深部煤层的AVO属性分析

AVO attributes of deep coal seam

根据岩石物理理论和深部煤田测井数据,建立了利用AVO属性预测深部煤层岩石物性的方法.由于煤层与上覆岩层一般有较大的阻抗差异,煤层的AVO特性类似于油气勘探中典型的第三类含气砂岩特性.不同于油气勘探的砂岩储层预测,煤层的特性类似于泥岩.在此基础上,通过建立AVO梯度截距交汇图,可以很好地将多数煤层与炭质泥岩或者泥质炭等岩性识别出来.利用梯度截距的AVO交汇图,还可指示出高孔隙含水砂岩的分布范围.

Based on rock physics theory and real well log data of deep coal seam, studied the AVO attributes of deep coal seam in order to establish a coal seam prediction method by using seismic data. Coal seams typically have high elastic contrasts with the overlaying sandstones, therefore most coal seams can cause strong seismic reflections similar to the bright spots in class three gas sand cases. By using AVO intercept-gradient crossplots, most coal seams can be discriminated and still part of coaly shale beds could be interpreted as coal seam. Furthermore, the distribution of coal seams in intercept-gradient crossplots can indicate the high-porosity areas of sandstone.