储层裂隙波场特征物理摸型实验研究
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摘要
储层中裂缝的存在必然引起地震波传播特征的变化，波场特征的变化同储层中裂缝密度和裂缝方位有关，因而这种特征变化可以作为检测裂隙存在的有效手段。本文利用物理模型方法研究了裂缝密度和方位角变化对地震波传播特征的影响。实验发现：裂缝密度较高时，可以观测到明显的横波分裂现象；而裂缝密度较低时，仅能观测到微小的速度异常。同时快横渡与慢横波在振幅和频率特征上也具有明显差异。这些波场特征的分析对于裂缝检测具有重要意义。
Fractures in reservoir must cause the variation of seismic wave characteristic.The variation of wave field characteristic is closely related to the density and azimuths of fractures in reservoir, so that it may be an effective means of ascertaining the fractures. Physical model experiment was done to analyse how variations of fracture density and fracture azimuth influence on seismic wave characteristic.Model experiment says that obvious shear wave splitting may be found when fractures are dense, and that only slight velocity variation may be observed when fractures are less dense. Fast shear wave is obviously different from slow shear wave in amplitude and frequency characteristics. The analysis of wave field characteristics is of great significance to fracture prediction.
Fractures in reservoir must cause the variation of seismic wave characteristic.The variation of wave field characteristic is closely related to the density and azimuths of fractures in reservoir, so that it may be an effective means of ascertaining the fractures. Physical model experiment was done to analyse how variations of fracture density and fracture azimuth influence on seismic wave characteristic.Model experiment says that obvious shear wave splitting may be found when fractures are dense, and that only slight velocity variation may be observed when fractures are less dense. Fast shear wave is obviously different from slow shear wave in amplitude and frequency characteristics. The analysis of wave field characteristics is of great significance to fracture prediction.
引文
1贺振华,黄德济等.复杂油气藏地震波场特征方法理论及应用,四川科学技术出版社,1999
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3赵鸿儒等.工程多波地震勘探,地震出版社,1996
4Tatham R H.A physical model study of shear-wave splitting and fracture intensity.Geophysics, 1992, 57(4):647～652
5Assad J M.A physical model study of microcrack-induced anisotropy.Geophysics, 1992,57(12):1562～1570
6 Crampin S.An introduction to wave propagation in anisotropic media. Geophys J R Astr Soc, 1984, 76:17～28
2李亚林,贺振华等.岩石孔隙流体对纵横波速度影响的实验研究及意义.矿物岩石,1998,增刊
3赵鸿儒等.工程多波地震勘探,地震出版社,1996
4Tatham R H.A physical model study of shear-wave splitting and fracture intensity.Geophysics, 1992, 57(4):647～652
5Assad J M.A physical model study of microcrack-induced anisotropy.Geophysics, 1992,57(12):1562～1570
6 Crampin S.An introduction to wave propagation in anisotropic media. Geophys J R Astr Soc, 1984, 76:17～28
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