DOI: 10.5176/2251-3353_GEOS14.19
Authors: Ida Herawati, Sonny Winardhie, Wahyu Triyoso, Awali Priyono
Abstract: Anisotropy analysis becomes important in seismic data processing. If not accounted properly, anisotropy effect can disturb pre-stack amplitude analysis and stacking image. For unconventional resources that involve shale and coal rock, information of anisotropic parameter along with rock physics study also help in understanding the reservoir. In anisotropic media, waves travel in different velocities varies with angle. Consequently, reflector event cannot be flattened using single velocity during moveout correction process. Therefore, residual moveout shown as hockey stick is still observed in gather data. This research proposed a method to derive anisotropic parameter, ε and δ, from seismic data based on weak anisotropy and hyperbolic moveout equation. The method calculates velocity information for each offset. Local event correlation and Stransform method is used to estimate residual moveout in time and frequency domain. An inversion method is then used to estimate ε and δ simultaneously. Synthetic models are built to test the validity of the method. Experiments show that residual moveout estimation using S-transform gave detail result and closer to model. Results show reasonable value of ε and δ can be obtained after data has been properly pre-conditioned. This paper will discuss results and techniques in deriving ε and δ.
Keywords: seismic anisotropy; Thomsen parameter; velocity dependent offset
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