RU2370593C1 - Method of protection of reservoir covered with ice from oil overflow - Google Patents

Abstract

FIELD: oil and gas production.

SUBSTANCE: here is disclosed method of protection of reservoir covered with ice from oil overflow by means of obstruction installed in opening of ice cover. The obstruction consists of a flexible elastic shell with weighting material along the lower edge; the shell is filled with water under excessive pressure. The obstruction additionally contains the second flexible elastic shell arranged above the first one. The upper shell is filled with air under excessive pressure at installation of the obstruction after its placement in the opening of ice cover; further, the lower shell is filled with water.

EFFECT: invention increases reliability of water reservoir and reduces time of construction of obstruction.

1 dwg

Description

The invention relates to environmental technologies used for contamination of an ice-covered water surface with liquid hydrocarbons of oil and oil products that occur during breakthroughs of subsea oil pipelines, integrity violations of oil-containing containers located in close proximity to water bodies, and other similar situations.

A known method of protecting an ice-covered pond using a device according to A.S. RF №1765292, class E02B 15/04 by localizing an oil slick using an ice-covered boom that is placed under ice through an ice hole.

A known method of localizing an oil pollution stain according to the patent of the Russian Federation No. 2107127, E02B 15/04 by making an ice hole in ice, placing a floating boom under an ice sheet with the formation of a closed loop in which hot air is injected.

The disadvantages of these methods are as follows: their efficiency is relatively low due to the ablation of part of the oil by the flow beyond the areas marked for protection, the boundaries of which are limited by the fixed location of the most important working bodies of devices and ice holes, and the transfer of these boundaries is difficult due to the low mobility of the devices used. These methods are unsafe due to the need to constantly work on the surface of the ice away from the coast, including in conditions of low temperatures, wind, snowfall. In addition, the second method requires the presence of hot air, which in conditions of remoteness from habitable places and off-road in Siberia is almost unrealistic.

A known method of protecting an ice-covered reservoir described in the article "Method for the localization and elimination of emergency oil spills at underwater crossings of oil pipelines", published in the journal "Pipeline transport of oil" No. 11 for 1999. The method consists in cutting the ice cover across the water stream at an angle to its dynamic axis and installing a barrier in it, which is made of separate shields of a rigid structure 6 × 1.5 m in size and installed in the ice sheet slots with a certain inclination, so that block the slot. With the correct setting of the fence, the contact of oil with cold air is excluded and it moves under the ice to the oil receiver.

However, the sections of the fence are large, which leads to some complexity and the duration of their transportation to the place of the accident. In addition, due to the rigid construction of the barrier, it is impossible to bridge all the gaps between the ice sheet and the barrier, which arise due to the uneven surface of the ice sheet, as a result, part of the oil floats into the working slot.

All these methods make it possible to localize an oil spill under freezing conditions and have conditions for the further collection of spilled oil.

The prototype of the proposed solution is a method of protecting an ice-covered reservoir from oil spills according to patent No. 2224842. This patent describes a method of protecting an ice-covered body of water from oil spills by using a barrier installed in the slots of the ice sheet, the barrier comprising a flexible flexible shell with a weight on the lower edge. This known method allows you to quickly and efficiently localize an oil spill in a pond under ice freezing conditions and to collect spilled oil in the future.

To install a barrier in the ice sheet, it is necessary to suspend the elastic shell on the transverse rods with cables at a certain height, for which it is necessary to determine the ice thickness and, accordingly, the cable length, which complicates the installation of the barrier. In addition, the water pumped into the elastic shell freezes in the future, which leads to the freezing of the elastic shell into the ice cover and to the inability to remove the barrier after completion of the oil spill removal.

An object of the present invention is to provide a method for protecting an ice-covered body of water, including flowing, from oil spills, which would allow to install and remove the fence with less labor and time.

To solve this problem, protection against oil spills of an ice-covered reservoir is carried out using a barrier installed in the ice sheet, and a flexible elastic shell with a weighting agent along the lower edge filled with water under overpressure is used as a barrier.

The difference from the prototype is that the barrier additionally contains a second flexible elastic shell located above the first, and when the barrier is installed after it is placed in the ice sheet, fill the upper shell with air under overpressure, and then fill the lower shell with water.

The drawing shows a cross section of the location of the fence in the ice sheet: 1 - ice cover, 2 - water, 3 - oil. As a barrier, the first (lower) flexible elastic shell 4 was used, for example, an inflatable boom with valves 5 for pumping water and bleeding off excess water, with a skirt 6 with weighting materials 7 along the lower edge. The barrier contains a second (upper) flexible elastic shell 8, for example, an inflatable boom with valves located above the first and intended to be filled with air. The barrier also contains devices 9 for fastening the shell to the ice cover, for example, a cable with a transverse rod, the length of which is greater than the width of the slot in the ice cover 1. The weighting device 7 can be, for example, a metal chain, which simultaneously increases the tensile strength of the shell. Discrete load can also be used. Sheath material - synthetic gas-oil-resistant material.

The method is as follows. When an oil pipeline breaks out or another similar situation, an oil slick spreads under the ice. If the accident occurred in a flowing body of water, then downstream from the place of spread of pollution, ice is cut through the water flow at an angle to its dynamic axis. In case of an accident in a pond with a small current or with still water, the area to be protected from oil spills is determined. For more efficient operation, it is advisable to determine the place of the fence in advance when designing the pipeline, taking into account hydrological studies of the coastline and access roads. Cutting the ice cover can be done in any way possible, for example using the BGM-1 bar rig on the MTZ-82.1 tractor. With a small width of the river and a small thickness of ice, you can use a chainsaw. The slot width is 0.1-0.15 m.

A barrier consisting of two elastic shells is deployed along the prepared slot on ice, fill the upper shell 8 with air, and lower the lower elastic shell 4 with the skirt and weighting 7 into the slot. The upper shell 8, wedging, does not allow the barrage to sink. If necessary, pump air under an overpressure of 0.3 atm into the shell 8, which takes the form of a slot, located throughout the thickness of the ice 1, providing an almost tight seal of the working slot at the ice-water interface and, therefore, eliminating the exit of water and oil into the working slot. The lower elastic shell 4 is freely located in water under the ice. After pumping water under excessive pressure into the lower shell 4, it takes the form of a dense cylinder, which creates an insurmountable obstacle to the movement of oil.

To remove the fence from the lower shell 4 using a pump, water is pumped out, and air is released from the upper shell 8, after which the fence is removed from under the ice using, for example, a device 9.

With a large width of the reservoir, you can use several sections of the specified shell, connecting them together in the same way as connecting sections of an inflatable boom.

The obstacle set in this way can be used to direct the oil flow along the resulting screen to the oil collector - an open mine, where oil floats up, and it can be collected by any oil collector available.

As tests have shown, the installation time of one section of the fence with a team of 2 people is 4-5 minutes. 1 worker can remove the fence. The clotting time of one section is 4-5 minutes. The assembled fence is compact and can be easily transported by any type of equipment.

Claims (1)

A method of protecting an ice-covered body of water from oil spills using a barrier installed in the ice sheet slot, the barrier comprising a flexible elastic shell with a weighting agent on the lower edge filled with water under overpressure, characterized in that the barrier further comprises a second flexible elastic shell located above first, and when installing the barrier after it is placed in the ice sheet, fill the upper shell with air under excessive pressure, and then fill the lower bolochku water.

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