基于立体层析反演的偏移速度建模应用研究

立体层析反演方法是一种可以同时反演反射点深度、反射层局部倾角与速度结构的层析反演方法。该方法在实践中最大的特色是数据空间的分布可以是稀疏的、不连续的,因此完全克服了传统反射层析中数据空间拾取困难这一问题。该方法重新定义了层析反演的数据分量和模型分量,使得数据的提取不再需要沿着连续的层位进行。除地震波走时之外,炮、检点位置与炮、检点处射线的局部传播方向也被用来约束速度模型。将该方法应用于南海某二维深水地震数据,基于倾斜叠加能量谱对炮、检点处的局部传播方向实施交互拾取获得了可靠的立体层析数据空间,将其输入立体层析反演算法获得了可靠的偏移速度模型,证明了立体层析反演方法的稳定性和可靠性。

Stereo-tomography inversion is a distinctive tomography method,which can be used to simultaneously invert the

velocity,the position and the dip of reflector.The biggest characteristic of the stereo-tomography inversion in practice is characterized that the spread of data space can be sparse and discontinuous,which overcomes the difficulty of picking in conventional reflection tomography completely.The method redefined the data space and model space of tomographic inversion so that data do not need to be picked along continuous horizons.Besides the traveltime,the coordinates of source and receiver,the slope of a local coherent wave-packet in shot and receiver gather have been included in data space to restrain velocity model.In the

application on the real 2D seismic data acquired in South China Sea,reliable migration velocity model has been achieved in use of reliable data space of which the critical slopes have been obtained with local slant stack in an interactive way,which demonstratedthe stability and reliability of stereo-tomography.