松辽盆地地层吸收特性和地震波衰减规律研究
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摘要
选取有代表性的岩石样本 ,实验室模拟地下岩层的实际物理状态 ,对P波的品质因数Q和波速进行了测试 ,结果表明 ,松辽盆地地下岩层的P波Q和波速皆随压力的增加呈线性增加 ,随温度的增加呈线性减小 ;且Q与波速符合幂律关系 .粘弹介质地震波场正演模拟表明 ,导致地震波衰减的主要是第四系低速带的影响 .通过地震测井资料估算 ,按目前的地震采集方式 ,即潜水面 (低速带 )以下激发 ,检波器地面接收 ,从激发到接收 ,地震波在第四系中高频成分将损失 170Hz .在最理想情况下 ,爆炸震源激发的初始子波频宽为 4 0 2Hz ,经过第四系和下伏地层吸收 ,第四系以下的反射波频带宽度不会超过 2 32Hz ,这是松辽盆地受地层吸收限制的高频采集极限
Bying simulating the actual physical conditions of rocks underground in laboratory,P wave Q and velocity of the rock samples in the SongLiao Basin have been tested.The experimental result shows that both Q and velocity of the rocks in the SongLiao Basin will increase with the pressure going up and decrease with the temperature going up as the linear rule.The result also verify that there is a power function relation between Q and velocity.Seismic modelling to the real strata indicates that wave attenuation occurs mainly in the Quarternary,and the lower velocity zone up the Quarternary take a large portion of the attenuation.Calculating derived from the seismic logging data proves that if the Source is below the lower velocity zone and geophone on the surface which has been a conventional seismic acqusition way in the SongLiao Basin,seismic wave will lose its high frequency amounts to 170Hz in the Quarternary.Under the favourable conditions,the explosive source can creates a wavelet with the maximum frequency band width of 402Hz.So,the reflected wave finally received from any layer below the Quarternary only has a frequency band width less than 232Hz.That is, in SongLiao Basin, owing to the wave attenuation, the limit of the highest frequency of the seismic reflection is 232Hz.
Bying simulating the actual physical conditions of rocks underground in laboratory,P wave Q and velocity of the rock samples in the SongLiao Basin have been tested.The experimental result shows that both Q and velocity of the rocks in the SongLiao Basin will increase with the pressure going up and decrease with the temperature going up as the linear rule.The result also verify that there is a power function relation between Q and velocity.Seismic modelling to the real strata indicates that wave attenuation occurs mainly in the Quarternary,and the lower velocity zone up the Quarternary take a large portion of the attenuation.Calculating derived from the seismic logging data proves that if the Source is below the lower velocity zone and geophone on the surface which has been a conventional seismic acqusition way in the SongLiao Basin,seismic wave will lose its high frequency amounts to 170Hz in the Quarternary.Under the favourable conditions,the explosive source can creates a wavelet with the maximum frequency band width of 402Hz.So,the reflected wave finally received from any layer below the Quarternary only has a frequency band width less than 232Hz.That is, in SongLiao Basin, owing to the wave attenuation, the limit of the highest frequency of the seismic reflection is 232Hz.
引文
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[14] KennettBL .SeismicWavePropagationinStratifiedMedia[M].England:CambridgeUniversity,Cambridge,1983.
[2] GeraldM .Mavko,AmosNur.Waveattenuationinpartiallysaturatedrocks[J].Geophysics,1979,44(2):161～178.
[3] MNTOKSOZ ,DHJohnstonandA .Timur.Attenuationofseismicindryandsaturatedrocks:PartⅠLaboratorymesurement[J].Geophysics,1979,44(4):681～690.
[4] MNTOKSOZ ,DHJohnston,ATimur.Attenuationofseismicindryandsaturatedrocks:PartⅡMechanisms[J].Geophysics,1979,44(4):691～711.
[5] 李庆忠.走向精确勘探的道路[M].北京:石油工业出版社,1994,31～44.
[6] 俞寿朋.高分辨率地震勘探[M].北京:石油工业出版社,1994,35～57.
[7] 孟凡顺,邓子辰.层状弹性半空间非轴对称动力问题的奇异解[J].力学学报,1996,6:215～221.
[8] 孟凡顺,陈运泰.柱坐标系下任意埋藏源层状弹性半空间问题的奇异解[J].地球物理学报,1997,40(4):512～521.
[9] 孟凡顺,郭海燕.任意荷载作用下多层半无限弹性体静力问题的解析解[J].工程力学,1997,(3).
[10] 孟凡顺,郭海燕.用传递矩阵法求解多层层状弹性半空间轴对称动力问题的奇异解.地震工程与工程振动,1995,(2):44～51.
[11] 孟凡顺,郭海燕.任意震源力作用下多层粘弹性半无限地基平面问题的奇异解[J].地震工程与工程振动,1995,(3):32～37.
[12] 李旭,陈运泰.合成地震图的广义反射透射系数矩阵方法[J].地震地磁观测与研究,1996,(3):315.
[13] 朱建林,牟永光.有限元粘滞弹性波VSP地震模型[J].石油地球物理勘探,1994,(6):21～24.
[14] KennettBL .SeismicWavePropagationinStratifiedMedia[M].England:CambridgeUniversity,Cambridge,1983.
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