Jornal de Geologia e Geofísica
Acesso livre

Abstrato

Attenuation of Coherent Noise in Onshore Seismic Data of Gelana Basin using Radial Trace Transform and Wave Number Filtering: Southern Main Ethiopian Rift

Bisrat Kebede*

The presence of the coherent noise in the seismic data is a common problem to study the earth subsurface using seismic reflection datasets in offshore as well as onshore environments. The 2D Frequency-Wave number (F-K) and the Radial Trace Transform (RTT) techniques were used to suppress dispersive ground roll energy from high resolution onshore seismic data with a fold of 150 acquired from Gelana Basin in Southern Main Ethiopian Rift. Both the F-K and RTT techniques are based on local wave field decomposition to attenuate coherent noise from acquired seismic data. The objective of the study was to establish which of the techniques would attenuate the coherent dispersive ground rolls most effectively. Selected shot from the input seismic reflection data was subjected to a Fourier transform to display their amplitude spectra and phase spectrum to design the optimum parameters for F-K filtering of the whole shot. Thereafter both the F-K and RTT techniques were applied to the selected seismic line-12 from Gelena basin and this study showed both techniques efficiently attenuate coherent noise or ground roll. However, Radial Trace Transform (RTT) filtering technique the primary events or reflections are greatly enhanced and coherent noise trace including the air blast (sound waves) are seen better attenuated and no trace of background noise are observed unlike F-K suppression technique. From results obtained, the RTT was recommended as a better technique for coherent noise attenuation than the traditional 2D F-K domain technique.