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US 3,960,448 AGranted
Holographic instrument for measuring stress in a borehole wall
AssigneeTRW Inc.
InventorsJames L. Schmidt, Jerold L. Jacoby, Garrett D. Shaw, Pravin G. Bhuta
Life of this patent
Estimating the term…
Abstract
An instrument for determining the stress in the wall of a borehole by recording successively on the same holographic recording medium two holograms of a selected surface region of the wall, and, in the interval between the two recordings, forming a stress relief in the wall in stress relieving relation to the surface region to produce on the recording medium a double exposure hologram. This hologram contains holographic information which represents the stress in the wall in the vicinity of the surface region and may be converted to data defining the magnitude and direction of the stress.
Claims13
A holographic instrument to be positioned within a borehole for determining the stress in the borehole wall, comprising:
- an elongate body which extends lengthwise of the borehole in which the instrument is positioned;
- said body having separable body sections;
- a holographic recording system in one body section including means for holding a holographic recording medium having a field of view in a transverse direction of said body, whereby when the instrument is positioned in a borehole, a surface region of the borehole wall is situated in said field of view, and means for recording first and second holograms of said wall region in succession on said recording medium to produce on said medium a double exposure hologram of said wall region;
- means on the other body section for cutting a stress relief in the borehole wall in stress relieving relation to said wall region in the interval between recording of said first and second holograms, whereby said double exposure hologram contains information representing the stress in said wall region;
- means for anchoring said body sections in the borehole;
- and
- coupling means releasably joining said body sections, whereby said sections may be joined for introduction into and removal from the borehole, and said coupling means may be released when said sections are anchored in the borehole to mechanically isolate said sections from one another and thereby permit operation of said stress relief forming means without disturbing said holographic system.
4 more elements
A holographic instrument to be positioned within a borehole for determining the stress in the borehole wall, comprising;
- an elongate generally tubular body which extends lengthwise of the borehole in which the instrument is positioned;
- said body including separable upper and lower sections;
- said supper section having a laterally facing window at its lower end;
- a holographic recording system in said upper body section including means at the lower end of said upper section behind said window for holding a holographic recording medium having a field of view in a transverse direction of said body through said window, whereby when the instrument is positioned in a borehole a surface region of the borehole wall is situated in said field of view, a laser, and holographic optics for illuminating said recording medium and wall region with reference and scene beams, respectively, from said laser, whereby said holographic system is adapted to record first and second holograms of said wall region in succession on said recording medium to produce on said recording medium a double exposure hologram of said wall region;
- drilling means on said lower body section for drilling a stress relief hole in said wall region in the interval between recording of said first and second holograms, whereby said double exposure hologram contains holographic information representing the stree in said wall region;
- said drilling means comprising means for supporting a drill with its axis transverse to the longitudinal axis of said body, means for driving the drill in rotation, and means for extending and retracting the drill along a first direction line parallel to said body axis and along a second direction line parallel to said drill axis to and from a retracted position below said field of view in said interval between recording of said first and second holograms in a manner such that the drill undergoes initial upward extension along said first direction line from said retracted position into said field of view and then extension along said second direction line into drilling engagement with said wall region to drill said stress relief hole in said wall region, and thereafter retraction along said second direction line out of drilling engagement with said wall region and then downward retraction along said first direction line back to said retracted position;
- and
- means for separately anchoring said body sections in the well bore, and coupling means releasably joining said body sections to one another, whereby said sections may be joined for introduction into and withdrawal from the borehole and said coupling means may be released when said body sections are anchored in the well bore to mechanically isolate said sections from one another and thereby permit operation of said drilling means without disturbing said holographic system.
5 more elements
Dependencies are inferred from the claim text.