【摘要】 本文借助三层双界面薄层模型推导了地震峰值频率与厚度的理论关系表达式,讨论了子波类型、子波相位及子波峰值频率对薄层峰值频率与厚度关系的影响。在此基础上,建立了不同顶、底反射系数组合下薄层地震峰值频率与厚度关系的量板,总结了地震峰值频率随薄层厚度变化的一般规律,提供了一种利用量板拾取薄层厚度的新思路,并得出以下认识:①不同子波对薄层调谐引起的频率变化特征不同,即子波的峰值频率越高,薄层调谐的频率变化越明显,但子波相位不影响薄层调谐引起的地震峰值频率变化;②在调谐厚度范围内,韵律型薄层的峰值频率始终大于入射子波的峰值频率,递变型薄层的峰值频率始终小于入射子波的峰值频率;③对于所有的薄层,地震峰值频率随薄层厚度的减小并非呈一直增大的趋势,即当薄层顶、底反射系数异号时,地震峰值频率随薄层厚度的减小呈先增大后减小的特征,当薄层顶、底反射系数同号时,地震峰值频率随薄层厚度的减小基本都呈现逐渐增大的趋势;④所有反射系数组合的薄层地震峰值频率与厚度关系曲线在地震峰值频率—厚度曲线关系量板上构成一个有界的曲线簇,且随顶、底反射系数之比呈有规律的变化,即对于已知顶、底反射系数之比的单一薄层,通过确定地震响应的峰值频率,便可以从该量板上直接读取其所对应薄层的厚度。更多还原

【Abstract】 Based on three-layer bi-interface thin layer model the theoretical relationship formula between seismic peak frequency and thickness was derived in this paper, the wavelet categories, the wavelet phase and the wavelet peak frequency’s impact on the relation between thin layer peak frequency’s and its thickness were also discussed, based on the studies the templates of thin layer peak frequency and its thickness for reflection coefficient combination of different tops and bottoms were established,the general rule for seismic peak frequency’s change with thin layer’s thickness was summarized, as a result the new idea for picking up thin layer’s thickness was developed, and at last the following understandings were achieved: (1). different wavelet causes different frequency variation characteristics for thin layer tuning, that is, the higher the wavelet’s peak frequency, the more obvious for frequency variation of the thin layer, however the wavelet’s phase does not affect the seismic peak frequency variation which the thin layer causes, (2). within tuning thickness the peak frequencies of the rhythm thin layers are always larger than the incidence wavelet’s peak frequency, while the peak frequencies of the progressive thin layers are always smaller than the incidence wavelet’s peak frequency. (3). for all thin layers, seismic peak frequency’s decrease with their thickness is not monotonic, that is, when the reflection coefficient of the top of the thin layer and the reflection coefficient of the bottom of the thin layer have different signs, the degree of the seismic peak frequency’s decrease with their thickness firstly goes up and then goes down, but when they have the same signs, the degree of the seismic peak frequency’s decrease with their thickness almost always goes up gradually, and (4). The curves for relationship between thin layers’ seismic peak frequency and their thicknesses for all reflection coefficient combinations compose a curve sets on the template, and the ratio of top reflection coefficient and bottom reflection coefficient shows regular variation, that is, for a single thin layer with a known ratio, its thickness can be directly read from the corresponding template.更多还原