【摘要】 柴达木盆地鄂博梁地区山地具有典型山地特征 ,单斜高陡 ,高速地层出露地表 ,第四系松散沉积与之共存 ,近地表速度横向变化剧烈。为了研究该区山地地震勘探问题 ,必须研究复杂条件下地震波传播规律 ,分析复杂近地表地质结构对地下中深层反射地震波的影响。由于主要目的是研究近地表单斜高陡地层对地震波传播及其成像的影响 ,所以在制作数学模型和物理模型时简化了山地地形的起伏 ,简化了中深层复杂的地质构造。数学模拟和物理模拟采用了相同的模型以利于对比分析 ,实验采用了多次覆盖观测系统。实验结果表明 :①山地特殊的近地表结构会强烈改造中深层的反射 ,并对中深层反射成像产生强烈影响 ,认识这种作用 ,对山地地震资料采集方式、处理流程和解释模式都有重要作用 ;②近地表高陡构造会产生类似于折射波的干扰波 ,这种干扰波在单炮记录或叠加剖面上很容易被认为是有效波 ;③在近地表地质结构为高陡地层并且不存在浅层折射界面 (在山地常出现这种情况 )时 ,初至波不是折射波 ,建议山地资料处理中慎用折射波静校正。图 4参 2 1更多还原

【Abstract】 Mountains in Eboliang region of Qaidam basin are characterized by monoclines of high velocity, which are coexisted with the Quaternary loosen deposits and by near surface velocity varying violently in cross. In order to study the seismic prospecting problems of this mountainous region, the traveling laws of seismic wave in complicated condition and the influence of the complicated near surface geological structure must be studied and analyzed. Either in mathematical modeling or physical modeling, it is necessary to simplify the realistic problem and to highlight principal contradiction. The purpose of this thesis is to study the influences of the complicated near surface, monoclinic, high, precipitous zone to seismic wave traveling and imaging, therefore the undulate of the mountainous region and the complicated geological structure of the middle and deep layers were simplified in mathematical and physical models. Same model parameters are used both in mathematical modeling and in physical modeling, in order to compare and analyze the results. In this experiment, multifold coverage geometry is adapted. The results of the modeling implies as follows:(1)The near surface structure of mountainous regions can violently reform the reflecting of the deep and middle layers, and influence the imaging of these layers. It is important for us to realize the influence and to improve the gathering mothod of mountainous seismic data, processing sequences and the modeling interpretation; (2)The near surface high and precipitous structure can produce noise similar to refracting wave; it is easy to take the noise as valid wave in singular shot record or stacked profile; and (3)When near surface geological structure is high and precipitous, and there is no shallower refracting surface (it is often in mountainous region). The first arrival is not refracted wave. Then it is suggested that the refracting static method should be applied carefully when processing seismic data from mountainous region.更多还原