Inelastic attenuation, quantified by , the seismic quality factor, has considerable impact on surface seismic reflection data. A new method for interval -factor estimation using near-offset VSP data was based on an objective function minimization measuring the difference between cumulative estimates and those calculated through interval . To calculate interval , we used all receiver pairs that provided reasonable values. To estimate between two receiver levels, we used the equation that links amplitudes at different levels and could provide more accurate values than the spectral-ratio method. To improve interval estimates, which rely on traveltimes, we used a high-accuracy approach in the frequency domain to determine time shifts. Application of this method to real data demonstrated reasonable correspondence between estimates and log data.