Surface Attenuation And Seismic Data Quality Evaluation

The key factors that determine the quality of the seismic data is energy efficient and effective bandwidth of the wave.Attenuation is the main reason for weakening the reflected signal and narrowing the width of the band,especially surface attenuation.So studying the attenuation characteristics of the surface layer has important value and significance to improve the quality of seismic data.In this paper,we study the physical properties of rock with using high-frequency analog method,for the attenuation characteristic of loose surface rock samples in Jizhong exploration area.First,we collect and preserve wild loose surface rock samples.Then transport them to the laboratory for experimental measurements.Finally,count and analyze parameters of all samples,include velocity,Q value,density and water content.Research results show that,the Q of loose surface rock samples is very low,and the physical laws of loose surface rocks are different with deep consolidated rocks,and water content is the main factor affecting the surface rock samples' Q.The next step is studying the influence of excitation parameters(amount of explosives and ghost reflection surface),combining the surface attenuation obtained from the experiment.Found the optimal design of excitation parameters in different conditions.Apply it to the new acquisition scheme,and finally achieve the goal of effectively improving the quality of seismic data.Experimental results show that,the amount of explosives is not as big as possible,most of the study area's suitable explosives is 5kg,some area's explosives could be increased to 8kg where attenuation is severe.The most suitable excitation well depth is 5-7m below ghost reflection surface.