沙漠区地震资料近地表吸收补偿方法研究

西部沙漠区地震勘探中,松散的近地表沙层导致了地震波能量,特别是高频成份严重吸收衰减,对此缺少针对性地震处理技术。为了消除近地表对地震波传播的影响,探讨了一种利用黏弹性波动方程波场延拓进行吸收衰减补偿的技术。通过微测井测量数据确定适合于工区的近地表黏弹介质模型,利用初至约束层析反演建立近地表速度模型;并根据近地表速度与品质因子的关系转换为近地表品质因子模型。最后通过基于黏弹介质的波场延拓将地表接收到的地震波下延到高速层顶,从而达到恢复地震波高频信息及拓宽有效频带的目的;该技术在实际资料应用后能有效拓宽频带10 Hz以上,取得了明显的效果。

Near-surface Absorption Compensation Method Of Seismic Data In Desert Area

In eastern alluvial plain and western desert of China, near-surface absorption is the main reason that leads to energy attenuation of seismic wave, especially for high-frequency components. To eliminate the effect of near-surface on seismic wave propagation, we put forward a new compensation technique based on visco-elastic wave equation continuation. First, build a mathematic model of near-surface from micro-log data. Then, joint with near-surface Q value velocity model from inversion, to obtain the wave field at top of high-velocity layer using visco-elastic wave equation continuation. The application of this new technique shows a good result: high-frequency information of seismic wave is recovered effectively and valid frequency bands are highly widened.