潜水面以下激发深度选取的理论分析

在大沙漠地区以及潜水面较浅的地区进行地震勘探，潜水面以下激发是获取高分辨率地震资料的主要手段之一。潜水面是一个较强波阻抗界面，所产生的虚反射对地震资料的频率有很强的滤波效应，而激发深度和药柱长度是决定滤波特性的两个主要因素。为此，首先对长药柱激发所产生的虚反射特性从理论上进行了研究，进而对潜水面虚反射振幅频率、振幅药柱长度、振幅激发深度特性关系进行了理论分析。在此基础上，结合几个地区的野外试验资料说明了理论方法的正确性，表明所给出的方法对于确定潜水面以下激发参数具有指导意义。

Determination of shooting depth under water table

Shooting under water table is one of commonly used means for acquiring high resolution seismic records in deserts or areas with shallow water table. The ghost from the water table, a strong wave impedance interface, strongly affects the frequency behavior of the seismic records. Shooting depth and length of dynamite column are two major factors that determine the filtering behaviors. Firstly theoretical research on ghost character is carried out in this paper, and then the relationships between amplitude and frequency of the ghost, amplitude and the length of dynamite column,as well as amplitude and shooting depth were studied. The results were verified in field acquisition.