| 摘要 |
An acoustic energy mode propagation speed or travel time measurement system for use in well logging is disclosed. A downhole sonde is provided with an acoustic transmitter and at least one acoustic receiver. The transmitter is repetitively driven with a unique or characteristic swept frequency signal. Propagated acoustic energy detected at the receiver is cross-correlated with the characteristic transmitter swept frequency signal to provide indications of the arrival of various modes of acoustic energy propagation at the receiver. Logs as a function of borehole depth of the speed of propagation of the various modes of propagation may be derived.
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