Quality Factor Characteristics of Six Metamorphic Kinds of Coal in China

Lab ultrasonic measurements to metamorphic kinds of coal reveal the relation between the maximum vitrinite reflectance and ultrasonic quality factor. And then the relations between ultrasonic velocities and quality factors, including the anisotropic characteristics of quality factors are analyzed. The results show that there are good linear correlations between the maximum vitrinite reflectance and P- and S-wave quality factors, between velocities in direction perpendicular to seams and quality factors, and between the P- wave quality and S-wave's quality factors in direction vertical to seams. Moreover, there are stronger anisotropies in seismic quality factors than velocities. Comparison of the measured S-wave Q values with estimated values, based on a theoretical formula, indicates an only 7.2% relative error in this method. It proves that this theoretical formula can be applied to attenuation compensation of the converted shear wave in processing of multi-component seismic data.