JPS58101913A - Platform having floating tank - Google Patents

Abstract

PURPOSE:To increase the buoyance of a platform by a method in which a recession larger than the outside diameter of an oil storage tank is formed at the center of a lower body, and the sea water is introduced into the recession to float the oil storage tank in it. CONSTITUTION:An upwardly opened recession 7 larger than the outside of an oil storage tank 6 is formed at the center of a lower body 2, and the sea water is introduced into the recession through a water conveyance path 8 with a valve piercingly provided on the side of the lower body, whereby permitting the oil storage tank 6 to be floated. Thus, when the water conveyance path 8 is closed and the inside of the recession 7 of the lower body 2 is vacated during the towing period of the platform, sufficient buoyance can be obtained in the portion. Accordingly, the platform on which a deck and various modules, etc., are mounted can be towed and the draft during the towing period can be lessened.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a plaque door ohm incorporating a floating tank, and more particularly to a plaque door ohm incorporating a floating tank used in offshore oil drilling.

There are various conventional gravity platforms with oil storage tanks, all of which have oil storage tanks of the oil/water displacement type.

The oil/water displacement lid is used to keep the oil level in the tank constant at all times by filling it with seawater at the bottom of the tank.When the amount of oil in the tank increases, the seawater underneath the oil is drained out and vice versa. If the amount of oil decreases, it means increasing the amount of water.

In such oil-water displacement type, the seawater discharged from the tank usually contains oil. In Japan, the oil concentration of this wastewater is regulated to 10 ppm or less. In order to discharge the oil with a concentration like oil, it is necessary to install a large oil separator pipe on the platform, which becomes uneconomical.

In addition, since oil from the seas near Japan and the coast of China contains a large amount of wax, an assimilation phenomenon occurs at the interface between oil and water in the oil-water displacement type. The only way to solve this assimilation phenomenon is to
The method is to heat it to 0°C to 70°C, but this requires a huge amount of equipment and is not economical.

Furthermore, emulsion carbon is generated near the oil-water interface due to mutual mixing, and sludge is deposited on the oil-water interface. These interfere with tank operation.

For the above reasons, if an oil-water displacement type is not allowed, an oil storage tank that only holds oil should be used, and the platform must be designed with the assumption that the oil storage tank will be empty when the oil is discharged. .

The problem with ζ is that the book door ohm built at the construction base should be towed and installed at the site as a floating body with as little water as possible. It is a contradictory reality that it is not benevolent to stay afloat even when you are in the middle of something.

To solve this problem, in conventional platforms, extra pallast is formed as a counterweight during installation by casting in-situ concrete or by filling it with stone, ore, etc. In this case, it was necessary to ensure that the oil storage tank had the necessary horizontal resistance against seismic forces even when it was empty.

The installation locations near Japan are generally on soft ground, and there are often restrictions on drainage. In other words, if the construction site is Japan,
The dry water is at dock -1 port, from 110+a to - from the water depth of the channel.
The water depth during towing and the water depth at the installation site is also limited to 13 ow. In order to deal with this stagnant side @, it is necessary to increase the buoyancy of the book door ohm,
When a skirt is provided under the platform as a countermeasure against soft ground, a conventional platform with a lid has the drawback of severely restricting the shape of the main body. Therefore, in such cases, conventionally, a part of the concrete main body of the book door ohm was installed inside the dock. Build a chisel, tow it out to sea, and anchor it in deep enough water.
[A] by a method that involves trying to understand the main body of A]. However, such a method has disadvantages in terms of construction period and construction cost.

Furthermore, when the oil storage tank is empty, a size water pressure difference acts between it and the G/(') storage tank, and the whole becomes an external pressure vessel, so the thickness of the parts must be increased, which is a problem. , and because of this, hiccups are even more disadvantageous in tournaments.

The platform incorporating the floating tank of the present invention may suffer from the above-mentioned drawbacks, but the upper body and
a lower body, a portion connecting the upper body and the lower body, and a recess formed in the lower body and opening upwardly, penetrating the lower body to introduce seawater into the recess. The mold consists of a water conduit with an on-off valve and nine oil storage tanks that are suspended in the seawater in the depression.

The present invention will be explained in detail below with reference to the drawings.

In the figure, 1 is the upper body of the platform on which, for example, excavation equipment, decks, various mosieres, etc. are placed, 2 is the lower body, 3 is the leg that connects the upper body 1 and the lower body 2, and 4 is the leg that connects the upper body 1 and the lower body 2. soft ground, 5 a skirt protruding from the lower surface of the lower body 2 to be inserted into the soft ground 4, and 6 an oil storage tank. This diameter forms a large concave 7 that opens upwards.

In addition to allowing seawater to be introduced into the recess 7 through a conduit 8 with an on-off valve provided through the side surface of the lower body 2,
The oil storage tank is fit loosely into the recess 7. If necessary, a tweezers (not shown) are applied to the inside of the recess 7.

Since the platform of the present invention has the above-mentioned configuration, the oil storage tank 6 is suspended in the seawater in the recess 7 through the conduit 8 according to the increase or decrease of O oil in the oil storage tank 6. Discharge seawater from inside the depression 7 or
The total weight of the platform, including the oil in the oil storage tank 6, can be kept constant at all times, and indirectly it can be made into an oil/water displacement type, which also solves the problem of horizontal resistance during earthquakes. Since oil and seawater do not come into direct contact with each other, environmental pollution and various problems caused by oil and water mixing can be eliminated.

In addition, in the platform of the present invention, the oil reservoir 6 is taken by the outer wall of the lower body 2 and has a round shape.
After the platform is installed, the outer wall acts to improve the safety of the oil storage tank by shielding external forces from waves and wind forces, and also functions as an oil barrier in the event that oil leaks from the oil storage tank. It becomes like this.

Furthermore, in the platform of the present invention, if the conduit 7 of the lower body 2 is emptied when the platform is towed, sufficient buoyancy can be obtained in this part. Equipped with this, it can be towed at 900 degrees, and it is possible to reduce the amount of water produced during towing.

The oil storage tank 6 used in the platform of the present invention can be made of steel or concrete depending on conditions such as oil storage amount and water depth, and the planar shape can be freely selected such as circular or rectangular. Moreover, since it is not subject to external forces such as wave forces, it can be made to have a thin and economical cross section, and is advantageous against earthquake forces because the natural frequencies of the platform body and the oil storage tank are different. Furthermore, 4J against temperature stress during oil storage
Since it is separated from the outer wall of the lower main body of IIt), no extra force is generated.

In addition, the platform in the above embodiment has a deck etc. placed on it, making it a so-called multi-purpose platform that has the functions of drilling, production, processing, and oil storage, but it is also possible to make it have only the oil storage function. Of course, it is also conceivable to use it in combination with a similar jacket structure.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional front view of the platform of the present invention, and FIG. 3 is a sectional view taken along the line A--Person. 1... Upper body, 2... Lower body, 3... Legs, 4
... Soft ground, 5... Skirt, 6 - Oil storage tank, 7... Hollow, 8... Headrace.

Claims (1)

[Claims] (1) An upper body, a lower body, a portion connecting the upper body and the lower body, a 119 recess formed in the upper part of the lower body, and a portion of the lower body for introducing seawater into the recess. A plaque door ohm having a built-in floating oil conduit characterized by a water conduit with nine opening/closing valves extending through it, and nine oil storage conduits which are made to float on the seawater in the recess.