GB2516923A

GB2516923A - Sub-Sea oil / gas capping device

Info

Publication number: GB2516923A
Application number: GB1314113.0A
Authority: GB
Inventors: John Butkus; Dale Richard Oades
Original assignee: Individual
Current assignee: Individual
Priority date: 2013-08-07
Filing date: 2013-08-07
Publication date: 2015-02-11
Also published as: GB201314113D0

Abstract

A subsea capping device for containing a flow of fluid, such as that arising from a leaking oil/gas well on the seabed. The device 10 comprises an open-bottomed collection chamber 11 which is fitted over leaking aperture A. The collection chamber 11 is circular in section has a tubular side wall 12, which is connected at its upper end to a frusta-conical end wall 13 from which a tubular flow outlet 14 axially extends. The collection chamber 11 is surrounded by an open-bottomed anchoring chamber 15 having a vacuum inlet 16. The anchoring chamber 15 is annular in section and is formed between the tubular wall 12 of the collection chamber 11 and a co-axial external tubular wall 17. Bracing members 18 extend between tubular walls 15 and 17. The bottom edge of both tubular walls 12,17 seal against the seabed S. A vacuum is then created in the anchoring chamber 15 by applying a vacuum to the vacuum inlet 14.

Description

SUB-SEA OIL/GAS CAPPING DEVICE This invention relates to a device for arresting and containing a flow of fluid or gas, such as that arising from a leaking Oil/Gas Well.

Oil/Gas can leak through apertures in the seabed either naturally or as a result of a drilling incident. If the oil/gas is not contained, a leak can have significant economic and environmental consequences. Oil/Gas is a valuable commodity, so the loss of oil/gas alone has a massive significant economic impact. Further economic impacts include the reduction in tourism and investment in regions affected by the oil/gas leak.

The environmental consequences of an oil/gas leak include mass mortality of fish and other marine wildlife, as well as destruction of marine and coastal habitats. It is therefore, desirable to collect any oil/gas that emerges from a leak. In order to achieve this, a seal must be formed between any flow arrester device and the surface from which the flow is emerging. This may be the seabed or a pipeline, etc. For the case of an oil/gas leak, the emerging fluid is generally at high pressure. This pressure poses a problem when trying to contain the oil/gas as the seal between the flow arrester and the target surface must be able to withstand this mass of pressure.

TidePower-Butkus has now devised a flow arrester device, which meets the above-mentioned objectives.

In accordance with the present invention, there is provided a device for arresting a flow of oil/gas from an aperture from a sub-sea surface. The device comprising an open-bottomed collection chamber arranged to enclose the aperture from which the flow is emerging, a flow outlet to collect the oil/gas from said collection chamber, and anchor means arranged to secure the device to the said surface. The anchor means comprising an open-bottomed anchoring chamber and evacuation means for applying a complete or partial vacuum to said anchoring chamber.

In use, the flow arrester may be positioned over an aperture in a seabed from which oil/gas is leaking such that the oil/gas emerges into the collection chamber. The bottom of the anchoring chamber seals against the seabed, whereupon the anchoring chamber is evacuated to thereby secure the flow arrester device to the seabed. The reduced pressure inside the anchoring chamber is set to be at least greater in magnitude than the positive pressure inside the collection chamber. In this manner, the device is held in-situ on the seabed. Preferably, the walls of both chambers are constructed from a rigid material, non-porous material such as steel.

Preferably, the anchoring chamber surrounds the collection chamber. Preferably, the device comprises inner and outer-side walls, said anchoring chamber (number 10) being disposed there between.

Preferably, the inner sidewall is tubular and defines said collection chamber.

Preferably, the collection chamber is circular in section.

Preferably, the collection chamber comprises an upper end wall, which tapers towards said flow outlet to effectively guide the oil/gas towards the flow outlet.

Preferably, the flow outlet is arranged to couple with a duct for conveying the collected oil/gas to a collection vessel.

Preferably, the inner and outer walls extend generally parallel to each other and are separated by a gap, which defines said anchoring chamber.

Preferably, the inner and outer walls are interconnected by bracing members which help to improve the rigidity of the device and which prevent deformation of the walls under the applied pressures.

Preferably, the evacuation means for applying a vacuum to the anchoring chamber comprises a duct connected to an opening in a wall of the anchoring chamber. As vacuum is induced, capping device is driven into the seabed by differential pressures.

An embodiment of this invention will now be described by way of an example only and with refirence to the accompanying drawings, in which Figure 1 is a sectional view through a device in accordance with the present invention for arresting and containing a flow of oil/gas from the sea bed; and Figure 2 is a bottom view of the device of Figure 1.

Referring to the drawings, there is shown a device in accordance with the present invention when standing on the surface (S) of the seabed and enclosing an aperture (A) such as a wellhead, from which oil/gas is leaking.

The device (10) comprises an open-bottomed collection chamber (11) which is fitted over the aperture (A) from which the oil/gas is leaking. The collection chamber (11) within (15) circular in section has a tubular sidewall (12) which is connected at its upper end to a frusta-conical end wall (13) from which a tubular flow outlet (14) axially extends. The flow outlet (14) is connected to a collection vessel (not shown) via an elongate duct (not shown). The collection chamber (11) is surrounded by an open-bottomed anchoring chamber (15) having a vacuum inlet (16). The anchoring chamber (11) is annular in section and is formed between the tubular wall (121) of the collection chamber (11) and co-axial external tubular wall (17). Bracing members (18) of steel or other strong material extend between tubular walls (12) and (17) to improve the rigidity of the device. In use, the bottom edge of both tubular walls (12,17) seal against the seabed. Then a complete or partial vacuum is then created in the anchoring chamber (15) by applying a vacuum to the vacuum inlet (14). It will be appreciated that the vacuum creates suction between the device (10, 12) and the seabed (S) and keeps the device (10,12) in the desired position. The first chamber (11) completely encloses the aperture (A) and thus all of the oil/gas emerging there from channelled to the flow outlet (14) for collection. The device will remain in situ as long as some of the external sea pressure and the pressure inside the anchoring chamber (15) is greater than the oil/gas pressure inside the collection chamber (11). If necessary, the vacuum pressure inside the anchoring chamber (15) can be adjusted to compensate for variations in the oil/gas pressure.

A device in accordance with this invention is simple and inexpensive in construction, yet is relatively easy to fit to a leaking oil/gas well or installation to contain the oil/gas leak.

Figure 3 shows the flood arrester sinking into the seabed due to differential pressures.

1) Position over the wellhead: 2) Vacuum is then applied and (10) starts to sink into the seabed.

3) The device continues to sink further into the seabed.

4) The wellhead is now enclosed allowing the oil/gas to be collected through (14) outlet pipe.