含煤地层AVO正演模型参数优选分析
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摘要
采用GEOVIEW软件,选取顶底板为泥岩,中间为煤层(厚度变化范围0～30m)的三层介质作模型,通过改变中间煤层的厚度、处理采样率、子波等参数,并保持上下围岩参数不变的方式来讨论相关参数对AVO响应的影响,结果表明当处理采样率越高时,AVO截距和梯度精度就越高;子波采样率过低,会引起AVO截距和梯度值的扰动现象;当子波采样率提高到一定程度时,扰动现象消除;子波主频的大小决定了调谐效应的范围,提高地震波主频,有利于提高分辨率;子波长度的变化对AVO截距和梯度值求取影响不大。上述结论为AVO正演模型参数优选提供了依据,其最佳参数的选取可有效提高含煤地层AVO正演模型的精度。
In order to get the accurate AVO forward model responses for coal-bearing strata,the AVO responses vary with the coal thickness,processing sample rate and wavelet parameters have been discussed on condition that the surrounding rock is unchangeable.The results show that the higher the processing sample rate,the better the accuracy of the intercept and gradient.Low wavelet sample rate will cause the fluctuation of intercept and gradient,but it can be eliminated when the wavelet sample rate has improved to a certain level.The dominant frequency decides the range of the tuning effect.To improve the dominant frequency will help to improve the resolution.The length of the wavelet has little effects to the intercept and gradient.The conclusions above could help to choose the appropriate parameters for the AVO forward modeling,thus to improve the accuracy of the AVO forward model for coal-bearing strata.
In order to get the accurate AVO forward model responses for coal-bearing strata,the AVO responses vary with the coal thickness,processing sample rate and wavelet parameters have been discussed on condition that the surrounding rock is unchangeable.The results show that the higher the processing sample rate,the better the accuracy of the intercept and gradient.Low wavelet sample rate will cause the fluctuation of intercept and gradient,but it can be eliminated when the wavelet sample rate has improved to a certain level.The dominant frequency decides the range of the tuning effect.To improve the dominant frequency will help to improve the resolution.The length of the wavelet has little effects to the intercept and gradient.The conclusions above could help to choose the appropriate parameters for the AVO forward modeling,thus to improve the accuracy of the AVO forward model for coal-bearing strata.
引文
[1]郑晓东.AVO正演方法及其应用[J].石油地球物理勘探,1991,26(6):766-776.
[2]Ramos A C B,T L Davis,3-D AVO analysis and modeling appliedto fracture detection in coalbed methane reservoirs[J].Geophysics,1997,62:1683-1695.
[3]张爱敏,汪洋,赵世尊.不同厚度煤层AVO特征及模型研究[J].中国矿业大学学报,1997,26(3):36-41.
[4]彭苏萍,高云峰.含煤地层振幅随偏移距变化正演模型研究[J].科学通报,2005,50(s1):131-137.
[5]董守华.地震资料煤层横向预测与评价方法[M].徐州:中国矿业大学出版社,2004:46-54.
[6]刘雯林.油气田开发地震[M].北京:石油工业出版社,1996:36-38.
[7]Shuey R T.A simplification of the Zoeppritz equations[J],Geophysics,1985,50(4)1985:609-614.
[8]殷八斤,等,AVO技术的理论与实践[M].北京:石油工业出版社,1995:68-71.
[9]张海燕,李庆忠.几种常用解析子波的特性分析[J].石油地球物理勘探,2007,42(6):651-657.
[10]陆基孟.地震勘探原理(下册)[M],北京:中国石油大学出版社,1993:312-313.
[2]Ramos A C B,T L Davis,3-D AVO analysis and modeling appliedto fracture detection in coalbed methane reservoirs[J].Geophysics,1997,62:1683-1695.
[3]张爱敏,汪洋,赵世尊.不同厚度煤层AVO特征及模型研究[J].中国矿业大学学报,1997,26(3):36-41.
[4]彭苏萍,高云峰.含煤地层振幅随偏移距变化正演模型研究[J].科学通报,2005,50(s1):131-137.
[5]董守华.地震资料煤层横向预测与评价方法[M].徐州:中国矿业大学出版社,2004:46-54.
[6]刘雯林.油气田开发地震[M].北京:石油工业出版社,1996:36-38.
[7]Shuey R T.A simplification of the Zoeppritz equations[J],Geophysics,1985,50(4)1985:609-614.
[8]殷八斤,等,AVO技术的理论与实践[M].北京:石油工业出版社,1995:68-71.
[9]张海燕,李庆忠.几种常用解析子波的特性分析[J].石油地球物理勘探,2007,42(6):651-657.
[10]陆基孟.地震勘探原理(下册)[M],北京:中国石油大学出版社,1993:312-313.
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