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

System for determining the free point of pipe stuck in a borehole

Patent ·
OSTI ID:5701227

A method for detecting the location at which a ferromagnetic pipe string is stuck within a borehole comprising the steps of: passing a wireline tool through the pipe string; stressing and unstressing the pipe string above the stuck location while the wireline tool is being passed through the aid pipe string; measuring a stressed magnetic permeability of the walls of each of two sections of the pipe string while the pipe string is stressed; measuring an unstressed magnetic permeability of the walls of the sections while the pipe string is unstressed; comparing the stressed and unstressed magnetic permeabilities for the sections.

Assignee:
NL Industries, Inc., New York, NY
Patent Number(s):
US 4708204
OSTI ID:
5701227
Country of Publication:
United States
Language:
English