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

Method for selectively operating a wireline tool releasing device

Patent ·
OSTI ID:5383685
This patent describes a wireline method for use in a wellbore and incorporating a wireline having a releasing device which includes a first tubular piston connectable to the wireline, a second tubular portion releasably connectable, at a first end, to the first portion and, at a second end, to a downhole tool, a releasing mechanism operable in response to a change in pressure for releasably connecting the second tubular portion to the first tubular portion, a precharge chamber located within the second tubular portion, and means for adjustably pressurizing the precharge chamber to apply a force against the releasing mechanism to prevent the first and second tubular portions from being disconnected. The method comprises: selecting a desired releasing pressure magnitude and pressurizing the precharge chamber of the releasing device to the magnitude to apply a given force against the releasing mechanism; connecting the releasing device to the downhole tool and to the wireline; extending the wireline, with the releasing device and the downhole tool attached thereto, into the wellbore; and maintaining the wellbore pressure at a level which is insufficient to overcome the force applied against the releasing mechanism if it is not desired to operate the releasing device downhole.
Assignee:
Conoco Inc., Houston, TX (USA)
Patent Number(s):
US 4997041; A
Application Number:
PPN: US 7-464484
OSTI ID:
5383685
Country of Publication:
United States
Language:
English