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地震AVO(amplitude versus offset)技术是一项利用振幅信息研究岩性、检测油气的地震勘探技术。常规方法基于Zoeppritz方程计算模型界面处的反射系数,而实际地下非均匀介质中地震反射特征不仅与入射角度、物性差异有关,还与入射波频率、地层厚度、薄互层结构等因素有关。为此,应用传播矩阵理论充分考虑与这些因素有关的调谐干涉等传播效应,针对实际数据计算非均匀地下介质的高精度合成地震记录,对比Zoeppritz方程、Shuey二项近似方程、Shuey三项近似方程以及传播矩阵算法的模拟效果。研究发现:在小角度时Zoeppritz方程及Shuey二项近似方程和Shuey三项近似方程的反射振幅和波形基本一致,大角度时Zoeppritz方程与Shuey三项近似方程接近;Zoeppritz算法的模拟结果在小角度和浅层情况下与传播矩阵算法差别较小,而在大角度和深层与传播矩阵差别较大,说明层间多次波的和调谐干涉等传播效应不可忽略。
The seismic amplitude-offset (AVO) technique is a seismic exploration technique that uses lithology to study lithology and detect oil and gas. The conventional method calculates the reflection coefficient at the model interface based on the Zoeppritz equation. However, the seismic reflection characteristics in the actual inhomogeneous media are not only related to the incident angle and physical properties, but also to the incident wave frequency, formation thickness and thin interlayered structure. Therefore, the transmission matrix theory is used to fully consider the propagation effects such as tuning interference, and the high-precision synthetic seismograms of inhomogeneous subsurface media are calculated according to the actual data. Comparing with the Zoeppritz equation, the Shuey binomial approximation equation and the Shuey three approximation equation As well as the simulation effect of propagation matrix algorithm. The results show that the amplitude and the waveforms of Zoeppritz equation, Shuey binomial equation and Shuey three approximation equations are basically the same at small angle. The Zoeppritz equation approximates to the Shuey three approximation equation at high angle. The simulation results of Zoeppritz algorithm at small angle In the shallow case, the difference from the propagation matrix algorithm is small, while the difference between the propagation matrix and the propagation matrix is large at the large angle and the depth, indicating that propagation effects such as interlayer multiples and tuning interference can not be neglected.