叠前逐层成像速度建模方法及其应用

Layer-by-layer prestack imaging velocity model building and application

1. 石油大学资源与信息学院,北京 102249;2. 中国石化人事教育部,北京 100083;3. 中国石化石油勘探开发研究院,北京 100083

College of Geo-Resource and Information, University of Petroleum, Beijing 102249, China

叠前深度偏移的效果如何取决于建立的速度一深度模型正确与否。通常以叠后偏移数据的构造解释结果为构造背景,以叠加偏移的均方根速度为初始速度,来制作初始速度一深度模型,然后再经反复迭代,求得最终的速度一深度模型。但是,当构造复杂、速度变化剧烈时,叠偏剖面成像差,不能得到正确的构造,使这种制作速度一深度模型的方法难以得到预期结果。以EAGE/SEG盐丘模型为例,探讨了在从叠加偏移剖面中无法得到正确构造形态和速度的情况下,采用叠前逐层成像速度建模的方法来求取叠前深度偏移速度一深度模型的处理方法,并将其应用于实际地震数据处理,得到了成像效果良好的剖面。

The effect of prestack depth migration depends on velocity-depth model. Generally velocity-depth model is built iteratively under the constraints of structure interpretation on poststack migration sections, starting from the root-mean-square velocity resulted from poststack migratioa Migration sections resulted from such velocity-depth models sometimes fail to reveal correct structure information. By taking EAGE/SEG salt model for an example, the author discusses the building of velocity-depth model for prestack depth migration by layer-by-layer modeling. The method has been adopted in real data processing.