基于叠前时间偏移速度扫描的四维建模技术及应用

Four-dimensional velocity modeling and its application on the basis of PreSTM

速度建模是做好叠前偏移的关键。主要介绍一种基于叠前时间偏移(PreSTM)的百分比速度扫描的四维速度建模技术。该技术通过对分析点的百分比速度扫描,得到一组不同百分比速度的偏移叠加剖面,经速度建模交互软件包形成四维数据体,通过速度模型的多次迭代和修正,形成最终偏移速度模型。这种速度建模技术在地质结构比较复杂的条件下也可以根据偏移成像结果提取速度函数以满足叠前时间偏移对复杂地质构造正确成像的需要。该技术在海上三维叠前时间偏移处理中得到了成功应用,并取得了较好的地质效果。

Velocity modeling is a key technology for 3D pre-stack migration. A method of 4D data velocity analysis based on pre-stack time migration velocity scans was introduced. By velocity scans, a group of migration stack section of different velocity can be obtained, which can make up 4D data volume through the package of velocity modeling software. By iteration and correction for many times, final velocity model can be constructed and this technology can pick up Velocity function by the result of migration image to satisfy the need of pre-stack time migration for the right imaging of complicated geological structure. This technology is successfully applied to 3D pre-stack time migration processing.