Stratum absorption and attenuation compensation based on improved generalized S-transform
Zhang Gu-lan1, Xiong Xiao-jun2, Rong Jiao-jun1, Zhang Yan-bin1, Cai Zhi-dong1
1. Borehole Seismic Centre, BGP Inc.of CNPC, Zhuozhou City, Hebei Province, 072751, China;
2. State Key Lab of Reservoir Geology and Development Engineering, Chengdu Universtiy of Technology, Chengdu City, Sichuan Province, 610059, China
Abstract:The Gauss function whose window width changes in inverse proportion with frequency was used in generalized S-transform,while for improved generalized S-transform the variable width window was used,the window's width change with frequency was proportional.That is,the window is narrower for low frequency with the high time resolution,while the window is wider for high frequency with the high frequency resolution.With the new method the lossless generalized S-inverse transform can be conducted and time-dependent Q value can be estimated,so the under-compensation and over compensation which developed in traditional Q compensation method were avoided.After compensation,the variation trend of the timefrequency spectrum are exactly the same at every moment,and the seismic frequency bands are the same.Application of the new method in the field VSP data shows that the new method works very well for absorption and attenuation compensation,it also raises resolution and improves data quality.