摘要
本文概述了复数道分析的目的在于求取表征地震波动力学特征的一些参数——瞬时振幅、瞬时相位、瞬时频率和视反射极性。这对解释油气藏和获取岩性信息有重要意义。 要获得较好的参数剖面,必须正确选择和改进某些计算公式,正确使用合理的处理方法。本文通过对合成记录的处理说明,对瞬时振幅做积分滤波处理可得到光滑可靠的瞬时振幅剖面,并可大大消除由随机干扰造成的假视极性。用反正弦公式代替常用的反正切公式求取瞬时相位,可获得与地震波周期一致的相位剖面,克服了相位畸变。利用经过积分滤波的瞬时振幅对瞬时频率做加权处理,可使瞬时频率更加稳定。 本文借用有限元素表示的射线轨迹法,在6912计算机上对一种常见的构造地质模型作了合成记录,用它计算了瞬时振幅、相位、频率和视极性剖面;分析了这些剖面的特征以及利用这些特征进行地震解释的可能性。 本文还对形成复数道的基本算法——离散希尔伯特变换的各种改进算法进行了比较,计算结果表明,在频率域中做希尔伯特变换较为有利。
Abstract
This paper gives us a brief introduction to the complex channel analysis which aims at obtaining the dynamic parameters with the characteristics of surface seismology, such as transient amplitude, transient phase, transient frequency and apparent reflected polarity. It is of great significence either in interpreting the oil-gas reserves and obtaining the lithologic information.If we expect to get a preferable parametive section, two measures ought to be taken, one is the right selecting and updating of certain formulae, the other is processing in a reasonable way. By way of synthetic seismogram processing, the author tries to elucidate that a smooth and dependable section of transient amplitude could be obtained provided that the transient amplitude would have been processed through integration filtering. Furthermore, the pseudo-apparent polarity due to random noise could be enormonsly eliminated, And to obtain the transient phase with the inverse sine formulae instead of the inverse tangent commonly used. In this case a phase section identical to seismic wave period can be obtained and phase distortion can be avoided. It would enable the transient freqency more stabilized, if the transient frequency were weighted by transient amplitude which has undergone integration filtering process.With the aid of ray tracing technique^55 indicated by finite element, a synthetic seismograph to a common model of structural geology on computer-6912. By which the transient amplitude, phase, frequency and apparent polarity sections were calculated; the characters of these section were analysed and the study of possibilities of making seismic interpretation was made by means of the.se characters.Moreover, the author also tried to compare the fundamental algorithm made up by complex channel with all the revised algorithm of discrete Hilbert transformation. As a result, it proves preferable that Hilbert transformation is to be used only in frequency domain.
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