| 边界吸收中镶边法的评价 |
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| 作者姓名： | 陈可洋 |
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| 作者单位： | 中国石油大庆油田有限责任公司勘探开发研究院, 大庆 163712 |
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| 摘 要： | 以均匀层状带凹陷特征的介质模型为例,分析镶边法在常规边界吸收问题中的独到优越性;采用均匀倾斜模型数值实例,详细探讨外侧镶边法在边界吸收中的弊端及其成因.综合数值试算分析表明,外侧镶边法会引入虚假反射波,其原因是边界处速度延拓产生了人为绕射点.提出了内侧镶边方法,即以牺牲局部有效波场来提高数值计算精度、信噪比和可信度,实例验证该方法正确可行.
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| 关 键 词： | 镶边法 吸收边界条件 弹性波正演数值模拟 信噪比 |
| 收稿时间： | 2009-10-12 |
| 修稿时间： | 2009-12-10 |
Evaluation of the bordering methods of the absorbing boundary condition |
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| Authors: | CHEN Ke-Yang |
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| Institution: | Exploration and Development Research Institute of Daqing Oilfield Company Limited of CNPC, Daqing 163712, China |
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| Abstract: | By taking an isotropic layered medium model with depressed characteristic as example, we analyzed the advantages of the bordering method in solving conventional boundary absorbing problems. By taking a numerical example of an isotropic tilt model, we discussed the drawbacks of the outside bordering method and the origins of the boundary absorption in detail. The generalized numerical analyses show that the outside bordering method could introduce bogus reflected waves, and the reason was that the velocity continuation on the boundary brought in man-made diffraction points. The inside bordering method is proposed for the purpose of improving numerical simulation precision, signal-to-noise ratio, and credibility at the cost of regional effective wave field. The example illustrates that the proposed method is reliable and workable. |
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| Keywords: | bordering method absorbing boundary condition elastic wave forward numerical simulation signal-to-noise |
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