Patent ID: 8950437
Filing Date: 2015-02-10
Classification: E21B,F16L

Abstract:
1. Apparatus for controlling leakage from a leak in a duct carrying a fluid at a known internal pressure, said apparatus comprising:— one or more sealing elements each comprising a solid in the form of an elastic material which contains one or more impermeable bubbles, the sealing elements to be introduced into the duct and capable of being transported along the duct by the flow of said fluid and capable of being drawn to the leak by the pressure differential in the region of the leak; characterised in that the bubble(s) in the one or more sealing elements are full of gas with the product of the volume of the bubble(s) and the pressure of the gas therein selected according to the internal pressure in the duct such that the pressure of the gas in the bubbles is greater than or equal to the internal pressure in the duct:— such that when introduced into the duct the sealing element(s) elastically contracts in response to the duct internal pressure as a result of the volume change of the gas contained in the bubble(s), such that when introduced into the duct the sealing element will have a transport volume at said internal pressure which is appropriate to flow into the region surrounding a leak and can be drawn towards and into the leak by the pressure differential in this region, and such that the sealing element will elastically expand from said transport volume in response to the reduced pressure associated with the locality of the leak sufficiently to seal that leak.