近距离煤层复合反射波相位及振幅变化规律初探

Preliminary Research on Law of Composite Reflection Phase and Amplitude Variation of Adjacent Coal Seams

近距离煤层的煤层厚度及煤层间距变化易引起多煤层反射波的复杂干涉,使地震波相位和振幅特征发生复杂变化,导致相位及振幅解释的多解性较强。为此,构建了两煤层厚度及煤层间距均连续等步长变化的近距离煤层模型,通过褶积正演分析了近距离煤层复合反射波的相位及振幅变化规律,探讨了振幅属性在煤层厚度、煤层间距变化以及煤层分岔、尖灭等地质现象解释中的适用条件。结果表明:对于近距离的2层煤,其反射波的干涉包括复合单波谷和复合双波谷2类,且当两煤层厚度或间距满足一定条件时,波峰、波谷等特征相位振幅呈现单调递增、单调递减或调谐变化等规律,对近距离煤层的煤层厚度、煤层间距变化及部分地质现象的解释具有一定的指导意义。

The variation of coal seams thickness and spacing easily generate the complex interference of the seismic reflection in the adjacent coal seams.This cause the complex variation of phase and amplitude so that the amplitude interpretation is represented ambiguity.Therefore,constructs the adjacent coal seams model in which the coal seams thickness and spacing all synchronously change.Analyzes the law of phase and amplitude variation according to convolution forward and discusses the application condition of amplitude in the geological phenomenon interpretation such as coal seams thickness,spacing,bifurcation and pinch-out.The results show that the interference type of reflection can be divided into composite single trough and composite double trough.And when coal seams thickness and spacing meets certain conditions,the amplitude has the law of monotonically increasing,monotonically decreasing or tuning.This has a certain guiding significance for the interpretation of coal seams thickness and spacing and some geological phenomena.