Method, system, and tool for investigating borehole casings

Patent · Tue Dec 27 00:00:00 EST 1988

OSTI ID:6059735

Davies, D

A system is described which investigates a casing fitted into a borehole traversing an earth formation, comprising: (a) a downhole tool capable of investigating the casing along the length of the casing; (b) a measurement control unit located in proximity to the surface of the earth formation; and (c) a cable having one end connected to the downhole tool and the other end connected to the measurement control unit, the cable including at least a plurality of first connection lines, the downhole tool comprising: (1) at least a first pair of longitudinally spaced electrodes, (2) means for causing the pair of electrodes to be contacted with the inner peripheral surface of the casing, (3) at least a pair of second connection lines, each of the second connection lines having one end connected to a corresponding one of the electrodes, and (4) relay means interposed between the first connection lines of the cable and the second connection lines of the downhole tool, the relay means being arranged to be positioned in first and second positions, wherein when the relay means is in the first position, the first connection lines of the cable are short-circuited by the relay means, and when the relay means is in the second position, the first connection lines are connected to their corresponding second connection lines thereby establishing an electrical connection between the measurement control unit and the electrodes.

• Assignee: Schlumberger Technology Corp., New York, NY
• Patent Number(s): US 4794322
• OSTI ID: 6059735
• Resource Relation: Patent File Date: Filed date 30 Oct 1986
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
03 NATURAL GAS
MEASURING INSTRUMENTS
WELL CASINGS
MEASURING METHODS
CONTROL SYSTEMS
ELECTRICAL PROPERTIES
ELECTRODES
NATURAL GAS WELLS
OIL WELLS
RELAYS
TESTING
TOOLS
ELECTRICAL EQUIPMENT
EQUIPMENT
PHYSICAL PROPERTIES
WELLS
020300* - Petroleum- Drilling & Production
030300 - Natural Gas- Drilling
Production
& Processing