Coherent noise attenuation

摘要

Methods and apparatuses for processing seismic data to generate images or determine properties of an interior section of the Earth. The seismic data is processed to filter coherent noise such as ground roll noise from seismic survey data. The noise is attenuated using 3D and/or 2D fan filters, which may have combined low-pass and band-pass filters derived from signal decomposition. The filters are designed with selected operator length, velocity bands of signals and noises and frequency range for a primary trace and adjacent traces within the operator length. The data is decomposed with the filters into signals and noises, and the noises are then filtered from the decomposed data. The process may be repeated for various frequencies and traces within the seismic data. The methods may be used for surveys that have either regular or irregular seismic receiver or seismic source positions.

主权项

1. A method for attenuating coherent ground roll noise while preserving reflection signals in seismic data, the method comprising:
(a) transforming the seismic data from time-space domain into frequency-space domain; (b) designing the fan filters with basis functions wherein the step of designing the filters comprises:
selecting an operator length, a velocity band of the signals, a velocity band of the noises, and a frequency range;selecting a primary trace and adjacent traces to the primary trace within the operator length;computing fan filters for the signals and fan filters for the noise for a frequency;computing weighing factors; (c) decomposing the data using the fan filters into the signals and the noise at the frequency; (d) filtering the noise from the decomposed data; (e) repeating steps (c) and (d) for a plurality of frequencies for the primary trace; (f) repeating steps (c), (d) and (e) one or more adjacent traces; and (g) transforming the filtered data from the frequency-space domain into the time-space domain.