基于屏方法的弹性波叠前深度偏移

弹性波成像是多分量地震勘探需要解决的关键技术之一。借鉴声波方程中傅立叶有限差分算子中的有限差分补偿方法,对弹性波相屏传播算子进行了大角度校正。在求取成像值时,采用了矢量成像条件,即通过极化矢量,将各分量投影极化方向,然后再成像,从而使波场中的信息得到充分利用,同时解决了P-SV波成像过程中的极性不一致问题。这样,便可以叠加多炮的成像结果,从而提高成像质量。利用模型数据,对大角度相位校正后的弹性屏延拓算子和矢量成像条件进行了试验,成像效果理想。 

Elastic wave prestack depth migration based on screen method

Elastic wave migration is one of the key technologies of multicomponent exploration. In this paper, the finite-difference compensation in Fourier finite-difference method of acoustic equation is applied to elastic screen propagator. Vector imaging condition is used through calculating polarized vector, and projecting component to polarized direction. It makes the information carried in wave field used efficiently and resolves the polarization issue of P-SV in imaging, which allows partial images from different sources and can be stacked to generate a final image. Finally, elastic screen propagator with wide angle correction and vector imaging condition are tested with model data, and the migration result is ideal.