use sea cranes. Completing the installation of the rest of the pile legs with a higher height can reduce the workload of the sea crane as much as possible and save the rental cost.

Referring to FIG. 2 and FIG. 3 , in the method of the present invention, in step S10 , the main hull 11 is positioned and floated in the dry dock 3 to facilitate the mooring positioning of the main hull 11 . In addition, the dry dock 3 is less affected by surges, and the water surface fluctuations are relatively small, so that the main hull 11 can be in a relatively stable state when positioned in the dry dock 3, and it is convenient to install the leg segments 122 on the main hull 11 .

The selection of dry dock 3 can be decided according to its depth and size, and its size should allow main hull 11 to move safely and flexibly therein, and the higher the depth of dry dock 3 docking distances from sea level, the better. The concrete steps that main hull 11 is positioned in dry dock 3 are:

S11: launching the main hull 11 with the foundation leg section 121 established;

S12: Move the main hull 11 to a predetermined position in the dry dock 3, close the dock door 31 of the dry dock 3, adjust the water level in the dry dock 3 to a specified height, and moor the main hull 11 for positioning.

Preferably, in step S12, the specified height is lower than the sea level of the sea area outside the dry dock 3, that is, when adjusting the water level in the dry dock 3, it specifically refers to lowering the water level in the dry dock 3. As shown in Figure 3, the water level in the dry dock 3 is lower than the water level outside the dock, forming a height difference H, so that the position of the main hull 11 is lowered. For the sea crane 2, the hoisting leg segment 122 needs to reach The height difference H is also reduced at the highest point, which reduces the length requirement of the sea crane 2 boom 22 and reduces the rental cost of the sea crane 2.

In addition, in step S12, the draft of the main hull 11 in the dry dock 3 can be adjusted to a set value as required, and the set value is as large as possible on the premise of ensuring the safety of the self-elevating platform 1 . Among them, the prerequisite for ensuring the safety of the jack-up platform 1 is: the distance D1 between the lowest point of the jack-up platform 1 (i.e. the lowest point of the spud shoe 120 of the spud leg 12) and the bottom of the dry dock 3 is greater than the minimum safe distance, so as to prevent The spud shoe 120 collides with the bottom of the dry dock 3 . By increasing the draft of the main hull 11, not only can the height of the center of gravity of the self-elevating platform 1 be adjusted, the stability of the platform can be improved, the swing amplitude can be reduced, and the height of the legs 12 relative to the sea crane 2 can also be reduced to a certain extent. The length requirements of the boom 22 of the sea crane 2.

Still refer to Fig. 2 and Fig. 3, step S20 sea crane 2 is positioned at the specified position of the sea area outside dry dock 3 during step S20 operation, and mooring location; The distance D2 between the hull 21 of sea crane 2 and the dock door 31 of dry dock 3 ( Including the horizontal distance between the tail of the hull 21 shown in Figure 2 and the dock door 31 and the distance between the bottom of the tail of the hull 21 shown in Figure 3 and the bottom of the dock door 31) is not less than the safety distance, and the crane 2 The operating range of the pole 22 needs to meet the requirement that the leg segment 122 can be hoisted above the base leg segment 121 on the main hull 11 .

Lifting lugs (not shown in the figure) are set on the leg segments 122. When the sea crane 2 needs to lift the leg segments 122, the lifting lugs are lifted by slings or wire ropes. When the leg segments 122 are closed to the main hull 11 , and then take off the shackle of suspenders or wire ropes from the lug of the leg segment 122, and the sea crane 2 is ready to lift the next segment of the leg segment 122 again. The hook of the sea crane 2 is connected to the boom 22 and can be lifted up and down. The sling or wire rope is connected to the hook. According to the hoisting regulations, the angle between the sling/wire rope and the horizontal plane is generally not less than 60 degrees. After the highest point is determined, the sea crane 2 can be made to meet the hoisting requirements by reducing the height of the lifting lugs of the leg segments 122. Under the premise of satisfying the lifting balance of the pile legs segmented, the position of the lifting lug in the leg segment 122 on the uppermost layer of the pile leg can be moved down a certain distance according to the capacity of the sea crane 2, and the sea crane can be improved. 2. The hoisting capacity and safety.

In one embodiment, step S20 uses the sea crane 2 to close up the pile leg segment 122 to be installed on the main hull 11. The specific steps are:

S21: Adjust the relative position of the sea crane 2 and the leg segment 122 to be installed on the main hull 11 .

S22: The sea crane 2 lifts the leg segment 122 to be installed above the base leg segment 121 of the main hull 11 .

S23: Position the leg segment 122 to be installed on the base leg segment 121 of the main hull 11 by closing the tooling and position welding to close it on the base leg segment 121 . In this step, conventional closing tooling can be used for positioning welding, or special positioning tooling can be used for positioning welding. Positioning by means of tooling overcomes the instability problem caused by both the main hull 11 and the sea crane 2 being in a floating state and being affected by surges, and makes the installation and positioning of the pile leg segments 122 more reliable.

Through step S21 to step S23, one section of leg segment 122 can be closed up, and before the next segment of leg segment 122 is closed, the following steps are preferably carried out:

S24: Adjust the floating state of the main hull 11 so that the installation position of the next leg segment is in a horizontal state, which can facilitate the positioning and installation of the next leg segment 122; in addition, since the main hull 11 generally has three legs 12 , and the leg segment 122 can only be installed on one base leg segment 121 at a time, which will cause the jack-up platform 1 to have an unbalanced weight distribution and tilt. By adjusting the floating state of the main hull 11, the spud can 120 can also be prevented from descending and colliding Destroyed at the bottom of Dry Dock 3. Wherein, adjusting the floating state of the main hull 11 can be realized by adjusting the ballast water in the main hull 11, which is simple and easy to adjust.

After adjusting the floating state of the main hull 11, repeat steps S21 to S23 to complete the closing of the next leg segment 122, and repeat this many times until the installation of all leg segments 122 is completed.

For the above step S21, preferably, by rotating the main hull 11 in the dry dock 3 to adjust the distance and angle between the section of the legs to be installed and the sea crane 2, since the main hull 11 floats on the water surface, The position of the main hull 11 can be easily adjusted, and the mooring positioning of the main hull 11 is also facilitated in the dry dock 3 . The relative position between the main hull 11 and the sea crane 2 is preferably such that the distance between the sea crane 2 and the section of the pile legs to be installed is as small as possible, and the elevation angle of the sea crane 2 boom is as large as possible, so as to reduce the sea crane 2 rental fee, The purpose of making the length of the sea crane 2 boom 22 as short as possible.

Referring to Fig. 4, the cross section of the leg segment 122 is an equilateral triangle. Preferably, in step S22, the sea crane 2 aligns the leg segment 122 from the side of the extension line from the apex A of the equilateral triangle to the center of gravity G direction. Hoisting. Refer to Fig. 5 and Fig. 6 for comparison. In Fig. 5 and Fig. 6, the hoisting height of the sea crane is the same, the length and elevation angle of the boom 22 are the same, and the top of the boom 22 is roughly located directly above the center of gravity G of the equilateral triangle 122 of the leg segment. , Fig. 5 is a schematic diagram of sea crane 2 hoisting on one side of the extension line from the center of gravity G of the equilateral triangle to the vertex A, and Fig. 6 is an extension line of the sea crane 2 from the vertex A of the equilateral triangle to the center of gravity G. Schematic diagram of side lifting. Obviously, comparing the two hoisting methods, the difference in the horizontal distance L0 between the leg segment 122 and the boom 22 of the sea crane 2 is the difference in the distance L2 between the center of gravity G and the apex A and the long distance L1 between the center of gravity G and the side . Taking the common segmental structure size of pile legs as an example, the side length of an equilateral triangle is 13 meters, and the height of the triangle is about 11 meters. The distance L2 is about 7.5 meters. When the leg segment 122 is hoisted in the manner shown in FIG. L2-L1), which effectively reduces the risk of collision with the structure of the sea crane 2 when the leg segment 122 is swinging in the sky. In order to ensure that the sea crane 2 remains approximately on the side of the extension line from the apex A to the center of gravity G, when rotating the main hull 11 in step S21, the placement angle between the main hull 11 and the sea crane 2 should be considered, so that the hoisted legs are separated. The section 122 corresponds to the base leg section 121 on the main hull 11 . In some embodiments, if the capacity of the sea crane 2 is sufficient, the way the sea crane 2 lifts the leg segment 122 may not be limited to the way shown in FIG. 6 .

Before the method of the present invention is implemented, the following preparatory steps can be done in advance:

1. Select a suitable dry dock and determine the initial position and angle of the main hull in the dry dock;

2. Determine the minimum safe distance between the lowest point of the spud can and the bottom of the dry dock;

3. Determine the minimum safe distance between the dry dock door and the sea crane;

4. Determine the position and cable (that is, mooring positioning) method during sea crane operation;

5. Determine the segmental installation sequence of pile legs and the rotation sequence of the main hull;

6. Determine the water surface difference inside and outside the dry dock, the draft of the main hull and the position of the lifting lug on the highest section of the pile leg;

7. Determine the main hull ballast water regulation scheme;

8. Choose a sea crane with a reasonable height.

After the above-mentioned preparatory steps are completed in advance, the installation of the pile legs can be quickly completed according to the predetermined scheme when implementing the invention of the present invention.

While this invention has been described with reference to several exemplary embodiments, it is understood that the terms which have been used are words of description and illustration, rather than of limitation. Since the present invention can be embodied in many forms without departing from the spirit or essence of the invention, it should be understood that the above-described embodiments are not limited to any of the foregoing details, but should be construed broadly within the spirit and scope of the appended claims. , all changes and modifications falling within the scope of the claims or their equivalents shall be covered by the appended claims.

Claims (11)

1. a mounting method for jack-up unit spud leg, is characterized in that, comprises step:

The main hull location setting up basic unit's spud leg section is made to float in dry dock;

Keep basic unit spud leg section relative to the inactive state of main hull in the vertical direction, utilize sea hang successively by spud leg segmental hoisting to be installed to closing up Kou Chu, welding is positioned to spud leg segmentation, until the spud leg section on main hull reaches predetermined height; Wherein, the assigned address being positioned the outer marine site of dry dock is hung in sea.

2. the mounting method of jack-up unit spud leg according to claim 1, is characterized in that, described in make to set up basic unit's spud leg section the main hull location step floated in dry dock be specially:

Make to set up water under the main hull of basic unit's spud leg section;

Main hull is moved to the precalculated position in dry dock, close the dock gate of dry dock, regulate water level in dry dock to specified altitude assignment, to locate main hull mooring.

3. the mounting method of jack-up unit spud leg according to claim 2, is characterized in that, described specified altitude assignment is lower than the sea level altitude in the outer marine site of described dry dock.

4. the mounting method of jack-up unit spud leg according to claim 2, is characterized in that, the draft of described main hull in described dry dock is a setting value.

5. the mounting method of jack-up unit spud leg according to claim 1, is characterized in that, described utilization sea is hung and spud leg segmental hoisting is also comprised step before closing up mouth place: regulate sea to hang the relative position with spud leg to be installed segmentation place on main hull.

6. the mounting method of jack-up unit spud leg according to claim 5, it is characterized in that, the described sea that regulates is hung and on main hull, the step of the relative position of spud leg to be installed segmentation place is specially: main hull is rotated in dry dock and regulate spud leg to be installed segmentation place and sea hang between Distance geometry angle.

7. the mounting method of jack-up unit spud leg according to claim 1, it is characterized in that, after one section of spud leg segment folding to next section of spud leg segment folding, also comprise step: adjustment main hull floading condition makes next section of spud leg segmentation installed position be level.

8. the mounting method of jack-up unit spud leg according to claim 7, is characterized in that, described main hull floading condition adjustment realizes by regulating ballast water in main hull.

9. the mounting method of the jack-up unit spud leg according to any one of claim 1-8, it is characterized in that, described spud leg segmentation cross section is equilateral triangle, and described sea is hung and lifted spud leg segmentation from the extended line side in summit to the center of gravity direction of described equilateral triangle.

10. the mounting method of the jack-up unit spud leg according to any one of claim 1-8, it is characterized in that, described spud leg segmentation to be installed is by closing up in tool locating to basic unit's spud leg section of described main hull and positioning welding and closing up in basic unit's spud leg section.

The mounting method of 11. jack-up unit spud legs according to any one of claim 1-8, it is characterized in that, the described main hull location setting up basic unit's spud leg section that makes floats on before in dry dock, utilizes straddle truck or shore tackle spud leg segmentation to be installed on main hull and forms described basic unit spud leg section.