瓦斯突出煤和非突出煤AVO响应的比较

AVO Response Comparison between Gas Outburst Coal and Non Outburst Coal

基于Zoeppritz方程,对煤层进行AVO正演模拟,得到煤层的AVO响应曲线。瓦斯突出煤与非突出煤的AVO响应对比表明,无论是瓦斯突出煤还是非突出煤,其顶界面AVO响应在总体上表现为地震振幅绝对值随偏移距增加而减小的特点,但是瓦斯突出煤的截距绝对值要大于非突出煤的截距绝对值,瓦斯突出煤的斜率要大于非突出煤的斜率。煤层厚度变化会对AVO响应产生影响,当瓦斯突出煤和非突出煤的厚度相同时,瓦斯突出煤的截距绝对值大于非突出煤;当厚度不同时,瓦斯突出煤的斜率大于非突出煤的斜率。瓦斯突出煤与非突出煤的AVO响应差异,可为地球物理参数进行煤与瓦斯突出危险性预测以提供技术参考。

Based on Zoeppritz equation, the AVO response curve of coal seam can be obtained by forward modeling. AVO response comparison between gas outburst coal and non outburst coal shows that the top interface AVO response both the gas outburst coal and non outburst coal, in general, presents seismic amplitude absolute value decrease when offset become large, but the coal gas outburst intercept absolute value and the slope is greater than non outburst coal. Changes in seam thickness have an impact on the AVO response, when the coal seam thickness is the same, the intercept absolute value of coal-gas outburst is greater than the non outburst coal; when the thickness is different, and the slope of the coal gas outburst is greater than the non outburst coal. AVO response differences between gas outburst coal and non outburst coal can provide for a technical reference in coal and gas outburst risk forecast by geophysical parameters.