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.