Harmonic Distortion and Elimination

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.