Seismic wave amplitude is attenuated when passing through the ground layers. Description parameter of the attenuation is the quality factor that is used as an attribute that detects presence of hydrocarbons and fracturing in the reservoir. Purpose of this study is to investigate the distribution of quality factor in ASMARI reservoir that is a fields in the southwest of Iran. In order to calculate the quality factor log in each well, spectral ratio method using vertical seismic profiling is used that is conventional method to calculation of the quality factor. Then, the distribution of quality factor in reservoir ASMARI is estimates using stepwise regression. Resulting cross correlation and estimation error are 91.04% and 2.06% respectively.