Quantitative Calculation and Analysis of Seismic Wave Attenuation in Western Sichuan Basin Depression
详细信息
- 责任者：Tu Yuangen (Southwest Exploration and Production Research Institute ; Southwest Branch Company ; SINOPEC ; Chengdu 610000 ; China) ; Wang Dayuan
- 刊名：Geophysical and Geochemical Exploration
- 出版年：2013
- 卷期：37(4)
- 关键词：弹性波 ; elastic waves ; 衰减 ; attenuation ; 四川盆地 ; Sichuan Basin
- 页码：p.596-602,632
- 图表：illus., 4 tables, 8 refs.
- 分类号：1600
- issnNo：ISSN1000-8918
- isbnNo：CN11-1906/P
摘要
In western Sichuan basin depression,the marine facies target layers are buried in great depth,resulting in narrow frequency band of reflected seismic data.Hence seiemic resolution can not meet the need of prospecting goals,and low seismic resolution is responsible for stratigraphic absorption attenuation.In order to understand completely the reason for the attenuation of seismic waves,the authors built a model for western Sichuan basin depression strata,then calculated quantitatively spherical divergence,absorption and transmission attenuation of seismic wave based on the model,and combined the calculated attenuation values with seismic data,VSP and Walkway-VSP data to analyze the factors affecting high frequency reflected signal acquisition recording of deep layers.It turns out that the serious absorption attenuation of shallow strata above 1500 meters is the fundamental cause responsible for high frequency component losses of deep layers in western Sichuan basin depression and,as for the marine facies target layers buried deeper than 5000 meters,field acquisition data can only reach about 40Hz frequency band.Therefore,the field acquisition methods aiming at deep target layers should focus on reducing background noises and increasing acquisition density to enhance weak reflection signals of deep layers so as to improve the seismic prospecting precision,rather than solely focus on improving the seismic resolution.