【摘要】 在平面波假设条件下,本文通过求解波动方程推导了双相介质中地震波衰减系数计算公式,并分析了衰减系数随频率的变化关系。结果表明,在常规地震勘探的频率范围内,地震波在双相介质中传播时,存在介质吸收效应,且衰减系数近似与圆频率成正比。衰减系数同时受地震波频率和耗散系数的影响,表现为频率越高,衰减系数越大,耗散系数越大,衰减系数随频率的变化越大,表明地震波在穿过双相介质时其不同频率成分对应的能量要发生变化,低频能量衰减小,高频能量衰减大,在频谱上表现为低频能量相对增强,高频能量相对减弱。据此提出了一种利用地震资料的低、高频段信息反演地下介质双相特性或含油气性的方法,理论模型与实际资料的反演结果均验证了文中方法是可行的。更多还原

【Abstract】 In this paper under the assumption of plane wave,by solving seismic wave equation the attenuation coefficient formula in dual-phase medium was derived,and the change relationship of the attenuation coefficient with frequency was analyzed,the results show that when seismic wave propagated in the frequency range of conventional seismic exploration in dual-phase medium,the medium absorption effect existed,and the attenuation coefficient was approximately proportional to circular frequency.The attenuation coefficient was affected by seismic wave and dissipation coefficient at the same time,showing that the higher the frequency,the greater the attenuation coefficient,and the greater the dissipation coefficient,the greater the attenuation coefficient changes with frequency,the results above shows that when seismic waves passed through the dual-phase medium the corresponding energy for the different frequency component changed,with a small low-frequency energy attenuation and a large high-frequency energy attenuation,resulting in low-frequency energy enhanced and high frequency energy relatively attenuated on the energy spectrum,therefore a method by which the dual-phase characteristic or oil-gas possibility in subsurface media were inverted by utilizing the information in both the low-frequency range and the high-frequency range was proposed,the theoretical model and actual data inversion results all verified the feasibility of the method.更多还原