Changes

Full waveform acoustic logging tools are similar to conventional acoustic logging tools. The main differences are that (1) the source is usually of lower frequency, centered at 5 to 10 kHz rather than at 20 kHZ; (2) the source-receiver spacing is longer, on the order of [[length::10 ft]] (3.05 m); and (3) the receiver is commonly an array consisting of four to twelve phones.

Full waveform acoustic logging tools are similar to conventional acoustic logging tools. The main differences are that (1) the source is usually of lower frequency, centered at 5 to 10 kHz rather than at 20 kHZ; (2) the source-receiver spacing is longer, on the order of [[length::10 ft]] (3.05 m); and (3) the receiver is commonly an array consisting of four to twelve phones.

The source generates a pressure pulse. Seismic waves propagating down the borehole are recorded by the receivers. Instead of just the first arrival, the whole wavetrain traveling down the borehole is recorded and digitized, with the typical digitization interval being 5 μsec. The length of the time window recorded varies from 2 to 10 msec, depending on the source-receiver separations<ref name=pt07r37>Minear, J. W., 1986, Full wave sonic logging—a brief perspective: Transactions of the Society of Professional Well Log Analysts 27th Annual Logging Symposium, Paper AAA.</ref>.

The source generates a pressure pulse. Seismic waves propagating down the borehole are recorded by the receivers. Instead of just the first arrival, the whole wavetrain traveling down the borehole is recorded and digitized, with the typical digitization interval being 5 μsec. The length of the time window recorded varies from 2 to 10 msec, depending on the source-receiver separations.<ref name=pt07r37>Minear, J. W., 1986, Full wave sonic logging—a brief perspective: Transactions of the Society of Professional Well Log Analysts 27th Annual Logging Symposium, Paper AAA.</ref>

==Wave types==

==Wave types==