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Measuring Attenuation in Microseismic Data - Log Spectral Ratio and Instantaneous Frequency Methods
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 75th EAGE Conference & Exhibition incorporating SPE EUROPEC 2013, Jun 2013, cp-348-00950
- ISBN: 978-90-73834-48-4
Abstract
This work looks at using the Log Spectral Ratio (LSR) and the Instantaneous Frequency (IF) method on microseismic data. Microseismic data is important in monitoring hydraulic fracturing as it is used to help characterise fluids, fractures and permeability. This work uses modelled wavelets and spectra to help understand the limitations of the two methods at microseismic frequencies and sampling rates. This work also looks at modelling the amount of attenuation we are likely to see in a microseismic dataset. Using Chapman’s 2003 squirt flow model we can estimate that the attenuation due to a realistic set of rock parameters causes Δt* to vary between 0 and 3x10-3 seconds. Using the modelled wavelets and an attenuation operator we can see how this affects the wavelets. This work shows that higher dominant frequencies (above 150Hz) and high signal to noise ratios (above ~3) will produce more accurate measurements.