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墨西哥湾盐丘的复杂构造和高速度差造成了一个地震成像难的问题。地震数据的3D叠前深度偏移(PreSDM)能够产生盐丘岩床下反射层和不规则外来岩体的成像。但是,3D叠前深度偏移不能填充盐丘下只有少数能量被反射的屏蔽区。另外,3D叠前深度偏移通常都处理不好由盐丘构造地震能量聚集和分散所引起的振幅变化。射线追踪模拟能够解释盐下成像问题,并且模拟结果应与勘探、开发方案相结合。 模拟过程包括:建立一个计算机模型,其中包括了盐丘形状和速度变化;用射线追踪模拟来模拟一个完全的3D地震测量,并将数据选排成CRP道集。模型建立和射线追踪时应注意,使产生的振幅结果与盐下反射产生的地震振幅有可比性。 由于版面所限,本项研究分三篇文章介绍。第一部分介绍了射线追踪模拟入门、射线追踪方法和简单的2D盐丘模型实例。第二部分对更复杂的2D和3D模型进行研究,以确定更为复杂构造的影响。在最后一部分中,用3D模型射线追踪的结果说明了同构造方位相关的激发方向的效果。在不同的情况下,对墨西哥湾3D叠前深度偏移测量中提取的真实地震数据中形状相似的盐丘进行了比较。本研究根据简单形状对可能的成像异常提出了新的认识,其结论可以外推到“真实世界”情况。然而,在真实构造中还有复杂的相互作用和速度变化,这也?
The complex tectonic and high-speed differential of the salt gulf in the Gulf of Mexico creates a difficult problem of seismic imaging. The 3D prestack depth migration (PreSDM) of seismic data enables the imaging of sub-bed reflectors and irregular alluvial rocks. However, the 3D prestack depth migration can not fill the shielded area where only a few energy is reflected beneath the salt dome. In addition, 3D prestack depth migration generally addresses poor amplitude variations caused by the accumulation and dispersion of seismic energy from salt dome tectonics. Ray-tracing simulations can explain sub-salient imaging issues, and simulation results should be combined with exploration and development options. The simulation process consists of: building a computer model that includes changes in salt dome shapes and velocities; simulating a complete 3D seismic survey with ray tracing simulations and sorting the data into CRP gathers. Care should be taken when modeling and ray tracing so that the resulting amplitude results are comparable to the seismic amplitudes produced by sub-salt reflection. Due to the limited edition, this research is divided into three articles. The first part introduces the introduction of ray tracing simulation, ray tracing method and a simple 2D salt dome model example. The second part of the more complex 2D and 3D models to study to determine the impact of more complex structures. In the last section, the results of the ray tracing with the 3D model illustrate the effect of the direction of excitation associated with the orientation of the formation. In different cases, similar-shaped salt domes in the real seismic data extracted from 3D prestack depth migration measurements in the Gulf of Mexico were compared. This study presents a new understanding of possible imaging anomalies based on simple shapes, and its conclusion can be extrapolated to the “real-world” situation. However, there are complex interactions and speed changes in real construction, too?