地震子波的时变与短程微曲多次反射

The time-variant seismic wavelet and the peg-leg multiple

无论是在地震记录的正演计算或反演过程中，地震子波都是一个十分重要的参数序列，如果子波不准，则正演结果就不精确，与实际地震资料也难以吻合；对于反演，所求得的波阻抗就不可靠；对于反褶积，则得不到高保真的反射系数序列或地震剖面。因此从这个意义上讲，精确的子波反演是地震精细处理及岩性参数反演的先决条件。本义首先从理论上分析了引起子波变化的各种因素，并探讨了哪些因素是可以通过一些处理手段加以补偿校正的，哪些是不能得到校正的。特别是对地震资料中的短程微曲多次波的传播特征进行了分析，得出了以线性动态系统来表达的方程式，最后给出了由短程微曲多次反射引起的时变地震子波的反演解法。并以理论模型和实际资料的处理研究了微曲多次反射对传统的子波反演的影响。

Seismic wavelet is an important parameter sequence for both the forward calculation and the inversion of seismic records. If the wavelet is not accurate, then the forward result will be inaccurate and cannot coincide with the real seismic data, the wave impedance derived from the inversion will be unreliable, and the deconvolution will not lead to high-fidelity reflectivity sequence or seismic section. So theaccurate wavlet inversion is a prerequisite for the seismic fine processing and lithological parameter inversion.In the paper, at first we analyze the various factors which affect the tchange of wavelet, and pointout which factors can be remedied by processing and which ones can not. Then we especially study thepropagation characteristic of the peg-leg multiple in seismic data, and get an equation expressed by lineardynamic system. Finally we give the inversion algorithm of the time-variant seismic wavelet due to thepeg-leg multiple. Also, the effect of the peg-leg multiple on the traditional wavelet inversion is researched through theoretical models and real data processing.