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U.S. Department of Energy
Office of Scientific and Technical Information

Well casing flotation device and method

Patent ·
OSTI ID:5202683
This patent describes an apparatus useful in installing a string of joined pipe sections from a surface into a well bore containing a first liquid. It comprises a pipe string portion, one end of the string portion forming one end of an air filled flotation cavity within the string; a slidable member sealing and forming the other end of the flotation cavity, the slidable member having a passageway for conducting air out of the flotation cavity and liquid into the flotation cavity; a plug sealing the passageway; one or more first shear pins attaching the plug to the sliding member; and one or more second shear pins attaching the sliding member to the pipe string.
Assignee:
Union Oil Co. of California, Los Angeles, CA (USA)
Patent Number(s):
US 4986361; A
Application Number:
PPN: US 7-401086
OSTI ID:
5202683
Country of Publication:
United States
Language:
English