深水崎岖海底地震资料叠前深度偏移的必要性

深海区域崎岖海底会造成地震波传播速度横向剧烈变化,从而导致时间偏移剖面中构造形态严重畸变,成像效果差。利用理论模型讨论了用常规时间偏移、叠后深度偏移及叠前深度偏移技术解决深水崎岖海底地震成像问题的有效性。通过对深水模型数据各种偏移结果的对比分析认为,常规时间偏移和叠后深度偏移均不能解决崎岖海底地区地震成像问题,而叠前深度偏移是解决这一问题的有效方法。实际资料处理结果证实了这一认识。

The necessity of pre-stack depth migration for seismic data from rough deep sea bottom

The roughness of deep submarine relief may cause lateral great changes in seismic velocity, resulting in structural distortion and poor imaging in time migration sections. Based on a theoretical model, therefore, the effectivenesses of conventional time migration, post stack depth migration and pre stack depth migration are discussed for solving the imaging problems on rough deep sea bottom. By comparison and analysis of various migration results from a deep water model, it can be concluded that the pre stack depth migration is the only effective method to solve the imaging problems, with the conventional time migration and post stack depth migration both ineffective. This conclusion has been confirmed by the processing results of real data.