Casing thickness estimation by frequency correlation

The thickness of borehole casing can be determined by ultrasound logging in conjunction with simulations of ultrasonic plane-wave echo waveforms across a range of frequencies for a plurality of casing thicknesses and correlation of synthetic frequency spectra derived from the simulated plane-wave ec...

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Bibliographische Detailangaben
Hauptverfasser:	Zhijuan Zhang, Nazareth Bedrossian
Format:	Patent
Sprache:	eng
Schlagworte:	DETECTING MASSES OR OBJECTS EARTH DRILLING EARTH DRILLING, e.g. DEEP DRILLING FIXED CONSTRUCTIONS GEOPHYSICS GRAVITATIONAL MEASUREMENTS MEASURING MEASURING ANGLES MEASURING AREAS MEASURING IRREGULARITIES OF SURFACES OR CONTOURS MEASURING LENGTH, THICKNESS OR SIMILAR LINEARDIMENSIONS MINING OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR ASLURRY OF MINERALS FROM WELLS PHYSICS TESTING
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Beschreibung
Zusammenfassung:	The thickness of borehole casing can be determined by ultrasound logging in conjunction with simulations of ultrasonic plane-wave echo waveforms across a range of frequencies for a plurality of casing thicknesses and correlation of synthetic frequency spectra derived from the simulated plane-wave echo waveforms for the various casing thicknesses against the frequency spectrum of a measured pulse-echo waveform. In accordance with various embodiments, a portion of the measured pulse-echo waveform that corresponds to the first reflection off the interface between the borehole casing and the borehole fluid is used as a driving pulse to weight the simulated plane-wave echo waveforms in the synthetic frequency spectrum.