Estimation of Seismic Quality Factor by Using Two Different Methods in Time Domain

Seismic waves would be attenuated while transmitting in the earth layers. Attenuation is defined by a factor called 1/Q which describes the scattering of waves in media. By increasing of attenuation, quality factor would be decreased. One of the newest ways for estimation of Q is using VSP data (Vertical Seismic Profiling) by considering the decrease of frequency and amplitude in different depths for downgoing waves. In this research quality factor would be estimated by zero-offset VSP data for an exploration well in Iran. Q would be estimated by amplitude decay method and analytical signal method. We show that sudden decrease of Q probably due to gas hydrocarbon existance.