Three magnet casing collar locator
A casing collar locator is described comprising: a nonmagnetic downhole tool body sized and adapted to be lowered axially in a well borehole; three serially positioned permanent bar magnets carried interiorly of the body and abutting at opposing poles wherein the center magnet forms a magnetic field directed outwardly therefrom and the magnetic field is focused radially outwardly by the remaining two magnets to magnetically interact with tubular member threaded joints in the well borehole; and detection coil means would over the magnets and located at the juncture of the opposing poles of the magnets to detect changing magnetic field signals from the threaded joints coupled thereto by the focused magnetic field.
- Assignee:
- Halliburton Co., Duncan, OK
- Patent Number(s):
- US 4808925
- OSTI ID:
- 6212659
- Resource Relation:
- Patent File Date: Filed date 19 Nov 1987
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
03 NATURAL GAS
SLEEVES
DETECTION
TOOLS
WELL CASINGS
ELECTRIC COILS
MAGNETIC FIELDS
NATURAL GAS WELLS
OIL WELLS
PERMANENT MAGNETS
THREADED JOINTS
ELECTRICAL EQUIPMENT
EQUIPMENT
JOINTS
MAGNETS
WELLS
020300* - Petroleum- Drilling & Production
030300 - Natural Gas- Drilling
Production
& Processing