3D Multiple Attenuation for a Deep Reservoir Case Study

By

Tianyue Hu¹, Fei Hong¹, Runqiu Wang², Guofa Li³

(1) Peking University, Beijing, China (2) University of Petroleum, Beijing, China (3) Dagang Oil Field, Tianjin, China

 Among the deep part of seismic data from a 3D survey at Qianmiqiao area in Dagang Oil Field, some remarkable internal and full-path multiples are generated by various sets of over-burden sediments such as the groups called Minhuazeng, Guantao, and Dongying. These multiples interfere with the primaries over 3500 meters significantly and become a big threaten for enhancing signal to noise ratio for the deep weak signals. Also, these multiples affect velocity analysis, DMO stack and migration. As a model based multiple attenuation method, Beamforming is developed to estimate and attenuate multiples efficiently from the recorded seismic data. The principle of beamforming is to extract seismic signals without distortion, whilst minimizing residual power. The key point of beamforming multiple attenuation method is to separate primaries and multiples in terms of the difference of their moveout. The results of applying beamforming technique show that after removing multiples, some misleading in seismic interpretation can be avoided and the structure shape and state of the internal reflection inside dive can be clearly shown out.