Perpustakaan Digital ITB

High resolution of seismic data is needed for detailed descriptions of oil and gas reservoirs; for determination of spatial heterogeneities such as the spatial variation of porosity, gas content or pore pressure: and for monitoring the changing within a reservoir during the production process. The amplitude of the seismic wave, generally decrease with depth and the width of the wavelet gradually broaden due to attenuation process. Estimated Q-factor values from VSP data, although reliable, are representative for relatively small volume (vicinity of the well). Having in mind, that wide area around the well is covered by numerous seismic lines (2D/3D - hundreds of square kilometers), investigation of the method that could be developed for Q-factor estimation from reflection seismic data could be very useful.Reflection seismic data (CDP gather, stacked section) contain information about changes of the physical properties of the various rock formations, which affect amplitude, phase and frequency characteristics of the reflected seismic wavelet. By comparison of relative change of the amplitude spectrum between referent and target reflection (stacked section) or near to far offset reflection (CDP gather), Qfactor has been estimated. In order to support the estimation of Q factor from seismic reflection data, some programs are developed, that perform various tasks, such as conditioning the data (estimation and removal additional gain applied), Gabor transformation, spectral estimation of reference/target reflection and Qfactor estimation procedure.