极浅海区水体地震响应正演模拟
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摘要
由于极浅海地区水体中多次鸣震和混响的旅行时间较短,容易与一次反射波发生混叠,难以有效应用预测反褶积等处理手段。为此本文从理论上针对水体多次波的类型,分别推导了它们所对应的时间域响应方程和频率域响应方程,在此基础上以一个四层介质模型进行了正演模拟,其中第一层为海水,海水深度由6m变化到50m。正演结果表明:各类水体多次波之间存在极性和强度的差别;当海水较浅时,水体多次波与一次波出现混叠,难以分开;随着海水深度增大,水体多次波与一次波分离,彼此时差增大,而且多次波能量逐渐衰减,因此两者极易识别。
As the short travel time of ringing and reverberation in water body of extra-shallow sea,it results in mix with primary reflection easily and makes such processing measures as predictive de-convolution difficult to be effectively used. For that reason, according to the kinds of multiples in water body, the paper deduced theoretically the e-quations of response in both time domain and frequency domain respectively and conducted forward modeling for a four-layers' medium model on that basis, among which the first layer is sea water, the depth of which changes from 6m to 50m. The modeled results showed the differences in polarity and strength exist among the different kinds of multiples in water body; multiples of water body mixes with primary reflections, and difficult to be separated in shallower depth of sea water; along with increasing the depth of sea water, the multiples of water body and primary reflections are gradually separable, and the moveout between them increases,and energy of multiples is gradually attenuated as well, which makes them to be identified easily.
As the short travel time of ringing and reverberation in water body of extra-shallow sea,it results in mix with primary reflection easily and makes such processing measures as predictive de-convolution difficult to be effectively used. For that reason, according to the kinds of multiples in water body, the paper deduced theoretically the e-quations of response in both time domain and frequency domain respectively and conducted forward modeling for a four-layers' medium model on that basis, among which the first layer is sea water, the depth of which changes from 6m to 50m. The modeled results showed the differences in polarity and strength exist among the different kinds of multiples in water body; multiples of water body mixes with primary reflections, and difficult to be separated in shallower depth of sea water; along with increasing the depth of sea water, the multiples of water body and primary reflections are gradually separable, and the moveout between them increases,and energy of multiples is gradually attenuated as well, which makes them to be identified easily.
引文
[1]牟永光．地震资料数字处理方法．北京:石油工业出版社．1989
[2]R E谢里夫(美),L P吉尔达特(加)．勘探地震学．北京:石油工业出版社,1999
[3]张永刚．地震波场数值模拟技术．石油物探．北京:石油工业出版社,2003
[2]R E谢里夫(美),L P吉尔达特(加)．勘探地震学．北京:石油工业出版社,1999
[3]张永刚．地震波场数值模拟技术．石油物探．北京:石油工业出版社,2003
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