鄂尔多斯盆地山西组二段煤层对下伏砂岩地震反射特征影响的数值模拟分析  

Numerical simulation analysis of the influence on underlying sandstone seismic reflection characteristics from coal seam in member 2 of Shanxi formation,Ordos Basin

作　　者：赖生华[1] 梁全胜[2] 袁通路[1] 

机构地区：[1]西安石油大学,陕西西安710065 [2]陕西延长石油(集团)有限责任公司,陕西延安716000

出　　处：《石油物探》2014年第3期351-359,共9页Geophysical Prospecting For Petroleum

基　　金：国家自然科学基金项目(41372118);陕西省科技计划项目(2014K10-12;2014XT-17);西安市科技计划项目(CXY1346(6))共同资助

摘　　要：针对含煤岩系中煤层对下伏砂岩储层地震响应的强烈干涉作用,基于鄂尔多斯盆地下二叠统山西组二段含煤岩系沉积序列,构建了两个地质模型进行正演模拟分析,从理论上研究了上覆煤层厚度及位置对下伏层状砂岩地震反射特征的影响。分析结果表明,煤层厚度、位置和地震子波频率会导致砂岩顶、底界面地震反射特征出现较大差异。由于上覆煤层的干涉作用,不仅下伏砂岩地震反射极性会发生反转,而且砂岩顶、底界面反射振幅也会随煤层厚度和位置的变化而变化;上覆煤层厚度或位置不稳定时,砂岩顶、底面地震反射振幅不能反映砂岩厚度变化,不能利用砂岩顶、底面地震反射振幅预测厚度小于1/4波长的薄层砂岩厚度。Coal seam in coal-bearing series has intensive interference on underlying sandstone reservoir.Two geological models are built for numerical simulation,and the impacts of thickness and location of overlapping coal seam on seismic reflection characteristics of underlying sandstone are theoretically studied,which is based on coalbearing series sedimentary sequence of member 2 of Shanxi formation in Ordos Basin.The results show that thickness and location of coal seam,frequency of seismic wavelet result in large difference of seismic reflection characteristics of top and bottom of sandstone layer.Polarity of seismic reflection of underlying sandstone will be changed because of interference of overlying coal seam; moreover,amplitude of seismic reflection from the top and bottom of sandstone will be changed along with the change of thickness and location of coal seam.Amplitude of seismic reflection can not indicate the change of thickness for sandstone if the thickness or location of overlying coal seam is unstable,thus the thickness of thin layer sandstone （＜λ/4）cannot be predicted using seismic reflection amplitude from the top and bottom of sandstone stratum.

关 键 词：鄂尔多斯盆地 煤层 砂岩 地震反射特征 正演数值模拟 零相位Ricker子波 

分 类 号：P631.4[天文地球—地质矿产勘探]