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本文系统论述了由地表各种障碍物(不均匀体)所次生激发的地震干扰波,并指出它是地震勘探中最值得注意的干扰波。次生干扰的复杂性在于:(1)次生干扰可以分布于全记录,无法躲开,也不能切除。(2)它与有效反射波几乎有相同的频带范围,无法用频率滤波滤去。(3)次生低速干扰常常表现为“随机性”,而克服随机干扰一般采用的是统计法,但统计法克服干扰的本领总是很有限的。(4)次生干扰可以从四面八方传到排列,因此在记录上的视速度常常很高,最高可接近无穷大。侧面次生高速干扰可以与反射有效波十分相象,真假难分。有些次生高速干扰甚至在叠加时会得到加强。(5)由于次生高速干扰的视速度普遍高于折射初至波的速度,因此与反射有效波在视速度域及视波长域总是难解难分,不可能在野外组合中把次生干扰去除干净,只能留给室内处理。本文又指出了传统的地震教科书中论述干扰波调查方法的片面性。次生高速干扰往往在干扰波调查记录上不易被发现。相反地在生产记录及水平叠加剖面上却清晰可见。文中指出,克服次生干扰波最有效的方法是面积组合,直线组合会带来不可弥补的缺陷,并对面积组合的各种形式作了具体介绍,强调用玫瑰图的分析方法指导组合实践。在处理过程中,克服干扰波不能只在一个地震道上做文章。文中指出目前地震资料处理中的通病,并认为混波、二维滤波及相干加强等方法是克服各种次生干扰波有效的方法。目前,进一步从记录中彻底消除干扰波的技术尚待研究完善。本文初步提出了低信噪比地震资料的处理方法。
This paper systematically discusses the seismic interference wave excited by various obstacles on the surface (inhomogeneous body) and points out that it is the most notable disturbance wave in seismic exploration. The complexity of secondary interference lies in: (1) secondary interference can be distributed in the full record, can not escape, can not be removed. (2) It has almost the same frequency range as the effective reflected wave and can not be filtered by frequency filtering. (3) Secondary low-speed interference often shows as “randomness”, while statistical methods are generally used to overcome random interference. However, the statistical methods to overcome the interference are always limited. (4) Secondary interference can be transmitted from all sides to the permutation, so the apparent velocity on the record is often high, up to infinity. Side of the secondary high-speed interference can be very similar with the reflection of the effective wave, true and false. Some secondary high-speed disturbances are even strengthened when superimposed. (5) Since apparent velocities of secondary high-speed interference are generally higher than those of refracted first arrivals, it is always difficult to distinguish them from reflected effective waves in the field of view velocity and in the viewing wavelength. It is impossible to combine secondary interference Remove clean, can only be left indoors. The paper also points out the unilateralism of the method of interference wave investigation in the traditional textbook of earthquake. Secondary high-speed interference is often not easily found in the interference wave investigation records. On the contrary, it is clearly visible on the production record and the horizontal stacking profile. It is pointed out that the most effective method to overcome the secondary interference wave is the area combination. The combination of the straight lines will bring irreparable defects. The various forms of the area combination are introduced in detail. Emphasis is put on the combination practice with Rose diagram analysis method. In dealing with the process, to overcome the interference wave can not only make an issue in a seismic track. The paper points out the common faults in the current seismic data processing, and considers that the methods of mixing, two-dimensional filtering and coherence enhancement are effective methods to overcome various secondary interference waves. At present, the technology of further eliminating interference waves from records remains to be studied and improved. This paper presents a preliminary approach to the processing of low S / N seismic data.