Stud. Geophys. Geod., 60 (2016), 1-xxx, DOI: 10.1007/s11200-015-0577-7 i © 2016 Inst. Geophys. CAS, Prague Attenuation from microseismic datasets 1 by the peak frequency method 2 benchmarked with the spectral ratio method 3 4 MIŁOSZ WCISŁO 1,2 AND LEO EISNER 1,3 5 6 1 Institute of Rock Structure and Mechanics, The Czech Academy of Sciences, 7 V Holešovičkách 94/41, 182 09 Praha 8, Czech Republic (wcislo@irsm.cas.cz, 8 milunw@interia.pl) 9 2 Department of Geology, Geophysics and Enviromental Protection, AGH University of 10 Science and Technology, Al. Mickiewicza 30, 30-059 Kraków, Poland 11 3 Seismik s.r.o., Kubišova 1265/8, 182 00 Praha 8, Czech Republic 12 13 Received: September 30, 2015; Revised: February 8, 2016; Accepted: May 7, 2016 14 ABSTRACT 15 Recently proposed peak-frequency method is used to estimate the P- and S-wave 16 quality factors from microseismic events. We use a downhole monitoring dataset of 10 17 high signal-to-noise ratio microseismic events to calculate P- and S-wave effective 18 attenuation of a carbonate reservoir. We benchmark these results with the spectral ratio 19 method and obtain mutually consistent results. Additionally we develop and test two 20 techniques of peak frequency determination. We show that the peak frequency method can 21 be successfully used in the estimation of the quality factor and it provides precise 22 measurements of attenuation. 23 24 K e y w o r d s : attenuation, microseismicity, inversion, ray tracing 25 1. INTRODUCTION 26 Attenuation of seismic waves is an important characteristic of medium both from 27 academic as well as exploration point of view. Seismologists use quality factor (Q) to 28 invert earthquake source properties (e.g., Tomic et al., 2009), characterize medium in 29 a reservoir (Aki et al., 1982; Klimentos, 1995), etc. Attenuation determines detectability of 30 perforations and microseismic events in microseismic monitoring (e.g., Einspigel and 31 Eisner, 2014). It is also an important factor in array design of seismic monitoring 32 networks as attenuation limits the detectability of seismic signals. Therefore different 33 methods of inversion of attenuation were proposed. Ricker (1953) used the fact that high 34 frequencies of a seismic signal are more attenuated. He proposed an inversion method 35 based on seismic pulse broadening. Gladwin and Stacey (1974) proposed an analogous 36 technique based on the change of the seismic pulse rise times. These methods are not 37 frequently used in the seismology as they require a (active) seismic source recorded in the 38 vicinity of the source location. On contrary, probably the most popular technique for 39