正交地震道在二维地震岩性解释中的应用
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摘要
正交地震道建立在复地震道的概念之上,与实地震道构成复地震道的虚部和实部。对实地震道进行90°相移滤波得到正交地震道的同时,地震子波的形态由零相位子波变为不对称子波。因此,正交地震道能突出反映实地震记录中某些模糊、朦胧的振幅信息。一般在常规显示的剖面中,二者没有明显区别,仅有90°相位差。当采用合适的显示参数后,有时振幅差异性较明显。在二维偏移地震剖面及其正交地震道剖面上将对应层段的振幅值进行对比解释,平面上找出振幅异常区,即为可能的岩性异常体的分布范围。笔者用该方法在塔里木盆地塔中32井以北、以西志留系内幕发现了一个振幅异常分布区,该异常与塔中32井、塔中34井钻探结果吻合较好。
The orthogonal seismic trace set up on the concept of complex seismic trace is combined with the real seismic trace to form the imaginary part and the real part of the complex seismic trace.Through the phase shift of 90°to real seismic trace,the orthogonal seismic trace is taken,and the shape of the seismic wavelet turns from the zero-phase wavelet to the unsymmetrical wavelet.So the orthogonal seismic trace can reflect clearly some fuzzy and dim amplitude information in the record of the real seismic trace.Generally in the routine display profile,orthogonal seismic trace and real seismic trace have not obvious difference but 90°phase difference.After the suitable display parameters are adopted,the difference in amplitude becomes relatively obvious.On the 2D offset seismic profile and its orthogonal seismic trace profile,comparison and explanation of the amplitude value corresponding to the same interval are conducted in order to find out the abnormal amplitude area in plane,i.e.the distribution range of possible lithologic anomalous body.By means of this method,one abnormal amplitude distribution area is found in Silurian system,the west and north of Well TZ-32 in Tarim basin.The anomaly well matches the drilling results of Well TZ34 and Well TZ32.
The orthogonal seismic trace set up on the concept of complex seismic trace is combined with the real seismic trace to form the imaginary part and the real part of the complex seismic trace.Through the phase shift of 90°to real seismic trace,the orthogonal seismic trace is taken,and the shape of the seismic wavelet turns from the zero-phase wavelet to the unsymmetrical wavelet.So the orthogonal seismic trace can reflect clearly some fuzzy and dim amplitude information in the record of the real seismic trace.Generally in the routine display profile,orthogonal seismic trace and real seismic trace have not obvious difference but 90°phase difference.After the suitable display parameters are adopted,the difference in amplitude becomes relatively obvious.On the 2D offset seismic profile and its orthogonal seismic trace profile,comparison and explanation of the amplitude value corresponding to the same interval are conducted in order to find out the abnormal amplitude area in plane,i.e.the distribution range of possible lithologic anomalous body.By means of this method,one abnormal amplitude distribution area is found in Silurian system,the west and north of Well TZ-32 in Tarim basin.The anomaly well matches the drilling results of Well TZ34 and Well TZ32.
引文
[1]陆基孟.地震勘探原理及资料解释[M].北京:石油工业出版社,1982.
[2]牟永光.地震勘探资料数字处理[M].北京:石油工业出版社,1991.
[3]渥.伊尔马滋.地震数据处理[M].北京:石油工业出版社,1994.
[4]李庆忠.走向精确勘探的道路[M].北京:石油工业出版社,1994.
[2]牟永光.地震勘探资料数字处理[M].北京:石油工业出版社,1991.
[3]渥.伊尔马滋.地震数据处理[M].北京:石油工业出版社,1994.
[4]李庆忠.走向精确勘探的道路[M].北京:石油工业出版社,1994.
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