时移动校正和叠加方法

基金项目: 中国石油天然气集团总公司中青年创新基金项目

AN APPROACH TO TIME-SHIFTED NORMAL MOVEOUT AND STACKING

1.
Hebei Institute of Architectural Science and Technology, Handan 056038, China
2.
Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China

摘要: 在水平层状介质假设情况下, 推导了反射波时距曲线的表达式, 指出: 在对水平层状介质情况下, 反射波时距曲线是一时移双曲线.通过对理论模型和实际资料的处理, 表明时移动校正和叠加方法具有高保真、高分辨率和明显的叠加成像效果.同时, 用时移动校正τ₀分析谱计算层速度较以往用Dix公式由叠加速度计算层速度精度要高.这种方法不仅可以用于复杂构造的地震资料的叠加成像, 也可以应用到高分辨率处理的流程中.
- 动校正 /
- 时距曲线 /
- 叠加
Abstract: The expression of the time-interval curve of the reflective waves is derived on the condition of the horizontal layered strata, indicating that the time-interval curve of the reflective waves is a time-shifted hyperbola in the layered strata. The processing of theoretical model and real data shows that the time-shifted normal moveout and stacking may produce a high-fidelity, high-resolution and accurate stacking image effect. At the same time, the interval velocity derived from the time-shift-corrected spectrum τ₀ is more accurate than that derived from the traditional Dix-equation-calculated stacking. This method is not only used for the stacking image of the seismic data in complex area, but also for the flow chart of the high-resolution processing.
- normal moveout /
- timeinterval curve /
- stack

图 1 三层介质模型分析结果

a.用射线追踪正演的共同中心点CMP道集记录; b.时移动校正τ₀分析谱: b₁.CMP记录; b₂.τ₀分析谱; b₃.聚焦能量; c.校正和叠加结果: c₁.常规动校正和叠加结果; c₂.时移动校正和叠加结果

Fig. 1. Analysed result of three＿layer medium model

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图 2 层速度计算结果

图中实线由时移动校正τ₀分析谱, 使用文中(21) 式计算得到, 与实际相差较小; 虚线由常规速度分析, 使用Dix公式计算得到

Fig. 2. Caculated interval velocities

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图 3 二维精细(a) 和时移动校正(b) 方法处理的地震叠加剖面

由图上可见在CMP190~270的范围内, 3.3 s左右的反射层明显清楚

Fig. 3. Processed stack sections by time＿shifted NMO and conventional method

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