Measuring and testing – Borehole or drilling – Downhole test
Patent
1982-05-28
1984-04-03
Myracle, Jerry W.
Measuring and testing
Borehole or drilling
Downhole test
E21B 4700
Patent
active
044400195
ABSTRACT:
The components for operation of the invention are three: (1) a downhole tool consisting basically of a sensitive coil suitably protected by an encasing sheath as it is run downhole inside a string of drill pipe, tubing or the like, (2) surface apparatus to pulse the coil by discharging a capacitor through it, and later to detect small voltages induced in the coil as a result of running it past magnetic spots in the string produced by the capacitor discharges, and (3) connecting elements for both running and pulling the downhole tool, e.g., a wire line, and for electrically connecting the coil to the surface apparatus.
Such apparatus is used in conjunction with standard equipment at the wellhead to stress the string by either pulling up on it or trying to rotate it, or both. In trying to pinpoint the depth at which the string is stuck, use of the invention exploits the fact that the lifting or torqueing force will cause strains in the material of the string along its entire free length, but no strains will be induced in the portion below the point of sticking. Also exploited is the fact that thus stressing the free part of the string will erase all magnetic spots previously placed there by pulsing the downhole tool. Since no stresses are produced below the point of sticking ("free point"), magnetic spots below such point will remain, and are detected as the tool travels past them.
REFERENCES:
patent: 2902640 (1959-09-01), Foster
patent: 2946926 (1960-07-01), Hawthorne
Myracle Jerry W.
Smith, Jr. Roy H.
LandOfFree
Free point indicator does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Free point indicator, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Free point indicator will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-661602