地球物理学报  2013, Vol. 56 Issue (6): 2023-2032 PDF

1. 东北石油大学地球科学学院, 大庆 163318;
2. 大庆油田有限责任公司勘探开发研究院, 大庆 163712

3D surface-related multiple prediction approach investigation based on wave equation
SHI Ying1, WANG Wei-Hong2, LI Ying1, JING Hong-Liang1
1. School of Earth Science, Northeast Petroleum University, Daqing 163318, China;
2. Exploration and Development Research Institute of Daqing Oil field Company Ltd., Daqing 163712, China
Abstract: Compare with the traditional 2D surface-related multiple prediction algorithm, 3D surface-related multiple prediction approach based on wave equation needs no assumption for underground medium. It is a powerful tool to deal with multiple prediction problem in seismic data processing, which is more conform to the actual situation that seismic wave propagate through the underground medium. Based on the fundamentals of multiple prediction, the matrix representation, calculation approach and realization condition for full 3D surface-related multiple prediction are proposed in this paper. Also using GPU (Graphic Processing Unit) to accelerate full 3D surface-related multiple prediction algorithm, compare to traditional CPU computation, the speed is 165 times faster. Multiple prediction tests are done on synthetic 3D seismic data with surface-related multiples, 2D and 3D surface-related multiple prediction effect from 2D and 3D algorithms are compared and analyzed, and the result demonstrates that full 3D surface-related multiple prediction approach based on wave equation has higher computation accuracy and better prediction effect than 2D algorithm. With the help of reasonable adaptive subtraction, we can obtain seismic prospecting data with high precision after surface-related multiple suppression..
Key words: Surface-related multiple      GPU      Wave equation      3D      Prediction
1 引言

 图 1 复杂介质中一阶表面多次波的射线路径 Fig. 1 Ray path of first order surface-related multiple from complicated medium

2 3D多次波预测的基本理论

SRME为全数据驱动的表面多次波压制方法，其直接利用隐含于叠前地震数据中的信息预测多次波，而无需地下介质的任何其他信息，并且可同时预测出所有阶的表面多次波.已知与检波点xr有关的共接收点道集Pxrxkt）和与震源xs有关的共炮点道集Pxkxst），利用它们的褶积和可预测多次波道mxrxst）.

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 图 2 观测系统示意图 （a）共炮点观测系统；（b）共接收点观测系统. Fig. 2 Geometry schematic diagram (a)Common shot geometry; (b)Common receiver geometry.

 图 3 数据预测表面多次波的矩阵表示 Fig. 3 3D data matrix representation for surface-related multiple prediction
3 理论模型应用实例

 图 4 水平层状介质表面多次波正演数据的速度模型 Fig. 4 Velocity model of forward modeling data with surface-related multiple for 3D horizontal layer medium
 图 5 某炮数据56条测线的地震记录 （a）某点放炮模拟的地震数据；（b）3D算法预测的多次波；（c）多次波压制后的结果. Fig. 5 Seismic record with 56 lines from one shot (a)Simulated one shot record; (b)Predicted multiple based on the proposed 3D predictive approach; (c)Result after multiple suppression

 图 6 某条测线的地震记录 （a）某条测线含多次波的地震数据；（b）3D方法预测的多次波；（c）多次波压制结果. Fig. 6 Seismic record from one line (a)Seismic data with multiples from one line; (b)Predicted multiple based on the proposed 3D approach; (c)Result after multiple suppression.
4 3D和2D多次波预测方法对比分析

 图 7 2D与3D算法预测多次波及压制效果对比 （a）含多次波的理论数据；（b）2D算法预测的多次波；（c）经2D算法预测的多次波压制结果；（d）3D算法预测的多次波；（e）经3D算法预测的多次波压制结果. Fig. 7 Comparison of multiple prediction and suppression result by 2D and 3D algorithm (a)Theoretical data with multiple; (b)Predicted multiple by 2D algorithm; (c)Multiple suppression result by 2D prediction algorithm; (d)Predicted multiple by 3D algorithm; (d)Multiple suppression result by 3D prediction algorithm.

 图 8 2D算法预测和压制多次波单道效果图 （a）原始道记录；（b）多次波压制结果；（c）预测的多次波. Fig. 8 Single trace comparison of multiple prediction and suppression by 2D algorithm (a)Initial trace record; (b)Multiple suppression result; (c)Predicted multiple.
 图 9 3D算法预测和压制多次波单道效果图 （a）原始道记录；（b）多次波压制结果；（c）预测的多次波. Fig. 9 Single trace comparison of multiple prediction and suppression by 3D algorithm (a)Initial trace record; (b)Multiple suppression result; (c)Predicted multiple.
5 结论