CN115704209A - Shallow water area offshore platform installation method - Google Patents

Abstract

The invention discloses a shallow water offshore platform installation method, which comprises the steps of selecting a bottom-mounted self-elevating engineering ship and a transportation barge to carry an offshore platform to a designated installation sea area, and using a crane to carry out module hoisting or integral hoisting on the offshore platform in a bottom-mounted and pile inserting mode. Large floating crane equipment with expensive rent and short resources is not required to be used, the working amount of deep excavation and dredging of a channel and an operation area can be avoided or reduced, and the construction operation cost and the operation period are obviously reduced; on the other hand, the crane has strong wind and wave resistance, meets the working requirements of the crane to the greatest extent, ensures the hoisting and mounting precision, can reduce the influence of weather and sea conditions on the mounting work, improves the working efficiency, and can greatly improve the safety performance of the mounting work process.

Description

A method for installing an offshore platform in shallow water

technical field

The invention relates to the technical field of offshore platform installation, in particular to a method for installing an offshore platform in shallow water.

Background technique

With the rapid development of the offshore oil industry, offshore platforms are becoming larger and more intensive, and the overall weight of offshore platforms is also increasing. This type of large-scale offshore platform adopts modular hoisting or overall installation. The modular hoisting method is limited by the external environment of the ocean, the load capacity of the floating crane, and the water depth conditions in the construction sea area, resulting in a long construction period for the platform and poor economic benefits. The hoisting or barge float-over method for overall installation usually requires large-scale operating ships and equipment, especially in shallow sea areas where large-scale construction equipment cannot enter the installation sea area due to the shallow water depth. Digging and dredging not only increases the cost of installation operations, but also prolongs the construction period of the platform.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for installing an offshore platform in shallow waters, which has a strong ability to resist wind and waves, reduces the influence of weather and sea conditions on the installation work, and can shorten the installation cycle of the offshore platform.

In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for installing an offshore platform in shallow water, comprising the following steps:

1) First prepare a sitting-bottom self-elevating engineering ship that integrates the functions of sitting on the bottom and jacking up, including: upper hull, crane, lower hull, outer legs and inner legs. The crane is installed on the upper hull, and the outer The legs are installed on the upper hull, and the outer leg is controlled by the rack-type lifting device. The lower hull is connected to the upper hull through the outer leg. The inner leg is installed on the lower hull, and the inner leg is controlled by the pin-type lifting device. The lower hull is provided with a ballast water system;

2) According to the water depth of the installation sea area, select the bottom jack-up engineering ship and transport barge to carry the offshore platform to the designated installation sea area;

3) After the self-elevating engineering ship sits on the bottom and reaches the designated position, use the rack type lifting device to extend the outer legs downward, and drive the lower hull to move downward until the lower hull sits on the seabed, keeping the outer legs to continue Moving downward, relying on the support force of the seabed to the lower hull and the buoyancy of the lower hull, the upper hull is lifted to a certain height from the water surface, so that the wind and waves can pass through;

4) Use the pin-type lifting device to extend the inner leg downwards and insert it into the seabed. At this time, the inner leg can not only resist the sliding of the horizontal force, but also bear part of the overturning caused by the hoisting operation of the upper hull crane It can also rely on its friction with the mud layer to bear part of the hull's own weight; the ballast water system injects water into the hull to meet the stability requirements of the hull when the offshore platform is installed;

5) After the self-elevating engineering ship and the transport barge are in place, use the crane to lift the offshore platform in modules or as a whole;

6) After the hoisting operation is completed, the ballast water system empties the lower hull, and the inner pile legs are recovered upwards by using the plug-type lifting device, and the inner pile is pulled out from the seabed by relying on the support force of the seabed to the lower hull and the buoyancy of the lower hull Legs, and then use the rack type lifting device to recover the outer legs upwards, lower the upper hull to the water surface, continue to recover the outer legs, and rely on the buoyancy of the upper hull to receive the lower hull below the upper hull.

The inner legs and the outer legs are arranged close to the vertical and horizontal sides of the upper hull, so as to reduce the overturning moment during the hoisting operation.

The lengths of the inner legs and outer legs are adjusted according to the water depth in the working area.

When the self-elevating engineering ship on the bottom is dispatched or towed, the inner legs and outer legs are retracted, and the lower hull is retracted to the bottom of the upper hull.

The lower hull can adjust the suction and displacement, so that the lower hull can obtain different buoyancy, which is used to change the pressure of the bottom on the seabed, and use the ballast water system to balance the overturning moment generated when the crane is hoisting.

The beneficial effects of the present invention are: to replace the traditional hoisting installation method and float-over installation method to realize the installation of offshore platforms in shallow waters, so that there is no need to use large-scale floating cranes with expensive rent and resource constraints, and it is also possible to avoid or reduce navigation channels and operations. The workload of regional deep excavation and dredging achieves the purpose of significantly reducing the installation cost and operation cycle of offshore platforms.

Description of drawings

Fig. 1 is a structural schematic diagram of a self-elevating engineering vessel sitting on the bottom in the present invention.

Fig. 2 is a schematic diagram of the state of the self-elevating engineering ship sitting on the bottom in the present invention.

Fig. 3 is a schematic diagram of the state of pile insertion after the self-elevating engineering ship sitting on the bottom sits on the bottom in the present invention.

Fig. 4 is a schematic view showing the position of the self-elevating engineering ship and the transport barge in the present invention.

Fig. 5 is a schematic diagram of installation of an offshore platform in the present invention.

Among them: 1. Upper hull, 2. Crane, 3. Lower hull, 4. Outer legs, 5. Inner legs, 6. Rack type lifting device, 7. Pin type lifting device, 8. Seabed, 9. Water surface, 10. Offshore platform, 11. Platform lower foundation, 12. Transport barge.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention; obviously, the described embodiments are only part of the embodiments of the present invention, not all embodiments, based on The embodiments of the present invention and all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

In the description of the present invention, it should be noted that the orientations or positional relationships indicated by the terms "upper", "lower", "inner", "outer", "top/bottom" etc. are based on the orientations shown in the drawings Or positional relationship is only for the convenience of describing the present invention and simplifying the description, but does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the present invention.

In the description of the present invention, it should be noted that, unless otherwise specified and limited, the terms "installed", "set with", "sleeved/connected", "connected", etc. should be understood in a broad sense, such as " Connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediary, and it can be an internal connection between two components. connectivity. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention in specific situations.

As shown in Figures 1-5, the offshore platform installation method in shallow waters of the present invention includes the following steps:

1) First prepare a bottom-seat self-elevating engineering ship integrating bottom-seat and self-elevate functions, including: upper hull 1, crane 2, lower hull 3, outer legs 4 and inner legs 5. The crane 2 is installed on the upper hull 1 . The outer leg 4 is installed on the upper hull 1, and the outer leg 4 is controlled by a rack type lifting device 6 to lift. The lower hull 3 is connected to the upper hull 1 by outer legs 4 . The inner pile leg 5 is installed on the lower hull 3, and the inner pile leg 5 is controlled by a bolt type lifting device 7 to lift. The lower hull 3 is provided with a ballast water system, as shown in FIG. 1 .

2) Select the transport barge 12 to carry the offshore platform 10 to the designated installation sea area according to the water depth of the installation sea area.

3) After the self-elevating engineering ship sitting on the bottom reaches the designated position, the outer pile leg 4 is extended downward by the rack type lifting device 6, and the lower hull 3 is driven to move downward until the lower hull 3 sits on the bottom of the seabed 8 . Keep the outer pile legs 4 to continue to move downward, rely on the support force of the seabed 8 to the lower hull 3 and the buoyancy of the lower hull 3, push the upper hull 1 to a certain height from the water surface 9, and let the wind and waves pass through, as shown in Figure 2 shown.

4) Utilize the bolt-type lifting device 7 to extend the inner leg 5 downwards and insert it into the seabed 8. At this time, the inner leg 5 can not only resist the sliding of the horizontal force, but also bear part of the load generated by the crane 2. The overturning moment also relies on its friction with the mud layer to bear part of the ship's own weight, as shown in Figure 3.

The ballast water system injects water into the lower hull 3 to meet the stability requirements of the hull when the offshore platform 10 is installed.

5) After the bottom jack-up engineering ship and transport barge 12 are in place, as shown in Figure 4, the offshore platform 10 is hoisted as a whole on the lower foundation 11 of the platform with the crane 2, as shown in Figure 5, by welding and pouring cement Or fasten the connection with bolts.

6) After the hoisting operation is completed, the ballast water system empties the lower hull 3, and the inner pile legs 5 are recovered upwards by using the pin-type lifting device 7, and the lower hull 3 is lifted from the sea by the support force of the seabed 8 and the buoyancy of the lower hull 3. Pull out the inner leg 5 in the bed 8, and then use the rack type lifting device 6 to recover the outer leg 4 upwards, lower the upper hull 1 to the water surface 9, continue to reclaim the outer leg 4, rely on the buoyancy of the upper hull 1 to move the lower The hull 3 is received below the upper hull 1 .

Further, the lower hull 3 has good rigidity, can partially sit on the mud surface of the seabed 8, and adapts to the slight slope and local unevenness of the mud surface of the seabed 8.

Further, the inner legs 5 and the outer legs 4 are arranged as close to the vertical and horizontal sides of the upper hull 1 as possible, so as to reduce the overturning moment during the hoisting operation.

Further, the lengths of the inner legs 5 and the outer legs 4 can be appropriately adjusted according to the water depth of the working area.

Furthermore, when the jack-up construction ship is dispatched or towed, the inner legs 5 and outer legs 4 are retracted, and the lower hull 3 is retracted below the upper hull 1 .

Further, the lower hull 3 can adjust the suction and displacement through the ballast water system, so that the lower hull 3 can obtain different buoyancy to change the pressure on the seabed 8 when sitting on the bottom, and use the ballast water system to balance the hoisting operation of the crane 3. overturning moment.

Because the present invention adopts the method of sitting on the bottom and inserting piles, on the one hand, it is suitable for extremely shallow waters, and it does not need to use large-scale floating cranes that are expensive in rent and resource-intensive, and can also avoid or reduce the workload of deep digging and dredging in waterways and operating areas. Significantly reduce the construction operation cost and operation cycle; on the other hand, it has a strong ability to resist wind and waves, which can meet the working requirements of the crane to the greatest extent, ensure the lifting and installation accuracy, reduce the influence of weather and sea conditions on the installation work, and improve the operation efficiency. Can greatly improve the safety performance of the installation process.

In summary, the content of the present invention is not limited to the above-mentioned embodiments, people of insight in the same field can easily propose other embodiments within the technical guidance of the present invention, but this embodiment All are included within the scope of the present invention.

Claims (5)

1. A shallow water offshore platform installation method is characterized by comprising the following steps:

1) Firstly, a bottom-sitting self-elevating engineering ship integrating the functions of bottom-sitting and self-elevating is prepared, which comprises: the water ballast device comprises an upper ship body, a crane, a lower ship body, an outer pile leg and an inner pile leg, wherein the crane is installed on the upper ship body, the outer pile leg is installed on the upper ship body and is controlled to lift through a rack type lifting device, the lower ship body is connected to the upper ship body through the outer pile leg, the inner pile leg is installed on the lower ship body and is controlled to lift through a bolt type lifting device, and a water ballast system is arranged on the lower ship body;

2) According to the water depth condition of an installation sea area, selecting a bottom-sitting self-elevating engineering ship and a transportation barge to carry the offshore platform to the appointed installation sea area;

3) After the bottom-sitting self-elevating engineering ship reaches a designated position, the outer pile leg is extended downwards by using the rack type lifting device to drive the lower ship body to move downwards until the lower ship body sits on the seabed, the outer pile leg is kept to move downwards continuously, and the upper ship body is jacked to a certain height above the water surface by virtue of the supporting force of the seabed on the lower ship body and the buoyancy of the lower ship body, so that wind waves pass through;

4) The inner pile leg extends downwards to be inserted into the seabed by using the bolt type lifting device, and at the moment, the inner pile leg can resist the sliding of horizontal force, can bear part of overturning moment generated during the hoisting operation of a crane on the hull, and can bear part of the dead weight of the hull by means of the friction force between the inner pile leg and a mud layer; the ballast water system injects water to the lower ship body, so that the stability requirement of the ship body when the offshore platform is installed is met;

5) After the bottom-sitting self-elevating engineering ship and the transportation barge are in place, a crane is used for hoisting the offshore platform in modules or integrally;

6) After the hoisting operation is completed, the ballast water system empties the lower hull, the inner pile leg is upwards recovered by the bolt type lifting device, the inner pile leg is pulled out from the seabed by depending on the supporting force of the seabed on the lower hull and the buoyancy of the lower hull, the outer pile leg is upwards recovered by the rack type lifting device, the upper hull is lowered to the water surface, the outer pile leg is continuously recovered, and the lower hull is retracted to the lower part of the upper hull by depending on the buoyancy of the upper hull.

2. The method for installing a shallow offshore platform as claimed in claim 1, wherein the inner and outer legs are disposed close to the vertical and horizontal sides of the upper hull to reduce the overturning moment during the hoisting operation.

3. The method of installing a shallow offshore platform as claimed in claim 1 wherein the lengths of the inner and outer legs are adjusted according to the depth of water in the area of operation.

4. The method of installing a shallow offshore platform as claimed in claim 1 wherein the inner legs and outer legs are retracted and the lower hull is stowed beneath the upper hull during deployment or towing of the submersible jack-up vessel.

5. The shallow water offshore platform installation method of claim 1, wherein the lower hull is capable of adjusting the suction and discharge amount of water so that the lower hull obtains different buoyancy for changing the pressure of the bottom to the seabed and balancing the overturning moment generated during the hoisting operation of the crane with a ballast water system.

Images