Seismic Wave Pre-Stack Reverse-Time Migration Imaging Condition Based on One-Way Wave Field Separation and Angle Domain Attenuation

To improve seismic wave reverse-time migration (RTM) quality of complex structures,a new RTM imaging condition is shown. Take 2D model as example,one-way wave field and formation reflection angle with Poynting vector are obtained. Correlation calculation between up-way and down-way wave field,and between left-way and right-way wave field of shot and receiver are made, which removes migration noise components. Further,it introduces weight of cosine function of reflection angle into cross-correlation RTM imaging condition to suppress noise. Model study shows that main cause of migration noise is cross-correlation image of different shot and receiver point propagating direction wave field. Cross-correlation image of same shot and receiver point propagating direction wave field can suppress migration noise effectively and maintain imaging ability on sharp angle layer and horizontal surface as well. Imaging results can be further improved with weight of cosine function. Practical seismic data verify the method. In summary,the imaging condition provides an important method guide for improving imaging quality in complex structure area.