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从二连盆地中南部的表层及地下地质结构出发,建立一个地质模型,并导出相应的一套数学模型。根据埋深、速度及最高频率要求,制作空间采样与信号波长、最大炮检距与界面的埋深及速度、组合基距与频率及地层倾角、激发深度与表层虚反射等一套关系曲线,使地震野外采集因素的设计建立在比较科学的基础上。为了查明埋深仅有580米的下白垩系目的层,则希望得好0.3秒的反射波,保护50Hz 的有效波高频成分,分辨40米厚、300米长的地质体。因此,在野外采集时,要尽量增加覆盖次数、选用50米组合基距、零偏移距、降低仪器灵敏度、综合选择激发因素,这样才能提高浅层反射波的信噪比和克服超调现象。实践说明,从定量分析的角度确定最佳因素,改善了浅层资料的质量,保护了50Hz 的有效信息不受损害,提高了对特殊地质体的分辨能力,突出了大倾角反射。
Based on the surface and underground geological structures in the middle and southern Erlian Basin, a geological model was established and a corresponding mathematical model was derived. According to the requirements of depth, speed and maximum frequency, a set of relation curves such as spatial sampling and signal wavelength, maximum offset and interface depth and speed, combined base distance and frequency, formation dip, excitation depth and surface ghost reflection, Make the design of field acquisition factors of earthquake based on comparative science. In order to find out the Cretaceous target layer with a depth of only 580 meters, it is hoped that a reflection wave of 0.3 second will be taken to protect the 50 Hz effective wave high-frequency component and to distinguish the geological body of 40 meters thick and 300 meters long. Therefore, when collecting in the wild, it is necessary to increase the number of coverage as much as possible. Select the combination of 50m base distance and zero offset to reduce the sensitivity of the instrument and comprehensively select the excitation factors so as to improve the signal-to-noise ratio of the shallow reflection wave and overcome the overshoot phenomenon . Practice shows that the best factors are determined from the perspective of quantitative analysis, the quality of shallow data is improved, the effective information of 50 Hz is protected from being damaged, the resolving power to special geological bodies is enhanced, and the dip angle reflection is highlighted.