Method and apparatus for ultrasonic imaging of a cased well
AssigneeSchlumberger Technology Corporation
InventorSmaine Zeroug
Life of this patent
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Abstract
A method and apparatus for utilizing flexural excitations to characterize and/or image a cased well is disclosed. Various applications of the method and apparatus are also discussed.
Claims60
A method for characterizing a cased well, said cased well comprising a borehole drilled in a geological formation, a fluid-filled casing disposed in said borehole and cement disposed in an annulus between said casing and said formation, said method comprising:
- (i) exciting a flexural wave in said casing by insonifying said casing with a pulsed, collimated acoustic excitation aligned at an angle greater than the shear critical angle of the fluid-casing interface, said angle being measured with respect to the normal to the local interior wall of said casing;
- (ii) receiving one or more echoes;
- and,
- (iii) analyzing said echoes to characterize said cased well.
A method for characterizing a cased well, said cased well comprising a borehole drilled in a geological formation, a fluid-filled casing disposed inside said borehole, and a cement region disposed between said casing and said formation, said method comprising:
- (i) exciting a flexural wave in said casing by insonifying said casing with a pulsed, collimated acoustic excitation aligned at an angle greater than about 25-29 degrees, said angle being measured with respect to the normal to the local interior wall of said casing;
- (ii) receiving one or more echoes;
- and,
- (iii) analyzing said echoes.
A method for imaging a cased well, comprising:
- (i) exciting predominantly a flexural wave in a well casing;
- (ii) receiving one or more echoes;
- (iii) analyzing said echoes;
- and,
- (iv) providing an image of at least of portion of said cased well.
A method for imaging a cased well, comprising:
- (i) creating an excitation, consisting essentially of a flexural wave, in a well casing;
- (ii) receiving one or more echoes;
- (iii) analyzing said echoes;
- and,
- (iv) providing an image of at least of portion of said cased well.
Apparatus for characterizing a cased well, said cased well comprising a borehole drilled in a geological formation, a fluid-filled casing disposed in said borehole and cement disposed in an annulus between said casing and said formation, said apparatus comprising:
- means for insonifying said casing with a pulsed, collimated acoustic excitation aligned at an angle greater than the shear critical angle of the fluid-casing interface, said angle being measured with respect to the normal to the local interior wall of said casing;
- means for receiving one or more echoes;
- and,
- means for analyzing said echoes to characterize said cased well.
Apparatus for characterizing a cased well, comprising:
- at least one pulsed, collimated acoustic source, said source aligned at an angle greater than about 25-29 degrees with respect to the normal to a local interior wall of said well;
- at least one acoustic receiver;
- and,
- a computer programmed to analyze echoes received by the receiver.
Apparatus for imaging a cased well, comprising:
- means for exciting a predominantly flexural wave in a well casing;
- at least one receiver receiving one or more echoes;
- a computer analyzing said echoes;
- and,
- an output device providing an image of at least of portion of said cased well.
Apparatus for analyzing a cased well comprising:
- one or more sonic source(s) positioned to creating an excitation—consisting prevailingly of a flexural wave—in a well casing;
- one or more receiver(s) receiving echo(es);
- and,
- a computer analyzing said echo(es).
Dependencies are inferred from the claim text.