海洋短排列高分辨率地震拖缆沉放深度测试分析

    DEPTH MEASUREMENT ANALYSIS FOR SHORT ARRAY HIGH RESOLUTION SEISMIC TOWING STREAMERS AT SEA

    • 摘要: 海洋短排列、小道距、高分辨率地震勘探具有分辨率、信噪比高和施工便捷的特点,是浅部高分辨率地震勘探的重要手段。由于拖缆整体拖曳长度较短,受作业环境和设备等限制,通常采用加配重物代替水鸟来调节拖缆沉放深度。施工采集状态下的实际监测发现,受潮流、船速、配重量等多种因素影响,电缆和地震震源沉放深度变化较大,有较强的规律性变化。笔者对震源、电缆沉放深度测试结果进行了分析总结,认为地震采集船速控制宜采用稳定对水速度,能在地震资料采集过程中合理地保证较稳定的震源、电缆沉放深度控制,针对高分辨率地震调查目的,地震电缆沉放深度越小越好。该认识对优化海洋短排列、小道距、高分辨率多道地震采集参数,地震精确处理提供了准确、高精度的数据和保障。

       

      Abstract: The short array high resolution seismic survey is an important survey method commonly used at sea because of its advantages of high resolution, high signal to noise ratio and easy operation. However, since the length of the towing streamers is too short, the sinking depth of the towing streamers is always limited by the operating conditions and the equipment itself. Generally, waterbird control is not used, and the towing streamers sinking depth is usually adjusted by weight. The source depth and the depth of the towing streamers depend upon many factors such as the tidal current, the speed and weight of survey vessel and the conditions of data acquisition. As the results, the sink depths of the source and streamers change greatly and regularly. In this paper, we summarized our experiences from offshore survey and recognized that for the purpose of high resolution seismic survey, when the data acquisition of seismic data is going on, the relative water velocity should be as stable as possible and smaller seismic cable sinking depth is preferred.

       

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