Title:
DEGRADABLE PLUG DEVICE FOR A PIPE
Document Type and Number:
WIPO Patent Application WO/2017/187117
Kind Code:
A9
Abstract:
The invention relates to a degradable plug device (12, 13, 41, 110, 140) for a pipe (10). The plug device has an outer plug body (16) and an inner plug (14) for preventing fluid flow through the pipe (10) until it or a part thereof has been removed from the outer plug body (16). The outer plug body 16 ()and the inner plug (14) are formed of a degradable material, such as magnesium. The inner plug (14) has a chamber (22) with a port (24) to the exterior of the inner plug (14). The exposed surfaces of the degradable plug (12, 13, 41) have a protective layer thereon. The inner plug (14) is disposable in at least a first position, in which the inner plug (14) prevents said fluid flow through the pipe (10), and is adapted to undergo, in use, a degradation initiation operation, such that fluid is able to enter the chamber (22) to initiate corrosion or dissolution of the inner plug (14) from inside the chamber (22). In an alternative form, the inner plug (14) is in sealing contact with the outer plug body (16) so as to define the chamber (22), and the plug body (16) has a cup-shaped cross-section, and, in the first position, the inner plug (14) is disposed at the mouth of the cup, thereby forming the chamber (22). The degradation initiation operation may comprise moving the inner plug (14) relative to the outer plug body (16) between the first position and a second position, in which fluid is able to enter the chamber (22) by applying a fluid pressure in the vicinity of the inner plug (14), or a direct force to inner plug (14), that exceeds a threshold to cause failure of a shear ring and release or allow limited movement of inner plug (14). Ό' ring seals are provided between the outer plug body and the inner plug to provide a seal therebetween, and during movement the port may move from between the Ό' ring seals to a position where it communicates with the interior of the pipe. In an alternative embodiment, the degradation initiation operation comprises at least partially removing, in use, the protective layer at or near one end of the inner plug by an abrasive member, thereby initiating corrosion or dissolution of the degradable member through contact with the fluid. An apparatus for temporarily blocking flow of fluid through a pipe, and a method of operating a degradable plug device for a pipe, are also disclosed.
Inventors:
MARTIN GEORGE BRUCE (GB)
Application Number:
PCT/GB2017/000061
Publication Date:
December 07, 2017
Filing Date:
April 26, 2017
Export Citation:
Assignee:
SPECIALISED OILFIELD SOLUTIONS LTD (GB)
International Classes:
E21B33/12
Attorney, Agent or Firm:
BATES, Daniel (GB)
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