CN1286665A - Offshore production and storage facility and method of installing same - Google Patents

Abstract

A concrete barge having concrete-coated oil storage tanks secured to its deck is sunk to the sea bottom at an oil production site. Oil from an adjecent caisson-supported facility is temporarily stored in the tanks. Compartments in the barge are filled with water for ballast and trim as the barge is towed to the site. The compartments are flooded with seawater to sink and hold the barge on the sea bottom. Descent of the barge is regulated by controlling the placement of and air pressure in the tanks. The barge and tanks are subsequently filled with seawater. Oil is introduced into the tanks from the production facility in a manner which displaces an equal volume of seawater. Oil is discharged from the top of the tanks to sales lines by introducing seawater into the tank bottoms.

Description

Marine production and storage equipment and its installation method

This invention relates to the storage of oil well fluids produced from offshore oil wells. More particularly, the present invention relates to an underwater storage system for temporarily storing oil produced from oil wells established at deep and remote offshore sites.

Oil and gas produced from offshore wells must be transported from the well site to land-based finishing, storage or transfer facilities for subsequent processing and distribution to end users. In most cases, those fluid products are transported from interim storage at the well site either via subsea pipelines or via tankers. In some cases, a large production facility can process well fluids before they are transported by tanker or subsea pipeline to the end user.

Usually, the economics of setting up and operating an ocean production facility requires that there should be a large number of oil wells or some extremely high-yield oil wells connected to it by underwater pipelines near the facility. Also, the cost of laying a pipeline to an offshore production area is only cost-effective if there are a relatively large number of wells in the ocean area and they are not too far from an onshore facility.

In many cases, the amount of oil produced is limited, and the cost of deploying pipelines and intermediate production equipment for the temporary storage of oil produced by a single well, ie, an independent well site, is not justified. In such cases, the use of tankers to collect oil from remote wells or temporary storage facilities at well sites may be the only practical way to ensure production from these isolated or low-producing wells.

In the past, temporary storage of oil and its fluids produced from some oil wells has been accomplished by placing production platforms with storage facilities at the well site and periodically discharging the stored fluids to a tanker. Also, in some cases subsea tanks or equipment have been employed to store the products of these wells. In all of these cases, these prior art methods of interim storage of well fluids are employed in relatively shallow waters where the cost of building a platform or installing subsea storage equipment is relative to the carbon produced in remote sites. It is a reasonable proportion for the value of hydrogen compound products. However, as the water depth increases, so does the cost of production platforms or subsea storage equipment, so using such systems at deeper waters has proven to be uneconomical.

In some areas, even in relatively shallow water, and even when product collection facilities are close enough to be connected by relatively short subsea pipelines, construction Nor can the expense of a traditional production platform be justified. However, there is also a class of wells which can be economically drilled and produced if the cost of building a suitable production platform is economical. In this case, production can be carried out at the well site with the desired economy, in addition to having suitable temporary storage facilities on site, or even subsea temporary storage facilities.

Oil and gas can be economically produced from critical production wells in relatively shallow, accessible areas, but here the cost of a caisson-supported production platform is significantly less than conventional production equipment. An example of an economical caisson installation production system is in US Patent Application No. assigned to the assignee of the present invention. Published in 08/573594. In the presented caisson production overall system, the production platform is supported by a caisson, which eliminates the need for multi-legged platforms that are anchored to the bottom of the water. The savings realized from using a caisson system as described in this application to complete the entire well enables the economical development of marginal wells.

The present invention provides a marine production and storage facility that can be economically applied to deep water and open sea areas. A production facility, such as a single caisson-type facility, is used in combination with a subsea temporary storage system that allows the temporary storage of fluids produced from oil wells and periodically feeds the fluids into a tanker for delivery to a land-based equipment. One or more oil wells in this marine area may be drilled using conventional jack up rigs or other suitable drilling rigs. The drilled well is completed with a suitable production platform. Fluids produced from the well are temporarily stored in a subsea tank system and periodically transported into tankers for delivery to land-based processing or distribution facilities.

The oil storage system consists of a series of steel tanks secured to the deck of an underwater concrete barge. The flat-bottomed concrete barge is compartmentalized to direct seawater into different compartments as the ship is towed from its fabrication yard to the offshore well site requiring ballast balancing and repositioning of the barge. Steel tanks are secured to the barge deck and are clad in concrete to protect them against pressure differentials developed during the submersion and to adjust the storage tanks in time.

At the well site, the barge compartment is filled with seawater and equalized to the corresponding seawater pressure. The air content in the tank is regulated by the surface container used in the barge layout. Sufficient seawater is added to the concrete-clad storage tanks. When the barge assembly is submerged, the tanks are filled with enough compressed air to prevent damaging pressure differentials across the tank walls. And at the same time when diving, adjust the buoyancy of this combined device so that it does not exceed the lifting capacity of the ship for positioning.

While resting on the seabed, the barge's tanks are connected with flow pipes from the production or collection facility and to the discharge or "sales" pipeline, which is connected to a surface buoy for interfacing with tankers. Water is pumped into the tank through a flow pipe extending from the surface to the barge. Air pressure is released from the tank as water fills the tank and pipes. The pressure relief is controlled by a control diaphragm (CS) to maintain the balance of the pressure inside and outside the tank. In operation, the fluid produced by the well is transported to the tank. At the same time, the same volume of seawater is discharged from the oil tank and flows to the sea surface through the pipeline to be processed. The hydrocarbon fluid produced by the well is lighter than seawater and thus rises to the top of the tank. This automatically deflects incoming oil bodies to the top of the tank. Keep full of fluid at all times to prevent damaging pressure differentials. This pressure differential can damage tanks under seawater pressure.

Draining the oil from the tank is accomplished by adding sea water to the bottom of the tank. This transports the oil from the tanks to offload sales pipelines that extend to surface tankers.

In some applications, the caisson can be supported by the barge as an additional structural support, a feature which is advantageous especially in hard seabed areas. The hard seabed makes the arrangement for anchoring the caisson stays difficult. Where the caisson can be easily secured with stays, a storage barge can be moored near the base of the caisson, its function independent of the structural connection of the caisson.

The steel tank forming the well fluid storage chamber is secured by internal supports to further increase its resistance to damage. The internal support structure is laterally open at the upper and lower ends to allow fluid transfer laterally when it is required to completely drain water or oil from the tank by introducing replacement fluid.

When the production of the well drops to the point where it is no longer economical to continue production, or when the well is shut in for some other reason, the temporary storage assembly can be modified and transported to another site for use. Correction of the storage barge from the seabed is carried out by pumping air into the storage tank to displace the water and then floating the combination to the surface. On the surface, the tanks can be completely emptied, the barge cavity partially drained of water and the barge rebalanced and adjusted for haulage to a new location.

As can be seen from the foregoing, a primary object of the present invention is to provide a mobile marine production and storage facility which can be used for the temporary storage in deep water of fluid products from production or collection units.

It is a further object of the present invention to provide a subsea storage facility which may be combined with a caisson type well assembly to provide structural support for the caisson in deep water in hard bottom areas.

Another object of the present invention is to provide a storage facility which can be controllably positioned and modifiable in deep water and which can also be used for the temporary storage of fluid products from oil wells in relatively deep water.

It is an important object of the present invention to provide a pressure resistant underwater storage facility which can be used in deep water and which can withstand the high destructive hydraulic forces which exist there.

Another object of the present invention is to provide a pressure-resistant oil tank, which includes a concrete cladding through which the resistance to pressure-induced destructive forces is increased to protect the potential of the storage tank. steel body.

Another object of the present invention is to provide an underwater temporary oil storage system which can be refloated and moved for use as a temporary oil storage system in another marine region.

The above objects, features and advantages of the present invention can be more fully understood and understood by referring to the following drawings, descriptions and claims.

Fig. 1 is a cross-sectional view of an ocean production and storage facility arranged according to the principles of the present invention;

Figure 2 is a cross-sectional view of a modification of a subsea production facility according to the present invention, wherein the facility provides structural support for a caisson-type well assembly,

Fig. 3 is a top view taken along line 3-3 in Fig. 2, which shows the oil tank fastened to the barge of the present invention;

Fig. 4 is a sectional view taken along line 4-4 in Fig. 3, which shows the structural details of an oil tank applied to the production equipment of the present invention;

Fig. 5 is a sectional view taken along line 5-5 in Fig. 4, which shows additional details of an oil tank structure applied to the production equipment of the present invention;

Fig. 6 is the view that part cuts along the vertical plane, and it has shown the sinking state of underwater storage equipment of the present invention;

Figure 7 is a view similar to Figure 6 showing the storage facility partially submerged;

Figure 8 is a view similar to Figures 6 and 7 showing the storage facility placed on the seabed ready to receive fluid produced from the associated well;

Fig. 9 is a fragmentary view showing another embodiment of the apparatus of the present invention.

Numeral 10 in Figure 1 generally designates the marine production and storage facility of the present invention. The installation 10 comprises a well, designated by numeral 11, which uses a caisson 12 to support a small area platform 13 extending above the surface S of the body of water W. In a typical installation, wellbore 14 extends through caisson 12 to production platform 13 . Where the production wellbore and tubing in the well are connected to a (not shown) wellhead. Guy wires 15 extend between the caisson and anchors 16 embedded and positioned in the bottom B of the body of water, which serve to keep the caisson standing vertically. In a conventional installation, three guy wires 15 are placed 120° from each other around the base of the caisson 12 .

If water bottom conditions permit, the caisson 12 and anchor 16 may be driven into the water body bottom 13 with a surface operated pipe drive. Where the bottom 13 of the body of water is too hard to be penetrated by the pipe drive, the bottom can be drilled with a drill rig to bury the caissons and anchors.

Depending on the requirements of the well site, the caissons can be placed in place by the drilling rig drilling the well 11, or they can be installed in place using a suitable installation vessel before or after the well has been drilled.

Oil produced from the well 11 is conveyed through a flow conduit 21 extending from the surface platform 13 along the side 12 of the caisson to an underwater storage facility of the present invention, generally indicated at 20 .

The oil temporarily stored in the storage facility 20 is periodically delivered to a surface tanker T through a sales pipeline 22 . The sales pipeline 22 extends to a discharge buoy 23 floating on the water. A discharge pipeline 24 communicating with the sales pipeline 22 extends from the tanker to the buoy 23 . A submerged buoy 25 supports the submerged pipeline 22 midway along the length of the pipeline so that the buoy 23 is not affected by the weight of the pipeline 22 so that the buoy 23 is kept in place during the transfer of oil from the facility 20 to the tanker T. keep it steady. Steel cables 26 are anchored in the water bottom B to keep the buoy 23 in a fixed position relative to the oil well 11 .

In operation, oil produced from the well 11 flows through the pipeline 21 into a temporary storage container provided by the device 20 . According to certain data determined by the amount of fluid produced by the oil well 11, the oil tanker T drives to the oil well site and connects its unloading pipeline 24 with a suitable joint on the buoy 23 to transport the fluid from the storage equipment to the container of the oil tanker. Oil taken from the storage facility 20 by the tanker is transported by the tanker to a remote processing or distribution facility.

6-8 illustrate the steps of positioning storage device 20 . The apparatus 20 is constructed in two main parts including: a flat bottomed barge section 30 and a storage tank section 31 . The barge section 30 constructed of reinforced concrete is provided with a series of interconnected hollow chambers 32 . The compartments 32 extend from the bottom of the barge to the deck of the barge and are distributed along the entire hull. The size and layout of the cabins in the barge are selected according to the barge size, its towing, submersion and support specifications. The chambers 32 are interconnected by suitable valves and flow conduits (not shown). During the time the barge is being towed, the valves and flow lines are controlled to selectively fill and empty the chamber 32 as required to properly ballast and adjust the subsea position of the device 20 . When the combination 20 is ready to be submerged to its position on the bottom B, the compartment 32 is completely filled with water. The tank portion 31 of the assembly 20 comprises a number of steel tanks 33 clad in concrete. Tanks 33 are also interconnected with flow piping and control valves and are used for temporary storage of fluids produced from well 11.

When the combined device 20 has been towed to its installation site above the water bottom B, two winch boats WB1 and WB2 are placed on either side of the device 20 . The winch boat and device 20 are then fastened to each other with suitable winch cables WL1 and WL2. The control system CS on the winch boat WB2 is connected to the steel oil tank 33 covered with concrete through flexible control lines 34, 35 so as to control the liquid water level and air pressure in the oil tank during the submersion. The flexible control lines 36, 37 connect the control system CS to the barge compartment 32 for controlling the fluid level in the compartment.

By operating the control system CS to open an air release valve (not shown) connected to the top of the chamber 32, the storage device 20 begins to submerge. At the same time, the control system CS also opens an opening (not shown) of a fluid inlet pipe into the bottom of the chamber 32 to allow seawater to be injected into the chamber 32 . The water entering the chamber 32 displaces the air so that the chamber 32 is completely filled with water.

During the subsequent submersion, the air supply valve openings and water line openings to all compartments are all left open to balance the weight of the device 20 and prevent the device 20 from moving across the wall of the compartment 32 as the device 20 descends. create a pressure difference between them. During the initial stages of the barge 30 sinking, the barge compartment 32 may optionally be partially filled with seawater to maintain control of the buoyant unit 20 . In a preferred embodiment, when the oil tank 33 is empty, its buoyancy should make the combined device 20 and the cabin 32 of the barge 30 still buoyant when it is completely filled with seawater, and the subsequent submersion of the combined device 20 is This is accomplished by allowing water to enter the tank 33 in sufficient quantities to increase the weight of the assembly 20 to overcome the buoyancy of the air left in the tank.

In terms of fully submerging the combination 20, the recommended solution for sinking the combination 20 to the bottom is to maintain a volume of water in the tank 33 which is effective to sink the combination 20 under gravity, But without making the combination 20 so heavy as to exceed the holding or maintaining power of the winches WL1 and WL2 on board the capstan. As combination 20 is submerged and subjected to increasing water pressure, control system CS is used to send compressed air substantially equivalent to this increased water pressure into oil tank 33 through lines 34 and 35 so as not to A pressure differential occurs across the tank wall leading to crushing. During this descent, the volume of liquid in tank 33 can be drained as needed to maintain the stability and correct orientation of assembly 20 .

Once the storage facility 20 is placed on the bottom B, the tank is completely filled with water so that any remaining air is expelled from the tank. When it is desired to store the produced fluid, the produced fluid is introduced into the oil tank, and at the same time an equal volume of seawater is discharged from the oil tank to the treatment device on the platform 13 through the flow pipeline, so that the discharged The oil is removed from the water and the water is safely discharged outward into the sea.

2-5 show the structural and operational details of an embodiment of the present invention. The storage facility, indicated at numeral 40 in Figure 2, cooperates with caisson 42 to provide a vertical support for cable-free installation. As can be seen most clearly in FIGS. 2-3, storage facility 40 is similar to storage facility 20 in that it includes a concrete barge section 60 carrying a bank of five tanks such as tanks 63 . The tanks are seated in curved groove sets in the horizontally extending bracket structure 64 . The structure 64 is preferably made as an integral piece with the barge section 60 . A recessed keyway 65 at one end of the barge 60 sits around the caisson 42 . A triangular spanning truss branch 66 extends upwardly from the distal end of the barge 60 to an intermediate connection point 67 on the caisson 42 . The branches 66 cooperate with the caisson 42 to provide a broad base structure that holds the caisson in its vertical upright position.

4 and 5 have shown the detailed structure of the oil tank 63 used in the storage device of the present invention. The preferred form of tank 63 is a steel cylindrical tank 68 with a hemispherical closed end. A concrete layer 69 closes the steel tank 68 increasing its resistance to the high water pressure acting on the tank wall. In addition, concrete provides an effective corrosion-resistant barrier to the exterior surface of the tank. The inner area of the tank is also reinforced with reinforcements 70 of annular T-section. The uppermost vertical part of the stiffener 70 has a transverse opening 71 . A similar lateral port 72 is also provided in the tank (70) on its lowermost vertical portion. Orifices 71 and 72 allow fluid on either side of reinforcement 70 to flow laterally through the reinforcement when the tank is filled or emptied.

Each tank is secured to the bracket structure 64 with steel straps 73 extending over each end of the tank and anchored to the bracket structure.

As previously mentioned, in the operation of a storage facility, tanks will contain a combined liquid, usually oil and water. Oil whose density is less than water will rise above the water in the oil tank, as shown in Figure 5. A flow line 75 branched off and connected to the upper area inside the tank as shown in Figure 2 is used to add or withdraw liquid from the upper area of the tank. A flow line 76 similarly branched off and connected to the lower region of the tank is used to drain liquid from the bottom of the tank. In a typical application, since the lighter oil is at the top of the tank, line 75 would be in communication with the oil and line 76 would be in communication with the water below the oil. When the tank is filled with oil, it should be understood that line 76 will also be in communication with oil.

In the operation of the system shown in Figure 2, the system is connected to the surface discharge buoy in the manner shown in Figure 1, and the oil produced from the oil well that cooperates with the caisson structure 42 is sent to the oil tank 63 through a control valve assembly CVA . Although the control valve system CVS has been briefly described as a single control unit, it is conceivable that the system employs remotely operated valves at each appropriate inlet and outlet point for controlling the flow of fluid through the apparatus 40, and also includes Sensors that monitor and record variables such as pressure, liquid level, liquid interface, temperature, flow rate, liquid density, and many more. The structure and operation of these control valve systems for properly monitoring and controlling the operation of the apparatus 40 is well known in the art and is not a novel feature of the present invention per se.

As oil is added to oil tank 63, line 76 is opened by control assembly CVA to allow the water in the bottom of the oil tank to be drained to accommodate the incoming oil. As mentioned above, this discharged water is treated to remove oil from it before being discharged into the sea. During this process, the oil tank 63 is always filled with fluid so that there are no air pockets in the oil tank. The liquid in the oil tank is generally oil and water separated by volume, or all oil, or all water. As oil is removed from the tank and sent to the tanker, the control valve assembly CVA is operated to fill the tank with water through line 76, while draining oil from the tank through line 75 and until Sea surface oil buoys and to oil tankers.

In a preferred embodiment of the marine production and storage facility of the present invention, the facility is designed to be installed and operated in water depths greater than 100 feet. The combined unit 20 or 40 of tanks and barges in a system can have a combined empty weight of about 30,000 tons and is intended to store 150,000 or more barrels of oil. Each tank 63 in this system has a diameter of approximately 40 feet and a length of approximately 138 feet. It is conceivable that larger or smaller barges and tanks can also be used. Additionally, multiple barge/tank systems could be employed and interconnected, with flow piping between individual barge/tank systems, if desired.

In the system shown in Figures 2, 3, the caisson 42 and triangular support may be hauled to the site as part of the assembly 40. During haulage, the caissons can be placed either erected or horizontally on the barge, and the caissons can be erected before or after the barge is submerged. The typical installation shown in Figures 2 and 3 should be desired where, for example, assemblies 40 and 42 are erected next to a previously drilled oil well whose environment has a hard water subfloor where tubular drive operation is not desirable.

It will be appreciated that apparatuses 20 and 40 are substantially identical in structure and operation, except that apparatus 40 is designed to provide structural support for an associated caisson.

In Figure 9 there is shown a modified embodiment of the storage facility of the present invention wherein the caisson and associated support branches are integral with the barge. Referring to FIG. 9 , the barge portion 80 has an opening 82 through which a caisson 84 extends and is fastened to the barge 80 . The lower end 86 of the caisson 84 terminates in a lower surface 88 of the barge 80 . A group of concreted storage tanks, generally indicated by the numeral 90, is mounted on barge 80 in the manner described above. The caisson 84 is further stabilized and secured to the barge 80 by a triangular span-supported truss branch 92 rigidly interconnecting the caisson 84 and the barge. As shown, production tubing 94 extends through caisson 84 and down into the production formation in a known manner. Fluids produced from the production formation flow up the production tubing 94 to be collected at the surface as described above. An advantage of the embodiment shown in Figure 9 is that the caisson 24 is integral with the barge so that the system can be placed at a desired site. The barge 80 with the tank assembly 90 is submerged to the seabed in the manner described above, after which all operations such as drilling, full operation and production can be carried out from a suitable platform (not shown) via the caisson 84 . In a sense, the embodiment shown in Figure 9 provides a combined drilling, production and storage facility for receiving oil from a subsea formation. It should be noted that the ballasting of the barge 80, the pressurization of the tank 90a to prevent damage and the resulting movement of fluid into and out of the tank 90a can all be implemented as described for the other embodiments above.

It is also conceivable that although the flow and distribution conduits are considered as separate conduits, the conduits could in fact be bundles of flow conduits and control conduits operating in a conventional manner to regulate the flow of liquid into or out of the Transportation of oil tanks. It will also be appreciated that although the system has been shown as a single caisson arrangement, in fact a single storage facility may be connected to several adjacent caisson-type facilities.

Thus, while a preferred form of the invention has been illustrated and described, those skilled in the art will appreciate that various modifications may be made in structural details and system operation without departing from the spirit and scope of the invention.

Claims (28)

1. system that is used for the liquid of interim storage one ocean oil well output comprises:

One submersible barge;

One links to each other with barge forms a storage oil tank of storing clustered aggregates, and this oil tank has on one internal storage zone and internal storage zone once;

One supplies with the service of this storage oil tank with liquid;

One with liquid from storing the discharge pipe that drain in the internal storage zone on the oil tank; And

One is used to control the control system that fluid goes out, goes into to store oil tank, and the liquid of draining from this storage oil tank by described discharge pipe is substituted by the fluid of dosing by this service, to keep this oil tank by fluid filled.

2. the system as claimed in claim 1 is characterized in that, also comprises a caisson type oil well assembly, and from then on the fluid of oil well assembly output is connected to described storage oil tank by described service.

3. the system as claimed in claim 1 is characterized in that, also comprises an interface float component, and this assembly is used to set up being connected between the charging tube on described marketing channel and the oil carrier.

4. the system as claimed in claim 1 is characterized in that, this barge is constructed with cement concrete.

5. the system as claimed in claim 1 is characterized in that, this barge is provided with a plurality of cabins, and this cabin can be filled water selectively with this barge of balance.

6. the system as claimed in claim 1 is characterized in that, described oil tank comprises the steel main body that a usefulness cement concrete coats.

7. the system as claimed in claim 1 is characterized in that, also comprises a plurality of storage oil tanks that interconnect and be installed on this barge.

8. system as claimed in claim 7 is characterized in that, described barge constitutes with cement concrete, and this oil tank then coats with cement concrete.

9. system as claimed in claim 8 is characterized in that, described storage clustered aggregates is by dive, and oil tank is filled a liquid.

10. system as claimed in claim 7 is characterized in that, it also comprises a caisson type oil well assembly, is connected with the storage oil tank by described service from the fluid of described oil well assembly output.

11. system as claimed in claim 9 is characterized in that, it also comprises a caisson type oil well assembly, and the fluid that produces from this oil well assembly is connected with this storage oil tank by described service.

12. system as claimed in claim 2 is characterized in that, it also comprises an interface float component, and this assembly is used for setting up being connected between the charging tube of described marketing channel and an oil carrier.

13. system as claimed in claim 12 is characterized in that, this barge is constructed with cement concrete.

14. system as claimed in claim 13 is characterized in that, this barge is provided with a plurality of cabins, and these cabins can be by water filling selectively, thereby makes the barge balance and stability.

15. system as claimed in claim 14 is characterized in that, described oil tank comprises the steel main body that a usefulness cement concrete coats.

16. system as claimed in claim 15 is characterized in that, it comprise a plurality of interconnective, be installed in the storage oil tank on the barge.

17. system as claimed in claim 16 is characterized in that, described bunkerage is by dive, and described oil tank is filled a liquid.

18. system as claimed in claim 2 is characterized in that, described caisson is supported from structure by described barge at least partially.

19., it is characterized in that this barge is mainly constructed with cement concrete as system as described in the claim 18.

20. system as claimed in claim 17 is characterized in that, described barge is mainly constructed with cement concrete.

21. one kind is the method that an oil well assembly is set up an interim fluid storage equipment, may further comprise the steps:

(a) barge and oil tank bunkerage are hauled to described assembly scene;

(b) make this bunkerage in described on-the-spot dive;

(c) with all gas of liquid discharge in described equipment;

(d) discharge liquid in described bunkerage with the liquid of described oil well assembly output;

(e) liquid collecting that will discharge from described bunkerage is in a water surface carrier.

22. method as claimed in claim 21 is characterized in that, described oil well assembly is a kind of caisson oil well assembly.

23. method as claimed in claim 22 is characterized in that, it also comprises a caisson that structurally supports this caisson type oil well assembly with described bunkerage at least partially.

24. method as claimed in claim 23 is characterized in that, described caisson is hauled to described scene by this barge and oil tank bunkerage.

25. method as claimed in claim 21 is characterized in that, described barge and oil tank are stored clustered aggregates and are mainly constructed by cement concrete.

26. method as claimed in claim 22 is characterized in that, the barge that described barge and oil tank are stored in the clustered aggregates is mainly constructed by cement concrete.

27. method as claimed in claim 26 is characterized in that, the barge that this barge and oil tank are stored in the clustered aggregates is mainly constructed by cement concrete.

28. method as claimed in claim 25 is characterized in that, the oil tank that described barge and oil tank are stored in the clustered aggregates comprises one or more steel oil tanks that coat with cement concrete.

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