4,231
edits
Changes
Jump to navigation
Jump to search
Line 348:
Line 348: − +
→Sonic
===Sonic===
===Sonic===
Sonic devices measure the velocity of various acoustic waves, most notably compressional, shear, and Stoneley waves. The velocity of the waves is a function of the elastic properties and the density of the formation. Logs normally present the inverse of velocity, called the ''interval transit time'' or ''delta t'' (Δ''t''). A number of empirical relationships have been developed to relate compressional velocity to porosity (which are explained in [[Standard Interpretation]]).
Sonic devices measure the velocity of various acoustic waves, most notably compressional, shear, and Stoneley waves. The velocity of the waves is a function of the elastic properties and the density of the formation. Logs normally present the inverse of velocity, called the ''[[interval transit time]]'' or ''delta t'' (Δ''t''). A number of empirical relationships have been developed to relate compressional velocity to porosity (which are explained in [[Standard Interpretation]]).
Two versions of the compressional sonic device are available: the compensated sonic and the full waveform sonic (FWS). The full waveform sonic contains an array of receivers that are used to determine both compressional and shear velocities. Sonics are available in a variety of transmitter-to-receiver spacings from 3 to [[length::12 ft]] or more. The longer spacings are capable of investigating deeper into the formation. Both the conventional sonic and the full waveform sonic devices are used to measure compressional velocity. A typical presentation of compressional sonic measurements is shown in the log in [[:Image:basic-open-hole-tools_fig1.png|Figure 1]].
Two versions of the compressional sonic device are available: the compensated sonic and the full waveform sonic (FWS). The full waveform sonic contains an array of receivers that are used to determine both compressional and shear velocities. Sonics are available in a variety of transmitter-to-receiver spacings from 3 to [[length::12 ft]] or more. The longer spacings are capable of investigating deeper into the formation. Both the conventional sonic and the full waveform sonic devices are used to measure compressional velocity. A typical presentation of compressional sonic measurements is shown in the log in [[:Image:basic-open-hole-tools_fig1.png|Figure 1]].