英雄岭山地地震干扰波分析与处理
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摘要
青海柴达木盆地英雄岭坚硬地层出露地表 ,地层倾角大 ,形成特殊的连续大沟、大坎地表地质条件。依据地震测线经过的山地特殊地表地质条件 ,建立了倾斜地层与冲沟的理论模型 ,通过正演模拟分析 ,对这种特殊的地表地质条件进行了干扰波分析 ,认为处理地震资料得不到有效同相轴主要与复杂地表条件有关 ,特别在深沟附近 ,地层的反射和深沟的侧面反射交叉在一起 ,使地震剖面出现深沟的侧面反射超过地层有效反射的情况 ,形成假像。在处理山地地震资料时 ,要分析不同地区、不同地段地震波传播特征与干扰波的影响 ,以形成在地表地质模型约束下的地震处理方法。英雄岭地区的实际山地地震资料因很强的地表影响而出现同相轴交叉 ,进行常规地震处理很难正确识别地层反射同相轴。在地表模型和地质条件约束下 ,分别利用双边资料或单边资料处理 ,得到了合理和较好的结果 ,处理后的地震剖面反映了地下地质构造。图 3参 1
The topography of seismic prospecting area in Yingxiongling Mountain of Qaidam basin is very complicated. In the mountain area, hard strata outcropped and the dip angle of formation is large. There are many channels in this area, which formed special surface geological condition. Based on mountain surface geological condition, the analysis model for dip formation and gully was studied with forward modeling. The analysis of disturbing wave for this special case was done. These show that the main reason of bad processing profiles of seismic data is related with complicated earth's surface, especially in area of gully. The strata reflection and offside reflection cross in the profile, which may result in false appearance. Thus the seismic data processing should be done under constrains of surface geological model to analyze seismic wave propagation and disturbing wave. The real seismic data processing shows no difference with the theoretical analyses. There is a very strong crossing evens, which are from mountain surface, in seismic profile. The conventional seismic data processing is difficult to identify correct evens from strata. While the better and reasonable profile can be obtained by using constrains of surface geological model. The final profile reflects the underground geological structure.
The topography of seismic prospecting area in Yingxiongling Mountain of Qaidam basin is very complicated. In the mountain area, hard strata outcropped and the dip angle of formation is large. There are many channels in this area, which formed special surface geological condition. Based on mountain surface geological condition, the analysis model for dip formation and gully was studied with forward modeling. The analysis of disturbing wave for this special case was done. These show that the main reason of bad processing profiles of seismic data is related with complicated earth's surface, especially in area of gully. The strata reflection and offside reflection cross in the profile, which may result in false appearance. Thus the seismic data processing should be done under constrains of surface geological model to analyze seismic wave propagation and disturbing wave. The real seismic data processing shows no difference with the theoretical analyses. There is a very strong crossing evens, which are from mountain surface, in seismic profile. The conventional seismic data processing is difficult to identify correct evens from strata. While the better and reasonable profile can be obtained by using constrains of surface geological model. The final profile reflects the underground geological structure.
引文
[1] 渥·伊尔马滋.地震数据处理[M].北京:石油工业出版社,1994.
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