大容量气枪震源陆地反射地震探测技术以“地学长江计划”铜陵段试验为例

Land seismic reflection detection technology of airgun source:A case study of the Tongling experiment of “Yangtze River Geoscience Project”

  • 摘要: 为了探索大容量气枪震源在探测区域结构以及在内陆水体进行水陆联测的可行性与有效性,2015年在安徽铜陵完成了长江航道走航激发、陆地接收反射波的“地学长江计划”铜陵段试验。本文从试验观测系统、共中心点分布、覆盖次数以及单炮数据属性等方面综合分析了大容量气枪震源陆地反射试验结果的影响因素。试验结果表明:① 大容量气枪震源在内陆水体激发能够用于地壳结构的探测;② 在水陆联测勘探中,根据目标层段合理设计反射角,能够有效地解决小炮检距反射角不足、大炮检距能量弱的问题;③ 在进行弯线数据采集时,需要对观测系统进行设计,以提高共中心面元的有效覆盖次数;④ 根据气枪震源容量的大小,进行最大、最小炮检距设计,是确保面元成像速度分析精度和面元炮检距属性分布合理的重要条件。

     

    Abstract: In order to explore the feasibility and effectiveness of the large capacity airgun source in the regional structure detection and whether the airgun source can be used for water-land measurements in flowing water body of inland, the Tongling experiment of “Yangtze River Geoscience Project” was carried out in 2015. This paper comprehensively analyzes the influencing factors of the land reflection experimental results of large capacity airgun source in the respects of the experimental observation system, distribution of common middle points, fold times and the data characteristics of single shots. The experimental results show that: ① Large capacity airgun source can be used for the detection of crustal structure in inland water body; ② According to the requirements of the target layer, the reflection angle analysis should be designed reasonably, thus it will solve the problems of insufficient reflection angle caused by small offset and the insufficient energy resulted from large offset; ③ During the process of curve data collection, the observation system needs to be designed so as to improve the coverage number of the common central bin; ④ According to the size of the airgun source, the maximum and minimum offsets are important to ensure the accuracy of the analysis of the surface imaging speed and the reasonable distribution of the surface offset attribute.

     

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