ÇAĞRILI KONUŞMALAR / KEYNOTES Invited Speeches ... - TPJD

Harmonic Distortion and Elimination
Orhan Gürelı̇
Nageco, Tripoli, Libya
Sweep parameters are the most important parameters in vibroseismic data acquisition. Harmonic
distortion apparently arising from nonlinear processes has generaly been observed in land seismic
operations utilizing a frequency modulated mechanical vibrator as a surface source. It has been
related especially to the coupling of the vibrator to the ground. In conventional data acquisition,
harmonic distortion generally considered to be the negligible parameter. But harmonic distortion
appears on the seismic records. Especially, the effect of harmonic distortion can frequently
appear on the recorded data which is using the new acquisition methods such as HFVS, HPVA ,
Slip sweep in recent years. Sweep and its harmonic, generated by vibrator, should be well-known
to remove or minimize distortion effect. If sweep parameters are prepared well, distortion can
be minimized or removed. Therefore, the sweep phase is the important parameter. Sweep phase
is used to remove harmonic distortion. In this study, the harmonic distortion is defined and it’s
relation to sweep parameters is explained. Also, the different sweep phase angles were used
while sweep generated for the effect of harmonic distortion on hardwire similarty tests and real
data. As a result of this tests, we see that the effects of harmonic distortion is decreased on shot
record.
Keywords: Sweep, Harmonic Distortion, Harmonic Distortion Elimination
205