基于静校正模型的速度场基准面转换方法

本文从基准面静校正技术和CMP参考面的定义出发，对速度场从CMP参考面转换至统一基准面存在的问题进行了深入研究，获得了静校正模型中高速顶界面或中间参考面在时间域和深度域均具有确切定义的认识，提出并实现了从CMP参考面至高速顶界面或中间参考面的介质剥离，从高速顶界面或中间参考面至统一基准面的常速介质充填的速度场基准面转换方法，较好地解决了速度场从CMP参考面到统一基准面的转换问题，为充分利用地震速度信息建立时深转换速度场奠定了基础。该方法具备明确的物理意义，所获得的统一基准面速度具有较高的时深转换精度，在鄂尔多斯盆地东缘煤层气新探区取得了良好的应用效果。

Velocity field datum conversion based on statics model

We transform a CMP floating datum to a common datum based on concepts of datum statics and definitions on CMP floating datum, and find out that the top of the high velocity layer or an intermediate reference surface from near surface model for datum statics has its exact definitions in both the time domain and the depth domain. We propose a method for velocity field datum conversion based on statics model. First we strip the layer from CMP datum to the top of the high velocity layer or to the intermediate reference surface. Then we fill in with constant-velocity media. So CMP floating datum can be effectively transformed to the common datum, and it is helpful to create a velocity field for time-depth conversion under the common datum. In addition, the proposed method strictly follows the physical meaning and concepts of datum statics. Applications of this method in eastern Ordos Basin show desirable accuracy of time-depth conversion.