| 面向目标的起伏地表组合震源延时参数计算方法 |
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| 引用本文： | 秦龙,尹成,崔永福,刘正文,张振,方兵,陶正武.面向目标的起伏地表组合震源延时参数计算方法[J].地球物理学报,2019,62(4):1492-1501. |
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| 作者姓名： | 秦龙 尹成 崔永福 刘正文 张振 方兵 陶正武 |
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| 作者单位： | 1. 中国石油塔里木油田分公司勘探开发研究院, 新疆库尔勒 841000;2. 西南石油大学地球科学与技术学院, 成都 610500 |
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| 基金项目： | 2018E-1807-复杂山地、黄土塬及大沙漠区地震关键技术研究与应用（22161G20607）项目资助. |
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| 摘 要： | 组合震源技术通过调节延迟激发时间和震源埋藏深度能够实现地震波场的定向传播,提高地震波的照明能量和地震数据信噪比.然而,目前国内外对基于特定目标的组合震源最佳聚焦方向的选取以及起伏地表组合震源定向理论的研究相对较少.在聚焦方向选取方面,目前基本是利用多种不同延时参数的组合震源分别进行试验,从而确定较好的组合震源延时参数.本文则利用爆炸反射面原理,在目的层界面上均匀布置震源同时激发地震波,能够产生垂直于地层界面传播的平面波,当初至波传播至地表时进行地表方向统计.根据互易性原理,以初至波传播方向的反方向为聚焦方向,激发产生的地震波主波束方向将垂直入射到目的层界面上,从而精确的计算出组合震源的最佳聚焦方向.在组合震源定向方面,目前主要是利用组合震源方向因子公式进行计算,但该方法要求震源布置在同一条直线上,并不能满足起伏地表的应用要求.本文以惠更斯-菲涅尔原理为理论基础,提出通过炮点向量在聚焦方向上的投影来确定组合震源传播至虚拟波前的走时,从而确定任意起伏地表组合震源的延迟激发时间.该方法不仅能够计算出沿给定地质模型的目的层界面垂直入射的组合震源聚焦方向,也能够确定任意起伏地表情况下形成沿该聚焦方向定向传播地震波场的组合震源延迟激发时间.因此,本文提出的面向目标的起伏地表组合震源延时参数计算方法对组合震源数据采集具有理论与实践意义.
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| 关 键 词： | 组合震源 起伏地表 地表方向统计 爆炸反射面 炮点向量 |
| 收稿时间： | 2017-05-13 |
A calculation method of delay explosion time of a source array on an undulating surface |
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| QIN Long,YIN Cheng,CUI YongFu,LIU ZhengWen,ZHANG Zhen,FANG Bing,TAO ZhengWu.A calculation method of delay explosion time of a source array on an undulating surface[J].Chinese Journal of Geophysics,2019,62(4):1492-1501. |
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| Authors: | QIN Long YIN Cheng CUI YongFu LIU ZhengWen ZHANG Zhen FANG Bing TAO ZhengWu |
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| Institution: | 1. Research Institute of Exploration and Development, Tarim Oil field Company, Petro China, Korla Xinjiang 841000, China;2. School of Geoscience and Technology, Southwest Petroleum University, Chengdu 610500, China |
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| Abstract: | Source array technology could attain directed propagation of the seismic wave field by adjusting delay explosion time and depth, which could enhance illumination energy of seismic waves and signal-to-noise ratio. However, there are relatively few studies on the selection of the best focusing direction and the implementation of this method in the case with an undulating surface. In the selection of the focus direction, the common approach is to use a variety of different delay parameters of the source array to conduct tests and then determine the better parameters. Different from this, according to the method of explosion reflecting interface, we evenly explode seismic waves at the target layer, which could generate plane waves perpendicular to the target layer. When the first break arrives the surface, we calculate the surface direction of propagation by the Poynting vector. And according to the principle of reciprocity, the seismic wave field in the opposite direction of the first arrival wave propagation will propagate to the target layer vertically. Then the exact focusing direction of the source array is calculated accurately. In the source array orientation, the current method mainly uses the source array direction factor formula for the calculation. But it requires the separation of the source array in the same line which cannot meet the application requirements of the undulating surface. To solve this problem, this paper determines the delay explosion time of source array by the projection of shot-points vector on the focusing direction based on Huygens-Fresnel principle. This method could not only calculate the focusing direction that is perpendicular to the target layer, but also determine the delay explosion time of the source array to the surface with any topography. Therefore, this work has important theoretical and practical significance for seismic data acquisition by source array on an undulating surface. |
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| Keywords: | Source array Undulating Surface Surface Direction statistic Explosion reflecting interface Shot-point vector |
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