A procedure to reduce side lobes of reflection wavelets: A contribution to low frequency information

Side lobes of the wavelets arise from the lack of low frequency content in a reflection wavelet. They tend to increase the time span of an individual reflection event and interfere with the other primary reflections or side lobes. Furthermore, their trace-by-trace consistency may produce pseudo-reflections and may cause misinterpretations of the side lobes as weak reflections.A procedure in order to improve the low frequency content of the seismic traces by suppressing the side lobe amplitudes based on the complex trace envelope is proposed. Using the average energies of the seismic trace and its envelope, the polarity table of the trace is obtained and used to correct the phase of the envelope. The resultant trace is termed “side lobe reduced (SLR) trace”. The method can be applied to the stack or migrated seismic data by a trace-by-trace basis. The only required parameter of the method is the moving average operator length which is used to calculate average energies of the input traces. In general, shorter operator lengths yield better results when the dominant frequency of the input increases.Results from synthetics and real seismic data sets show that the procedure improves the low frequency components of the input trace and side lobes in the output SLR trace are significantly suppressed. The method may be considered as a seismic amplitude attribute, which aids the interpreter to obtain the true seismic signature of the geological formations by removing the side lobes of the wavelet and restoring the low frequency components if the lower frequencies of deeper reflections are of primary concern.